Cell Death & Disease

ATF3 characterizes aggressive drug-tolerant persister cells in HGSOC

AbstractHigh-grade serous ovarian cancer (HGSOC) represents the most common and lethal subtype of ovarian cancer. Despite initial response to platinum-based standard therapy, patients commonly suffer from relapse that likely originates from drug-tolerant persister (DTP) cells. We generated isogenic clones of treatment-naïve and cisplatin-tolerant persister HGSOC cells. In addition, single-cell RNA sequencing of barcoded cells was performed in a xenograft model with HGSOC cell lines after platinum-based therapy. Published single-cell RNA-sequencing data from neo-adjuvant and non-treated HGSOC patients and patient data from TCGA were analyzed. DTP-derived cells exhibited morphological alterations and upregulation of epithelial-mesenchymal transition (EMT) markers. An aggressive subpopulation of DTP-derived cells showed high expression of the stress marker ATF3. Knockdown of ATF3 enhanced the sensitivity of aggressive DTP-derived cells to cisplatin-induced cell death, implying a role for ATF3 stress response in promoting a drug tolerant persister cell state. Furthermore, single cell lineage tracing to detect transcriptional changes in a HGSOC cell line-derived xenograft relapse model showed that cells derived from relapsed solid tumors express increased levels of EMT and multiple endoplasmic reticulum (ER) stress markers, including ATF3. Single cell RNA sequencing of epithelial cells from four HGSOC patients also identified a small cell population resembling DTP cells in all samples. Moreover, analysis of TCGA data from 259 HGSOC patients revealed a significant progression-free survival advantage for patients with low expression of the ATF3-associated partial EMT genes. These findings suggest that increased ATF3 expression together with partial EMT promote the development of aggressive DTP, and thereby relapse in HGSOC patients.

LncRNA IL21-AS1 facilitates tumour progression by enhancing CD24-induced phagocytosis inhibition and tumorigenesis in ovarian cancer

AbstractCD24 is overexpressed in various tumours and considered a regulator of cell migration, invasion, and proliferation. Recent studies have found that CD24 on ovarian cancer (OC) and triple-negative breast cancer cells interacts with the inhibitory receptor sialic-acid-binding Ig-like lectin 10 (Siglec-10) on tumour-associated macrophages (TAMs) to inhibit phagocytosis by macrophages. Because of its multiple roles in regulating the immune response and tumorigenesis, CD24 is a very promising therapeutic target. However, the regulatory mechanism of CD24 in OC remains unclear. Here, we found that the long noncoding RNA (lncRNA) IL21-AS1, which was upregulated in OC, inhibited macrophage-mediated phagocytosis and promoted OC cell proliferation and apoptosis inhibition. More importantly, after IL21-AS1 knockdown, a significant survival advantage was observed in mice engrafted with tumours. Mechanistically, we identified IL21-AS1 as a hypoxia-induced lncRNA. Moreover, IL21-AS1 increased HIF1α-induced CD24 expression under hypoxic conditions. In parallel, we found that IL21-AS1 acted as a competing endogenous RNA (ceRNA) for miR-561-5p to regulate CD24 expression. Finally, IL21-AS1 increased CD24 expression in OC and facilitated OC progression. Our findings provide a molecular basis for the regulation of CD24, thus highlighting a potential strategy for targeted treatment of OC.

Extracellular vesicles in ovarian cancer chemoresistance, metastasis, and immune evasion

AbstractChemoresistance and metastasis are the major challenges for the current ovarian cancer treatment. Understanding the mechanisms of ovarian cancer progression and metastasis is critically important for developing novel therapies. The advances in extracellular vesicles (EVs) research in recent years have attracted extensive attention. EVs contain a variety of proteins, RNAs, DNAs, and metabolites. Accumulating evidence indicates that ovarian cancer cells secrete a large amount of EVs, playing an important role in tumor progression and recurrence. In the microenvironment of ovarian tumor, EVs participate in the information transmission between stromal cells and immune cells, promoting the immune escape of ovarian cancer cells and facilitating cancer metastasis. Here, we review the recent advances of EVs in chemoresistance, mechanisms of metastasis, and immune evasion of ovarian cancer. Furthermore, we also discuss the challenges of EV research and future application of EVs as promising biomarker sources in response to therapy and in therapy-delivery approaches for ovarian cancer patients.

SIK2 enhances synthesis of fatty acid and cholesterol in ovarian cancer cells and tumor growth through PI3K/Akt signaling pathway

AbstractSalt-inducible kinase 2 (SIK2) has been established as a regulator of diverse biological processes including cell metabolism. A recent study has reported that SIK2 is required for adipocyte-induced ovarian cancer (OC) survival through facilitating fatty acid oxidation. However, whether SIK2 also plays a role in the lipid synthesis in OC cells remains elusive. Here, we showed that SIK2 significantly promoted the lipid synthesis in OC cells. On the one hand, SIK2 enhanced fatty acid synthesis through upregulating the expression of sterol regulatory element binding protein 1c (SREBP1c) and thus the transcription of major lipogenic enzyme FASN. On the other hand, SIK2 promoted cholesterol synthesis through upregulating the expression of sterol regulatory element binding protein 2 (SREBP2) and thus the transcription of major cholesterol synthesis enzymes HMGCR. Moreover, PI3K/Akt signaling pathway was found to be involved in the upregulation of SREBP1c and SREBP2 in OC cells. Moreover, in vitro and in vivo assays indicated that the SIK2-regulated fatty acid and cholesterol synthesis played a critical role in the growth of OC cells. Our findings demonstrate that SIK2 is a critical regulator of lipid synthesis in OC cells and thus promotes OC growth, which provides a strong line of evidence for this molecule to be used as a therapeutic target in the treatment of this malignancy.

Calcium and TRPV4 promote metastasis by regulating cytoskeleton through the RhoA/ROCK1 pathway in endometrial cancer

AbstractTransient receptor potential vanilloid 4 (TRPV4) is a calcium-permeable cation channel that has been associated with several types of cancer. However, its biological significance, as well as its related mechanism in endometrial cancer (EC) still remains elusive. In this study, we examined the function of calcium in EC, with a specific focus on TRPV4 and its downstream pathway. We reported here on the findings that a high level of serum ionized calcium was significantly correlated with advanced EC progression, and among all the calcium channels, TRPV4 played an essential role, with high levels of TRPV4 expression associated with cancer progression both in vitro and in vivo. Proteomic and bioinformatics analysis revealed that TRPV4 was involved in cytoskeleton regulation and Rho protein pathway, which regulated EC cell migration. Mechanistic investigation demonstrated that TRPV4 and calcium influx acted on the cytoskeleton via the RhoA/ROCK1 pathway, ending with LIMK/cofilin activation, which had an impact on F-actin and paxillin (PXN) levels. Overall, our findings indicated that ionized serum calcium level was significantly associated with poor outcomes and calcium channel TRPV4 should be targeted to improve therapeutic and preventive strategies in EC.

Dual blockades of TIM-3 and PD-1 effectively prevent hyper-progression and enhance the efficacy of anti-PD-1 therapy in high-grade serous ovarian cancer

Abstract The programmed cell death 1 (PD-1), exhibits limited efficacy in high-grade serous ovarian cancer (HGSOC), with an average response rate of 10 to 15%. Furthermore, hyper-progression disease (HPD), which mostly occurs under immune checkpoint blockade (ICB) therapy, is a potentially deleterious side effect of ICB therapy that accelerates disease progression in HGSOC patients. Our study aims to identify the approach to improve the efficacy of anti-PD-1 treatment on HGSOC in preclinical settings. The prominent TIM-3 upregulation in CD8 + tumor-infiltrating lymphocytes (TILs) and tumor-infiltrating dendritic cells (TIDCs) and the phenomenon of HPD were observed in ID8 VEGF -bearing mice after anti-PD-1 treatment. TIM-3 and PD-1 co-blockades prevented the occurrence of HPD in pre-clinical models and prolonged their survival. Meanwhile, TIM-3 and PD-1 co-blockades effectively enhanced the function and proliferation of CD8 + TILs and TIDCs from ID8 VEGF -bearing mice. Notably, TIM-3 and PD-1 inhibitors effectively enhanced the anti-tumor immunity of CD8 + TILs and CD11c + myeloid cells from HGSOC patients. Our study uncovers the significance of TIM-3 inhibition in preventing the occurrence of HPD and enhancing the efficacy of anti-PD-1 therapy in HGSOC.

Inhibition of glycolysis and stimulation of mitochondrial biogenesis lead to increased ROS levels and cell death in HNF-1ß positive clear cell carcinoma

Abstract Ovarian clear cell carcinoma is characterized by HNF-1ß overexpression and is known to be resistant to chemotherapy. An inhibitor screening that specifically targets HNF-1ß led us to identify Actinonin as a candidate for cancer treatment. Actinonin, which is known to inhibit aminopeptidase M, has also been recognized for its antibacterial properties. We confirmed that GSK-3ß interference/inhibition, as a component of the HNF-1ß pathway, combined with Actinonin, has a highly potent antitumor effect compared to monotherapy. The same effect was observed in renal clear cell carcinoma lines expressing HNF-1ß. Actinonin promoted mitochondrial production by suppressing aerobic respiration, which decreased AMPK levels and increased ROS production. However, it also elevated GADD45α expression and induced mitophagy. GSK-3ß inhibition suppressed glycolysis and shifted energy production to OXPHOS, leading to increased ROS production. Furthermore, this combination produced excess ROS beyond metabolic capacity, which accumulated in lipid bilayers, leading to a further increase in CHOP gene expression and suppression of mitochondrial turnover. The GSK-3ß inhibitor and Actinonin combination demonstrated a powerful tumor-suppressive effect in vivo without severe side effects. Combining GSK-3ß inhibition with Actinonin can effectively eliminate cancer cells with HNF-1ß overexpression by inhibiting glycolysis and promoting mitochondrial turnover, highlighting new options for cancer therapy.

Multi-omics analysis reveals that ALYREF-mediated m5C modification promotes platinum resistance in ovarian cancer via the NSUN2/ALYREF/LGR4 axis

Abstract Platinum resistance remains a major obstacle to effective treatment and improved prognosis in ovarian cancer. Although 5-methylcytosine (m 5 C) RNA modification has been implicated in chemoresistance, its precise functional role in ovarian cancer remains unclear. In this study, we integrated RNA-Seq and single-cell transcriptomic data from cisplatin-resistant ovarian cancer cell lines and patient samples, identifying the m 5 C reader protein ALYREF as a key regulator of platinum resistance. Functional studies using ALYREF and NSUN2 knockdown, overexpression, and mutant constructs—combined with multi-omics analyses (RNA-Seq, m 5 C-BIS-Seq, and RIP-Seq)—revealed that ALYREF binds to m 5 C-modified LGR4 mRNA, enhancing its stability and promoting activation of the Wnt/β-catenin signaling pathway. Critically, this regulatory mechanism is dependent on NSUN2-mediated m 5 C modification of LGR4 mRNA. Together, our findings demonstrate that the NSUN2/ALYREF/LGR4 axis mediates platinum resistance through m 5 C-dependent stabilization of LGR4 and downstream Wnt signaling activation. Thus, targeting ALYREF may represent a promising strategy to overcome platinum resistance in ovarian cancer.

Nutrient stress diverts RRN3 from rRNA transcription to alternative polyadenylation of autophagy mRNAs in ovarian cancer

Abstract Stress-induced alternative processing of mRNA is emerging as an essential mechanism to drive almost every hallmark of cancer. Through a genome-wide screening based on an abnormal transcriptional readthrough event favoring the malignant progression of ovarian carcinoma (OC), we identified novel mRNA processing regulators including RRN3, an essential factor for the transcriptional initiation of rRNA. The long-read RNA sequencing and PAR-CLIP analyses revealed that RRN3 was involved in the usage of alternative polyadenylation (APA) sites, resulting in the altered stability of autophagy-related mRNAs. More interestingly, we discovered that nutrient-deprivation-induced phosphorylation of RRN3 at serine 199 was sufficient to divert RRN3 out of the nucleolus to the nuclear plasma, where RRN3 regulated the APA of autophagy mRNAs, such as OPTN, to enhance their stability and eventually promoted autophagy. Further in vivo experiments showed that nutrient-stress-triggered switch of RRN3 from rRNA transcription to APA regulation was essential for the growth and dissemination of OC in mice.

Distinct functional heterogeneity of TP53 R175 mutations in platinum-resistant ovarian cancer: unveiling molecular mechanisms and therapeutic targets

Abstract Ovarian cancer (OC) is a highly aggressive malignancy in women, and platinum resistance remains a major clinical obstacle. p53 mutations are prevalent in OC and exhibit functional heterogeneity that is associated with therapeutic response and disease progression. However, the roles and mechanisms underlying the functional heterogeneity of p53 mutations in platinum-resistant OC remain elusive. This investigation delineated that p53 mutations within the Loop 2, Loop 3, and β-strand S10 regions were closely linked to platinum resistance. In particular, functional assays unveiled that p53 R175H and p53 R175G mutations at Arg175 revealed distinct roles in tumor cell migration and drug resistance, with p53 R175G conferring resistance to agents targeting p53 R175H . Through multi-omics sequencing analysis, it was discerned that p53 R175H and p53 R175G promoted tumor progression through distinct cofactors and regulatory networks. p53 R175H mediated upregulation of extracellular matrix-related genes, whereas p53 R175G activated pathways associated with cytokine receptor interaction and membrane trafficking. Notably, the chromatin remodeling protein CHD1 selectively interacted with p53 R175G , but not p53 R175H , and regulated the transcriptional activity of p53 R175G , including target genes such as IL7R . Moreover, CHD1 knockdown or pharmacological inhibition of IL7R synergistically enhanced platinum sensitivity, suggesting promising combination therapies specifically targeting the R175G mutation. The findings revealed that p53 mutations at the same residue exhibited distinct functional properties and relied on unique cofactors, offering valuable insights for precision therapy in OC.

UHRF1-mediated HIF-1α stabilization promotes ovarian cancer through metabolic reprogramming and angiogenesis

Abstract Ubiquitin-like PHD and RING finger domain-containing protein 1 (UHRF1) is an important epigenetic regulatory factor that is highly expressed in various cancers and participates in tumorigenesis and progression. However, the role and molecular mechanisms of UHRF1 in ovarian cancer (OC) remain unclear. Through survival analysis, cellular functional experiments, and animal studies, we identified UHRF1 as a key gene influencing OC progression and prognosis. Hypoxia-inducible factor-1 (HIF-1α), a well-known pro-cancer molecule, undergoes classic degradation via the ubiquitin–proteasome pathway. We discovered that UHRF1 interacts with HIF-1α, affecting its hydroxylation level, thereby inhibiting HIF-1α polyubiquitination and degradation. Functional experiments revealed that knocking down HIF-1α in stable UHRF1-overexpressing cell lines significantly reversed the malignant phenotype of OC cells. Furthermore, UHRF1 can also regulate the expression of key downstream molecules such as GLUT1, HK2, LDHA, and VEGFA by modulating HIF-1α, thus influencing tumor cell metabolism and angiogenesis. In summary, our findings suggest that UHRF1 plays a crucial role in the development of OC by regulating the expression of HIF-1α.

YY1-induced USP43 drives ferroptosis suppression by FASN stabilization and subsequent activation of SLC7A11 in ovarian cancer

Abstract The ubiquitin-specific protease (USP) family is a major member of the deubiquitinating enzyme family that plays important and diverse roles in multiple tumors. The roles and mechanisms of action of USP family members in ovarian cancer are not well understood. This study aimed to screen all the USP family members and explored the specific function of USP43 in ovarian cancer. The expression levels of USP family members in ovarian cancer were screened using bioinformatics analysis, and the specific function of USP43 was explored through in vitro and in vivo experiments. Functional assays, including cell viability, ferroptosis, and tumor xenograft models, were employed. In short, USP43 drives the ferroptosis suppression by activating the expression of SLC7A11 through FASN-HIF1α pathway. USP43 is an important prognostic factor for ovarian cancer, with its overexpression promoting ovarian cancer progression and its knockdown inhibiting it. Mechanistically, USP43, which is transcriptionally activated by YY1, stabilizes FASN through deubiquitination, and FASN activates SLC7A11 expression by stabilizing HIF1α. Furthermore, the combination of cisplatin and the SLC7A11 inhibitor HG106 significantly inhibits the growth of ovarian tumors. Thus, targeting the USP43-FASN-HIF1α-SLC7A11 axis can inhibit ferroptosis and promote platinum sensitivity in ovarian cancer.

MRPL13 enhances mitochondrial function and promotes tumor progression in ovarian cancer by inhibiting mPTP opening via SLC25A6

Abstract Tumor cells typically exhibit dysregulation of mitochondrial energy metabolism and cell death. The role of mitochondrial function in ovarian cancer (OC) progression has garnered substantial attention, yet its precise molecular mechanisms remain elusive. Mitochondrial ribosomal protein L13 (MRPL13), involved in the translation of oxidative phosphorylation (OXPHOS) complex subunits, plays a critical role in regulating mitochondrial function. Our study demonstrated that MRPL13 is highly expressed in OC tissues and correlated with poor prognosis. Both in vitro and in vivo experiments confirmed that MRPL13 overexpression significantly promotes the malignant biological behavior of OC, while MRPL13 knockdown induces the opposite phenotype. Moreover, MRPL13 knockdown impairs mitochondrial function in OC cells, leading to decreased OXPHOS and ATP levels, increased reactive oxygen species (ROS) generation, mitochondrial depolarization, aberrant opening of the mitochondrial permeability transition pore (mPTP), and mitochondrial structural damage. Mechanistically, MRPL13 specifically interacts with SLC25A6 and facilitates its degradation via lysine (K)48-linked ubiquitination. MRPL13 inhibits mPTP opening by accelerating the degradation of SLC25A6, thereby preventing cytochrome c release into the cytoplasm, inhibiting cell death, and enhancing mitochondrial function. In conclusion, our study elucidates the mechanism by which the MRPL13-SLC25A6 axis enhances mitochondrial function and promotes tumor progression in OC by inhibiting mPTP opening, suggesting that MRPL13 holds significant potential for prognostic evaluation and targeted therapy in OC.

SOX5 inhibition overcomes PARP inhibitor resistance in BRCA-mutated breast and ovarian cancer

Abstract Poly (ADP-ribose) polymerase (PARP) inhibitors are effective in cells with homologous recombination (HR) deficiency, including BRCA1/2 mutation. However, PARP inhibitors remain a therapeutic challenge in breast and ovarian cancer due to inevitably acquired resistance in most cases. Therefore, strategies to overcome PARP inhibitor resistance are unmet clinical need. SRY-box transcription factor 5 (SOX5) plays a crucial role in development of various cancers but the role of SOX5 in PARP inhibitor resistance is poorly understood. This study identified SOX5 as a potential biomarker associated with PARP inhibitor resistance and addressed potential treatment strategies to overcome PARP inhibitor resistance using the olaparib-resistant preclinical model. We observed that SOX5 was significantly upregulated in olaparib-resistant cells and contributed to PARP inhibitor resistance by upregulating DNA repair pathway genes. Ectopic SOX5 overexpression contributed to PARP inhibitor resistance by suppressing DNA double-strand breaks (DSBs) in BRCA-mutated breast and ovarian cancer. SOX5 small interfering RNA combined with olaparib sensitized olaparib-resistant cells and suppressed the growth of olaparib-resistant xenografts in mice via increased DSBs represented by ɣH2AX formation. Mechanistically, SOX5 directly interacted with yes-associated protein 1 (YAP1) and promoted its nuclear translocation by suppressing the Hippo pathway. YAP1, in association with TEA domain family members (TEAD), upregulated HR-related gene expression and conferred PARP inhibitor resistance. Furthermore, the clinical relevance of SOX5 as a therapeutic target was supported by a significant association between SOX5 overexpression and poor prognosis in ovarian cancer on public mRNA microarray data sets. Therefore, we propose SOX5 as a promising therapeutic target for overcoming PARP inhibitor resistance in BRCA1/2-mutated breast and ovarian cancer.

The deubiquitinase YOD1 suppresses tumor progression by stabilizing ZNF24 in clear cell renal carcinoma

Abstract Metastasis remains a significant challenge in the management of clear cell renal cell carcinoma (ccRCC), and a continued focus on its underlying mechanisms is crucial for improving patient outcomes and optimizing clinical therapies. The ovarian-tumor related protease (OTU) is involved in regulating critical cell signaling pathways, but the functions of most OTUs have yet to be explored. In this study, an unbiased RNAi screening revealed that ovarian tumor domain-containing 2 (YOD1) knockdown significantly promoted cell metastasis. YOD1 downregulation promoted ccRCC growth and metastasis both in vitro and in vivo. Notably, YOD1 knockdown stimulated the growth of organoids derived from ccRCC patients. Further investigation revealed that YOD1 directly interacted with and stabilized Zinc finger protein 24 (ZNF24) expression by deubiquitination in a manner dependent on its catalytic activity. YOD1 inhibition attenuated ZNF24 transcriptional repression of vascular endothelial growth factor A (VEGFA), thereby promoting VEGFA gene expression. Furthermore, ZNF24 was identified as a key mediator of YOD1 function. The expression of YOD1 and ZNF24 was significantly downregulated in tumor tissues, with a strong correlation between them. Importantly, reduced YOD1 and ZNF24 levels were strongly associated with poor clinical outcomes in ccRCC patients. Our results reveal the mechanism by which YOD1 regulates VEGFA transcription and suppresses tumorigenesis by deubiquitinating ZNF24, providing a therapeutic target in ccRCC.

TFE3 and HIF1α regulates the expression of SHMT2 isoforms via alternative promoter utilization in ovarian cancer cells

Abstract Ovarian cancer ranks first lethally among gynecological malignancies. Platinum-based chemotherapy constitutes the first-line therapeutic regime. However, primary or acquired resistance seriously affects the survival rate of patients with ovarian cancer. Serine hydroxy methyltransferase (SHMT) catalyzes conversion of serine to glycine and is responsible for production of S-adenosylmethionine (SAM) for methylation. There are cytosolic SHMT1 and mitochondrial SHMT2 in human. Alternative promoter usage is a proteome-expanding mechanism that allows multiple pre-mRNAs to be transcribed from a single gene. The current study demonstrated that cisplatin-sensitive and cisplatin-resistant ovarian cancer cells expressed discrete SHMT2 isoforms, which was ascribed to the selective utilization of SHMT2 alternative promoters. SHMT2 isoforms exerted somewhat paradoxical roles in ovarian cancer cells, with tumor-suppressive role of isoform 1, and tumor-promotive role of isoform 3. In addition, the current study demonstrated that SHMT2 alternative promoter usage mediated by HIF1α and TFE3 might represent adaptive response of ovarian cancer cells to metabolic stress. Collectively, regulation of SHMT2 isoform expression via alternative promoter usage by transcription factors HIF1α and TFE3 provides a novel basis and potential drug targets for the clinical treatment of platin-resistant ovarian cancer.

Long noncoding RNA GDIL acts as a scaffold for CHAC1 and XRN2 to promote platinum resistance of colorectal cancer through inhibition of glutathione degradation

Abstract Acquired resistance poses a significant obstacle to the effectiveness of platinum-based treatment for cancers. As the most abundant antioxidant, glutathione (GSH) enables cancer cell survival and chemoresistance, by scavenging excessive reactive oxygen species (ROS) induced by platinum. Therapeutic strategy targeting GSH synthesis has been developed, however, failed to produce desirable effects in preventing cancer progression. Thus, uncovering mechanisms of rewired GSH metabolism may aid in the development of additional therapeutic strategies to overcome or delay resistance. Here, we identify upregulation of long noncoding RNA (lncRNA) GDIL (GSH Degradation Inhibiting LncRNA) in platinum resistant colorectal cancer (CRC) and ovarian cancer cells compared with parental ones. High expression of GDIL in resistant CRC is associated with poor survival and hyposensitivity to chemotherapy. We demonstrate that GDIL boosted GSH levels and enhances clearance of ROS induced by platinum. Metabolomic and metabolic flux analysis further reveals that GDIL promotes GSH accumulation by inhibiting GSH degradation. This is attributed by downregulation of CHAC1, an enzyme that specifically degrades intracellular GSH. Mechanistically, GDIL binds and re-localizes the nuclear protein XRN2 to the cytoplasm, where GDIL further serve as a scaffold for XRN2 to identify and degrade CHAC1 mRNA. Suppression of GDIL with selective antisense oligonucleotide, restored drug sensitivity in platinum resistant cell lines and delayed drug resistance in cell line- and patient-derived xenografts. Thus, lncRNA GDIL is a novel target to promote GSH degradation and augment platinum therapy.

Deciphering the ghost proteome in ovarian cancer cells by deep proteogenomic characterization

Abstract Proteogenomics is becoming a powerful tool in personalized medicine by linking genomics, transcriptomics and mass spectrometry (MS)-based proteomics. Due to increasing evidence of alternative open reading frame-encoded proteins (AltProts), proteogenomics has a high potential to unravel the characteristics, variants, expression levels of the alternative proteome, in addition to already annotated proteins (RefProts). To obtain a broader view of the proteome of ovarian cancer cells compared to ovarian epithelial cells, cell-specific total RNA-sequencing profiles and customized protein databases were generated. In total, 128 RefProts and 30 AltProts were identified exclusively in SKOV-3 and PEO-4 cells. Among them, an AltProt variant of IP_715944, translated from DHX8 , was found mutated (p.Leu44Pro). We show high variation in protein expression levels of RefProts and AltProts in different subcellular compartments. The presence of 117 RefProt and two AltProt variants was described, along with their possible implications in the different physiological/pathological characteristics. To identify the possible involvement of AltProts in cellular processes, cross-linking-MS (XL-MS) was performed in each cell line to identify AltProt-RefProt interactions. This approach revealed an interaction between POLD3 and the AltProt IP_183088, which after molecular docking, was placed between POLD3-POLD2 binding sites, highlighting its possibility of the involvement in DNA replication and repair.

Ovarian cancer-derived TGF-β1 induces cancer-associated adipocytes formation by activating SMAD3/TRIB3 pathway to establish pre-metastatic niche

AbstractOvarian cancer (OC) is prone to adipose tissue metastasis. However, the underlying molecular mechanisms remain elusive. Here, we observed that omental adipocytes were induced into cancer-associated adipocytes (CAAs) by OC-derived TGF-β1 to establish a pre-metastatic niche (PMN) through collagen and fibronectin secretion. Mechanistically, OC-derived TGF-β1 binds to adipocyte membrane receptors and thus activates intracellular signaling by SMAD3 phosphorylation. The activation of TGF-β1/SMAD3 signaling pathway dedifferentiates adipocytes into CAAs by upregulating Tribbles homolog 3 (TRIB3), which suppresses the phosphorylation of CEBPβ. Additionally, CAAs secrete collagen I, collagen VI, and fibronectin to remodel the extracellular matrix and promote the adhesion of OC cells. Pharmacological inhibition of the TGF-β1/SMAD3 pathway significantly inhibits CAAs and PMN formation, thereby reducing the OC metastatic burden. Our findings indicate that the formation of CAAs and PMN in adipose tissues facilitates OC cell implantation and blocking the TGF-β1/SMAD3 signaling pathway could prevent OC omental metastasis.

LOC730101 improves ovarian cancer drug sensitivity by inhibiting autophagy-mediated DNA damage repair via BECN1

AbstractDrug resistance and recurrence are still the bottlenecks in the clinical treatment of ovarian cancer (OC), seriously affecting patients’ prognosis. Therefore, it is an urgent challenge for OC to be overcome towards precision therapy by studying the mechanism of OC drug resistance, finding new drug resistance targets and developing new effective treatment strategies. In this study, we found that lncRNA LOC730101 played an essential role in attenuating drug resistance in OC. LOC730101 was significantly down-regulated in platinum-resistant ovarian cancer tissues, and ectopic overexpression of LOC730101 substantially increased chemotherapy-induced apoptosis. Mechanistically, LOC730101 specifically binds to BECN1 and inhibits the formation of autophagosome BECN1/VPS34 by reducing phosphorylation of BECN1, thereby inhibiting autophagy and promoting drug sensitivity in ovarian cancer cells following treatment with cisplatin and PARP inhibitors. Moreover, LOC730101 inhibits the expression and activity of RNF168 via p62, which in turn affects H2A ubiquitination-mediated DNA damage repair and promotes drug sensitivity in ovarian cancer cells. Our findings demonstrated that LOC730101 played an important role in regulating the formation of the autophagic complex and that inhibition of autophagy significantly enhances the drug sensitivity of OC. And LOC730101 may be used as a prognostic marker to predict the sensitivity of OC to platinum and PARP inhibitors.

Stabilization of SQLE mRNA by WTAP/FTO/IGF2BP3-dependent manner in HGSOC: implications for metabolism, stemness, and progression

AbstractThe metabolic reprogramming in high-grade serous ovarian carcinoma (HGSOC) affects the tumor stemness, which mediates tumor recurrence and progression. Knowledge of the stemness and metabolic characteristics of HGSOC is insufficient. Squalene epoxidase (SQLE), a key enzyme in cholesterol metabolism, was significantly upregulated in HGSOC samples with a fold change of about 4 in the RNA sequencing analysis. SQLE was positively related to peritoneal metastasis and poor prognosis of HGSOC patients. Functionally, SQLE drove cancer cell proliferation and inhibited apoptosis to accelerate HGSOC growth. SQLE was highly expressed in ALDH+CD133+ FACS-sorted cells derived from HGSOC cells and ovarian cancer stem cells (OCSCs)-enriched tumorspheres. SQLE overexpression resulted in enhanced CSC-like properties, including increased tumorsphere formation and stemness markers expression. In vivo, SQLE not only promoted cell line-derived xenografts growth but extended the OCSCs subpopulation of single-cell suspension. Moreover, non-targeted metabolomics profiling from UPLC-MS/MS system identified 90 differential metabolites responding to SQLE overexpression in HGSOC cells. Among them, the dysfunctional metabolisms of cholesterol and glutathione were involved in the maintenance of HGSOC stemness. Previous studies showed the alteration of N6-Methyladenosine (m6A) modification in HGSOC development. Herein, the m6A modification in the 3’UTR and CDS regions of SQLE mRNA was increased due to upregulated methyltransferases WTAP and downregulated demethylases FTO, which was recognized by m6A-binding proteins IGF2BP3, rather than IGF2BP1 or IGF2BP2, thereby stabilizing the SQLE mRNA. These results suggested that SQLE was a novel potential clinical marker for predicting the HGSOC development and prognosis, as well as a potential therapeutic target of HGSOC.

MIR937 amplification potentiates ovarian cancer progression by attenuating FBXO16 inhibition on ULK1-mediated autophagy

AbstractHigh-grade serous ovarian carcinoma (HGSOC) is one of the most lethal gynecological cancer. Genetic studies have revealed gene copy number alterations (CNAs) frequently occurred in HGSOC pathogenesis, however the function and mechanism of CNAs for microRNAs are still not fully understood. Here, we show the dependence on gene copy number amplification of MIR937 that enhances cell autophagy and dictates HGSOC proliferative activity. Data mining of TCGA database revealed MIR937 amplification is correlated with increased MIR937 expression and cell proliferation of HGSOC. Deletion of MIR937 in HGSOC cells led to impaired autophagy and retarded cell proliferation, and the extent for its inhibitory effects scaled with the degree of MIR937 copy loss. Rescue assay confirmed miR-937-5p, a mature product of MIR937, was sufficient to restore its oncogenic function. Mechanistically, MIR937 amplification raised the expression of miR-937-5p, enhanced its binding to 3′ UTR of FBXO16 transcript, and thereby restricting FBXO16 degradative effects on ULK1. Our results demonstrate that MIR937 amplification augments cell autophagy and proliferation, and suggest an alternative strategy of MIR937/FBXO16/ULK1 targeting for HGSOC treatment.

NEK6 dampens FOXO3 nuclear translocation to stabilize C-MYC and promotes subsequent de novo purine synthesis to support ovarian cancer chemoresistance

AbstractDe novo purine synthesis metabolism plays a crucial role in tumor cell survival and malignant progression. However, the specific impact of this metabolic pathway on chemoresistance in ovarian cancer remains unclear. This study aims to elucidate the influence of de novo purine synthesis on chemoresistance in ovarian cancer and its underlying regulatory mechanisms. We analyzed metabolic differences between chemosensitive and chemoresistant ovarian cancer tissues using mass spectrometry-based metabolomics. Cell growth, metabolism, chemoresistance, and DNA damage repair characteristics were assessed in vitro using cell line models. Tumor growth and chemoresistance were assessed in vivo using ovarian cancer xenograft tumors. Intervention of purines and NEK6-mediated purine metabolism on chemoresistance was investigated at multiple levels. Chemoresistant ovarian cancers exhibited higher purine abundance and NEK6 expression. Inhibiting NEK6 led to decreased de novo purine synthesis, resulting in diminished chemoresistance in ovarian cancer cells. Mechanistically, NEK6 directly interacted with FOXO3, contributing to the phosphorylation of FOXO3 at S7 through its kinase activity, thereby inhibiting its nuclear translocation. Nuclear FOXO3 promoted FBXW7 transcription, leading to c-MYC ubiquitination and suppression of de novo purine synthesis. Paeonol, by inhibiting NEK6, suppressed de novo purine synthesis and enhanced chemosensitivity. The NEK6-mediated reprogramming of de novo purine synthesis emerges as a critical pathway influencing chemoresistance in ovarian cancer. Paeonol exhibits the potential to interfere with NEK6, thereby inhibiting chemoresistance.

CRLF1 bridges AKT and mTORC2 through SIN1 to inhibit pyroptosis and enhance chemo-resistance in ovarian cancer

AbstractOvarian cancer, the second most leading cause of gynecologic cancer mortality worldwide, is challenged by chemotherapy resistance, presenting a significant hurdle. Pyroptosis, an inflammation-linked programmed cell death mediated by gasdermins, has been shown to impact chemoresistance when dysregulated. However, the mechanisms connecting pyroptosis to chemotherapy resistance in ovarian cancer are unclear. We found that cytokine receptor-like factor 1 (CRLF1) is a novel component of mTORC2, enhancing AKT Ser473 phosphorylation through strengthening the interaction between AKT and stress-activated protein kinase interacting protein 1 (SIN1), which in turn inhibits the mitogen-activated protein kinase kinase kinase 5 (ASK1)-JNK-caspase-3-gasdermin E pyroptotic pathway and ultimately confers chemoresistance. High CRLF1-expressing tumors showed sensitivity to AKT inhibition but tolerance to cisplatin. Remarkably, overexpression of binding-defective CRLF1 variants impaired AKT-SIN1 interaction, promoting pyroptosis and chemosensitization. Thus, CRLF1 critically regulates chemoresistance in ovarian cancer by modulating AKT/SIN1-dependent pyroptosis. Binding-defective CRLF1 variants could be developed as tumor-specific polypeptide drugs to enhance chemotherapy for ovarian cancer.

Tumor microenvironment-induced FOXM1 regulates ovarian cancer stemness

AbstractIn ovarian tumors, the omental microenvironment profoundly influences the behavior of cancer cells and sustains the acquisition of stem-like traits, with major impacts on tumor aggressiveness and relapse. Here, we leverage a patient-derived platform of organotypic cultures to study the crosstalk between the tumor microenvironment and ovarian cancer stem cells. We discovered that the pro-tumorigenic transcription factor FOXM1 is specifically induced by the microenvironment in ovarian cancer stem cells, through activation of FAK/YAP signaling. The microenvironment-induced FOXM1 sustains stemness, and its inactivation reduces cancer stem cells survival in the omental niche and enhances their response to the PARP inhibitor Olaparib. By unveiling the novel role of FOXM1 in ovarian cancer stemness, our findings highlight patient-derived organotypic co-cultures as a powerful tool to capture clinically relevant mechanisms of the microenvironment/cancer stem cells crosstalk, contributing to the identification of tumor vulnerabilities.

The emerging roles of miRNA-mediated autophagy in ovarian cancer

AbstractOvarian cancer is one of the common tumors of the female reproductive organs. It has a high mortality rate, is highly heterogeneous, and early detection and primary prevention are very complex. Autophagy is a cellular process in which cytoplasmic substrates are targeted for degradation in lysosomes through membrane structures called autophagosomes. The periodic elimination of damaged, aged, and redundant cellular molecules or organelles through the sequential translation between amino acids and proteins by two biological processes, protein synthesis, and autophagic protein degradation, helps maintain cellular homeostasis. A growing number of studies have found that autophagy plays a key regulatory role in ovarian cancer. Interestingly, microRNAs regulate gene expression at the posttranscriptional level and thus can regulate the development and progression of ovarian cancer through the regulation of autophagy in ovarian cancer. Certain miRNAs have recently emerged as important regulators of autophagy-related gene expression in cancer cells. Moreover, miRNA analysis studies have now identified a sea of aberrantly expressed miRNAs in ovarian cancer tissues that can affect autophagy in ovarian cancer cells. In addition, miRNAs in plasma and stromal cells in tumor patients can affect the expression of autophagy-related genes and can be used as biomarkers of ovarian cancer progression. This review focuses on the potential significance of miRNA-regulated autophagy in the diagnosis and treatment of ovarian cancer.

Single-cell transcriptome profiles the heterogeneity of tumor cells and microenvironments for different pathological endometrial cancer and identifies specific sensitive drugs

AbstractEndometrial cancer (EC) is a highly heterogeneous malignancy characterized by varied pathology and prognoses, and the heterogeneity of its cancer cells and the tumor microenvironment (TME) remains poorly understood. We conducted single-cell RNA sequencing (scRNA-seq) on 18 EC samples, encompassing various pathological types to delineate their specific unique transcriptional landscapes. Cancer cells from diverse pathological sources displayed distinct hallmarks labeled as immune-modulating, proliferation-modulating, and metabolism-modulating cancer cells in uterine clear cell carcinomas (UCCC), well-differentiated endometrioid endometrial carcinomas (EEC-I), and uterine serous carcinomas (USC), respectively. Cancer cells from the UCCC exhibited the greatest heterogeneity. We also identified potential effective drugs and confirmed their effectiveness using patient-derived EC organoids for each pathological group. Regarding the TME, we observed that prognostically favorable CD8+ Tcyto and NK cells were prominent in normal endometrium, whereas CD4+ Treg, CD4+ Tex, and CD8+ Tex cells dominated the tumors. CXCL3+ macrophages associated with M2 signature and angiogenesis were exclusively found in tumors. Prognostically relevant epithelium-specific cancer-associated fibroblasts (eCAFs) and SOD2+ inflammatory CAFs (iCAFs) predominated in EEC-I and UCCC groups, respectively. We also validated the oncogenic effects of SOD2+ iCAFs in vitro. Our comprehensive study has yielded deeper insights into the pathogenesis of EC, potentially facilitating personalized treatments for its varied pathological types.

Regulation of ULK1 by WTAP/IGF2BP3 axis enhances mitophagy and progression in epithelial ovarian cancer

AbstractThere is a pressing need for innovative therapeutic strategies for patients with epithelial ovarian cancer (EOC). Previous studies have shown that UNC-51-like kinase 1 (ULK1), a serine/threonine kinase, is crucial in regulating cellular autophagy and mitophagy across various tumor types. However, the clinical implications, biological functions, and potential mechanisms of ULK1 in EOC remain poorly understood. This study demonstrates that ULK1 expression is upregulated in EOC tissue samples and EOC cell lines, with increased ULK1 expression correlating with poor prognosis. Functionally, overexpressed ULK1 enhances the proliferation and migration abilities of EOC cells both in vitro and in vivo. Mechanistically, ULK1 was identified as an m6A target of WTAP. WTAP-mediated m6A modification of ULK1 enhanced its mRNA stability in an IGF2BP3-dependent manner, leading to elevated ULK1 expression and enhanced mitophagy in EOC. In summary, our research reveals that the WTAP/IGF2BP3-ULK1 axis significantly influences protective mitophagy in EOC, contributing to its progression. Therefore, the regulatory mechanisms and biological function of ULK1 identify it as a potential molecular target for therapeutic intervention in EOC.

Decoding the mechanisms of chimeric antigen receptor (CAR) T cell-mediated killing of tumors: insights from granzyme and Fas inhibition

AbstractChimeric antigen receptor (CAR) T cell show promise in cancer treatments, but their mechanism of action is not well understood. Decoding the mechanisms used by individual T cells can help improve the efficacy of T cells while also identifying mechanisms of T cell failure leading to tumor escape. Here, we used a suite of assays including dynamic single-cell imaging of cell-cell interactions, dynamic imaging of fluorescent reporters to directly track cytotoxin activity in tumor cells, and scRNA-seq on patient infusion products to investigate the cytotoxic mechanisms used by individual CAR T cells in killing tumor cells. We show that surprisingly, overexpression of the Granzyme B (GZMB) inhibitor, protease inhibitor-9 (PI9), does not alter the cytotoxicity mediated by CD19-specific CAR T cells against either the leukemic cell line, NALM6; or the ovarian cancer cell line, SkOV3-CD19. We designed and validated reporters to directly assay T cell delivered GZMB activity in tumor cells and confirmed that while PI9 overexpression inhibits GZMB activity at the molecular level, this is not sufficient to impact the kinetics or magnitude of killing mediated by the CAR T cells. Altering cytotoxicity mediated by CAR T cells required combined inhibition of multiple pathways that are tumor cell specific: (a) B-cell lines like NALM6, Raji and Daudi were sensitive to combined GZMB and granzyme A (GZMA) inhibition; whereas (b) solid tumor targets like SkOV3-CD19 and A375-CD19 (melanoma) were sensitive to combined GZMB and Fas ligand inhibition. We realized the translational relevance of these findings by examining the scRNA-seq profiles of Tisa-cel and Axi-cel infusion products and show a significant correlation between GZMB and GZMA expression at the single-cell level in a T cell subset-dependent manner. Our findings highlight the importance of the redundancy in killing mechanisms of CAR T cells and how this redundancy is important for efficacious T cells.

The potential impact of RNA splicing abnormalities on immune regulation in endometrial cancer

Abstract RNA splicing controls the post-transcriptional level of gene expression, allowing for the synthesis of many transcripts with various configurations and roles. Variations in RNA splicing regulatory factors, including splicing factors, signaling pathways, epigenetic modifications, and environmental factors, are typically the origin of tumor-associated splicing anomalies. Furthermore, thorough literature assessments on the intricate connection between tumor-related splicing dysregulation and tumor immunity are currently lacking. Therefore, we also thoroughly discuss putative targets associated with RNA splicing in endometrial cancer (EC) and the possible impacts of aberrant RNA splicing on the immune control of tumor cells and tumor microenvironment (TME), which contributes to enhancing the utilization of immunotherapy in the management of EC and offers an alternative viewpoint for the exploration of cancer therapies and plausible prognostic indicators.

LIN28B induced PCAT5 promotes endometrial cancer progression and glycolysis via IGF2BP3 deubiquitination

AbstractEndometrial cancer (EC) cells exhibit abnormal glucose metabolism, characterized by increased aerobic glycolysis and decreased oxidative phosphorylation. Targeting cellular glucose metabolism in these cells could be an effective therapeutic approach for EC. This study aimed to assess the roles of LIN28B, PCAT5, and IGF2BP3 in the glucose metabolism, proliferation, migration, and invasion of EC cells. LIN28B highly expressed in EC, binds and stabilizes PCAT5. PCAT5, overexpressed in EC, and its 1485-2288nt region can bind to the KH1-2 domain of IGF2BP3 to prevent MKRN2 from binding to the K294 ubiquitination site of IGF2BP3, thus stabilizing IGF2BP3. Finally, IGF2BP3 promotes the aerobic glycolysis, proliferation, migration and invasion of EC cells by stabilizing the key enzymes of glucose metabolism HK2 and PKM2. Taken together, our data reveal that the LIN28B/PCAT5/IGF2BP3 axis is critical for glucose reprogramming and malignant biological behavior in EC cells. Therefore, targeting this axis may contribute to the development of a novel therapeutic strategy for EC metabolism.

SNRPD2-mediated regulation of DDX39B splicing promotes endometrial cancer progression by suppressing the activation of CTSC cryptic exons

Abstract Recent studies have reported the overexpression of Sm proteins in several cancers, suggesting their potential as therapeutic targets; however, the specific Sm family members involved in endometrial cancer and their mechanisms remain unclear. Here, we show that the Sm protein SNRPD2 is markedly upregulated in both fresh-frozen and formalin-fixed paraffin-embedded (FFPE) endometrial cancer specimens and that its overexpression correlates with poorer clinical outcomes. In vitro and in vivo functional assays demonstrate that silencing SNRPD2 suppresses endometrial cancer cell proliferation and metastasis. Specifically, antisense oligonucleotides (ASOs) targeting SNRPD2 markedly reduced tumor growth in a patient-derived xenograft (PDX) model. Mechanistic analyses reveal that SNRPD2 knockdown induces the retention of intron 5 in DDX39B , resulting in the production of a noncoding transcript that is degraded by the nonsense-mediated decay (NMD) pathway and thereby decreases DDX39B expression. Reduced DDX39B levels permit the activation of a cryptic exon (Exon 2_3) in the CTSC mRNA, which introduces premature termination codons (PTCs) and triggers additional NMD-mediated degradation, leading to decreased CTSC expression. Thus, SNRPD2 maintains high DDX39B expression by preventing intron retention, and in turn, elevated DDX39B expression suppresses cryptic exon usage in CTSC to preserve CTSC expression, ultimately supporting malignant phenotypes of endometrial cancer. These results define a novel SNRPD2–DDX39B–CTSC regulatory axis and identify SNRPD2 as a promising therapeutic target for endometrial cancer.

Lactate transmission from hypoxic tumor cells promotes macrophage senescence and M2 polarization via the DNMT1-NHE7 axis to accelerate endometrial cancer progression

Abstract Although hypoxia is a well-known key driver of metabolic reprogramming in endometrial cancer (EC), its role in lactate-mediated macrophage activation remains unclear. This study investigates whether hypoxia-mediated lactate metabolism reprogramming facilitated EC progression via macrophages. Our data demonstrated that hypoxia-inducible factor 1 subunit alpha (HIF1A) drives a lactate-regulated metabolic cascade, elevating glycolytic genes and monocarboxylate transporter 3 (MCT3) in EC cells to produce and export more lactate. This lactate is transported to macrophages by MCT1 to drive M2 macrophage polarization. Mechanistically, lactate induces lactylation of Histone 3 in the promoter of DNA methyltransferase 1 (DNMT1) gene and activates transcription in macrophages, leading to the silencing of NHE7 gene expression, a key regulator of intracellular pH. Critically, NHE7 downregulation drives M2 polarization and senescence through the mitogen-activated protein kinase (MAPK) pathway activation in macrophages, ultimately facilitating EC progression. In vivo, we successfully established a xenograft tumor model using Ishikawa cells, and the data further confirmed that NHE7-overexpressing macrophages effectively abrogate exogenous lactate-accelerated xenograft tumor growth, as well as its M2 polarization and senescence. These findings uncover that hypoxia-mediated lactate production and transmission promote tumor-macrophage crosstalk via the DNMT1-NHE7 axis and EC progression, which offers novel therapeutic targets for EC.

Immune evasion mechanisms in early-stage I high-grade serous ovarian carcinoma: insights into regulatory T cell dynamics

Abstract The mechanisms driving immune evasion in early-stage I high-grade serous ovarian carcinoma (HGSOC) remain poorly understood. To investigate this, we performed single-cell RNA-sequencing analysis. Our findings revealed a highly immunosuppressive HGSOC microenvironment, characterized by abundant infiltration of regulatory T cells (Tregs). Trajectory analysis uncovered differentiation pathways of naïve Tregs, which underwent either activation and proliferation or transcriptional instability. The predicted Treg-cell interaction network, including crosstalk within tumor cells, facilitates Treg mobility and maturation while reinforcing their immunosuppressive function and persistence in the tumor. Moreover, their interactions with immune cells likely inhibit CD8 T cells and antigen-presenting cells, supporting tumor immune escape. Additionally, more immunogenic tumor conditions, marked by IFNγ production, may contribute to Treg destabilization. Our findings underscore the pivotal role of Tregs in early immune evasion of HGSOC and provide insights into potential therapeutic strategies targeting their activity and differentiation fate.

Phosphorylation of INF2 by AMPK promotes mitochondrial fission and oncogenic function in endometrial cancer

AbstractMitochondria are highly dynamic organelles capable of altering their sizes and shapes to maintain metabolic balance through coordinated fission and fusion processes. In various cancer types, mitochondrial hyperfragmentation has been frequently observed, contributing to the progression of cancer toward metastasis. Inverted formin 2 (INF2), which resides in the endoplasmic reticulum (ER), has been found to accelerate actin polymerization and drive mitochondrial fission. In this study, we demonstrate that INF2 expression is significantly upregulated in endometrial cancer (EC) and is associated with a poor prognosis in EC patients. INF2 promotes anchorage-dependent and independent EC cell growth in part by facilitating mitochondrial fission. Furthermore, in conditions of energy stress, AMP-activated protein kinase (AMPK) phosphorylates INF2 at Ser1077, leading to increased localization of INF2 to the ER and enhanced recruitment of the dynamin-related protein 1 (DRP1) to mitochondria. This AMPK-mediated phosphorylation of INF2 at Ser1077 facilitates mitochondrial division and promotes EC cell growth. Pathological examination using immunohistochemical analyses revealed a positive correlation between AMPK activity and phosphorylated INF2 (Ser1077) in EC specimens. Collectively, our findings uncover novel molecular mechanisms involving the AMPK-INF2 axis, which regulates mitochondrial dynamics and malignant cell growth in EC.

Extracellular matrix stiffness in endometrial cancer: driving progression and modulating treatment sensitivity via the ROCK1/YAP1 axis

Abstract Endometrial cancer (EC) is among the most prevalent gynecological malignancies, with advanced or recurrent cases posing significant treatment challenges due to limited responses to conventional therapies. Growing evidence highlights the critical role of extracellular matrix (ECM) stiffness in driving tumor progression by shaping the tumor microenvironment. In this study, we demonstrate that ECM stiffness is significantly higher in EC tissues compared to normal endometrium, correlating with elevated expression of ROCK1, a mechanosensitive kinase. Using atomic force microscopy (AFM), we quantified ECM stiffness, while polyacrylamide gels with varying stiffness were employed to mimic ECM conditions in vitro. Bioinformatics analyses, immunofluorescence, Western blotting, and co-immunoprecipitation experiments revealed that ROCK1 modulates the phosphorylation of YAP1, promoting its nuclear localization and transcriptional activity, thereby driving aggressive tumor behaviors, including enhanced proliferation, migration, invasion, and reduced apoptosis. Pharmacological inhibition of ROCK1 with Y-27632 mitigated these effects, suppressing tumor growth, restoring apoptosis, and inducing cell cycle arrest. Treatment with Y-27632 improved sensitivity to chemotherapy and radiotherapy, and significantly enhanced macrophage-mediated phagocytosis, thereby boosting anti-tumor immune responses. In hormone-resistant EC cells, ROCK1 inhibition restored sensitivity to progesterone therapy. Notably, in vivo experiments in a xenograft mouse model confirmed the therapeutic potential of Y-27632, as combination therapy with progesterone showed superior tumor-suppressive effects compared to monotherapy. These findings underscore the dual role of ECM stiffness and ROCK1 in driving tumor progression and influencing treatment outcomes. By elucidating the relationship between ECM stiffness, ROCK1/YAP1 signaling, and treatment sensitivity, this study highlights the potential of targeting the ROCK1/YAP1 axis as a therapeutic strategy. ROCK1 serves as both a biomarker for prognosis and a target for improving personalized treatment approaches, offering new avenues to enhance clinical outcomes for EC patients.

High glucose levels promote glycolysis and cholesterol synthesis via ERRα and suppress the autophagy–lysosomal pathway in endometrial cancer

Abstract Endometrial cancer (EC) patients with Diabetes Mellitus (DM) always have a poor prognosis. Estrogen-related receptor α (ERRα) is known as the metabolic-related prognostic factor for EC. However, the mechanism linking glycolipid metabolism dysfunction mediated by ERRα to poor prognosis of EC with DM is still unclear. In vitro, high-glucose (HG) levels showed enhancement of ERRα expression, cell proliferation, and inhibition of the autophagic lysosomes and apoptosis by flow cytometry analysis, transmission electron microscopy, and CCK-8 assays. Mechanistically, lose-and-gain function assay, DNA sequencing, and CO-IP revealed HG increased ERRα expression to promote the transcription of HK2 and HMGCS1, which were the key rate-limiting enzyme of glycolysis-cholesterol synthesis and their metabolites suppressed the autophagy–lysosomal pathway in an ERRα-dependent manner. Furthermore, CO-IP and molecular dynamics simulation uncovered the protein residues (ARG 769HK2 vs. ARG 313HMGCS1) of HK2 and HMGCS1 could bind to p62 to form stable protein complexes involved in the autophagy–lysosomal pathway. In EC tissue from patients with comorbid DM, ERRα was significantly higher expressed compared to EC tissue from patients without evidence for DM (p < 0.05). The 3D EC organoid model with HG stimulation showed that the cell viability of XCT790 + carboplatin treatment was similar to that of metformin+carboplatin treatment, while the obviously bigger volume of organoids was more visible in the metformin+carboplatin group, indicating the therapy of XCT790 + carboplatin had the better inhibition of EC organoids with the same carboplatin dose. Besides insights into the interaction of HG and the autophagy–lysosomal pathway via ERRα, our present study points out the potential benefit of targeting ERRα in patients with EC with dysregulation of glucose and cholesterol metabolism.

ABX-1431 inhibits the development of endometrial adenocarcinoma and reverses progesterone resistance by targeting MGLL

Abstract Endometrial cancer is a common gynecological malignancy. With the onset of EC patients younger, conservative treatment with progesterone has become an important option for patients trying to preserve reproductive function. However, progesterone resistance is a key factor affecting the efficacy of therapy and it is urgent to clarify the mechanism so as to propose a potential target and inhibit the development of endometrial adenocarcinoma and progesterone resistance. MGLL, an important factor involved in lipid mobilization, is overexpressed in many tumors, however the biological function of MGLL in the development of endometrial adenocarcinoma and the process of progesterone resistance still remains unclear. In this study, we first found MGLL was highly expressed in progesterone resistant samples of endometrial adenocarcinoma, and then we verified its expression was increased in endometrial adenocarcinoma. Through in vitro and in vivo experiments, we demonstrated that overexpression of MGLL promoted tumor proliferation, metastasis and the occurrence of progestogen resistance, knockdown MGLL inhibited tumor proliferation, metastasis and reversed progestogen resistance. In addition, knockdown of MGLL can sensitize endometrial adenocarcinoma cells to progesterone, possibly by affecting ROS generation and reducing the expression of AKR1C1. Finally, it was verified that ABX-1431, MGLL inhibitor, reversed progesterone resistance and enhanced the sensitivity of endometrial adenocarcinoma to progesterone both in vitro and in vivo. In conclusion, the high expression of MGLL is involved in the occurrence and development of endometrial adenocarcinoma and progesterone resistance. Targeted inhibition of MGLL by inhibitors may be an effective method for the treatment of progesterone resistance in endometrial adenocarcinoma.

RAB17 promotes endometrial cancer progression by inhibiting TFRC-dependent ferroptosis

AbstractStudies have indicated that RAB17 expression levels are associated with tumor malignancy, and RAB17 is more highly expressed in endometrial cancer (EC) tissues than in peritumoral tissues. However, the roles and potential mechanisms of RAB17 in EC remain undefined. The present study confirmed that the expression of RAB17 facilitates EC progression by suppressing cellular ferroptosis-like alterations. Mechanistically, RAB17 attenuated ferroptosis in EC cells by inhibiting transferrin receptor (TFRC) protein expression in a ubiquitin proteasome-dependent manner. Because EC is a blood-deprived tumor with a poor energy supply, the relationship between RAB17 and hypoglycemia was investigated. RAB17 expression was increased in EC cells incubated in low-glucose medium. Moreover, low-glucose medium limited EC cell ferroptosis and promoted EC progression through the RAB17-TFRC axis. The in vitro results were corroborated by in vivo studies and clinical data. Overall, the present study revealed that increased RAB17 promotes the survival of EC cells during glucose deprivation by inhibiting the onset of TFRC-dependent ferroptosis.

Iron promotes ovarian cancer malignancy and advances platinum resistance by enhancing DNA repair via FTH1/FTL/POLQ/RAD51 axis

AbstractIron is crucial for cell DNA synthesis and repair, but an excess of free iron can lead to oxidative stress and subsequent cell death. Although several studies suggest that cancer cells display characteristics of ‘Iron addiction’, an ongoing debate surrounds the question of whether iron can influence the malignant properties of ovarian cancer. In the current study, we initially found iron levels increase during spheroid formation. Furthermore, iron supplementation can promote cancer cell survival, cancer spheroid growth, and migration; vice versa, iron chelators inhibit this process. Notably, iron reduces the sensitivity of ovarian cancer cells to platinum as well. Mechanistically, iron downregulates DNA homologous recombination (HR) inhibitor polymerase theta (POLQ) and relieves its antagonism against the HR repair enzyme RAD51, thereby promoting DNA damage repair to resist chemotherapy-induced damage. Additionally, iron tightly regulated by ferritin (FTH1/FTL) which is indispensable for iron-triggered DNA repair. Finally, we discovered that iron chelators combined with platinum exhibit a synergistic inhibitory effect on ovarian cancer in vitro and in vivo. Our findings affirm the pro-cancer role of iron in ovarian cancer and reveal that iron advances platinum resistance by promoting DNA damage repair through FTH1/FTL/POLQ/RAD51 pathway. Our findings highlight the significance of iron depletion therapy, revealing a promising avenue for advancing ovarian cancer treatment.

A first-in-class POLRMT specific inhibitor IMT1 suppresses endometrial carcinoma cell growth

AbstractExploring novel molecularly-targeted therapies for endometrial carcinoma is important. The current study explored the potential anti-endometrial carcinoma activity by a first-in-class POLRMT (RNA polymerase mitochondrial) inhibitor IMT1. In patient-derived primary human endometrial carcinoma cells and established lines, treatment with IMT1 potently inhibited cell viability, proliferation, cell-cycle progression and motility, while inducing robust caspase-apoptosis activation. Treatment with the PLORMT inhibitor impaired mitochondrial functions, leading to mtDNA (mitochondrial DNA) transcription inhibition, mitochondrial membrane potential decline, reactive oxygen species formation, oxidative stress and ATP loss in the endometrial carcinoma cells. Similarly, POLRMT depletion, through shRNA-induced silencing or CRISPR/Cas9-caused knockout (KO), inhibited primary endometrial carcinoma cell proliferation and motility, and induced mitochondrial dysfunction and apoptosis. Importantly, IMT1 failed to induce further cytotoxicity in POLRMT-KO endometrial carcinoma cells. Contrarily, ectopic overexpression of POLRMT further augmented proliferation and motility of primary endometrial carcinoma cells. In vivo, oral administration of a single dose of IMT1 substantially inhibited endometrial carcinoma xenograft growth in the nude mice. mtDNA transcription inhibition, oxidative stress, ATP loss and apoptosis were detected in IMT1-treated endometrial carcinoma xenograft tissues. Together, targeting PLORMT by IMT1 inhibited endometrial carcinoma cell growth in vitro and in vivo.

PVT1/miR-136/Sox2/UPF1 axis regulates the malignant phenotypes of endometrial cancer stem cells

Abstract Tumor stem cells (TSCs) are thought to contribute to the progression and maintenance of cancer. Previous studies have suggested that plasmacytoma variant translocation 1 (PVT1) has a tumor-promoting effect on endometrial cancer; however, its mechanism of action in endometrial cancer stem cells (ECSCs) is unknown. Here, we found that PVT1 was highly expressed in endometrial cancers and ECSCs, correlated with poor patient prognosis, promoted the malignant behavior and the stemness of endometrial cancer cells (ECCs) and ECSCs. In contrast, miR-136, which was lowly expressed in endometrial cancer and ECSCs, had the opposite effect, and knockdown miR-136 inhibited the anticancer effects of down-regulated PVT1. PVT1 affected miR-136 specifically binding the 3’ UTR region of Sox2 by competitively “sponging” miR-136, thus positively saving Sox2. Sox2 promoted the malignant behavior and the stemness of ECCs and ECSCs, and overexpression Sox2 inhibited the anticancer effects of up-regulated miR-136. Sox2 can act as a transcription factor to positively regulate Up-frameshift protein 1 (UPF1) expression, thereby exerting a tumor-promoting effect on endometrial cancer. In nude mice, simultaneously downregulating PVT1 and upregulating miR-136 exerted the strongest antitumor effect. We demonstrate that the PVT1/miR-136/Sox2/UPF1 axis plays an important role in the progression and maintenance of endometrial cancer. The results suggest a novel target for endometrial cancer therapies.

Inhibition of collagen XI alpha 1-induced fatty acid oxidation triggers apoptotic cell death in cisplatin-resistant ovarian cancer

AbstractCollagen type XI alpha 1 (COL11A1) is a novel biomarker associated with cisplatin resistance in ovarian cancer. However, the mechanisms underlying how COL11A1 confers cisplatin resistance in ovarian cancer are poorly understood. We identified that fatty acid β-oxidation (FAO) is upregulated by COL11A1 in ovarian cancer cells and that COL11A1-driven cisplatin resistance can be abrogated by inhibition of FAO. Furthermore, our results demonstrate that COL11A1 also enhances the expression of proteins involved in fatty acid synthesis. Interestingly, COL11A1-induced upregulation of fatty acid synthesis and FAO is modulated by the same signaling molecules. We identified that binding of COL11A1 to its receptors, α1β1 integrin and discoidin domain receptor 2 (DDR2), activates Src-Akt-AMPK signaling to increase the expression of both fatty acid synthesis and oxidation enzymes, although DDR2 seems to be the predominant receptor. Inhibition of fatty acid synthesis downregulates FAO despite the presence of COL11A1, suggesting that fatty acid synthesis might be a driver of FAO in ovarian cancer cells. Taken together, our results suggest that COL11A1 upregulates fatty acid metabolism in ovarian cancer cells in a DDR2-Src-Akt-AMPK dependent manner. Therefore, we propose that blocking FAO might serve as a promising therapeutic target to treat ovarian cancer, particularly cisplatin-resistant recurrent ovarian cancers which typically express high levels of COL11A1.

FOXP4-mediated induction of PTK7 activates the Wnt/β-catenin pathway and promotes ovarian cancer development

AbstractOvarian cancer (OV) poses a significant challenge in clinical settings due to its difficulty in early diagnosis and treatment resistance. FOXP4, belonging to the FOXP subfamily, plays a pivotal role in various biological processes including cancer, cell cycle regulation, and embryonic development. However, the specific role and importance of FOXP4 in OV have remained unclear. Our research showed that FOXP4 is highly expressed in OV tissues, with its elevated levels correlating with poor prognosis. We further explored FOXP4’s function through RNA sequencing and functional analysis in FOXP4-deficient cells, revealing its critical role in activating the Wnt signaling pathway. This activation exacerbates the malignant phenotype in OV. Mechanistically, FOXP4 directly induces the expression of protein tyrosine kinase 7 (PTK7), a Wnt-binding receptor tyrosine pseudokinase, which causes abnormal activation of the Wnt signaling pathway. Disrupting the FOXP4-Wnt feedback loop by inactivating the Wnt signaling pathway or reducing FOXP4 expression resulted in the reduction of the malignant phenotype of OV cells, while restoring PTK7 expression reversed this effect. In conclusion, our findings underscore the significance of the FOXP4-induced Wnt pathway activation in OV, suggesting the therapeutic potential of targeting this pathway in OV treatment.

UPF1 contributes to the maintenance of endometrial cancer stem cell phenotype by stabilizing LINC00963

AbstractEndometrial cancer stem cells (ECSCs) play a vital role in endometrial cancer (EC) metastasis, relapse, and chemoresistance. However, the molecular mechanisms that sustain ECSCs remain elusive. Here, we showed that the expression of UPF1 was upregulated in EC tissues and ECSCs and correlated with poor clinicopathological characteristics. UPF1 silencing suppressed ECSC hallmarks, such as sphere formation ability, carboplatin resistance, migration and invasion, and cell cycle progression. UPF1 regulated the behavior and fate of ECSCs by stabilizing LINC00963. LINC00963 further shares the same miRNA response element with the core transcription factor SOX2 and relieved the suppression of SOX2 by miR-508-5p in self-renewing ECSCs. Notably, inhibition of UPF1 and LINC00963 in combination severely impaired the in vivo tumorigenic potential of ECSCs. We demonstrate that the UPF1/LINC00963/miR-508-5p/SOX2 axis has potential value in modulating ECSC maintenance, chemoresistance, and tumorigenesis in EC, which highlights a novel promising target for EC treatment.

M5C-driven stabilization of SERPINB5 promotes cervical cancer progression and chemotherapy resistance

Abstract RNA 5-methylcytosine (m 5 C) plays a critical role in cancer, yet its functional mechanisms and therapeutic relevance in cervical cancer remain unclear. Here, we generate the first base-resolution m 5 C transcriptome maps in cervical cancer, revealing globally elevated m 5 C levels in tumors. By integrating spatial transcriptomics and single-cell RNA-seq, we identify SERPINB5 as a novel m 5 C-regulated oncogenic effector. m 5 C modification enhances SERPINB5 mRNA stability and protein expression, promoting tumor growth, metastasis, and resistance to microtubule-targeting chemotherapeutics. Mechanistically, SERPINB5 upregulates mitotic regulators and microtubule motor proteins, including CENPE, enhancing mitotic progression and counteracting drug-induced mitotic arrest. Loss-of-function experiments demonstrate that SERPINB5 depletion sensitizes cervical cancer cells to paclitaxel and vincristine, while its reintroduction restores chemoresistance even in m 5 C-deficient cells. Our study uncovers a previously unrecognized m 5 C–SERPINB5 axis as a central driver of cervical cancer malignancy and chemoresistance, highlighting SERPINB5 as a clinically actionable target to improve outcomes for patients receiving microtubule-targeting chemotherapy.

Exosomal transfer of tumor-associated macrophage-derived hsa_circ_0001610 reduces radiosensitivity in endometrial cancer

AbstractThe occurrence of radioresistance is a clinical obstacle to endometrial cancer (EC) treatment and induces tumor relapse. In this study, we found that tumor-associated macrophages (TAMs) enriched in EC specimens were determined to present an M2-like phenotype. In vitro, the coculture of M2-polarized macrophages significantly downregulated the radiosensitivity of EC cells by releasing exosomes. Hsa_circ_0001610 was found to be abundant in exosomes derived from M2-polarized macrophages (EXOs), and hsa_circ_0001610 knockdown eliminated the reduction effect of EXOs on the radiosensitivity of EC cells. The following mechanism research revealed that hsa_circ_0001610 functioned as the competing endogenous RNA of miR-139-5p, thereby upregulating cyclin B1 expression, which is a vital pusher of radioresistance in several types of cancer by regulating the cell cycle. Hsa_circ_0001610 overexpression reduced the radiosensitivity of EC cells, which was then reversed by miR-139-5p overexpression. In vivo, the promotion effect of EXOs on xenograft tumor growth in nude mice treated with irradiation was further reinforced after hsa_circ_0001610 overexpression. In conclusion, TAM-derived exosomes transferred hsa_circ_0001610 to EC cells, and the overexpressed hsa_circ_0001610 in EC cells released cyclin B1 expression through adsorbing miR-139-5p, thereby weakening the radiosensitivity of EC cells.

Splicing factor SF3B1 promotes endometrial cancer progression via regulating KSR2 RNA maturation

AbstractAlthough endometrial cancer is the most common cancer of the female reproductive tract, we have little understanding of what controls endometrial cancer beyond the transcriptional effects of steroid hormones such as estrogen. As a result, we have limited therapeutic options for the ~62,000 women diagnosed with endometrial cancer each year in the United States. Here, in an attempt to identify new prognostic and therapeutic targets, we focused on a new area for this cancer—alternative mRNA splicing—and investigated whether splicing factor, SF3B1, plays an important role in endometrial cancer pathogenesis. Using a tissue microarray, we found that human endometrial tumors expressed more SF3B1 protein than non-cancerous tissues. Furthermore, SF3B1 knockdown reduced in vitro proliferation, migration, and invasion of the endometrial cancer cell lines Ishikawa and AN3CA. Similarly, the SF3B1 inhibitor, Pladienolide-B (PLAD-B), reduced the Ishikawa and AN3CA cell proliferation and invasion in vitro. Moreover, PLAD-B reduced tumor growth in an orthotopic endometrial cancer mouse model. Using RNA-Seq approach, we identified ~2000 differentially expressed genes (DEGs) with SF3B1 knockdown in endometrial cancer cells. Additionally, alternative splicing (AS) events analysis revealed that SF3B1 depletion led to alteration in multiple categories of AS events including alternative exon skipping (ES), transcript start site usage (TSS), and transcript termination site (TTS) usage. Subsequently, bioinformatics analysis showed KSR2 as a potential candidate for SF3B1-mediated functions in endometrial cancer. Specifically, loss of SF3B1 led to decrease in KSR2 expression, owing to reduced maturation of KSR2 pre-mRNA to a mature RNA. Importantly, we found rescuing the KSR2 expression with SF3B1 knockdown partially restored the cell growth of endometrial cancer cells. Taken together, our data suggest that SF3B1 plays a crucial oncogenic role in the tumorigenesis of endometrial cancer and hence may support the development of SF3B1 inhibitors to treat this disease.

Chloroquine reverses chemoresistance via upregulation of p21WAF1/CIP1 and autophagy inhibition in ovarian cancer

AbstractOvercoming drug-resistance is a big challenge to improve the survival of patients with epithelial ovarian cancer (EOC). In this study, we investigated the effect of chloroquine (CQ) and its combination with cisplatin (CDDP) in drug-resistant EOC cells. We used the three EOC cell lines CDDP-resistant A2780-CP20, RMG-1 cells, and CDDP-sensitive A2780 cells. The CQ-CDDP combination significantly decreased cell proliferation and increased apoptosis in all cell lines. The combination induced expression of γH2AX, a DNA damage marker protein, and induced G2/M cell cycle arrest. Although the CQ-CDDP combination decreased protein expression of ATM and ATR, phosphorylation of ATM was increased and expression of p21WAF1/CIP1 was also increased in CQ-CDDP-treated cells. Knockdown of p21WAF1/CIP1 by shRNA reduced the expression of γH2AX and phosphorylated ATM and inhibited caspase-3 activity but induced ATM protein expression. Knockdown of p21WAF1/CIP1 partly inhibited CQ-CDDP-induced G2/M arrest, demonstrating that knockdown of p21WAF1/CIP1 overcame the cytotoxic effect of the CQ-CDDP combination. Ectopic expression of p21WAF1/CIP1 in CDDP-treated ATG5-shRNA/A2780-CP20 cells increased expression of γH2AX and caspase-3 activity, demonstrating increased DNA damage and cell death. The inhibition of autophagy by ATG5-shRNA demonstrated similar results upon CDDP treatment, except p21WAF1/CIP1 expression. In an in vivo efficacy study, the CQ-CDDP combination significantly decreased tumor weight and increased expression of γH2AX and p21WAF1/CIP1 in A2780-CP20 orthotopic xenografts and a drug-resistant patient-derived xenograft model of EOC compared with controls. These results demonstrated that CQ increases cytotoxicity in combination with CDDP by inducing lethal DNA damage by induction of p21WAF1/CIP1 expression and autophagy inhibition in CDDP-resistant EOC.

RAB33A promotes metastasis via RhoC accumulation through non-canonical autophagy in cervical cancer

Abstract Cervical cancer metastasis is characterized by the systemic spread of tumor cells. However, the underlying mechanism remains incompletely understood. Herein, we demonstrate that RAB33A promoted metastasis by enhancing RhoC accumulation and that higher RAB33A expression predicted poorer prognosis in patients with cervical cancer. Mechanistically, RhoC typically degraded via canonical autophagy due to the binding of two LIR motifs (LC3 interaction region) in RhoC to LC3; however, RAB33A induced non-canonical autophagy, resulting in RhoC stabilization, which facilitated pseudopodia formation and consequently cervical cancer metastasis. The fusion of RAB33A-induced autophagosomes with lysosomes was impaired, as RAB33A inactivated RAB7 by interacting with TBC1D2A, a GTPase-activating protein that targets RAB7. Our findings reveal a pivotal role of the RAB33A-RhoC axis in cervical cancer metastasis, indicating that RhoC inhibitors may be beneficial for treating cervical cancer patients with high levels of RAB33A.

IL7R remodels immunosuppression tumor microenvironment and promotes macrophage polarization by regulating NF-κB/CXCL1 axis in ovarian cancer

Abstract In the ovarian cancer microenvironment, the polarization of tumor-associated macrophages (TAMs) is closely associated with immunosuppressive phenotypes. Although elevated levels of circulating interleukin-7 (IL-7) have been linked to a poor prognosis, the regulatory mechanisms underlying this association remain incompletely understood. This study demonstrated that increased IL7R expression in ovarian cancer is correlated with the polarization of CD206 + macrophages, the remodeling of the immunosuppressive microenvironment, and unfavorable patient prognosis. By employing 3D bioprinted co-culture systems and mouse models, we showed that the knockdown or knockout of IL7R inhibits tumor progression and intraperitoneal dissemination. Mechanistically, IL7R signaling promotes the polarization of macrophages toward an immunosuppressive phenotype through the NF-κB/CXCL1 axis. This is supported by the upregulated expression of Arg1 and IL-10, as well as the downregulated expression of pro-inflammatory markers. These polarized macrophages further enhance tumor cell proliferation and invasion, thereby forming a tumor-immune feedback loop. In conclusion, this study clarifies how IL7R signaling mediates crosstalk between ovarian cancer cells and macrophages to maintain the homeostasis of the immunosuppressive tumor microenvironment (TME).

USP28 promotes PARP inhibitor resistance by enhancing SOX9-mediated DNA damage repair in ovarian cancer

Abstract PARP inhibitor (PARPi) resistance presents a significant challenge in ovarian cancer treatment, necessitating the development of effective therapeutic strategies to overcome this resistance and improve patient outcomes. Our study demonstrated that elevated expression of SRY-box 9 (SOX9) contributes to olaparib resistance in ovarian cancer. Mechanistically, the deubiquitinating enzyme USP28 was identified as a novel interacting partner of SOX9. USP28 inhibited the ubiquitination and subsequent degradation of SOX9, which is mediated by the E3 ubiquitin ligase FBXW7 during olaparib treatment. ChIP-Seq analysis revealed that SOX9 binds to the promoters of key DNA damage repair (DDR) genes (SMARCA4, UIMC1, and SLX4), thereby regulating DDR processes in ovarian cancer. Additionally, USP28 promoted olaparib resistance by stabilizing SOX9 protein and enhancing DNA damage repair. Furthermore, the USP28 specific inhibitor AZ1 reduced SOX9 protein stability and increased the sensitivity of ovarian cancer cells to olaparib. In conclusion, targeted inhibition of USP28 promoted ubiquitination-mediated degradation of SOX9, thereby impairing DNA damage repair capabilities and sensitizing ovarian cancer cells to PARPi. These findings elucidate the underlying mechanisms of PARPi resistance in ovarian cancer and suggest the potential efficacy of combining USP28 inhibitors with PARPi to overcome this resistance.

Gap junction protein beta 5 interacts with Gαi3 to promote Akt activation and cervical cancer cell growth

Abstract Identifying novel therapeutic targets for cervical cancer is crucial for improving patient outcomes and reducing the global burden of this disease. Gap junction protein beta 5 (GJB5) is a member of the connexin family of proteins involved in cell-to-cell communication. This study investigated GJB5’s expression and functional significance in cervical cancer. Analysis of The Cancer Genome Atlas (TCGA) data demonstrated significantly increased GJB5 mRNA expression in cervical cancer tissues compared to normal cervical epithelium. Moreover, high GJB5 expression correlated with reduced overall survival and other adverse clinical outcomes. Single-cell RNA sequencing corroborated GJB5 overexpression within the malignant tumor cell population. The downregulation of GJB5 through shRNA or CRISPR/Cas9 gene knockout techniques significantly impaired the viability, proliferation, and migratory capacity of cervical cancer cells, while concurrently inducing apoptotic processes. Conversely, the forced overexpression of GJB5 resulted in enhanced malignant behaviors. Investigations into the underlying mechanisms revealed that GJB5 is integral to the activation of the Akt-mTOR (mammalian target of rapamycin) signaling pathway. GJB5 knockdown or knockout led to diminished phosphorylation of Akt and S6 kinase, whereas GJB5 overexpression correlated with increased Akt-mTOR signaling in primary human cervical cancer cells. Additionally, we identified a novel interaction between GJB5 and the Gαi3 (G alpha inhibitory protein 3), underscoring the crucial role of GJB5 in mediating Akt activation via Gαi3. In vivo studies utilizing xenograft models provided further evidence for the oncogenic function of GJB5. The knockdown of GJB5 resulted in a marked reduction in the growth of cervical cancer xenografts. Observations of proliferation arrest, inactivation of the Akt-mTOR pathway, and the induction of apoptosis were noted in GJB5-depleted cervical cancer xenograft tissues. Collectively, these findings underscore GJB5 as a key oncogenic driver in cervical cancer and indicate that targeting GJB5 could be a promising therapeutic approach for this disease.

YTHDF3 suppresses interferon-stimulated gene (ISG)-dependent antitumor immunity and promotes HPV carcinogenesis in cervical cancer

Abstract Interferon-stimulated genes (ISGs) serve as evolutionarily conserved mediators of antiviral defense and tumor surveillance. Emerging evidence underscores the non-oncogenic addiction of high-risk human papillomavirus (hrHPV) E6/E7 oncoproteins in maintaining malignant phenotypes and cervical carcinogenesis. Here, we leveraged CRISPR/Cas9-engineered YTHDF3-knockout (YTHDF3 −/− ) SiHa cells and Ythdf3 −/ − mice to dissect the molecular arbiters governing m 6 A-dependent RNA regulation in HPV-driven carcinogenesis. To further elucidate the role of YTHDF3 in HPV-induced immunosuppressive tumor microenvironment (ITME) formation, we demonstrated that YTHDF3, an m 6 A RNA reader, suppresses type I ISGs responses. Notably, elevated m 6 A modification and YTHDF3 protein levels were observed in HPV + CCa tissues. Mechanistically, YTHDF3 bound to the m 6 A methylation site of STAT3 mRNA, enhancing its stability and transcription efficiency. This YTHDF3-STAT3 axis repressed ISG (e.g., IRF7) transcription and IFN-α production, thereby compromising antiviral immunity and facilitating HPV E6/E7 persistence. Correspondingly, Ythdf3 − mice bearing TC-1 xenografts exhibited a significant reduction in immunosuppressive immune cell infiltration, including Tregs, M2 macrophages, and MDSCs, accompanied by enhanced CD8 + T cell activation. Collectively, our findings unveiled that YTHDF3-mediated upregulation of STAT3 suppresses the type I ISG expression, thus promoting HPV carcinogenesis and establishing an ITME. Taken together, our results suggest that targeting the YTHDF3/STAT3/IRF7 axis could be a promising therapeutic strategy against HPV-associated malignancies.

PRDM1-driven SLC30A9 overexpression contributes to the malignant phenotype of cervical cancer cells via promoting mitochondrial hyperfunction

Abstract Mitochondrial hyperfunction is important for cervical cancer progression. Solute carrier family 30 member 9 (SLC30A9) is a member of the solute carrier family 30, specifically a zinc transporter that plays a critical role in mitochondrial zinc homeostasis and maintaining mitochondrial function. We investigated the expression, function, and underlying mechanisms of SLC30A9 in the context of cervical cancer. Single-cell RNA sequencing analysis revealed a marked overexpression of SLC30A9 within the malignant epithelial cell population of cervical squamous cell carcinoma. This elevated SLC30A9 expression was further corroborated in clinical specimens from local patients and across various established and primary cervical cancer cells. SLC30A9 shRNA or knockout (via CRISPR/Cas9 method) significantly impeded the viability, proliferation, cell cycle progression and migration, and triggered apoptosis in cervical cancer cells. SLC30A9 depletion disrupted mitochondrial function, inhibiting mitochondrial respiration, mitochondrial membrane potential, mitochondrial complex I activity, and ATP production, also caused mitochondrial Zn 2+ accumulation, reactive oxygen species (ROS) production and oxidative injury. Conversely, overexpression of SLC30A9 in cervical cancer cells demonstrated enhanced mitochondrial complex I activity, increased ATP production, and augmented cellular proliferation and migration. Bioinformatic analysis, coupled with functional validation, identified PRDM1 (PR Domain Containing 1) as a key transcription factor regulating SLC30A9 expression. Silencing or knockout of PRDM1 resulted in a significant reduction in SLC30A9 promoter activity, as well as decreased SLC30A9 mRNA and protein levels in primary cervical cancer cells. Chromatin immunoprecipitation (ChIP) assays confirmed increased PRDM1 binding to the SLC30A9 promoter region in cervical cancer tissues. In vivo studies showed that SLC30A9 knockdown led to a remarkable decrease in the growth of xenografts formed by primary cervical cancer cells. These SLC30A9-silenced xenografts exhibited mitochondrial dysfunction, proliferation inhibition and apoptosis induction. These findings collectively suggest that PRDM1-driven SLC30A9 overexpression significantly contributes to the malignant phenotype of cervical cancer, possibly through promoting mitochondrial hyperfunction.

Dissecting endometrial cancer complexity in response to standard and targeted therapies

Abstract Endometrial cancer (EC) is one of the most common gynecologic malignancies amongst women worldwide. Its incidence and mortality rates have been increasing in the last decade. In the present work, we built a patient EC-derived organoid (PDOs) platform that faithfully recapitulated tumor phenotype, genomic alterations, and expression profiles of matched-primary cancer tissues. Interestingly, we found that the response of EC-derived PDOs to both standard therapy and a wide range of targeted drugs accordingly to their specific druggable genetic alterations was congruent with that of the originating patients. We also isolated and genomically characterized matched-PDO stromal cells, specifically cancer-associated fibroblasts (CAFs). Unlike PDOs matched CAFs were poorly responsive and underwent to pro-inflammatory senescence upon treatment with standard therapy. Collectively, our findings established a EC-PDOs preclinical platform which allows assessing the therapeutic response of tumor and surrounding tumor microenvironment cellular landscape.

Endometrial cancer progression driven by PTEN-deficiency requires miR-424(322)~503

Abstract Endometrial cancer is the most frequent type of cancer in the female reproductive tract. Loss-of-function alterations in PTEN, leading to enhanced PI3K/AKT activation, are among the most frequent molecular alterations in endometrial cancer. Increased PI3K/AKT signaling resulting from PTEN loss promotes cellular proliferation and confers resistance to TGFβ-mediated apoptosis, a key regulator of endometrial homeostasis. In this study, we have analyzed the role of miRNAs in driving these altered cellular responses. A comprehensive transcriptomic analysis of miRNA expression revealed the upregulation of several miRNAs caused by PTEN deficiency and/or TGFβ stimulation. The miR-424(322)~503 cluster drew our attention due to its involvement in regulating apoptosis and proliferation. However, miR-424(322)~503 cluster has a paradoxical role in cancer, exhibiting either oncogenic and tumor suppressive functions depending on cell type or context. To ascertain the function of miR-424(322)~503 in endometrial carcinogenesis caused by PTEN deficiency, we generated a double Pten/miR-424(322)~503 knock-out mice. We demonstrate that loss of miR-424(322)~503 impairs proliferation of both wild type or Pten deficient endometrial organoids by interfering with growth factor and PI3K/AKT signaling. Furthermore, the absence of miR-424(322)~503 restores TGFβ-induced apoptosis, which is otherwise compromised by PTEN deficiency. In vivo, Pten/miR-424(322)~503 knock-out mice exhibit reduced endometrial cancer progression compared to Pten deficient mice through a cell-autonomous mechanism.

piR-26441 inhibits mitochondrial oxidative phosphorylation and tumorigenesis in ovarian cancer through m6A modification by interacting with YTHDC1

Abstract Ovarian cancer (OC) is a heterogeneous cancer. In contrast to other tumor cells, which rely primarily on aerobic glycolysis (Warburg effect) as their energy source, oxidative phosphorylation (OXPHOS) is also one of its major metabolic modes. Piwi-interacting RNAs (piRNAs) play a regulatory function in various biological processes in tumor cells. However, the role and mechanisms of piRNAs in OC and mitochondrial OXPHOS remain to be elucidated. Here, we found that piR-26441 was aberrantly downregulated in OC, and its overexpression suppressed the malignant features of OC cells and tumor growth in a xenograft model. Moreover, overexpression of piR-26441 significantly reduced mitochondrial OXPHOS levels in OC cells. Furthermore, piR-26441 directly binds to and upregulates the expression of YTHDC1 in OC cells. piR-26441 also increased m6A levels, thereby interacting with YTHDC1 to destabilize the mRNA of TSFM. The resultant TSFM loss reduced mitochondrial complex I activity and mitochondrial OXPHOS, leading to mitochondrial dysfunction in OC cells, increased reactive oxygen species levels, and thus, DNA damage and apoptosis in OC cells, thereby inhibiting OC progression. Additionally, ago-piR-26441 suppressed tumor growth and mitochondrial metabolism in the patient-derived organoid model. Altogether, piR-26441 could inhibit OC cell growth via the YTHDC1/TSFM signaling axis, underscoring its significant importance in the context of OC, as well as offering potential as a therapeutic target.

Single-cell RNA sequencing of cervical exfoliated cells reveals potential biomarkers and cellular pathogenesis in cervical carcinogenesis

AbstractCervical cancer (CC) is a common gynecological malignancy. Despite the current screening methods have been proved effectively and significantly decreased CC morbidity and mortality, deficiencies still exist. Single-cell RNA sequencing (scRNA-seq) approach can identify the complex and rare cell populations at single-cell resolution. By scRNA-seq, the heterogeneity of tumor microenvironment across cervical carcinogenesis has been mapped and described. Whether these alterations could be detected and applied to CC screening is unclear. Herein, we performed scRNA-seq of 56,173 cervical exfoliated cells from 15 samples, including normal cervix, low-grade squamous intraepithelial lesion (LSIL), high-grade squamous intraepithelial lesion (HSIL), and malignancy. The present study delineated the alteration of immune and epithelial cells derived during the cervical lesion progression. A subset of lipid-associated macrophage was identified as a tumor-promoting element and could serve as a biomarker for predicting the progression of LSIL into HSIL, which was then verified by immunofluorescence. Furthermore, cell–cell communication analysis indicated the SPP1-CD44 axis might exhibit a protumor interaction between epithelial cell and macrophage. In this study, we investigated the cervical multicellular ecosystem in cervical carcinogenesis and identified potential biomarkers for early detection.

IGF2BP3 enhances lipid metabolism in cervical cancer by upregulating the expression of SCD

AbstractCervical cancer (CC) is the most common gynecologic malignancy, which seriously threatens the health of women. Lipid metabolism is necessary for tumor proliferation and metastasis. However, the molecular mechanism of the relationship between CC and lipid metabolism remains poorly defined. We revealed the expression of IGF2BP3 in CC exceeded adjacent tissues, and was positively associated with tumor stage using human CC tissue microarrays. The Cell Counting Kit-8, colony formation assay, 5-ethynyl-2′-deoxyuridine assay, transwell assays, wound-healing assays, and flow cytometry assessed the role of IGF2BP3 in proliferation and metastasis of CC cells. Besides, exploring the molecular mechanism participating in IGF2BP3-driven lipid metabolism used RNA-seq, which determined SCD as the target of IGF2BP3. Further, lipid droplets, cellular triglyceride (TG) contents, and fatty acids were accessed to discover that IGF2BP3 can enhance lipid metabolism in CC. Moreover, RIP assay and methylated RNA immunoprecipitation experiments seeked the aimed-gene-binding specificity. Lastly, the IGF2BP3 knockdown restrained CC growth and lipid metabolism, after which SCD overexpression rescued the influence in vitro and in vivo using nude mouse tumor-bearing model. Mechanistically, IGF2BP3 regulated SCD mRNA m6A modifications via IGF2BP3-METTL14 complex, thereby enhanced CC proliferation, metastasis, and lipid metabolism. Our study highlights IGF2BP3 plays a crucial role in CC progression and represents a therapeutic latent strategy. It is a potential tactic that blocks the metabolic pathway relevant to IGF2BP3 with the purpose of treating CC.

TUFT1 regulates cancer progression by suppressing centrosome amplification and mitotic spindle multipolarity

Abstract Centrosome amplification (CA) has been observed in various solid tumors and contributes to chromosomal instability (CIN) and poor clinical prognosis in patients with cancer. CA also inhibits cell proliferation by inducing cell-cycle arrest and cell death. However, the mechanism of regulation of centrosome number in cancer cells and its effect on CIN and cell proliferation remains elusive. Here, we report that tuftelin (TUFT1) is a novel centrosomal protein that localizes to the proximal ends of parent centrioles. TUFT1 prevents CA and mitotic spindle multipolarity by suppressing premature polo-like kinase 1 activation. In addition, TUFT1 is phosphorylated by NIMA-related kinase 2 (NEK2), and the phosphorylation status of TUFT1 is essential for coordinating centrosome number and cell proliferation in cervical and breast cancers. Data from clinical breast cancer samples indicate that the combined detection of TUFT1 and NEK2 expression reflects tumor malignancy and patient survival with higher precision. Overall, these results reveal a crucial role of TUFT1 in the regulation of tumor progression through centrosome number control. Thus, TUFT1 represents a promising target for diagnostic and therapeutic approaches for cancers.

USP25-driven KIFC1 regulates MYCBP expression and promotes the progression of cervical cancer

Abstract Cervical cancer (CCa) continues to exhibit high mortality rates, compounded by the scarcity of effective therapeutic targets. This study highlights the significant upregulation of Kinesin Family Member C1 (KIFC1), a member of the kinesin-14 family, in CCa tissues. Elevated KIFC1 expression correlates with poorer prognoses in CCa patients. USP25, a deubiquitinating enzyme, stabilizes KIFC1 protein through deubiquitination, facilitating its accumulation in CCa tissues. Our in vitro and in vivo experiments demonstrate KIFC1’s pivotal role in enhancing tumorigenesis and metastasis of CCa cells. Furthermore, we discovered that KIFC1 expression variability could modulate the levels of MYCBP, a known binding partner of the oncogenic protein c-MYC, which influences tumorigenesis. The suppression of USP25 results in decreased KIFC1 and MYCBP protein levels, independent of mRNA changes. However, reintroducing KIFC1 into USP25-deficient cells restores MYCBP expression levels. Simultaneously, targeting USP25, KIFC1 and MYCBP disrupts the malignant phenotype of CCa cells. Collectively, our findings elucidate the previously unknown functions and mechanisms of the USP25/KIFC1/MYCBP signaling axis in CCa progression, underscoring KIFC1 as a promising therapeutic target for cervical cancer.

PGRN protects against serum deprivation-induced cell death by promoting the ROS scavenger system in cervical cancer

Abstract Progranulin (PGRN), an autocrine growth factor with tumorigenic roles in a variety of tumors, is a putative survival factor for normal and cancer cells in vitro. However, the fundamental mechanism of PGRN-mediated survival of cancer cells suffering from various types of microenvironmental stresses, such as serum deprivation, remains unknown. We show here that serum deprivation decreases intracellular PGRN protein levels in cervical cancer cells. PGRN protects cervical cancer cells against serum deprivation-induced apoptosis, limits reactive oxygen species (ROS) levels, maintains mitochondria integrity, and reduces oxidative damage of protein, lipid and DNA. PGRN enhances the ROS scavenger system, as evidenced by increased superoxide dismutase (SOD), catalase protein expression and activity, elevated GSH and NADPH levels and increased phase II detoxification enzyme expression in cervical cancer cells after serum withdrawal. The role of PGRN in ROS clearance is mediated by the PGRN-stimulated nuclear factor erythroid-derived 2-like 2 (NFE2L2)-antioxidant response element (ARE) pathway. Our study reveals an antioxidant role of PGRN in supporting the survival of cervical cancer cells under oxidative stress. This insight provides a new perspective on the how cervical cancer cells adapt to microenvironmental stress, contributing to cell viability and other malignant characteristics.

CSTF3 contributes to platinum resistance in ovarian cancer through alternative polyadenylation of lncRNA NEAT1 and generating the short isoform NEAT1_1

AbstractPlatinum-based chemotherapy is the standard postoperative adjuvant treatment for ovarian cancer (OC). Despite the initial response to chemotherapy, 85% of advanced OC patients will have recurrent disease. Relapsed disease and platinum resistance are the major causes of death in OC patients. In this study, we compared the global regulation of alternative polyadenylation (APA) in platinum-resistant and platinum-sensitive tissues of OC patients by analyzing a set of single-cell RNA sequencing (scRNA-seq) data from public databases and found that platinum-resistant patients exhibited global 3’ untranslated region (UTR) shortening due to the different usage of polyadenylation sites (PASs). The APA regulator CSTF3 was the most significantly upregulated gene in epithelial cells of platinum-resistant OC. CSTF3 knockdown increased the sensitivity of OC cells to platinum. The lncRNA NEAT1 has two isoforms, short (NEAT1_1) and long (NEAT1_2) transcript, because of the APA processing in 3’UTR. We found that CSTF3 knockdown reduced the usage of NEAT1 proximal PAS to lengthen the transcript and facilitate the expression of NEAT1_2. Downregulation of the expression of NEAT1 (NEAT1_1/_2), but not only NEAT1_2, also increased the sensitivity of OC cells to platinum. Overexpressed NEAT1_1 reversed the platinum resistance of OC cells after knocking down CSTF3 expression. Furthermore, downregulated expression of CSTF3 and NEAT1_1, rather than NEAT1_2, was positively correlated with inactivation of the PI3K/AKT/mTOR pathway in OC cells. Together, our findings revealed a novel mechanism of APA regulation in platinum-resistant OC. CSTF3 directly bound downstream of the NEAT1 proximal PAS to generate the short isoform NEAT1_1 and was conducive to platinum resistance, which provides a potential biomarker and therapeutic strategy for platinum-resistant OC patients.

Eliminating VEGFA+ tumor-associated neutrophils by antibody-drug conjugates boosts antitumor immunity and potentiates PD-1 immunotherapy in preclinical models of cervical cancer

Abstract Tumor-associated neutrophils (TANs) actively interact with antibody-drug conjugates (ADCs) within the tumor microenvironment (TME), though the detailed mechanisms governing their response to ADC treatment remain to be fully elucidated. Herein, we explored how ICAM1-targeted ADCs affect TAN dynamics in preclinical models of cervical cancer. We discovered that I-DXd, our in-house ADC targeting cervical cancer, effectively eliminates tumor cells through specific antigen recognition while concurrently depleting pro-tumor VEGFA + TANs via Fcγ receptor-mediated phagocytosis. This dual action promotes an immunologically favorable TME. Through comprehensive preclinical studies, we established a foundational understanding of the synergistic benefits of combining I-DXd treatment with PD-1 immune checkpoint inhibition, thereby opening new avenues for therapeutic intervention in advanced cervical cancer.

DDR1 promotes metastasis of cervical cancer and downstream phosphorylation signal via binding GRB2

AbstractCervical cancer is a leading cause of cancer-related death among women and its recurrence and metastasis poses challenges to treatment. Discoidin domain receptor 1 (DDR1) was associated with cellular migration and invasion in several types of cancers. However, its function in cervical cancer is still unclear. In this study, we found that DDR1 was significantly more expressed in cervical cancer samples than in normal tissues. SRY-Box transcription factor 2 (SOX2), a known oncogene in cervical cancer, showed a positive correlation with DDR1 and regulated DDR1 transcription, contributing to the elevated expression of DDR1 in cervical cancer. Regarding the function of DDR1 in cervical cancer, the overexpression of DDR1 caused an increase in the migration, invasion, and epithelial-mesenchymal transition (EMT) of cervical cancer cells. In contrast, cervical cancer cells with reduced DDR1 expression exhibited a lower migration rate, fewer invasive cells, and decreased levels of EMT markers. In vivo, mice injected with cervical cancer cells with overexpressed DDR1 showed more pulmonary metastasis and nodule number. Opposite results were found in mice injected with DDR1 silenced cervical cancer cells. Since DDR1 can cause phosphorylation of downstream targets, a phosphorylation omics was employed to reveal the downstream targets of DDR1, including eukaryotic translation initiation factor 4E binding protein 1 and EPH receptor A2. Furthermore, DDR1 bound directly with Src homology 2 domain of growth factor receptor bound protein 2 (GRB2) which mediated the function of DDR1 in the malignant behaviors of cervical cancer and the phosphorylation of downstream targets. In conclusion, DDR1 binds directly to GRB2 and then affects downstream phosphorylation signals, ultimately exacerbating the metastasis of cervical cancer cells. This work sheds light on the mechanism by which DDR1 functions in cervical cancer cells, providing therapeutic strategy for the treatment of cervical cancer.

YTHDF1 boosts the lactate accumulation to potentiate cervical cancer cells immune escape

AbstractLactate is a major metabolic product of tumor cells in microenvironment. Increasing evidence has indicated that lactate accumulation could alter the immune response in human cancers, including cervical cancer. However, the function and significance of N6-methyladenosine (m6A) reader YTHDF1 in cervical cancer cells’ lactate metabolism and immunotherapy remain obscure. Results illustrated that YTHDF1 predicted unfavorable clinical outcomes of cervical cancer, which was negatively correlated with CD8+ T cell infiltration. In the co-culture of tumor cells with CD8+ T cells, YTHDF1 overexpression promoted the lactate accumulation and attenuated the cytotoxic CD8+ T cell’s killing effect. Correspondingly, YTHDF1 knockdown exerted the opposite effects. Mechanistically, YTHDF1 targeted the m6A site on SLC16A1 gene (MCT1) to determine its fate. YTHDF1 upregulated MCT1 expression by enhancing MCT1 stability mediated by m6A-modified manner. Collectively, our results revealed an oncogenic role played by YTHDF1 in cervical cancer through m6A/MCT1-dependent manner. In conclusion, these findings unveil the immune escape-promoting effect of YTHDF1 in cervical cancer by boosting the lactate accumulation, which might illuminate a novel target for more precise immunotherapy.

HNRNPC mediates lymphatic metastasis of cervical cancer through m6A-dependent alternative splicing of FOXM1

AbstractCervical cancer (CCa) patients with lymph node (LN) metastasis face poor prognoses and have limited treatment options. Aberrant N6-methyladenosine (m6A) modification of RNAs are known to promote tumor metastasis, but their role in CCa remains unclear. Our study reveals that HNRNPC, an alternative splicing (AS) factor and m6A reader, increases tumor-related variants through m6A-dependent manner, thereby promoting lymphatic metastasis in CCa. We found that HNRNPC overexpression correlates with lymphatic metastasis and poorer prognoses in CCa patients. Functionally, knocking down HNRNPC markedly inhibited the migration and invasion of several CCa cell lines, while supplementing HNRNPC restored the malignant phenotypes of these cells. Mechanistically, HNRNPC regulates exon skipping of FOXM1 by binding to its m6A-modified motif. Mutating the m6A site on FOXM1 weakened the interaction between HNRNPC and FOXM1 pre-RNA, leading to a reduction in the metastasis-related FOXM1-S variant. In conclusion, our findings demonstrate that m6A-dependent alternative splicing mediated by HNRNPC is essential for lymphatic metastasis in CCa, potentially providing novel clinical markers and therapeutic strategies for patients with advanced CCa.

Inhibition of SF3B1 improves the immune microenvironment through pyroptosis and synergizes with αPDL1 in ovarian cancer

AbstractOvarian cancer is resistant to immune checkpoint blockade (ICB) treatment. Combination of targeted therapy and immunotherapy is a promising strategy for ovarian cancer treatment benefit from an improved immune microenvironment. In this study, Clinical Proteomic Tumor Analysis Consortium (CPTAC) and The Cancer Genome Atlas (TCGA) cohorts were used to screen prognosis and cytotoxic lymphocyte infiltration-associated genes in upregulated genes of ovarian cancer, tissue microarrays were built for further verification. In vitro experiments and mouse (C57/BL6) ovarian tumor (ID8) models were built to evaluate the synergistic effect of the combination of SF3B1 inhibitor and PD-L1 antibody in the treatment of ovarian cancer. The results show that SF3B1 is shown to be overexpressed and related to low cytotoxic immune cell infiltration in ovarian cancer. Inhibition of SF3B1 induces pyroptosis in ovarian cancer cells and releases mitochondrial DNA (mtDNA), which is englobed by macrophages and subsequently activates them (polarization to M1). Moreover, pladienolide B increases cytotoxic immune cell infiltration in the ID8 mouse model as a SF3B1 inhibitor and increases the expression of PD-L1 which can enhance the antitumor effect of αPDL1 in ovarian cancer. The data suggests that inhibition of SF3B1 improves the immune microenvironment of ovarian cancer and synergizes ICB immunotherapy, which provides preclinical evidence for the combination of SF3B1 inhibitor and ICB to ovarian cancer treatment.

The DDUP protein encoded by the DNA damage-induced CTBP1-DT lncRNA confers cisplatin resistance in ovarian cancer

Abstract Sustained activation of DNA damage response (DDR) signaling has been demonstrated to play vital role in chemotherapy failure in cancer. However, the mechanism underlying DDR sustaining in cancer cells remains unclear. In the current study, we found that the expression of the DDUP microprotein, encoded by the CTBP1-DT lncRNA, drastically increased in cisplatin-resistant ovarian cancer cells and was inversely correlated to cisplatin-based therapy response. Using a patient-derived human cancer cell model, we observed that DNA damage-induced DDUP foci sustained the RAD18/RAD51C and RAD18/PCNA complexes at the sites of DNA damage, consequently resulting in cisplatin resistance through dual RAD51C-mediated homologous recombination (HR) and proliferating cell nuclear antigen (PCNA)-mediated post-replication repair (PRR) mechanisms. Notably, treatment with an ATR inhibitor disrupted the DDUP/RAD18 interaction and abolished the effect of DDUP on prolonged DNA damage signaling, which resulted in the hypersensitivity of ovarian cancer cells to cisplatin-based therapy in vivo. Altogether, our study provides insights into DDUP-mediated aberrant DDR signaling in cisplatin resistance and describes a potential novel therapeutic approach for the management of platinum-resistant ovarian cancer.

NCAPH, ubiquitinated by TRIM21, promotes cell proliferation by inhibiting autophagy of cervical cancer through AKT/mTOR dependent signaling

AbstractAutophagy is closely related to the occurrence and development of human malignancies; however, the detailed mechanisms underlying autophagy in cervical cancer require further investigation. Previously, we found that the ectopic expression of NCAPH, a regulatory subunit of condensed protein complexes, significantly enhanced the proliferation of tumor cells; however, the underlying mechanisms were unclear. Here, we revealed that NCAPH is a novel autophagy-associated protein in cervical cancer that promotes cell proliferation by inhibiting autophagosome formation and reducing autophagy, with no effect on the cell cycle, apoptosis, or aging. Tripartite motif-containing protein 21 (TRIM21) is well known to be involved in inflammation, autoimmunity and cancer, mainly via its E3 ubiquitin ligase activity. Mass spectrometry and immunoprecipitation assays showed that TRIM21 interacted with NCAPH and decreased the protein stability of NCAPH via ubiquitination at the K11 lysine residue. Structural domain mutation analysis revealed that TRIM21 combined with NCAPH through its PRY/SPRY and CC domains and accelerated the degradation of NCAPH through the RING domain. Furthermore, TRIM21 promoted autophagosome formation and reduced cell proliferation by inhibiting NCAPH expression and the downstream AKT/mTOR pathway in cervical cancer cells. Immunohistochemical staining revealed that the protein expression of TRIM21 was negatively correlated with that of NCAPH and positively correlated with that of beclin-1 in cervical cancer tissues. Therefore, we provide evidence for the role of the TRIM21-NCAPH axis in cervical cancer autophagy and proliferation and the involvement of the AKT/mTOR signaling pathway in this process. These results deepen our understanding of the carcinogenesis of cervical cancer, broaden the understanding of the molecular mechanisms of TRIM21 and NCAPH, and provide guidance for individualized treatment of cervical cancer in the future.

ATAD2 is a driver and a therapeutic target in ovarian cancer that functions by upregulating CENPE

AbstractOvarian cancer is a complex disease associated with multiple genetic and epigenetic alterations. The emergence of treatment resistance in most patients causes ovarian cancer to become incurable, and novel therapies remain necessary. We identified epigenetic regulator ATPase family AAA domain-containing 2 (ATAD2) is overexpressed in ovarian cancer and is associated with increased incidences of metastasis and recurrence. Genetic knockdown of ATAD2 or its pharmacological inhibition via ATAD2 inhibitor BAY-850 suppressed ovarian cancer growth and metastasis in both in vitro and in vivo models. Transcriptome-wide mRNA expression profiling of ovarian cancer cells treated with BAY-850 revealed that ATAD2 inhibition predominantly alters the expression of centromere regulatory genes, particularly centromere protein E (CENPE). In ovarian cancer cells, changes in CENPE expression following ATAD2 inhibition resulted in cell-cycle arrest and apoptosis induction, which led to the suppression of ovarian cancer growth. Pharmacological CENPE inhibition phenotypically recapitulated the cellular changes induced by ATAD2 inhibition, and combined pharmacological inhibition of both ATAD2 and CENPE inhibited ovarian cancer cell growth more potently than inhibition of either alone. Thus, our study identified ATAD2 as regulators of ovarian cancer growth and metastasis that can be targeted either alone or in combination with CENPE inhibitors for effective ovarian cancer therapy.

Cervical cancer-produced neuromedin-B reprograms Schwann cells to initiate perineural invasion

AbstractPerineural invasion (PNI) is a new approach of cervical cancer invasion and metastasis, involving the cross-talk between tumor and nerve. However, the initiating signals and cellular interaction mechanisms of PNI remain largely elusive. The nerve-sparing radical hysterectomy (NSRH) proposed to improve postoperative quality of life is only applicable to cervical cancer patients without PNI. Therefore, it is important to elucidate the underlying mechanisms initiating PNI, and suggest the effective biomarkers to predict PNI before NSRH surgery. Here, we found that PNI is the characteristic of advanced cervical cancer, and Schwann cells were the antecedent cells that initiating PNI. Further, neuropeptide neuromedin B (NMB) produced by cervical cancer cells was determined to induce PNI by reprogramming Schwann cells, including driving their morphological and transcriptional changes, promoting their proliferation and migration, and initiating PNI by secreting CCL2 and directing axon regeneration. Mechanistically, cervical cancer cells-produced NMB activated its receptor NMBR in Schwann cells, and opened the T-type calcium channels to stimulate Ca2+ influx through PKA signaling, which could be blocked by the inhibitor. Clinically, combined examination of serum NMB and CCL2 levels was suggested to effectively predict PNI in cervical cancer patients. Our data demonstrate that cervical cancer-produced NMB initiates the reprograming of Schwann cells, which then direct axon regeneration, thus causing PNI onset. The elevated serum NMB and CCL2 levels may be useful for the decision-making to nerve sparing during hysterectomy surgery of cervical cancer patients.

Single-cell RNA-seq highlights a specific carcinoembryonic cluster in ovarian cancer

AbstractExpounding the heterogeneity for ovarian cancer (OC) with the cognition in developmental biology might be helpful to search for robust prognostic markers and effective treatments. In the present study, we employed single-cell RNA-seq with ovarian cancers, normal ovary, and embryo tissue to explore their heterogeneity. Then the differentiation process of clusters was explored; the pivotal cluster and markers were identified. Furthermore, the consensus clustering algorithm was used to explore the different clinical phenotypes in OC. At last, a prognostic model was construct and used to assess the prognosis for OCs. As a result, eight diverse clusters were identified, and the similarity existed in some clusters between embryo and tumours based on their gene expression. Meaningfully, a subtype of malignant epithelial cluster, PEG10+ EME, was associated with poor survival and was an intermediate stage of embryo to tumour. PEG10 was a CSC marker and might influence CSC self-renewal and promote cisplatin resistance via NOTCH pathway. Utilising specific gene profiles of PEG10+ EME based on public data sets, four phenotypes with different survival and clinical response to anti-PD-1/PD-L1 immunotherapy were identified. These insights allowed for the investigation of single-cell transcriptome of OCs and embryo, which advanced our current understanding of OC pathogenesis and resulted in promising therapeutic strategies.

FBXO2 targets glycosylated SUN2 for ubiquitination and degradation to promote ovarian cancer development

AbstractSAD1/UNC84 domain protein-2 (SUN2) plays a tumor suppressor role in various types of cancer by inhibiting cancer cell proliferation, migration and promoting apoptosis. However, the post-translational regulation of SUN2 and the cellular mechanism responsible for its proteasomal degradation remains largely unknown. Here, we show that FBXO2, an E3 ubiquitin ligase of the F-box proteins (FBPs) family targets glycosylated SUN2 for ubiquitination and degradation via the ubiquitin-proteasome system (UPS). By integrating the Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO), and the Encyclopedia of Cancer Cell Lines (CCLE) databases, we revealed that FBXO2 was selectively highly expressed in ovarian cancer (OV) tissues and cells. Patients with relatively high FBXO2 expression levels were associated with worse prognosis. Manipulation of the expression of FBXO2 affecting ovarian cancer cell proliferation, migration/invasion in vitro, and tumor growth in mice in vivo. The transcription factor SOX6 promoted FBXO2 expression by recognizing a putative response element localized on the promoter region of FBXO2. Abnormally highly expressed FBXO2 recognized and targeted glycosylated SUN2 protein for ubiquitination-depended degradation to prevent cell apoptosis, promote cell proliferation, and ultimately promote the progression of OV. Thus, we revealed a new SOX6-FBXO2-SUN2 axis that contributed to the development of OV, and targeting this axis may represent an effective OV treatment strategy.

ARL6IP5 reduces cisplatin-resistance by suppressing DNA repair and promoting apoptosis pathways in ovarian carcinoma

AbstractOvarian carcinoma (OC) is the most lethal gynecological malignancy due to frequent recurrence resulting from cisplatin-resistance. ARL6IP5 is a novel gene implicated to suppress cisplatin-resistance by activating apoptosis and inhibiting DNA repair through XRCC1 and PARP1. We investigated the clinicopathological and prognostic significance of the immunohistochemical ARL6IP5 expression on 79 post-chemotherapy OC patient tissue samples; in vitro, the effect of ARL6IP5 overexpression (OE) and knockdown (KD) on cancer hallmark functions and the effect of ARL6IP5 on the expression of DNA repair and apoptosis-related proteins were observed in OC cells and their cisplatin-resistant (CisR) counterparts. ARL6IP5 expression was significantly associated with chemotherapeutic response and was an independent prognosticator of progression-free and overall survival of high-grade serous OC patients. ARL6IP5-OE decreased cellular proliferation, invasion, migration, adhesion, and increased apoptosis (p < 0.05); the opposite was observed for ARL6IP5-KD. Notably, ARL6IP5-OE reduced cisplatin-resistance of both OC and CisR OC cells, while ARL6IP5-KD increased cisplatin-resistance (p < 0.05). ARL6IP5-OE suppressed the expressions of DNA repair proteins and increased those of pro-apoptotic proteins; the opposite was observed for ARL6IP5-KD. The recombinant ARL6IP5 protein (rARL6IP5) had the greatest apoptotic effect among cisplatin and olaparib, in both OC and CisR OC cells; moreover, rARL6IP5 was the only single agent in CisR OC cells to retain higher apoptotic efficacy compared with control (p < 0.05), indicating that the apoptotic pathway influenced by rARL6IP5 remained effective in CisR OC cells compared to cisplatin and olaparib. In conclusion, we demonstrated that ARL6IP5 is an independent prognosticator of OC patients with cellular functions of a tumor-suppressor, possibly influencing the development of cisplatin-resistance and progression of OC cells through regulation of DNA repair and apoptosis. rARL6IP5 had significantly greater apoptotic efficacy compared to conventional chemotherapeutic agents in both OC and CisR OC cells, suggesting that ARL6IP5 may be a valuable novel chemotherapeutic against CisR OC.

Targeting metabolic vulnerability by combining NAMPT inhibitors and disulfiram for treatment of recurrent ovarian cancer

Abstract Ovarian cancer (OV) has the highest mortality rate among gynecological cancers. As OV progresses, tumor cells spread outside the ovaries to the peritoneal and abdominal cavities, forming cell clusters that float in the ascitic fluid caused by peritonitis carcinomatosa, leading to further dissemination and metastasis. These cell clusters are enriched with cancer stem cells (CSCs) which are responsible for treatment resistance, recurrence, and metastasis. Therefore, targeting CSCs is a potentially effective approach for treating OV. However, understanding how CSCs acquire treatment resistance and identifying targets against CSCs remains challenging. In this study, we demonstrate that 3D-spheroids of OV cell lines exhibit higher stemness than conventional adherent cells. Metabolomics profiling studies have revealed that 3D-spheroids maintain a high-energy state through increased glucose utilization in the citric acid cycle (TCA), efficient nucleotide phosphorylation, and elevated phosphocreatine as an energy buffer. We also found that nicotinamide phosphoribosyltransferase (NAMPT), the rate-limiting enzyme for NAD + production, is highly expressed in OV. Furthermore, the approach based on NAMPT dependence rather than histology found NAMPT to be a potential therapeutic target against CSCs, while also serving as a prognostic indicator in OV. Moreover, we identified a previously unrecognized anti-tumor mechanism whereby disulfiram, an aldehyde dehydrogenase (ALDH) inhibitor, synergistically inhibited mitochondrial function when combined with NAMPT inhibitors - leading to cell cycle arrest in G2/M. Finally, the combination of a NAMPT inhibitor and disulfiram showed significant anti-tumor effects and extended survival in an animal model. Our findings demonstrate the potential of spheroids as a preclinical model for targeting OV CSCs and also indicate that the combination of NAMPT inhibitors and disulfiram is a promising therapeutic strategy to overcome recurrent OV.

IGF2BP3/ESM1/KLF10/BECN1 positive feedback loop: a novel therapeutic target in ovarian cancer via lipid metabolism reprogramming

Abstract Ovarian cancer (OC) is often detected at an advanced stage and has a high recurrence rate after surgery or chemotherapy. Thus, it is essential to develop new strategies for OC treatment. This study tended to investigate the effects of endothelial cell-specific molecule 1 (ESM1) in OC. The impact of ESM1 on lipid metabolism was investigated through the regulation of ESM1 expression. Differential genes regulated by ESM1 were screened by mRNA sequencing. The role of autophagy in ESM1 regulation on lipid metabolism was explored using autophagy inhibitor chloroquine (CQ). Co-IP, dual-luciferase reporter assay, actinomycin D treatment assay, and others were used to analyze the mechanism of ESM1 regulation on lipid metabolism. The xenograft mouse model was constructed to explore the impact of ESM1 regulation on OC development. The regulatory mechanism of ESM1 in OC patient samples was verified by using microarray analysis and the Log-rank (Mantel-Cox) test. After ESM1 silencing, cholesterol synthesis decreased and lipolysis increased. mRNA sequencing revealed that ESM1 regulation on lipid metabolism was related to Beclin 1 (BECN1). In vitro experiments, ESM1 inhibited lipolysis by suppressing BECN1-mediated autophagy. BECN1 expression was regulated by the transcription factor Kruppel-like factor 10 (KLF10). The competitive binding between BECN1 and HSPA5 promoted the ubiquitination degradation of HMGCR, thereby inhibiting cholesterol production. The intervention experiment with exogenous cholesterol showed a positive correlation between m6A reader IGF2BP3 expression and cholesterol content. Mechanistically, IGF2BP3 regulated the stability of ESM1 mRNA. In vivo experiments, ESM1 modified by m6A methylation promoted cholesterol synthesis and inhibited lipolysis. High expression of ESM1 predicted poor prognosis in OC patients. ESM1 regulated lipid metabolism through IGF2BP3/ESM1/KLF10/BECN1 positive feedback, which was a promising target for OC treatment.

CBX2 phase-separation contributes to homologous recombination repair and drug resistance in ovarian cancer

Abstract Drug resistance jeopardizes the prognosis of high-grade serous ovarian carcinoma (HGSOC) patients via DNA damage repair-coupled mechanism. The role of biomolecular phase separation in DNA damage repair has loomed. Here we find that CBX2 condensates are associated with drug resistance and contribute to DNA double-strand break (DSB) repair in HGSOC. Specifically, CBX2 condensates facilitate the recruitment of key DSB repair factors PARP1, 53BP1, and BRCA1 to chromatin. Patients with a CBX2-negative pattern exhibit the best prognosis, followed by those with non-condensate CBX2, while the worst outcomes are observed in patients with condensate CBX2. By drug screening, Ibrutinib is identified as an effective inhibitor of HGSOC cells and patient-derived organoids with CBX2 condensates. Overall, CBX2 phase separation enhances DSB repair-mediated drug resistance in HGSOC cells, and Ibrutinib may offer a viable therapeutic option for CBX2-positive HGSOC patients.

Repression of EGFR by new biguanide 4C potentiated ovarian cancer to PARP inhibitors through down-regulation of BRCA2 and Rad51

Abstract EGFR, one of the most successful therapeutic targets, has recently been found to exert a novel function for regulating homologous recombination (HR). Activation of HR is the critical event of treatment failure of PARPi in BRCA1/2 wild-type ovarian cancer (OC). Besides, the antitumor effects of biguanides have also been a focus of attention. Here, we discovered that the new biguanide 4C inhibited HR and sensitized BRCA1/2 wild-type OC cells to PARPi by targeting EGFR. Mechanistically, EGFR promoted nuclear accumulation of both BRCA2 and Rad51, and HR activation by competitively inhibiting the binding of BRCA2 and Rad51 to E3 ubiquitin ligase c-Cbl, thereby reducing cancer cell sensitivity to PARPi following ATM-mediated DNA damage signal transmission from the nucleus to the cytoplasm. Interestingly, EGFR was downregulated by 4C , which in turn enhanced the interaction of BRCA2 and Rad51 with c-Cbl. Consequently, BRCA2 and Rad51 were then ubiquitinated and degraded to inhibit HR and increase the sensitivity of OC to PARPi. Thus, these findings reveal that the combination of 4C with PARPi leading to “synthetic lethality” is an effective strategy for treating BRCA1/2 wild-type OC.

Arginine dependency in omental metastasis of epithelial ovarian cancer reveals a therapeutic vulnerability

Abstract Epithelial ovarian cancer (EOC) is the leading cause of death among gynecological malignancies, and the tumors with advanced-stage are frequently characterized by extensive metastasis. Although metabolic reprogramming of amino acids represents a hallmark of cancer, its specific role in the metastatic progression of EOC remains poorly understood. Here, we identified a critical metabolic vulnerability in omental metastasis of EOC. Despite defective endogenous synthesis, arginine accumulation depends on exogenous uptake. In vivo experiments demonstrated that dietary arginine deprivation suppressed tumor growth and metastasis, whereas supplementation or enhanced uptake of arginine promoted tumor cell proliferation, invasion, and migration in vitro. Mechanistically, increased arginine binds to the RNA helicase DDX3X, inducing nuclear retention of DDX3X and further promoting the transcription of DNA damage response (DDR)-related genes, thereby facilitating DDR through activating the ATM/CHK2/P53 axis to enable cancer cells to survive under metastatic stress. Notably, arginine restriction or pharmacological inhibition of DDX3X did effectively suppress both primary tumor growth and omental metastasis in mouse models. Collectively, our findings reveal that arginine is a metabolic vulnerability in omental metastasis of EOC, indicating that arginine restriction and DDX3X inhibition represent promising therapeutic strategies.

Splice-switching of the oncogenic BCS1L isoform suppresses ovarian cancer progression by disrupting mitochondrial function

Abstract Increasing evidences demonstrate that mitochondrial function is essential for cancer cell survival and metastasis. However, the role of mitochondrial metabolic reprogramming in ovarian cancer progression remains largely unknown. Here, we report that mitochondrial chaperone BCS1L generates two major alternative-spliced isoforms, a full-length isoform ( BCS1L-L ) and a short isoform lacking exon 2 ( BCS1L-S ). Interestingly, BCS1L-L is elevated in several human cancers, and it significantly increased oxidative phosphorylation and ATP production in the present work, which is required for the survival of cancer cells. In contrast, BCS1L-S was unable to localize to the mitochondria as BCS1L-L did, and this led to impaired metabolic function. Mechanistically, splicing factor USP39 promoted exon 2 inclusion, thus facilitating the generation of oncogenic BCS1L-L and, thereby, maintaining mitochondrial homeostasis and survival of ovarian cancer cells. Importantly, we developed splice-switch antisense oligonucleotides (ASOs) that successfully induced exon 2 skipping and decreased BCS1L-L abundance, resulting in impaired tumor growth. These findings suggest that targeting oncogenic BCS1L-L by ASOs is a novel approach for ovarian cancer treatment.

PDIA6, which is regulated by TRPM2-AS/miR-424-5p axis, promotes endometrial cancer progression via TGF-beta pathway

AbstractPDIA6 have been reported to be involved in a variety of cancers, however, the underlying role in endometrial cancer is still unclear. In this study, we aimed to study the function of PDIA6 in endometrial cancer. Firstly, we verified that PDIA6 was significantly upregulated in endometrial cancer, which was correlated with the progression of endometrial cancer patients. Furthermore, we identified PDIA6 significantly altered the ability of endometrial cancer cells to proliferate and metastasize. In addition, our result illustrated the oncogene effects of PDIA6 in promoting malignant biological behavior of endometrial cancer cells by regulating TGF-β pathway and being modulated by TRPM2-AS/miR-424-5p axis for the first time. Taken together, this study suggested that PDIA6 may be a new candidate target for endometrial cancer therapy.

Fatostatin reverses progesterone resistance by inhibiting the SREBP1-NF-κB pathway in endometrial carcinoma

AbstractProgesterone resistance can significantly restrict the efficacy of conservative treatment for patients with endometrial cancer who wish to preserve their fertility or those who suffer from advanced and recurrent cancer. SREBP1 is known to be involved in the occurrence and progression of endometrial cancer, although the precise mechanism involved remains unclear. In the present study, we carried out microarray analysis in progesterone-sensitive and progesterone-resistant cell lines and demonstrated that SREBP1 is related to progesterone resistance. Furthermore, we verified that SREBP1 is over-expressed in both drug-resistant tissues and cells. Functional studies further demonstrated that the inhibition of SREBP1 restored the sensitivity of endometrial cancer to progesterone both in vitro and in vivo, and that the over-expression of SREBP1 promoted resistance to progesterone. With regards to the mechanism involved, we found that SREBP1 promoted the proliferation of endometrial cancer cells and inhibited their apoptosis by activating the NF-κB pathway. To solve the problem of clinical application, we found that Fatostatin, an inhibitor of SREBP1, could increase the sensitivity of endometrial cancer to progesterone and reverse progesterone resistance by inhibiting SREBP1 both in vitro and in vivo. Our results highlight the important role of SREBP1 in progesterone resistance and suggest that the use of Fatostatin to target SREBP1 may represent a new method to solve progesterone resistance in patients with endometrial cancer.

Targeted demethylation of the EphA7 promoter inhibits tumorigenesis via the SP1/DNMT1 and PI3K/AKT axes and improves the response to multiple therapies in cervical cancer

Abstract Aberrant methylation of the EphA7 promoter has been observed in cervical cancer (CC); however, its precise function and role in CC remain largely unknown. In this study, we investigated the role and molecular mechanisms of EphA7 promoter methylation in cervical carcinogenesis. First, our results indicated that the reactivation of EphA7 expression via a CRISPR demethylation tool (dCas9-Tet1) had antitumor effects. It restrained tumor proliferation and invasion while promoting apoptosis via the PI3K/AKT signaling pathway in both CaSki and SiHa cells. The upstream interacting factors were subsequently captured by CRISPR-mediated pull-down in situ, and the result revealed that SP1 and MAZ interacted with the promoter of EphA7. However, the perturbation results revealed that EphA7 expression was associated with SP1/DNMT1 but not MAZ. Furthermore, 17-β-estradiol (E2) can upregulate EphA7 expression through demethylation via the SP1/DNMT1 axis. A rescue experiment revealed that interference with SP1 expression could restore the effect of E2 on increasing the expression of EphA7 by upregulating estrogen receptor expression. In addition, EphA7 demethylation reduced the half-maximal inhibitory concentration (IC50) of cisplatin and paclitaxel. Pooled analysis revealed that EphA7 promoter hypermethylation was positively correlated with tumor purity but negatively correlated with immune cell infiltration, cytotoxic T lymphocyte (CTL) and immune checkpoint (IC) activity, and the expression of EphA7 was significantly positively correlated with tumor mutational burden (TMB), microsatellite instability (MSI) and the presence of single nucleotide variant (SNV) neoantigens, suggesting a better prognosis for patients with EphA7 promoter hypomethylation and high expression. Collectively, these findings indicate that targeted demethylation of the EphA7 promoter and restoration of endogenous EphA7 expression by dCas9-Tet1 are promising therapeutic approaches and are favorable for the prognosis of CC patients.

Fallopian tube lesions as potential precursors of early ovarian cancer: a comprehensive proteomic analysis

Abstract Ovarian cancer is the leading cause of death from gynecologic cancer worldwide. High-grade serous carcinoma (HGSC) is the most common and deadliest subtype of ovarian cancer. While the origin of ovarian tumors is still debated, it has been suggested that HGSC originates from cells in the fallopian tube epithelium (FTE), specifically the epithelial cells in the region of the tubal-peritoneal junction. Three main lesions, p53 signatures, STILs, and STICs, have been defined based on the immunohistochemistry (IHC) pattern of p53 and Ki67 markers and the architectural alterations of the cells, using the Sectioning and Extensively Examining the Fimbriated End Protocol. In this study, we performed an in-depth proteomic analysis of these pre-neoplastic epithelial lesions guided by mass spectrometry imaging and IHC. We evaluated specific markers related to each preneoplastic lesion. The study identified specific lesion markers, such as CAVIN1, Emilin2, and FBLN5. We also used SpiderMass technology to perform a lipidomic analysis and identified the specific presence of specific lipids signature including dietary Fatty acids precursors in lesions. Our study provides new insights into the molecular mechanisms underlying the progression of ovarian cancer and confirms the fimbria origin of HGSC.

NORAD orchestrates endometrial cancer progression by sequestering FUBP1 nuclear localization to promote cell apoptosis

AbstractLong noncoding RNAs (lncRNAs) are emerging as critical regulators in tumor initiation and progression. However, the biological mechanisms and potential clinical application of lncRNA NORAD in endometrial cancer (EC) remain unknown. Herein, we identified NORAD underwent promoter hypermethylation-associated downregulation in EC. Epigenetic inactivation of NORAD was correlated with EC progression (FIGO stage) and poor outcome. Overexpression of NORAD significantly inhibited cell growth and promoted apoptosis in EC cells. Mechanistic studies revealed that multiple regions of NORAD served as a platform for binding with the central domain of anti-apoptotic factor FUBP1. Our findings further indicated that the NORAD/FUBP1 interaction attenuated FUBP1 nuclear localization and thus impaired the occupancies of FUBP1 on its target pro-apoptotic gene promoters, resulting in apoptosis induction in EC. Moreover, knockdown of NORAD promoted tumor growth in the xenograft mice model. While, introduction of NORAD-4 fragment, which bound with FUBP1, successfully reversed tumor growth and apoptosis inhibition mediated by NORAD knockdown in vivo. Our findings provide mechanistic insight into the critical roles of NORAD as a tumor suppressor in EC progression. NORAD could possibly serve as a novel prognostic biomarker and provide the rationale for EC therapy.

CSE reduces OTUD4 triggering lung epithelial cell apoptosis via PAI-1 degradation

AbstractOvarian tumor family deubiquitinase 4 (OTUD4), a member of the OTU deubiquitinating enzyme, is implicated to decrease in cancer to regulate cell apoptosis. However, the role of OTUD4 in cigarette smoke induced epithelial cell apoptosis and its mechanism have not been elucidated. In this study, we showed that OTUD4 protein reduced in CSE treated mice and airway epithelial cells. OTUD4 silence aggravated cell apoptosis and emphysematous change in the lung tissue of cigarette smoke extract (CSE) treated mice. Additionally, restoration of OTUD4 in the lung of mice alleviated CSE induced apoptosis and emphysematous morphology change. The effect of OTUD4 on cell apoptosis was also confirmed in vitro. Through protein profile screening, we identified that OTUD4 may interact with plasminogen activator inhibitor 1(PAI-1). We further confirmed that OTUD4 interacted with PAI-1 for de-ubiquitination and inhibiting CSE induced PAI-1 degradation. Furthermore, the protective role of OTUD4 in airway epithelial cells apoptosis was blocked by PAI-1 deactivation. Taken together, our data suggest that OTUD4 regulates cigarette smoke (CS)-triggered airway epithelial cell apoptosis via modulating PAI-1 degradation. Targeting OUTD4/PAI-1 signaling might potentially provide a therapeutic target against the lung cell apoptosis in cigarette smoke (CS)-induced emphysema.

Differential effects of the LncRNA RNF157-AS1 on epithelial ovarian cancer cells through suppression of DIRAS3- and ULK1-mediated autophagy

AbstractAnalyses of several databases showed that the lncRNA RNF157 Antisense RNA 1 (RNF157-AS1) is overexpressed in epithelial ovarian cancer (EOC) tissues. In our study, suppressing RNF157-AS1 strikingly reduced the proliferation, invasion, and migration of EOC cells compared with control cells, while overexpressing RNF157-AS1 greatly increased these effects. By RNA pulldown assays, RNA binding protein immunoprecipitation (RIP) assays, and mass spectrometry, RNF157-AS1 was further found to be able to bind to the HMGA1 and EZH2 proteins. Chromatin immunoprecipitation (ChIP) assays showed that RNF157-AS1 and HMGA1 bound to the ULK1 promoter and prevented the expression of ULK1. Additionally, RNF157-AS1 interacted with EZH2 to bind to the DIRAS3 promoter and diminish DIRAS3 expression. ULK1 and DIRAS3 were found to be essential for autophagy. Combination autophagy inhibitor and RNF157-AS1 overexpression or knockdown, a change in the LC3 II/I ratio was found using immunofluorescence (IF) staining and western blot (WB) analysis. The autophagy level also was confirmed by autophagy/cytotoxicity dual staining. However, the majority of advanced EOC patients require platinum-based chemotherapy, since autophagy is a cellular catabolic response to cell stress. As a result, RNF157-AS1 increased EOC cell sensitivity to chemotherapy and death under cis-platinum (DDP) treatment by suppressing autophagy, as confirmed by cell count Kit-8 (CCK8) assays, flow cytometry, and autophagy/cytotoxicity dual staining. Therefore, the OS and PPS times were longer in EOC patients with elevated RNF157-AS1 expression. RNF157-AS1-mediated autophagy has potential clinical significance in DDP chemotherapy for EOC patients.

Upregulation of FAM83F by c-Myc promotes cervical cancer growth and aerobic glycolysis via Wnt/β-catenin signaling activation

AbstractCervical cancer (CC) seriously affects women’s health. Therefore, elucidation of the exact mechanisms and identification of novel therapeutic targets are urgently needed. In this study, we identified FAM83F, which was highly expressed in CC cells and tissues, as a potential target. Our clinical data revealed that FAM83F protein expression was markedly elevated in CC tissues and was positively correlated with poor prognosis. Moreover, we observed that FAM83F knockdown significantly inhibited cell proliferation, induced apoptosis, and suppressed glycolysis in CC cells, while its overexpression displayed opposite effects. Mechanistically, FAM83F regulated CC cell growth and glycolysis by the modulation of Wnt/β-catenin pathway. The enhancing effects of FAM83F overexpression on CC cell proliferation and glycolysis could be impaired by the Wnt/β-catenin inhibitor XAV939. Moreover, we found that c-Myc bound to the FAM83F promoter and activated the transcription of FAM83F. Notably, knockdown of FAM83F impaired the enhancement of cell proliferation and glycolysis induced by ectopic c-Myc. Consistent with in vitro findings, results from a xenograft mouse model confirmed the promoting role of FAM83F. In summary, our study demonstrated that FAM83F promoted CC growth and glycolysis through regulating the Wnt/β-catenin pathway, suggesting that FAM83F may be a potential molecular target for CC treatment.

CRABP2 affects chemotherapy resistance of ovarian cancer by regulating the expression of HIF1α

AbstractOvarian cancer is the most lethal malignancy among gynecologic cancers, and primary and secondary chemotherapy resistance is one of the important reasons for poor prognosis of ovarian cancer patients. However, the specifics of resistance to chemotherapy in ovarian cancer remain unclear. Herein, we find that the expression level of cellular retinoic acid binding protein 2 (CRABP2) is up-regulated in drug-resistant ovarian cancer tissues and cell lines, and the expression levels of CRABP2 in epithelial ovarian cancer tissues are closely related to tumor clinical stage and patients’ prognosis, suggesting that CRABP2 plays an important role in the progression of ovarian cancer and the corresponding ability of tumor to chemotherapy. With the in-depth study, we demonstrates that CRABP2 is related to the high metabolic activity in drug-resistant cells, and all-trans retinoic acid exacerbates this activity. Further molecular mechanism exploration experiments show that CRABP2 not only up-regulates the expression level of HIF1α, but also increases the localization of HIF1α in the nucleus. In drug-resistant ovarian cancer cells, knocking down HIF1α can block the resistance of CRABP2 to chemotherapy drugs in ovarian cancer cells. Taken together, our findings suggest for the first time that CRABP2 affects chemotherapy resistance of ovarian cancer by regulating the expression of HIF1α. This study provides a possible molecular mechanism for drug resistance and a possible molecular target for clinical treatment of ovarian cancer.

FBXO7, a tumor suppressor in endometrial carcinoma, suppresses INF2-associated mitochondrial division

AbstractEndometrial carcinoma (ECa) is the most common malignant gynecological cancer, with an increased incidence and fatality rate worldwide, while the pathogenesis is still largely unknown. In this study, we confirmed that FBXO7, a gene coding FBXO7 E3 ubiquitin ligase, is significantly downregulated and mutated (5.87%; 31/528) in ECa specimens, and the abnormal low expression and mutations of FBXO7 are associated with the occurrence of ECa. We also identify the excessive expression of INF2 protein, a key factor that triggers mitochondrial division by recruiting the DRP1 protein, and the elevated INF2 protein is significantly negatively correlated with the low FBXO7 protein in ECa specimens. Mechanistically, FBXO7 restrains ECa through inhibiting INF2-associated mitochondrial division via FBXO7-mediated ubiquitination and degradation of INF2. Moreover, we found that ECa-associated FBXO7 mutants are defective in the ubiquitination and degradation of INF2, promoting ECa cells proliferation, migration and apoptosis inhibition via inducing mitochondrial hyper-division. In addition, we found that it could reverse FBXO7 deletion or ECa-associated FBXO7 mutants-induced proliferation, migration, apoptosis inhibition and mitochondrial hyper-division of ECa cells by INF2 or DNM1L knockdown, or DRP1 inhibitor Mdivi-1. In summary, our study shows that FBXO7 acts as a novel tumor suppressor in ECa by inhibiting INF2-DRP1 axis-associated mitochondrial division through the ubiquitination and degradation of INF2 while the effect is destroyed by ECa-associated FBXO7 and INF2 mutants, highlights the key role of FBXO7-INF2-DRP1 axis in ECa tumorigenesis and provides a new viewpoint to treat ECa patients with FBXO7 deletion or mutations by targeting INF2-DRP1 axis-associated mitochondrial division.

The roles of m6A methylation in cervical cancer: functions, molecular mechanisms, and clinical applications

AbstractCervical cancer (CC) is a gynecological neoplasm with the highest incidence rate, primarily attributed to the persistent infection of high-risk Human papillomavirus (HPV). Despite extensive research, the pathogenesis of CC remains unclear. N6-methyladenosine (m6A) methylation, the most prevalent form of epigenetic modification in RNA, is intricately linked to cell proliferation, metastasis, metabolism, and therapeutic resistance within the tumor microenvironment (TME) of CC. The involvement of the writer, reader, and eraser in m6A modification impacts the advancement of tumors through the regulation of RNA stability, nuclear export, translation efficiency, and RNA degradation. Here, we discuss the biogenesis of m6A, the atypical expressions of m6A regulators, the mechanisms of molecular interactions, and their functions in CC. Furthermore, we elucidate m6A modification of non-coding RNA. In the context of precision medicine, and with the advancements of genomics, proteomics, and high-throughput sequencing technologies, we summarize the application of m6A in the clinical diagnosis and treatment of CC. Additionally, new perspectives on detection methods, immune regulation, and nano-drug development are presented, which lay the foundation for further research of m6A and provide new ideas for the clinical treatment of CC.

UBE2E2 enhances Snail-mediated epithelial-mesenchymal transition and Nrf2-mediated antioxidant activity in ovarian cancer

Abstract Dissemination of ovarian cancer (OvCa) cells can lead to inoperable metastatic lesions in the bowel and omentum, which have a poor prognosis despite surgical and chemotherapeutical options. A better understanding of the mechanisms underlying metastasis is urgently needed. In this study, bioinformatics analyses revealed that UBE2E2, a less-studied ubiquitin (Ub)-conjugating enzyme (E2), was upregulated in OvCa and was associated with poor prognosis. Subsequently, we performed western blot analysis and IHC staining with 88 OvCa and 26 normal ovarian tissue samples, which further confirmed that UBE2E2 protein is highly expressed in OvCa tissue but weakly expressed in normal tissue. Furthermore, the silencing of UBE2E2 blocked OvCa cell migration, epithelial-mesenchymal transition (EMT) and metastasis in vitro, whereas UBE2E2 overexpression exerted the opposite effects. Mechanistically, UBE2E2 promoted p62 accumulation and increased the activity of the Nrf2-antioxidant response element (ARE) system, which ultimately activated the Snail signaling pathway by inhibiting the ubiquitin-mediated degradation of Snail. Additionally, co-IP and immunofluorescence demonstrated that a direct interaction exists between UBE2E2 and Nrf2, and the N-terminal of UBE2E2 (residues 1-52) is required and sufficient for its interaction with Nrf2 protein. Mutations in the active site cysteine (Cys139) impaired both the function and cellular distribution of UBE2E2. More importantly, the deletion of UBE2E2 reduced tumorigenicity and metastasis in xenograft OvCa mouse models. Taken together, our findings reveal the role of the UBE2E2-Nrf2-p62-Snail signaling axis in OvCa and thus provides novel therapeutic targets for the prevention of OvCa metastasis.

Mitochondrial carrier 1 (MTCH1) governs ferroptosis by triggering the FoxO1-GPX4 axis-mediated retrograde signaling in cervical cancer cells

AbstractCervical cancer is one of the leading causes of cancer death in women. Mitochondrial-mediated ferroptosis (MMF) is a recently discovered form of cancer cell death. However, the role and the underlying mechanism of MMF in cervical cancer remain elusive. Here, using an unbiased screening for mitochondrial transmembrane candidates, we identified mitochondrial carrier 1 (MTCH1) as a central mediator of MMF in cervical cancers. MTCH1-deficiency disrupted mitochondrial oxidative phosphorylation while elevated mitochondrial reactive oxygen species (ROS) by decreasing NAD+ levels. This mitochondrial autonomous event initiated a mitochondria-to-nucleus retrograde signaling involving reduced FoxO1 nuclear translocation and subsequently downregulation of the transcription and activity of a key anti-ferroptosis enzyme glutathione peroxidase 4 (GPX4), thereby elevating ROS and ultimately triggering ferroptosis. Strikingly, targeting MTCH1 in combination with Sorafenib effectively and synergistically inhibited the growth of cervical cancer in a nude mouse xenograft model by actively inducing ferroptosis. In conclusion, these findings enriched our understanding of the mechanisms of MMF in which MTCH1 governed ferroptosis though retrograde signaling to FoxO1-GPX4 axis, and provided a potential therapeutic target for treating cervical cancer.

The interaction of β-arrestin1 with talin1 driven by endothelin A receptor as a feature of α5β1 integrin activation in high-grade serous ovarian cancer

AbstractDissemination of high-grade serous ovarian cancer (HG-SOC) in the omentum and intercalation into a mesothelial cell (MC) monolayer depends on functional α5β1 integrin (Intα5β1) activity. Although the binding of Intα5β1 to fibronectin drives these processes, other molecular mechanisms linked to integrin inside-out signaling might support metastatic dissemination. Here, we report a novel interactive signaling that contributes to Intα5β1 activation and accelerates tumor cells toward invasive disease, involving the protein β-arrestin1 (β-arr1) and the activation of the endothelin A receptor (ETAR) by endothelin-1 (ET-1). As demonstrated in primary HG-SOC cells and SOC cell lines, ET-1 increased Intβ1 and downstream FAK/paxillin activation. Mechanistically, β-arr1 directly interacts with talin1 and Intβ1, promoting talin1 phosphorylation and its recruitment to Intβ1, thus fueling integrin inside-out activation. In 3D spheroids and organotypic models mimicking the omentum, ETAR/β-arr1-driven Intα5β1 signaling promotes the survival of cell clusters, with mesothelium-intercalation capacity and invasive behavior. The treatment with the antagonist of ETAR, Ambrisentan (AMB), and of Intα5β1, ATN161, inhibits ET-1-driven Intα5β1 activity in vitro, and tumor cell adhesion and spreading to intraperitoneal organs and Intβ1 activity in vivo. As a prognostic factor, high EDNRA/ITGB1 expression correlates with poor HG-SOC clinical outcomes. These findings highlight a new role of ETAR/β-arr1 operating an inside-out integrin activation to modulate the metastatic process and suggest that in the new integrin-targeting programs might be considered that ETAR/β-arr1 regulates Intα5β1 functional pathway.

Increased endogenous PKG I activity attenuates EGF-induced proliferation and migration of epithelial ovarian cancer via the MAPK/ERK pathway

AbstractThe type I cGMP-dependent protein kinase (PKG I) is recognized as a tumor suppressor, but its role in EGFR regulated epithelial ovarian cancer (EOC) progression remains unclear. We evaluated the in vivo and in vitro effects of activated PKG I in EGF-induced EOC cell proliferation, migration, and invasion. The expressions of EGFR and PKG I were elevated, but the activated PKG I was decreased in EOC tissues of patients and cells lines. The addition of 8-Br-cGMP, a specific PKG I activator, attenuated the EGF-induced EOC cell proliferation, migration, and invasion in vitro. Similarly, activated PKG I also attenuated EOC progression in vivo using an EOC xenograft nude mouse model. The activated PKG I interacted with EGFR, causing increased threonine (693) phosphorylation and decreased tyrosine (1068) phosphorylation of EGFR, which resulted in disrupted EGFR-SOS1-Grb2 combination. Subsequently, the cytoplasmic phosphorylation of downstream proteins (c-Raf, MEK1/2, and ERK1/2) were declined, impeding the phosphorylated ERK1/2’s nucleus translocation, and this reduction of phosphorylated tyrosine (1068) EGFR and ERK1/2 were also abolished by Rp-8-Br-cGMPS. Our results suggest that the activation of PKG I attenuates EGF-induced EOC progression, and the 8-Br-cGMP-PKG I-EGFR/MEK/ERK axis might be a potential target for EOC therapy.

Glucocorticoids induce differentiation and chemoresistance in ovarian cancer by promoting ROR1-mediated stemness

AbstractGlucocorticoids are routinely used in the clinic as anti-inflammatory and immunosuppressive agents as well as adjuvants during cancer treatment to mitigate the undesirable side effects of chemotherapy. However, recent studies have indicated that glucocorticoids may negatively impact the efficacy of chemotherapy by promoting tumor cell survival, heterogeneity, and metastasis. Here, we show that dexamethasone induces upregulation of ROR1 expression in ovarian cancer (OC), including platinum-resistant OC. Increased ROR1 expression resulted in elevated RhoA, YAP/TAZ, and BMI-1 levels in a panel of OC cell lines as well as primary ovarian cancer patient-derived cells, underlining the translational relevance of our studies. Importantly, dexamethasone induced differentiation of OC patient-derived cells ex vivo according to their molecular subtype and the phenotypic expression of cell differentiation markers. High-throughput drug testing with 528 emerging and clinical oncology compounds of OC cell lines and patient-derived cells revealed that dexamethasone treatment increased the sensitivity to several AKT/PI3K targeted kinase inhibitors, while significantly decreasing the efficacy of chemotherapeutics such as taxanes, as well as anti-apoptotic compounds such as SMAC mimetics. On the other hand, targeting ROR1 expression increased the efficacy of taxane drugs and SMAC mimetics, suggesting new combinatorial targeted treatments for patients with OC.

Melatonin suppresses chronic restraint stress-mediated metastasis of epithelial ovarian cancer via NE/AKT/β-catenin/SLUG axis

AbstractChronic stress has been shown to facilitate progression of epithelial ovarian cancer (EOC), however, the neuro-endocranial mechanism participating in this process still remains unclear. Here, we reported that chronic restraint stress (CRS) promoted the abdominal implantation metastasis of EOC cells and the expression of epithelial–mesenchymal transition-related markers in tumor-bearing mouse model, including TWIST, SLUG, SNAIL, and β-catenin. We observed that β-catenin co-expressed with SLUG and norepinephrine (NE) in tumor tissues obtained from nude mice. Further ex vivo experiments revealed that NE promoted migration and invasion of ovarian cancer cells and SLUG expression through upregulating expression and improving transcriptional function of β-catenin in vitro. A human phosphor-kinase array suggested that NE activated various kinases in ovarian cancer cells, and we further confirmed that AKT inhibitor reduced NE-mediated pro-metastatic impacts and activation of the β-catenin/SLUG axis. Furthermore, the expression levels of NE and β-catenin were examined in ovarian tumor tissues by using tumor tissue arrays. Results showed that the expression levels of both NE and β-catenin were associated with poor clinical stage of serous EOC. Moreover, we found that melatonin (MLT) effectively reduced the abdominal tumor burden of ovarian cancer induced by CRS, which was partially related to the inhibition of the NE/AKT/β-catenin/SLUG axis. Collectively, these findings suggest a novel mechanism for CRS-mediated ovarian cancer metastasis and MLT has a potential therapeutic efficacy against ovarian cancer.

Tumor-associated macrophages promote ovarian cancer cell migration by secreting transforming growth factor beta induced (TGFBI) and tenascin C

AbstractA central and unique aspect of high-grade serous ovarian carcinoma (HGSC) is the extensive transcoelomic spreading of tumor cell via the peritoneal fluid or malignant ascites. We and others identified tumor-associated macrophages (TAM) in the ascites as promoters of metastasis-associated processes like extracellular matrix (ECM) remodeling, tumor cell migration, adhesion, and invasion. The precise mechanisms and mediators involved in these functions of TAM are, however, largely unknown. We observed that HGSC migration is promoted by soluble mediators from ascites-derived TAM, which can be emulated by conditioned medium from monocyte-derived macrophages (MDM) differentiated in ascites to TAM-like asc-MDM. A similar effect was observed with IL-10-induced alternatively activated m2c-MDM but not with LPS/IFNγ-induced inflammatory m1-MDM. These observations provided the basis for deconvolution of the complex TAM secretome by performing comparative secretome analysis of matched triplets of different MDM phenotypes with different pro-migratory properties (asc-MDM, m2c-MDM, m1-MDM). Mass spectrometric analysis identified an overlapping set of nine proteins secreted by both asc-MDM and m2c-MDM, but not by m1-MDM. Of these, three proteins, i.e., transforming growth factor beta-induced (TGFBI) protein, tenascin C (TNC), and fibronectin (FN1), have been associated with migration-related functions. Intriguingly, increased ascites concentrations of TGFBI, TNC, and fibronectin were associated with short progression-free survival. Furthermore, transcriptome and secretome analyses point to TAM as major producers of these proteins, further supporting an essential role for TAM in promoting HGSC progression. Consistent with this hypothesis, we were able to demonstrate that the migration-inducing potential of asc-MDM and m2c-MDM secretomes is inhibited, at least partially, by neutralizing antibodies against TGFBI and TNC or siRNA-mediated silencing of TGFBI expression. In conclusion, the present study provides the first experimental evidence that TAM-derived TGFBI and TNC in ascites promote HGSC progression.

MYC-regulated pseudogene HMGA1P6 promotes ovarian cancer malignancy via augmenting the oncogenic HMGA1/2

AbstractPseudogenes have long been considered as nonfunctional genomic sequences. Recent studies have shown that they can potentially regulate the expression of protein-coding genes and are dysregulated in diseases including cancer. However, the potential roles of pseudogenes in ovarian cancer have not been well studied. Here we characterized the pseudogene expression profile in HGSOC (high-grade serous ovarian carcinoma) by microarray. We identified 577 dysregulated pseudogenes and most of them were up-regulated (538 of 577). HMGA1P6 (High mobility group AT-hook 1 pseudogene 6) was one of the overexpressed pseudogenes and its expression was inversely correlated with patient survival. Mechanistically, HMGA1P6 promoted ovarian cancer cell malignancy by acting as a ceRNA (competitive endogenous RNA) that led to enhanced HMGA1 and HMGA2 expression. Importantly, HMGA1P6 was transcriptionally activated by oncogene MYC in ovarian cancer. Our findings reveal that MYC may contribute to oncogenesis through transcriptional regulation of pseudogene HMGA1P6 in ovarian cancer.

Laminins in tumor-derived exosomes upregulated by ETS1 reprogram omental macrophages to promote omental metastasis of ovarian cancer

AbstractTumor-derived exosomes participate in omental metastatic colonization of ovarian cancer by inducing an adaptive response in the tumor microenvironment. However, cell–cell communication via exosomes between primary tumor cells and the microenvironment of distant omentum and the mechanism of pre-metastatic niche formation are poorly understood. Here, we demonstrated that ETS1-overexpressing ovarian cancer cells secreted larger exosomes with higher laminin levels. In addition, ovarian cancer exosomes could be taken up by omental macrophages through integrin and laminin interaction. Compared with control exosomes, exosomes derived from ETS1-overexpressing ovarian cancer cells (LV-ETS1 Exos) stimulated the polarization of more macrophages toward the M2 phenotype (CD163 marker), as well as the production of more CXCL5 and CCL2 in macrophages, via integrin αvβ5/AKT/Sp1 signaling. In vivo experiments showed that LV-ETS1 Exos promoted omental metastasis of ovarian cancer by mediating the tumor-promoting effect of macrophages, which could be neutralized by integrin ανβ5 inhibitor cilengitide. These results indicated that ETS1 could drive ovarian cancer cells to release exosomes with higher laminin levels, thereby accelerating the exosome-mediated pro-metastatic effects of omental macrophages via the integrin αvβ5/AKT/Sp1 signaling pathway, and the integrin ανβ5 inhibitor cilengitide could inhibit omental metastasis of ovarian cancer driven by tumor-derived exosomes.

Targeting mitochondrial translation and OXPHOS in high-grade serous ovarian carcinoma eliminates stem-like cells

Abstract Ex vivo stem cell self-renewal and maintenance is supported by absence of serum-derived mitogens. In the present study, we sought to elucidate the proteomes of stem-like cells grown in serum-free media across a panel of high-grade serous ovarian cancer cell lines, which encompass a gradient from epithelial, intermediate and mesenchymal cell phenotypes to recapitulate the heterogeneity of the disease. MaxQuant-based label-free quantification of proteins identified that despite their different cellular and molecular architectures, all phenotypes exhibited mitochondria- and stemness-related pathways under conditions of serum starvation, although the specific proteins involved were discrete to each phenotype. This suggests that common cellular programs in a disease can be mediated through variable biological networks that generates molecular heterogeneity. We further explored if these pathways are inter-related, co-regulated or just incidentally associated in response to an environment depleted of growth factors and mitogens. Irrespective of their phenotype, cell lines on serum-starvation displayed an increased amount of mitochondrial DNA, mitochondrial biogenesis and mitochondrial activity with a switch from glycolysis to oxidative phosphorylation fuelled by the fatty acid oxidation. Ultra-structural studies implicated this metabolic fluctuation was regulated by dynamic mitochondrial remodelling. This also led us to explore a possible therapeutic strategy of targeting mitochondrial function to restrict tumor regenerative potential and disease recurrence. Conclusively, these new avenues contribute to a more comprehensive understanding of ovarian cancer.

Characterization of BRCA2 R3052Q variant in mice supports its functional impact as a low-risk variant

AbstractPathogenic variants in BRCA2 are known to significantly increase the lifetime risk of developing breast and ovarian cancers. Sequencing-based genetic testing has resulted in the identification of thousands of BRCA2 variants that are considered to be variants of uncertain significance (VUS) because the disease risk associated with them is unknown. One such variant is p.Arg3052Gln, which has conflicting interpretations of pathogenicity in the ClinVar variant database. Arginine at position 3052 in BRCA2 plays an important role in stabilizing its C-terminal DNA binding domain. We have generated a knock-in mouse model expressing this variant to examine its role on growth and survival in vivo. Homozygous as well as hemizygous mutant mice are viable, fertile and exhibit no overt phenotype. While we did not observe any hematopoietic defects in adults, we did observe a marked reduction in the in vitro proliferative ability of fetal liver cells that were also hypersensitive to PARP inhibitor, olaparib. In vitro studies performed on embryonic and adult fibroblasts derived from the mutant mice showed significant reduction in radiation induced RAD51 foci formation as well as increased genomic instability after mitomycin C treatment. We observed mis-localization of a fraction of R3052Q BRCA2 protein to the cytoplasm which may explain the observed in vitro phenotypes. Our findings suggest that BRCA2 R3052Q should be considered as a hypomorphic variant.

N6-methyladenosine METTL3 promotes cervical cancer tumorigenesis and Warburg effect through YTHDF1/HK2 modification

AbstractN6-methyladenosine (m6A) serves as the most common and conserved internal transcriptional modification. However, the roles of m6A on cervical cancer (CC) tumorigenesis are still unclear. Here, results indicated that METTL3 was significantly upregulated in CC tissue and cells, which was closely correlated with the lymph node metastasis and poor prognosis of CC patients. MeRIP-Seq analysis revealed the m6A profiles in CC cells. Functionally, METTL3 promoted the proliferation and Warburg effect (aerobic glycolysis) of CC cells. Mechanistically, METTL3 targeted the 3’-Untranslated Region (3’-UTR) of hexokinase 2 (HK2) mRNA. Moreover, METTL3 recruited YTHDF1, a m6A reader, to enhance HK2 stability. These findings demonstrated that METTL3 enhanced the HK2 stability through YTHDF1-mediated m6A modification, thereby promoting the Warburg effect of CC, which might promote a novel insight for the CC treatment.

Combined inhibition of JAK1/2 and DNMT1 by newly identified small-molecule compounds synergistically suppresses the survival and proliferation of cervical cancer cells

AbstractDespite substantial advances in treating cervical cancer (CC) with surgery, radiation and chemotherapy, patients with advanced CC still have poor prognosis and significantly variable clinical outcomes due to tumor recurrence and metastasis. Therefore, to develop more efficacious and specific treatments for CC remains an unmet clinical need. In this study, by virtual screening the SPECS database, we identified multiple novel JAK inhibitor candidates and validated their antitumor drug efficacies that were particularly high against CC cell lines. AH057, the best JAK inhibitor identified, effectively blocked the JAK/STAT pathways by directly inhibiting JAK1/2 kinase activities, and led to compromised cell proliferation and invasion, increased apoptosis, arrested cell cycles, and impaired tumor progression in vitro and in vivo. Next, by screening the Selleck chemical library, we identified SGI-1027, a DNMT1 inhibitor, as the compound that displayed the highest synergy with AH057. By acting on a same set of downstream effector molecules that are dually controlled by JAK1/2 and DNMT1, the combination of AH057 with SGI-1027 potently and synergistically impaired CC cell propagation via dramatically increasing apoptotic cell death and cell-cycle arrest. These findings establish a preclinical proof of concept for combating CC by dual targeting of JAK1/2 and DNMT1, and provide support for launching a clinical trial to evaluate the efficacy and safety of this drug combination in patients with CC and other malignant tumors.

Low GAS5 expression may predict poor survival and cisplatin resistance in cervical cancer

Abstract Cisplatin resistance is a major challenge in cervical cancer (CC) chemotherapy. Growth arrest‐specific 5 (GAS5) has been reported to be a tumour suppressor gene in CC. However, the mechanism of GAS5 in chemoresistance remains undetermined. Our research evaluated GAS5 expression in normal and CC tissues by qPCR and in situ hybridization (ISH). Statistical analysis was conducted to analyse the association of GAS5 expression with survival. Biochemical methods were used to screen upstream and downstream regulators of GAS5. Then, interactions were confirmed by ChIP, RNA pull-down, RNA immunoprecipitation (RIP), dual-luciferase reporter and real-time PCR assays. The cisplatin sensitivity of GAS5-overexpressing CC cells was demonstrated in vitro and in vivo. The results showed that low GAS5 expression was correlated with poor overall survival. Mechanistically, GAS5 was transcriptionally modulated by P-STAT3 and served as a competing endogenous RNA (ceRNA) of miR-21 to indirectly affect cisplatin sensitivity through PDCD4 regulation in CC cells. Animal studies confirmed that GAS5 enhanced cisplatin sensitivity and promoted PDCD4 expression in vivo. GAS5 was regulated by P-STAT3 and affected the sensitivity of CC to cisplatin-based chemotherapy through the miR-21/PDCD4 axis. This result may provide new insight into cisplatin-based therapy.

Photodynamic therapy simultaneously induces ferroptosis- and apoptosis-like lipid signatures in ovarian cancer cells

Abstract Resistance to apoptosis-inducing chemotherapy is a major factor contributing to treatment failure and poor survival outcomes in high-grade serous ovarian cancer (HGSOC). Ferroptosis, a regulated form of cell death driven by lipid peroxidation, has emerged as a promising effector mechanism because it remains available in HGSOC cells with impaired apoptosis signaling. While most research has focused on pharmacological ferroptosis inducers, there is growing interest in strategies that could trigger lipid autoxidation through externally delivered energy, such as photons. Photodynamic therapy (PDT), which utilizes light and light-activatable photosensitizers to generate reactive molecular species, offers a means of initiating lipid peroxidation with a high degree of precision and minimal systemic toxicities. However, the precise lipid targets of PDT, the influence of varying tumor lipidomic landscapes, and the role of ferroptosis sensitivity on PDT-lipid interactions have yet to be elucidated. In this study, we systematically compare PDT to ferroptosis induced by the inhibition of glutathione peroxidase 4, focusing on lipid redox states and composition in HGSOC cell lines. While PDT was similarly effective in both ferroptosis-sensitive and -resistant cells, its effects on cellular lipidomes differed markedly. PDT robustly induced lipid radical formation in both cell types; however, a dose-dependent accumulation of lipid hydroxides and hydroperoxides was only observed in ferroptosis-sensitive cells rich in unsaturated phospholipids. Further analysis revealed a significant overlap in lipid oxidation targets between PDT and ferroptosis. Notably, in both cell types, and in vivo, PDT upregulated ceramides, a lipid class strongly associated with mitochondrial apoptosis. In summary, PDT exhibited comparable efficacy in both ferroptosis-sensitive and -resistant cells by triggering a combination of lipid peroxidation and ceramide upregulation, suggesting the activation of both ferroptosis and apoptosis pathways. Further studies are needed to explore the role of PDT-induced lipidomic changes in the initiation of various cell death pathways and in overcoming chemoresistance in HGSOC.

The long-noncoding RNA SOCS2-AS1 suppresses endometrial cancer progression by regulating AURKA degradation

AbstractAberrant long-noncoding RNA (lncRNA) expression has been shown to be involved in the pathogenesis of endometrial cancer (EC). Herein, we report a novel tumor suppressor lncRNA SOCS2-AS1 in EC. Quantitative real-time PCR was performed to detect RNA expression. In situ hybridization and nuclear/cytoplasmic fractionation assays were used to detect the subcellular location. We found that SOCS2-AS1 was downregulated in EC tissues. Its reduced expression was correlated with advanced clinical stage and poor prognosis. Forced expression of SOCS2-AS1 suppressed EC cell proliferation and induced cell-cycle arrest and apoptosis. SOCS2-AS1-binding proteins were detected using RNA pull-down assay and mass spectrometry. Mechanistically, SOCS2-AS1 bound to Aurora kinase A (AURKA) and increased its degradation through the ubiquitin-proteasome pathway. In conclusion, SOCS2-AS1 may thus serve as a prognostic predictor and a biomarker for AURKA-inhibitor treatment in EC patients.

MicroRNA-379-5p attenuates cancer stem cells and reduces cisplatin resistance in ovarian cancer by regulating RAD18/Polη axis

Abstract Ovarian cancer (OC) is an aggressive malignancy of the female reproductive organs, associated with a low 5-year survival rate. Emerging evidence suggests the pivotal role of microRNAs (miRNAs) in regulating chemoresistance and metastasis in OC, primarily through cancer stem cells (CSCs), also known as cancer stem-like cells (CSLCs). Herein, we demonstrate that miR-379-5p is downregulated in several OC cell populations including both cell lines and patient tumor samples. Furthermore, overexpression of miR-379-5p effectively inhibits CSCs and counteracts cisplatin-induced expansion of CSCs. Further mechanistic investigations identify RAD18, a DNA repair protein involved in translesion DNA synthesis (TLS), as a direct target of miR-379-5p. Moreover, a negative correlation between miR-379-5p and RAD18 expression is observed in ovarian CSCs isolated from OC patients. The downregulation of RAD18 inhibits stem-like phenotypes and enhances the sensitivity of ovarian CSCs to cisplatin treatment. Importantly, miR-379-5p-mediated inhibition of RAD18 prevents the repair synthesis in CSCs by promoting the accumulation of DNA damage. In vivo studies further reveal that miR-379-5p enhances DNA damage, which, in turn, inhibits tumor cell proliferation in athymic nude mice. Remarkably, targeting of RAD18 by miR-379-5p prevents monoubiquitination of proliferating cell nuclear antigen (PCNA), resulting in reduced DNA Polymerase η (a TLS polymerase that helps to bypass DNA lesions) recruitment to lesion sites. In the absence of Polη, the persisting DNA lesions cause activation of cell cycle arrest and apoptosis pathway in CSCs. Therefore, our findings unveil a novel mechanism whereby miR-379-5p overexpression curtails CSCs by modulating the RAD18/Polη axis.

BRDT promotes ovarian cancer cell growth

AbstractBromodomain testis-specific factor (BRDT) is a member of the bromodomain and extra-terminal (BET) family proteins. Its expression and potential functions in ovarian cancer were examined. We show that BRDT is overexpressed in human ovarian cancer tissues and in established (CaOV3)/primary ovarian cancer cells. However, its expression is low in ovarian epithelial tissues and cells. Significantly, shRNA-induced silencing or CRISPR/Cas9-mediated knockout of BRDT inhibited ovarian cancer cell growth, viability, proliferation and migration, and induced significant apoptosis activation. Conversely, exogenous overexpression of BRDT, by a lentiviral construct, augmented CaOV3 cell proliferation and migration. In CaOV3 cells expression of two key BRDT target genes, polo-like kinase 1 (PLK1) and aurora kinase C (AURKC), was downregulated by BRDT shRNA or knockout, but upregulated with BRDT overexpression. In vivo, xenograft tumors-derived from BRDT-knockout CaOV3 cells grew significantly slower than control tumors in severe combined immunodeficient (SCID) mice. Furthermore, intratumoral injection of BRDT shRNA lentivirus potently inhibited the growth of primary ovarian cancer xenografts in SCID mice. Downregulation of PLK1 and AURKC was detected in BRDT-knockout and BRDT-silenced tumor tissues. Collectively, BRDT overexpression promotes ovarian cancer cell progression. Targeting BRDT could be a novel strategy to treat ovarian cancer.

Bim, Puma and Noxa upregulation by Naftopidil sensitizes ovarian cancer to the BH3-mimetic ABT-737 and the MEK inhibitor Trametinib

AbstractOvarian cancer represents the first cause of mortality from gynecologic malignancies due to frequent chemoresistance occurrence. Increasing the [BH3-only Bim, Puma, Noxa proapoptotic]/[Bcl-xL, Mcl-1 antiapoptotic] proteins ratio was proven to efficiently kill ovarian carcinoma cells and development of new molecules to imbalance Bcl-2 member equilibrium are strongly required. Drug repurposing constitutes an innovative approach to rapidly develop therapeutic strategies through exploitation of established drugs already approved for the treatment of noncancerous diseases. This strategy allowed a renewed interest for Naftopidil, an α1-adrenergic receptor antagonist commercialized in Japan for benign prostatic hyperplasia. Naftopidil was reported to decrease the incidence of prostate cancer and its derivative was described to increase BH3-only protein expression in some cancer models. Based on these arguments, we evaluated the effects of Naftopidil on ovarian carcinoma and showed that Naftopidil reduced cell growth and increased the expression of the BH3-only proteins Bim, Puma and Noxa. This effect was independent of α1-adrenergic receptors blocking and involved ATF4 or JNK pathway depending on cellular context. Finally, Naftopidil-induced BH3-only members sensitized our models to ABT-737 and Trametinib treatments, in vitro as well as ex vivo, in patient-derived organoid models.

miR-6086 inhibits ovarian cancer angiogenesis by downregulating the OC2/VEGFA/EGFL6 axis

AbstractmiRNAs have emerged as a pivotal component of gene regulatory networks, mediating cytokines secretion, cell cycle, and differentiation regulation. However, how miRNAs collaborate with transcription factors and downstream effector proteins that determine the fate of ovarian cancer cells remains to be understood, especially regarding to mechanism of tumor angiogenesis regulation. Based on the qRT-PCR and IHC analysis, we found that miR-6086 was maintained a very low level both in ovarian cancer cell lines and tissues. Further, we identified OC2 and EGFL6 as the direct targets of miR-6086 by luciferase assay and we observed an inverse relationship between the expression of miR-6086 and the OC2/VEGFA/EGFL6 axis. The Western blotting analysis suggested that OC2 could directly upregulate VEGFA and indirectly up-regulate EGFL6 through VEGFA. Moreover, miR-6086 could indirectly downregulate VEGFA through OC2. In addition, miR-6086, siOC2 and siEGFL6 could negatively regulate the tumor growth and angiogenesis of ovarian cancer (Skov3) in the animal studies, with the inhibition rates of 77.07%, 69.89%, and 73.62%, respectively (**p < 0.01). Moreover, the tumor cell proliferation, migration, and invasion of ovarian cancer cell lines (Caov3 and Skov3) and vascular formation (HUVECs) were significantly suppressed in vitro, by decreasing the AKT/MAPK pathways (*p < 0.05). Taken together, our results reveal that miR-6086 can suppress the angiogenesis networks in ovarian cancer by down-regulating the OC2/VEGFA/EGFL6 axis, directly or indirectly, which may provide potential targets for tumor therapeutics.

Glucose metabolism characteristics and TLR8-mediated metabolic control of CD4+ Treg cells in ovarian cancer cells microenvironment

AbstractImmunotherapy is expected to become the most promising new treatment for ovarian cancer owing to its immunogenicity. However, immunosuppression in the tumor microenvironment is a major obstacle to the efficacy of tumor therapy. Studies have found different metabolism ways of regulatory T cells (Tregs) in the cancer environment may be related to the immunosuppression and Toll-like receptor 8 (TLR8) can reverse the suppression function of Tregs. But it is still unclear that if the TLR8-mediated function reversal is associated with the change of glucose metabolism of Tregs. It was found that the positive expression rates of Glut1, HIF-1α, and Ki67 in CD4+ Treg cells of OC were significantly higher than that in benign ovarian tumor and HC, and also significantly higher than that in CD4+ Teffs of OC. What’s more, compared with CD4+ Teff group, CD4+ Tregs highly expressed seven genes and three proteins related to glucose metabolism and had higher levels of glucose uptake and glycolysis. After activating TLR8 signal of CD4+ Tregs, the proliferation level of naive CD4+ T cells was higher than that of the control group. At the same time, the expression levels of eight genes and five proteins related to glucose metabolism in CD4+ Treg cells with TLR8 activated were decreased and levels of glucose uptake and glycolysis were also lower. Furthermore, TLR8 signaling also downregulated the mTOR pathway in CD4+ Tregs. CD4+ Tregs pretreated with 2-deoxy-d-Glucose (2-DG) and galloflavin also attenuated the inhibition of Teffs proliferation. Although CD4+ Tregs pretreated with 2-DG and galloflavin before activating TLR8 signal had no significant difference compared with the group only treated with inhibitors, which suggested TLR8-mediated reversal of CD4+ Treg cells inhibitory function in ovarian cancer cells co-cultured microenvironment had a causal relationship with glucose metabolism.

ID1 confers cancer cell chemoresistance through STAT3/ATF6-mediated induction of autophagy

AbstractChemoresistance is one of the major reasons leading to ovarian cancer high mortality and poor survival. Studies have shown that the alteration of cellular autophagy is associated with cancer cell chemoresistance. Here, we investigated whether the ovarian cancer chemoresistance is associated with the autophagy induced by the inhibitor of DNA binding 1 (ID1). By using gene overexpression or silencing, luciferase assay and human specimens, we show that ID1 induces high autophagy and confers cancer cell chemoresistance. The mechanistic study demonstrates that ID1 first activates the NF-κB signaling through facilitating the nuclear translocation of NF-κB p65, which strengthens the expression and secretion of IL-6 from cancer cells to subsequently activate the signal transducer and activator of transcription 3 (STAT3) through the protein phosphorylation at Y705. We further identified that STAT3 functions to promote the transcription of the activating transcription factor 6 (ATF6), which induces endoplasmic reticulum stress to promote cellular autophagy, granting cancer cell resistance to both cisplatin and paclitaxel treatment. Moreover, we found a significant correlation between the expression of ID1 and ATF6 in 1104 high grade serous ovarian cancer tissues, and that patients with the high expression of ID1 or ATF6 were resistant to platinum treatment and had the poor overall survival and progression-free survival. Thus, we have uncovered a mechanism in which ID1 confers cancer cell chemoresistance largely through the STAT3/ATF6-induced autophagy. The involved molecules, including ID1, STAT3, and ATF6, may have a potential to be targeted in combination with chemotherapeutic agents to improve ovarian cancer survival.

The β-arrestin1/endothelin axis bolsters ovarian fibroblast-dependent invadosome activity and cancer cell metastatic potential

AbstractRecruitment of fibroblasts to tumors and their activation into cancer-associated fibroblasts (CAFs) is a strategy used by tumor cells to direct extracellular matrix (ECM) remodeling, invasion, and metastasis, highlighting the need to investigate the molecular mechanisms driving CAF function. Endothelin-1 (ET-1) regulates the communication between cancer and stroma and facilitates the progression of serous ovarian cancer (SOC). By binding to Endothelin A (ETA) and B (ETB) receptors, ET-1 enables the recruitment of β-arrestin1 (β-arr1) and the formation of signaling complexes that coordinate tumor progression. However, how ET-1 receptors might “educate” human ovarian fibroblasts (HOFs) to produce altered ECM and promote metastasis remains to be elucidated. This study identifies ET-1 as a pivotal factor in the activation of CAFs capable of proteolytic ECM remodeling and the generation of heterotypic spheroids containing cancer cells with a propensity to metastasize. An autocrine/paracrine ET-1/ETA/BR/β-arr1 loop enhances HOF proliferation, upregulates CAF marker expression, secretes pro-inflammatory cytokines, and increases collagen contractility, and cell motility. Furthermore, ET-1 facilitates ECM remodeling by promoting the lytic activity of invadosome and activation of integrin β1. In addition, ET-1 signaling supports the formation of heterotypic HOF/SOC spheroids with enhanced ability to migrate through the mesothelial monolayer, and invade, representing metastatic units. The blockade of ETA/BR or β-arr1 silencing prevents CAF activation, invadosome function, mesothelial clearance, and the invasive ability of heterotypic spheroids. In vivo, therapeutic inhibition of ETA/BR using bosentan (BOS) significantly reduces the metastatic potential of combined HOFs/SOC cells, associated with enhanced apoptotic effects on tumor cells and stromal components. These findings support a model in which ET-1/β-arr1 reinforces tumor/stroma interaction through CAF activation and fosters the survival and metastatic properties of SOC cells, which could be counteracted by ETA/BR antagonists.

PSMC2/CCND1 axis promotes development of ovarian cancer through regulating cell growth, apoptosis and migration

AbstractOvarian cancer is known as one of the most common malignancies of the gynecological system, whose treatment is still not satisfactory because of the unclear understanding of molecular mechanism. PSMC2 is an essential component of 19 S regulatory granules in 26 S proteasome and its relationship with ovarian cancer is still not clear. In this study, we found that PSMC2 was upregulated in ovarian cancer tissues, associated with tumor grade and could probably predict poor prognosis. Knocking down the endogenous PSMC2 expression in ovarian cancer cells could decrease colony formation ability, cell motility and cell proliferation rate, along with increasing cell apoptosis rate. Cells models or xenografts formed by cells with relatively lower expression of PSMC2 exhibited weaker oncogenicity and slower growth rate in vivo. Moreover, gene microarray was used to analyze the alteration of gene expression profiling of ovarian cancer induced by PSMC2 knockdown and identify CCND1 as a potential downstream of PSMC2. Further study revealed the mutual regulation between PSMC2 and CCND1, and demonstrated that knockdown of CCND1 could enhance the regulatory effects induced by PSMC2 knockdown and overexpression of CCND1 reverses it. In summary, PSMC2 may promote the development of ovarian cancer through CCND1, which may predict poor prognosis of ovarian cancer patients.

CircRAB11FIP1 promoted autophagy flux of ovarian cancer through DSC1 and miR-129

AbstractAt present, no systematic and in-depth study is available on the function and potential mechanisms of circular RNA in autophagy. This study aimed to screen the expression profiles of circRNA, miRNA, and mRNA of ovarian cancer cells induced by Torin 1 (10 µM). The expression profiles of circRNA, miRNA, and mRNA were analyzed with next-generation sequencing technology. CircRAB11FIP1 expression was elevated in epithelial ovarian cancer (EOC) tissues than in normal ovarian tissues. Silencing circRAB11FIP1 inhibited the autophagic flux of ovarian cancer SKOV3 cells. However, circRAB11FIP1 overexpression activated the autophagic flux of ovarian cancer A2780 cells. CircRAB11FIP1-induced autophagy accelerated EOC proliferation and invasion. Also, circRAB11FIP1 directly bound to miR-129 and regulated its targets ATG7 and ATG14. CircRAB11FIP1 bound to desmocollin 1to facilitate its interaction with ATG101. Also, circRAB11FIP1 directly bound to the mRNA of fat mass and obesity-associated protein and promoted its expression. Then, circRAB11FIP1 mediated mRNA expression levels of ATG5 and ATG7 depending on m6A. In general, this study demonstrated that circRAB11FIP1 regulated ATG7 and ATG14 by sponging miR-129. The data suggested that circRAB11FIP1 might serve as a candidate biomarker for EOC diagnosis and treatment.

HPV E7-mediated NCAPH ectopic expression regulates the carcinogenesis of cervical carcinoma via PI3K/AKT/SGK pathway

AbstractCervical cancer is one of the most common gynecological tumors in the world, and human papillomavirus (HPV) infection is its causative agent. However, the molecular mechanisms involved in the carcinogenesis of cervical cancer still require clarification. Here we found that knockdown of Non-SMC (Structural Maintenance of Chromosomes) condensin I complex subunit H (NCAPH) gene expression significantly inhibited the proliferation, migration, invasion and epithelial–mesenchymal transition (EMT) of cervical cancer cells in vitro, and restrained xenograft tumor formation in vivo. Intriguingly, HPV E7 could form a positive feedback loop with NCAPH. E7 upregulated NCAPH gene expression via E2F1 which initiated NCAPH transcription by binding to its promoter directly. Silencing of NCAPH reduced E7 transcription via promoting the transition of AP-1 heterodimer from c-Fos/c-Jun to Fra-1/c-Jun. Moreover, the E7-mediated NCAPH overexpression was involved in the activation of the PI3K/AKT/SGK signaling pathway. In vivo, NCAPH expression in cervical cancer tissues was significantly higher than which in normal cervix and high-grade squamous intraepithelial lesion (HSIL) tissues, and its expression was significantly correlated with tumor size, depth of invasion and lymph node metastasis. Patients with high NCAPH expression had a significantly better survival outcomes than those with low-expression, suggesting that NCAPH-induced cell proliferation might sensitize cancer cells to adjuvant therapy. In conclusion, our results revealed the role of NCAPH in the carcinogenesis of cervical cancer in vitro and in vivo. The interaction between E7 and NCAPH expands the mechanism of HPV induced tumorigenesis and that of host genes regulating HPV E7.

Inhibition of long non-coding RNA XIST upregulates microRNA-149-3p to repress ovarian cancer cell progression

AbstractLong non-coding RNAs (lncRNAs) and microRNAs (miRNAs) play critical roles in human diseases. We aimed to clarify the role of lncRNA X-inactive specific transcript (XIST)/miR-149-3p/forkhead box P3 (FOXP3) axis in ovarian cancer (OC) cell growth. XIST, miR-149-3p and FOXP3 expression in OC tissues and cell lines was assessed, and the predictive role of XIST in prognosis of OC patients was analyzed. The OC cell lines were screened and accordingly treated with silenced/overexpressed XIST plasmid or miR-149-3p mimic/inhibitor, and then the proliferation, invasion, migration, colony formation ability, apoptosis, and cell cycle distribution of OC cells were measured. Effect of altered XIST and miR-149-3p on tumor growth in vivo was observed. Online website prediction and dual luciferase reporter gene were implemented to detect the targeting relationship of lncRNA XIST, miR-149-3p, and FOXP3. XIST and FOXP3 were upregulated, whereas miR-149-3p was downregulated in OC tissues and cells. High XIST expression indicated a poor prognosis of OC. Inhibition of XIST or elevation of miR-149-3p repressed proliferation, invasion, migration, and colony formation ability, and promoted apoptosis and cell cycle arrest of HO-8910 cells. In SKOV3 cells upon treatment of overexpressed XIST or reduction of miR-149-3p, there exhibited an opposite tendency. Based on online website prediction, dual luciferase reporter gene, and RNA pull-down assays, we found that there was a negative relationship between XIST and miR-149-3p, and miR-149-3p downregulated FOXP3 expression. This study highlights that knockdown of XIST elevates miR-149-3p expression to suppress malignant behaviors of OC cells, thereby inhibiting OC development.

MIEF2 reprograms lipid metabolism to drive progression of ovarian cancer through ROS/AKT/mTOR signaling pathway

AbstractMIEF2 (mitochondrial elongation factor 2) is one of the key regulators of mitochondrial fission. Bioinformatics analysis indicated that high expression of MIEF2 predicted a poor prognosis in ovarian cancer patients. However, the relationship between MIEF2 and aberrant lipid metabolism in OC remains elusive. In this study, we demonstrated that MIEF2 significantly promoted lipid synthesis, while has no significant effect on fatty acid uptake and oxidation in OC cells. MIEF2 enhanced de novo fatty acid synthesis through up-regulating the expression of sterol regulatory element binding protein 1 (SREBP1) and its transcriptional target lipogenic genes ACC1, FASN and SCD1. Meanwhile, MIEF2-promoted cholesterol biosynthesis through up-regulating the expression of sterol regulatory element binding protein 2 (SREBP2) and its transcriptional target cholesterol biosynthesis genes HMGCS1 and HMGCR. Mechanistically, increased mitochondrial reactive oxygen species (ROS) production and subsequently activation of AKT/mTOR signaling pathway was found to be involved in the up-regulation of SREBP1 and SREBP2 in OC cells. Moreover, cell growth and metastasis assays indicated that MIEF2-regulated fatty acid synthesis and cholesterol biosynthesis played a critical role in the progression of OC. Taken together, our findings indicate that MIEF2 is a critical regulator of lipid synthesis in OC, which provides a strong line of evidence for this molecule to serve as a drug target in the treatment of this malignancy.

LSD1 silencing contributes to enhanced efficacy of anti-CD47/PD-L1 immunotherapy in cervical cancer

AbstractAnti-CD47/PD-L1 immunotherapies aiming to enhance antitumor immunity are being intensively investigated and show promising results in cancer therapy; however, not all patients treated with these new drugs respond. Thus, developing new immunotherapy agents or combination treatments to enhance the efficacy of immunotherapy is an urgent challenge. Here, we found that LSD1 knockdown directly downregulated the expression of CD47 and PD-L1 through upregulating H3K4me2 levels in the CD47 and CD274 promoter regions. In addition, the LSD1/wild-type p53/miR-34a signaling axis was also involved in the regulation of CD47/PD-L1 expression by targeting the 3′ untranslated regions (3′UTRs) of CD47/PD-L1. Further, the results showed that an LSD1 inhibitor (ORY-1001) combined with anti-CD47/PD-L1 monoclonal antibodies inhibited tumor growth in an established subcutaneous xenograft model more effectively than a single blockade strategy. Collectively, these findings indicate that LSD1 inhibition enhances the therapeutic efficacy of PD-L1/CD47 blockade by reducing CD47 and PD-L1 expression in cervical cancer.

PABPC3 drives ovarian cancer metastasis and drug sensitivity by downregulating CLDN1 expression

Abstract Ovarian cancer remains one of the most lethal malignancies affecting women, with its high mortality rate primarily attributed to the aggressive metastatic nature of the disease, leading to late-stage diagnoses. The challenges posed by tumor metastasis and treatment resistance significantly complicate disease management and substantially reduce survival rates. Thus, elucidating the mechanisms underlying ovarian cancer metastasis is crucial for developing targeted therapies and improving patient outcomes. In this study, through single-nucleus RNA sequencing and analysis of clinical samples, we identify PABPC3 as a key regulator of ovarian cancer metastasis and patient survival. Functional experiments reveal that PABPC3 knockdown markedly inhibits ovarian cancer cell proliferation and migration, whereas its overexpression exerts the opposite effects. Furthermore, in vivo models confirm that PABPC3 overexpression significantly enhances metastatic potential. Mechanistically, PABPC3 promotes tumor metastasis by modulating the expression of CLDN1, a critical component of tight junctions. PABPC3 knockdown leads to a significant upregulation of CLDN1, while simultaneous CLDN1 knockdown partially rescues the migration-inhibitory effects induced by PABPC3 depletion. Additionally, clinical analyses demonstrate that high PABPC3 expression correlates with shorter overall survival, even among patients receiving chemotherapy. Notably, increased PABPC3 protein levels in metastatic lesions are associated with reduced progression-free survival. In conclusion, this study underscores the pivotal role of PABPC3 in ovarian cancer metastasis and patient prognosis, highlighting it as a potential therapeutic target for improving clinical outcomes.

Tumor- and host-derived heparanase-2 (Hpa2) attenuates tumorigenicity: role of Hpa2 in macrophage polarization and BRD7 nuclear localization

Abstract Little attention was given to heparanase 2 (Hpa2) over the last two decades, possibly because it lacks a heparan sulfate (HS)-degrading activity typical of heparanase. Emerging results suggest, nonetheless, that Hpa2 plays a role in human pathologies, including cancer progression where it functions as a tumor suppressor. Here, we examined the role of Hpa2 in cervical carcinoma. We report that high levels of Hpa2 correlate with prolonged survival of cervical carcinoma patients. Strong staining intensity of Hpa2 also correlates with low tumor grade. Overexpression of Hpa2 in SiHa cervical carcinoma cells resulted in tumor xenografts that were two-fold smaller than control tumors. Interestingly, even smaller tumor xenografts were developed by SiHa cells overexpressing the Pro140Arg and Asn543Ile Hpa2 missense mutations that were identified in patients diagnosed with urofacial syndrome (UFS). Utilizing the Ras recruitment system, we identified bromodomain-containing protein 7 (BRD7) to interact with Hpa2 and found that both BRD7 and the Hpa2 mutants are translocated to the cell nucleus in tumors developed by the Pro140Arg and Asn543Ile Hpa2 mutants. Utilizing our newly developed conditional Hpa2-KO mice, we further show that Hpa2 plays a critical role in macrophage polarization; in the absence of Hpa2, macrophages are shifted towards pro-tumorigenic, M2 phenotype. Notably, implanting SiHa cervical carcinoma cells together with Hpa2-KO macrophages promoted tumor growth. These results support, and further expand, the notion that Hpa2 functions as a tumor suppressor, co-operating with another tumor suppressor, BRD7.

NAD+ Metabolism-Mediated SURF4-STING Axis Enhances T-Cell Anti-Tumor Effects in the Ovarian Cancer Microenvironment

Abstract The anti-tumor function of T cells in the ovarian cancer (OC) microenvironment influences the prognosis of OC. Previous studies have indicated that metabolic competition among microenvironmental cells regulates the function of immune cells. Recent research has shown that NAD+ metabolism plays a significant role in modulating immune cell activity, and increasing NAD+ levels is a promising therapeutic strategy to enhance the effector functions of immune cells. However, the regulatory mechanisms of NAD+ metabolism on the anti-tumor function of T cells in the OC microenvironment remain unclear. This study found that exogenous supplementation of NAM to increase NAD+ levels in T cells significantly activates the endogenous p-STING axis and downstream interferon signaling within T cells, thereby enhancing T cell activation and anti-tumor effects. Concurrently, we discovered that elevated NAD+ levels promote the retention of STING on the Golgi apparatus. Mechanistically, we elucidated that the increase in NAD+ levels mediated by NAM downregulates the expression of SURF4 protein through ubiquitination and degradation, subsequently activating the p-STING axis in T cells. Furthermore, exogenous NAM supplementation can further enhance the activation of the T cell STING axis by PARP inhibitor (PARPi)-treated OC cells, and the combination of PARPi and NAM significantly augments the anti-tumor function of T cells, inhibiting the progression of OC. Our findings provide a molecular basis for the regulation of T cell anti-tumor function by NAD+, highlighting the potential strategy of targeting T cell metabolic reprogramming for the treatment of OC.

Methylation of BRD4 by PRMT1 regulates BRD4 phosphorylation and promotes ovarian cancer invasion

Abstract Bromodomain-containing protein 4 (BRD4), the major component of bromodomain and extra-terminal domain (BET) protein family, has important functions in early embryonic development and cancer development. However, the posttranslational modification of BRD4 is not well understood. Multiple approaches were used to explore the mechanism of PRMT1-mediated BRD4 methylation and to determine the biological functions of BRD4 and PRMT1 in ovarian cancer. Here we report that BRD4 is asymmetrically methylated at R179/181/183 by PRMT1, which is antagonized by the Jumonji-family demethylase, JMJD6. PRMT1 is overexpressed in ovarian cancer tissue and is a potential marker for poor prognosis in ovarian cancer patients. Silencing of PRMT1 inhibited ovarian cancer proliferation, migration, and invasion in vivo and in vitro. PRMT1-mediated BRD4 methylation was found to promote BRD4 phosphorylation. Compared to BRD4 wild-type (WT) cells, BRD4 R179/181/183K mutant-expressing cells showed reduced ovarian cancer metastasis. BRD4 arginine methylation is also associated with TGF-β signaling. Our results indicate that arginine methylation of BRD4 by PRMT1 is involved in ovarian cancer tumorigenesis. Targeting PRMT1-mediated arginine methylation may provide a novel diagnostic target and an effective therapeutic strategy for ovarian cancer treatment.

HLF promotes ovarian cancer progression and chemoresistance via regulating Hippo signaling pathway

AbstractHepatic leukemia factor (HLF) is aberrantly expressed in human malignancies. However, the role of HLF in the regulation of ovarian cancer (OC) remains unknown. Herein, we reported that HLF expression was upregulated in OC tissues and ovarian cancer stem cells (CSCs). Functional studies have revealed that HLF regulates OC cell stemness, proliferation, and metastasis. Mechanistically, HLF transcriptionally activated Yes-associated protein 1 (YAP1) expression and subsequently modulated the Hippo signaling pathway. Moreover, we found that miR-520e directly targeted HLF 3′-UTR in OC cells. miR-520e expression was negatively correlated with HLF and YAP1 expression in OC tissues. The combined immunohistochemical (IHC) panels exhibited a better prognostic value for OC patients than any of these components alone. Importantly, the HLF/YAP1 axis determines the response of OC cells to carboplatin treatment and HLF depletion or the YAP1 inhibitor verteporfin abrogated carboplatin resistance. Analysis of patient-derived xenografts (PDXs) further suggested that HLF might predict carboplatin benefits in OC patients. In conclusion, these findings suggest a crucial role of the miR-520e/HLF/YAP1 axis in OC progression and chemoresistance, suggesting potential therapeutic targets for OC.

Onvansertib treatment overcomes olaparib resistance in high-grade ovarian carcinomas

AbstractOccurrence of resistance to olaparib, a poly(ADP-ribose) polymerase (PARP) inhibitor (PARPi) approved in ovarian carcinoma, has already been shown in clinical settings. Identifying combination treatments to sensitize tumor cells and/or overcome resistance to olaparib is critical. Polo-like kinase 1 (PLK1), a master regulator of mitosis, is also involved in the DNA damage response promoting homologous recombination (HR)-mediated DNA repair and in the recovery from the G2/M checkpoint. We hypothesized that PLK1 inhibition could sensitize tumor cells to PARP inhibition. Onvansertib, a highly selective PLK1 inhibitor, and olaparib were tested in vitro and in vivo in BRCA1 mutated and wild-type (wt) ovarian cancer models, including patient-derived xenografts (PDXs) resistant to olaparib. The combination of onvansertib and olaparib was additive or synergic in different ovarian cancer cell lines, causing a G2/M block of the cell cycle, DNA damage, and apoptosis, much more pronounced in cells treated with the two drugs as compared to controls and single agents treated cells. The combined treatment was well tolerated in vivo and resulted in tumor growth inhibition and a statistically increased survival in olaparib-resistant-BRCA1 mutated models. The combination was also active, although to a lesser extent, in BRCA1 wt PDXs. Pharmacodynamic analyses showed an increase in mitotic, apoptotic, and DNA damage markers in tumor samples derived from mice treated with the combination versus vehicle. We could demonstrate that in vitro onvansertib inhibited both HR and non-homologous end-joining repair pathways and in vivo induced a decrease in the number of RAD51 foci-positive tumor cells, supporting its ability to induce HR deficiency and favoring the activity of olaparib. Considering that the combination was well tolerated, these data support and foster the clinical evaluation of onvansertib with PARPis in ovarian cancer, particularly in the PARPis-resistant setting.

Selective targeting of IRAK1 attenuates low molecular weight hyaluronic acid-induced stemness and non-canonical STAT3 activation in epithelial ovarian cancer

AbstractAdvanced epithelial ovarian cancer (EOC) survival rates are dishearteningly low, with ~25% surviving beyond 5 years. Evidence suggests that cancer stem cells contribute to acquired chemoresistance and tumor recurrence. Here, we show that IRAK1 is upregulated in EOC tissues, and enhanced expression correlates with poorer overall survival. Moreover, low molecular weight hyaluronic acid, which is abundant in malignant ascites from patients with advanced EOC, induced IRAK1 phosphorylation leading to STAT3 activation and enhanced spheroid formation. Knockdown of IRAK1 impaired tumor growth in peritoneal disease models, and impaired HA-induced spheroid growth and STAT3 phosphorylation. Finally, we determined that TCS2210, a known inducer of neuronal differentiation in mesenchymal stem cells, is a selective inhibitor of IRAK1. TCS2210 significantly inhibited EOC growth in vitro and in vivo both as monotherapy, and in combination with cisplatin. Collectively, these data demonstrate IRAK1 as a druggable target for EOC.

Ovarian tumor cell-derived JAGGED2 promotes omental metastasis through stimulating the Notch signaling pathway in the mesothelial cells

AbstractThe primary site of metastasis for epithelial ovarian cancer (EOC) is the peritoneum, and it occurs through a multistep process that begins with adhesive contacts between cancer cells and mesothelial cells. Despite evidence that Notch signaling has a role in ovarian cancer, it is unclear how exactly it contributes to ovarian cancer omental metastasis, as well as the cellular dynamics and intrinsic pathways that drive this tropism. Here we show that tumor cells produced the Notch ligand Jagged2 is a clinically and functionally critical mediator of ovarian cancer omental metastasis by activating the Notch signaling in single-layered omental mesothelial cells. In turn, Jagged2 promotes tumor growth and therapeutic resistance by stimulating IL-6 release from mesothelial cells. Additionally, Jagged2 is a potent downstream mediator of the omental metastasis cytokine TGF-β that is released during omental destruction. Importantly, therapeutic inhibition of Jagged2-mediated omental metastasis was significantly improved by directly disrupting the Notch pathway in omental mesothelial cells. These findings highlight the key role of Jagged2 to the functional interplay between the TGF-β and the Notch signaling pathways during the metastatic process of ovarian cancer cells to the omentum and identify the Notch signaling molecule as a precision therapeutic target for ovarian cancer metastasis.

Unveiling the ZNF384-INTS13-hnRNPC axis as a therapeutic vulnerability in cervical cancer

Abstract Cervical cancer remains a major global health burden, necessitating the identification of novel therapeutic targets to overcome the limitations of current treatments. Here, we comprehensively investigated the role of integrator complex subunit 13 (INTS13) in cervical cancer progression. Our analysis of publicly available The Cancer Genome Atlas (TCGA) datasets revealed that INTS13 is significantly overexpressed in cervical cancer tissues across various histological subtypes, correlating with advanced tumor T-stage and predicting poorer overall survival. Single-cell RNA sequencing further localized INTS13 expression predominantly to malignant epithelial cells within the tumor microenvironment, where its expression correlated with genes involved in critical cellular processes. Furthermore, elevated expression has been observed in cervical cancer tissues from surgically-treated patients and in various primary human cervical cancer cells. In vitro functional studies demonstrated that genetic silencing or CRISPR/Cas9-mediated knockout of INTS13 significantly inhibited the proliferation, migration, and invasion of primary cervical cancer cells, while selectively inducing apoptosis. Conversely, ectopic INTS13 overexpression markedly enhanced these malignant phenotypes. Mechanistically, we identified heterogeneous nuclear ribonucleoprotein C (hnRNPC) as a critical downstream effector, with INTS13 regulating hnRNPC expression, and the restoration of hnRNPC effectively reversing the anti-cervical cancer effects observed upon INTS13 silencing. Furthermore, the transcription factor ZNF384 (zinc finger protein 384) was identified as an upstream regulator that directly binds to and positively governs INTS13 expression. Finally, in vivo animal models confirmed that targeted silencing of INTS13 significantly impeded cervical cancer xenograft growth in nude mice, reduced cellular proliferation, and augmented apoptosis, consistently accompanied by a reduction in hnRNPC expression. These findings collectively establish INTS13 as a crucial precancerous gene in cervical cancer, promoting malignant phenotypes primarily through the ZNF384-INTS13-hnRNPC signaling axis.

The P286R mutation of DNA polymerase ε activates cancer-cell-intrinsic immunity and suppresses endometrial tumorigenesis via the cGAS-STING pathway

AbstractEndometrial carcinoma (EC) is a prevalent gynecological tumor in women, and its treatment and prevention are significant global health concerns. The mutations in DNA polymerase ε (POLE) are recognized as key features of EC and may confer survival benefits in endometrial cancer patients undergoing anti-PD-1/PD-L1 therapy. However, the anti-tumor mechanism of POLE mutations remains largely elusive. This study demonstrates that the hot POLE P286R mutation impedes endometrial tumorigenesis by inducing DNA breakage and activating the cGAS-STING signaling pathway. The POLE mutations were found to inhibit the proliferation and stemness of primary human EC cells. Mechanistically, the POLE mutants enhance DNA damage and suppress its repair through the interaction with DNA repair proteins, leading to genomic instability and the upregulation of cytoplasmic DNA. Additionally, the POLE P286R mutant also increases cGAS level, promotes TBK1 phosphorylation, and stimulates inflammatory gene expression and anti-tumor immune response. Furthermore, the POLE P286R mutation inhibits tumor growth and facilitates the infiltration of cytotoxic T cells in human endometrial cancers. These findings uncover a novel mechanism of POLE mutations in antagonizing tumorigenesis and provide a promising direction for effective cancer therapy.

MAP4K4 mediates the SOX6-induced autophagy and reduces the chemosensitivity of cervical cancer

AbstractThere are nearly 40% of cervical cancer patients showing poor response to neoadjuvant chemotherapy that can be induced by autophagy, however, the underlying mechanism has not yet been fully clarified. We previously found thatSex-determining region of Y-related high-mobility-group box 6(SOX6), a tumor suppressor gene or oncogene in several cancers, could induce autophagy in cervical cancer. Accordingly, this study aims to investigate the mechanism of SOX6-induced autophagy and its potential significance in the platinum-based chemotherapy of cervical cancer. Firstly, we found that SOX6 could promote autophagy in cervical cancer cells depending on its HMG domain.Mitogen-activated protein kinase kinase kinase kinase-4(MAP4K4) gene was identified as the direct target gene of SOX6, which was transcriptionally upregulated by binding the HMG domain of SOX6 protein to its double-binding sites withinMAP4K4gene promoter. MAP4K4 mediated the SOX6-induced autophagy through inhibiting PI3K-Akt-mTOR pathway and activating MAPK/ERK pathway. Further, the sensitivity of cervical cancer cells to cisplatin chemotherapy could be reduced by the SOX6-induced autophagy in vitro and in vivo, while such a phenomenon could be turned over by autophagy-specific inhibitor and MAP4K4 inhibitor, respectively. Moreover, cisplatin itself could promote the expression of endogenous SOX6 and subsequently the MAP4K4-mediated autophagy in cervical cancer cells, which might in turn reduce the sensitivity of these cells to cisplatin treatment. These findings uncovered the underlying mechanism and potential significance of SOX6-induced autophagy, and shed new light on the usage of MAP4K4 inhibitor or autophagy-specific inhibitor for sensitizing cervical cancer cells to the platinum-based chemotherapy.

Long non-coding RNA NRSN2-AS1 promotes ovarian cancer progression through targeting PTK2/β-catenin pathway

Abstract As a common malignant tumor among women, ovarian cancer poses a serious threat to their health. This study demonstrates that long non-coding RNA NRSN2-AS1 is over-expressed in ovarian cancer tissues using patient sample and tissue microarrays. In addition, NRSN2-AS1 is shown to promote ovarian cancer cell proliferation and metastasis both in vitro and in vivo. Mechanistically, NRSN2-AS1 stabilizes protein tyrosine kinase 2 (PTK2) to activate the β-catenin pathway via repressing MG-53-mediated ubiquitinated degradation of PTK2, thereby facilitating ovarian cancer progression. Rescue experiments verify the function of the NRSN2-AS1/PTK2/β-catenin axis and the effects of MG53 on this axis in ovarian cancer cells. In conclusion, this study demonstrates the key role of the NRSN2-AS1/PTK2/β-catenin axis for the first time and explores its potential clinical applications in ovarian cancer.

Lamin-A interacting protein Hsp90 is required for DNA damage repair and chemoresistance of ovarian cancer cells

AbstractOvarian cancer is the most malignant gynecologic cancer. Previous studies found that lamin-A was associated with DNA damage repair proteins but the underlying mechanism remains unclear. We speculate that this may be related to its interacting proteins, such as Hsp90. The aim of this study is to investigate the effects of Hsp90 on DNA damage repair and chemoresistance of ovarian cancer cells. In our research, co-immunoprecipitation (co-IP) and mass spectrometry (MS) were used to identify proteins interacting with lamin-A and the interaction domain. Next, the relationship between lamin-A and Hsp90 was explored by Western blotting (WB) and immunofluorescence staining. Then, effect of Hsp90 inhibition on DNA damage repair was assessed through detecting Rad50 and Ku80 by WB. Furthermore, to test the roles of 17-AAG on cell chemosensitivity, CCK-8 and colony formation assay were carried out. Meanwhile, IC50 of cells were calculated, followed by immunofluorescence to detect DNA damage. At last, the mouse xenograft model was used in determining the capacity of 17-AAG and DDP to suppress tumor growth and metastatic potential. The results showed that lamin-A could interact with Hsp90 via the domain of lamin-A1-430. Besides, the distribution of Hsp90 could be affected by lamin-A. After lamin-A knockdown, Hsp90 decreased in the cytoplasm and increased in the nucleus, suggesting that the interaction between lamin-A and Hsp90 may be related to the nucleocytoplasmic transport of Hsp90. Moreover, inhibition of Hsp90 led to an obvious decrease in the expression of DSBs (DNA double-strand break) repair proteins, as well as cell proliferation ability upon DDP treatment and IC50 of DDP, causing more serious DNA damage. In addition, the combination of 17-AAG and DDP restrained the growth of ovarian cancer efficiently in vivo and prolonged the survival time of tumor-bearing mice.

Constitutive BAK/MCL1 complexes predict paclitaxel and S63845 sensitivity of ovarian cancer

Abstract We previously found that preformed complexes of BAK with antiapoptotic BCL2 proteins predict BH3 mimetic sensitivities in lymphohematopoietic cells. These complexes have not previously been examined in solid tumors or in the context of conventional anticancer drugs. Here we show the relative amount of BAK found in preformed complexes with MCL1 or BCLX L varies across ovarian cancer cell lines and patient-derived xenografts (PDXs). Cells bearing BAK/MCL1 complexes were more sensitive to paclitaxel and the MCL1 antagonist S63845. Likewise, PDX models with BAK/MCL1 complexes were more likely to respond to paclitaxel. Mechanistically, BIM induced by low paclitaxel concentrations interacted preferentially with MCL1 and displaced MCL1-bound BAK. Further studies indicated that cells with preformed BAK/MCL1 complexes were sensitive to the paclitaxel/S63845 combination, while cells without BAK/MCL1 complexes were not. Our study suggested that the assessment of BAK/MCL1 complexes might be useful for predicting response to paclitaxel alone or in combination with BH3 mimetics.

TTK inhibition increases cisplatin sensitivity in high-grade serous ovarian carcinoma through the mTOR/autophagy pathway

AbstractHigh-grade serous ovarian cancer (HGSOC) is the most lethal gynecological malignancy. However, the molecular mechanisms underlying HGSOC development, progression, chemotherapy insensitivity and resistance remain unclear. Two independent GEO datasets, including the gene expression profile of primary ovarian carcinoma and normal controls, were analyzed to identify genes related to HGSOC development and progression. A KEGG pathway analysis of the differentially expressed genes (DEGs) revealed that the cell cycle pathway was the most enriched pathway, among which TTK protein kinase (TTK) was the only gene with a clinical-grade inhibitor that has been investigated in a clinical trial but had not been studied in HGSOC. TTK was also upregulated in cisplatin-resistant ovarian cancer cells from two other datasets. TTK is a regulator of spindle assembly checkpoint signaling, playing an important role in cell cycle control and tumorigenesis in various cancers. However, the function and regulatory mechanism of TTK in HGSOC remain to be determined. In this study, we observed TTK upregulation in patients with HGSOC. High TTK expression was related to a poor prognosis. Genetic and pharmacological inhibition of TTK impeded the proliferation of ovarian cancer cells by disturbing cell cycle progression and increasing apoptosis. TTK silencing increased cisplatin sensitivity by activating the mammalian target of rapamycin (mTOR) complex to further suppress cisplatin-induced autophagy in vitro. In addition, the enhanced sensitivity was partially diminished by rapamycin-mediated inhibition of mTOR in TTK knockdown cells. Furthermore, TTK knockdown increased the toxicity of cisplatin in vivo by decreasing autophagy. These findings suggest that the administration of TTK inhibitors in combination with cisplatin may lead to improved response rates to cisplatin in patients with HGSOC presenting high TTK expression. In summary, our study may provide a theoretical foundation for using the combination therapy of cisplatin and TTK inhibitors as a treatment for HGSOC in the future.

FBXO16-mediated hnRNPL ubiquitination and degradation plays a tumor suppressor role in ovarian cancer

AbstractHeterogeneous nuclear ribonucleoprotein L (hnRNPL) is a type of RNA binding protein that highly expressed in a variety of tumors and plays a vital role in tumor progression. However, its post-translational regulation through ubiquitin-mediated proteolysis and the cellular mechanism responsible for its proteasomal degradation remains unclear. F-box proteins (FBPs) function as the substrate recognition subunits of SCF ubiquitin ligase complexes and directly bind to substrates. The aberrant expression or mutation of FBPs will lead to the accumulation of its substrate proteins that often involved in tumorigenesis. Here we discover FBXO16, an E3 ubiquitin ligase, to be a tumor suppressor in ovarian cancer, and patients with the relatively high expression level of FBXO16 have a better prognosis. Silencing or depleting FBXO16 significantly enhanced ovarian cancer cell proliferation, clonogenic survival, and cell invasion by activating multiple oncogenic pathways. This function requires the F-box domain of FBXO16, through which FBXO16 assembles a canonical SCF ubiquitin ligase complex that constitutively targets hnRNPL for degradation. Depletion of hnRNPL is sufficient to inactive multiple oncogenic signaling regulated by FBXO16 and prevent the malignant behavior of ovarian cancer cells caused by FBXO16 deficiency. FBXO16 interacted with the RRM3 domain of hnRNPL via its C-terminal region to trigger the proteasomal degradation of hnRNPL. Failure to degrade hnRNPL promoted ovarian cancer cell proliferation in vitro and tumor growth vivo, phenocopying the deficiency of FBXO16 in ovarian cancer.

The role of S-nitrosylation of PFKM in regulation of glycolysis in ovarian cancer cells

AbstractOne of the malignant transformation hallmarks is metabolism reprogramming, which plays a critical role in the biosynthetic needs of unchecked proliferation, abrogating cell death programs, and immunologic escape. However, the mechanism of the metabolic switch is not fully understood. Here, we found that the S-nitrosoproteomic profile of endogenous nitrogen oxide in ovarian cancer cells targeted multiple components in metabolism processes. Phosphofructokinase (PFKM), one of the most important regulatory enzymes of glycolysis, was S-nitrosylated by nitric oxide synthase NOS1 at Cys351. S-nitrosylation at Cys351 stabilized the tetramer of PFKM, leading to resist negative feedback of downstream metabolic intermediates. The PFKM-C351S mutation decreased the proliferation rate of cultured cancer cells, and reduced tumor growth and metastasis in the mouse xenograft model. These findings indicated that S-nitrosylation at Cys351 of PFKM by NOS1 contributes to the metabolic reprogramming of ovarian cancer cells, highlighting a critical role of endogenous nitrogen oxide on metabolism regulations in tumor progression.

SENP1-mediated deSUMOylation of JAK2 regulates its kinase activity and platinum drug resistance

AbstractThe JAK2/STAT pathway is hyperactivated in many cancers, and such hyperactivation is associated with a poor clinical prognosis and drug resistance. The mechanism regulating JAK2 activity is complex. Although translocation of JAK2 between nucleus and cytoplasm is an important regulatory mechanism, how JAK2 translocation is regulated and what is the physiological function of this translocation remain largely unknown. Here, we found that protease SENP1 directly interacts with and deSUMOylates JAK2, and the deSUMOylation of JAK2 leads to its accumulation at cytoplasm, where JAK2 is activated. Significantly, this novel SENP1/JAK2 axis is activated in platinum-resistant ovarian cancer in a manner dependent on a transcription factor RUNX2 and activated RUNX2/SENP1/JAK2 is critical for platinum-resistance in ovarian cancer. To explore the application of anti-SENP1/JAK2 for treatment of platinum-resistant ovarian cancer, we found SENP1 deficiency or treatment by SENP1 inhibitor Momordin Ic significantly overcomes platinum-resistance of ovarian cancer. Thus, this study not only identifies a novel mechanism regulating JAK2 activity, but also provides with a potential approach to treat platinum-resistant ovarian cancer by targeting SENP1/JAK2 pathway.

Splicing factor USP39 promotes ovarian cancer malignancy through maintaining efficient splicing of oncogenic HMGA2

AbstractAberrant expression of splicing factors was found to promote tumorigenesis and the development of human malignant tumors. Nevertheless, the underlying mechanisms and functional relevance remain elusive. We here show that USP39, a component of the spliceosome, is frequently overexpressed in high-grade serous ovarian carcinoma (HGSOC) and that an elevated level of USP39 is associated with a poor prognosis. USP39 promotes proliferation/invasion in vitro and tumor growth in vivo. Importantly, USP39 was transcriptionally activated by the oncogene protein c-MYC in ovarian cancer cells. We further demonstrated that USP39 colocalizes with spliceosome components in nuclear speckles. Transcriptomic analysis revealed that USP39 deletion led to globally impaired splicing that is characterized by skipped exons and overrepresentation of introns and intergenic regions. Furthermore, RNA immunoprecipitation sequencing showed that USP39 preferentially binds to exon-intron regions near 5′ and 3′ splicing sites. In particular, USP39 facilitates efficient splicing of HMGA2 and thereby increases the malignancy of ovarian cancer cells. Taken together, our results indicate that USP39 functions as an oncogenic splicing factor in ovarian cancer and represents a potential target for ovarian cancer therapy.

FBXO6-mediated RNASET2 ubiquitination and degradation governs the development of ovarian cancer

AbstractRNASET2 (Ribonuclease T2) functions as a tumor suppressor in preventing ovarian tumorigenesis. However, the mechanisms underlying the regulation of RNASET2 protein are completely unknown. Here we identified the F-box protein FBXO6, a substrate recognition subunit of an SCF (Skp1-Cul1-F-box protein) complex, as the ubiquitin E3 ligase for RNASET2. We found that the interaction between FBXO6 and RNASET2 induced RNASET2 instability through the ubiquitin-mediated proteasome degradation pathway. FBXO6 promoted K48-dependent ubiquitination of RNASET2 via its FBA domain. Through analysis of the TCGA dataset, we found that FBXO6 was significantly increased in ovarian cancer tissues and the high expression of FBXO6 was related to the poor overall survival (OS) of ovarian cancer patients at advanced stages. An inverse correlation between the protein levels of FBXO6 and RNASET2 was observed in clinic ovarian cancer samples. Depletion of FBXO6 promoted ovarian cancer cells proliferation, migration, and invasion, which could be partially reversed by RNASET2 silencing. Thus, our data revealed a novel FBXO6-RNASET2 axis, which might contribute to the development of ovarian cancer. We propose that inhibition of FBXO6 might represent an effective therapeutic strategy for ovarian cancer treatment.

Stat1 confers sensitivity to radiation in cervical cancer cells by controlling Parp1 levels: a new perspective for Parp1 inhibition

AbstractCervical cancer (CC) is the fourth most common cause of cancer-related death in women. According to international guidelines, a standard treatment for locally advanced cervical cancer (LACC) consists of exclusive concurrent chemoradiation treatment (CRT). However, chemoradioresistance and subsequent relapse and metastasis of cancer occur in many patients, and survival for these women has generally remained poor. Therefore, strategies to overcome resistance are urgently needed. We have recently reported a radiosensitizing effect of the signal transducer and activator of transcription 1 (STAT1) in CC, associated with the control of [Poly(ADP-ribose) polymerase −1] PARP1 levels, a key factor in cell response to DNA damage induced by radiation. Here, we sought to decipher the underlying mechanism of STAT1-mediated control of PARP1, elucidating its role as a radiosensitizer in CC. Functional and molecular biology studies demonstrated that STAT1 may act at both transcriptional and posttranscriptional levels to modulate PARP1 expression in CC cells. In light of these results, we tested the effect of Olaparib in sensitizing CC cells to radiation and investigated signaling pathways involved in the activity observed. Results showed that PARP1 inhibition, at clinically achievable doses, may indeed selectively improve the sensitivity of resistant CC cells to DNA-damaging treatment. The translational relevance of our findings was supported by preliminary results in a limited patient cohort, confirming that higher PARP1 levels are significantly associated with a radioresistant phenotype. Finally, bioinformatics analysis of GEPIA and TCGA databases, demonstrated that PARP1 mRNA is higher in CC than in normal tissues and that increased PARP1 mRNA expression levels are associated with poor prognosis of LACC patients. Overall, our data open new opportunities for the development of personalized treatments in women diagnosed with CC.

FoxP3-miR-150-5p/3p suppresses ovarian tumorigenesis via an IGF1R/IRS1 pathway feedback loop

AbstractOvarian cancer (OC) causes more deaths than any other gynecological cancer. Many cellular pathways have been elucidated to be associated with OC development and progression. Specifically, the insulin-like growth factor 1 receptor/insulin receptor substrate 1 (IGF1R/IRS1) pathway participates in OC development. Moreover, accumulating evidence has shown that microRNA deregulation contributes to tumor initiation and progression. Here, our study aimed to investigate the molecular functions and regulatory mechanisms of miR-150, specifically, in OC. We found that the expression of miR-150-5p/3p and their precursor, mir-150, was downregulated in OC tissues; lower mir-150 levels were associated with poor OC patient outcomes. Ectopic mir-150 expression inhibited OC cell growth and metastasis in vitro and in vivo. Furthermore, both IRS1 and IGF1R were confirmed as direct targets of miR-150-5p/3p, and the miR-150-IGF1R/IRS1 axis exerted antitumor effects via the PI3K/AKT/mTOR pathway. Forkhead box protein 3 (FoxP3) positively regulated the expression of miR-150-5p/3p by binding to the mir-150 promoter. In turn, the PI3K/AKT/mTOR pathway downregulated FoxP3 and miR-150-5p/3p. Taken together, these findings indicate that a complex FoxP3-miR-150-IGF1R/IRS1-PI3K/AKT/mTOR feedback loop regulates OC pathogenesis, providing a novel mechanism for miR-150 as a tumor suppressor miRNA in OC.

Exosomes in ovarian cancer ascites promote epithelial–mesenchymal transition of ovarian cancer cells by delivery of miR-6780b-5p

AbstractThe poor prognosis of ovarian cancer is mainly due to metastasis, and the specific mechanism underlying ovarian cancer metastasis is not clear. Ascites-derived exosomes (ADEs) play an important role in the progression of ovarian cancer, but the mechanism is unknown. Here, we found that ADEs promoted ovarian cancer metastasis not only in vitro but also in vivo. This promotive function was based on epithelial–mesenchymal transition (EMT) of ovarian cancer cells. Bioinformatics analysis of RNA sequencing microarray data indicated that miR-6780b-5p may be the key microRNA (miRNA) in ADEs that facilitates cancer metastasis. Moreover, the expression of exosomal miR-6780b-5p correlated with tumor metastasis in ovarian cancer patients. miR-6780b-5p overexpression promoted and miR-6780b-5p downregulation suppressed EMT of ovarian cancer cells. These results suggest that ADEs transfer miR-6780b-5p to ovarian cancer cells, promoting EMT and finally facilitating ovarian cancer metastasis.

Selective killing of cancer cells harboring mutant RAS by concomitant inhibition of NADPH oxidase and glutathione biosynthesis

AbstractOncogenic RAS is a critical driver for the initiation and progression of several types of cancers. However, effective therapeutic strategies by targeting RAS, in particular RASG12D and RASG12V, and associated downstream pathways have been so far unsuccessful. Treatment of oncogenic RAS-ravaged cancer patients remains a currently unmet clinical need. Consistent with a major role in cancer metabolism, oncogenic RAS activation elevates both reactive oxygen species (ROS)-generating NADPH oxidase (NOX) activity and ROS-scavenging glutathione biosynthesis. At a certain threshold, the heightened oxidative stress and antioxidant capability achieve a higher level of redox balance, on which cancer cells depend to gain a selective advantage on survival and proliferation. However, this prominent metabolic feature may irrevocably render cancer cells vulnerable to concurrent inhibition of both NOX activity and glutathione biosynthesis, which may be exploited as a novel therapeutic strategy. In this report, we test this hypothesis by treating the HRASG12V-transformed ovarian epithelial cells, mutant KRAS-harboring pancreatic and colon cancer cells of mouse and human origins, as well as cancer xenografts, with diphenyleneiodonium (DPI) and buthionine sulfoximine (BSO) combination, which inhibit NOX activity and glutathione biosynthesis, respectively. Our results demonstrate that concomitant targeting of NOX and glutathione biosynthesis induces a highly potent lethality to cancer cells harboring oncogenic RAS. Therefore, our studies provide a novel strategy against RAS-bearing cancers that warrants further mechanistic and translational investigation.

Molecular imaging of the kinetics of hyperactivated ERK1/2-mediated autophagy during acquirement of chemoresistance

AbstractAlterations in key kinases and signaling pathways can fine-tune autophagic flux to promote the development of chemoresistance. Despite empirical evidences of strong association between enhanced autophagic flux with acquired chemoresistance, it is still not understood whether an ongoing autophagic flux is required for both initiation, as well as maintenance of chemoresistance, or is sufficient for one of the either steps. Utilizing indigenously developed cisplatin–paclitaxel-resistant models of ovarian cancer cells, we report an intriguing oscillation in chemotherapy-induced autophagic flux across stages of resistance, which was found to be specifically elevated at the early stages or onset of chemoresistance. Conversely, the sensitive cells and cells at late stages of resistance showed stalled and reduced autophagic flux. This increased flux at early stages of resistance was found to be dictated by a hyperactive ERK1/2 signaling, which when inhibited either pharmacologically (U0126/Trametinib) or genetically, reduced p62 degradation, number of LC3+veLAMP1+ve puncta, autophagolysosome formation, and led to chemo-sensitization and apoptosis. Inhibition of ERK1/2 activation also altered the level of UVRAG and Rab7, the two key proteins involved in autophagosome–lysosome fusion. Noninvasive imaging of autophagic flux using a novel autophagy sensor (mtFL-p62 fusion reporter) showed that combinatorial treatment of platinum–taxol along with Trametinib/chloroquine blocked autophagic flux in live cells and tumor xenografts. Interestingly, Trametinib was found to be equally effective in blocking autophagic flux as chloroquine both in live cells and tumor xenografts. Combinatorial treatment of Trametinib and platinum–taxol significantly reduced tumor growth. This is probably the first report of real-time monitoring of chemotherapy-induced autophagy kinetics through noninvasive bioluminescence imaging in preclinical mouse model. Altogether our data suggest that an activated ERK1/2 supports proper completion of autophagic flux at the onset of chemoresistance to endure initial chemotherapeutic insult and foster the development of a highly chemoresistant phenotype, where autophagy becomes dispensable.

Global characterization of extrachromosomal circular DNAs in advanced high grade serous ovarian cancer

AbstractHigh grade serous ovarian cancer (HGSOC) is the most aggressive subtype of ovarian cancer and HGSOC patients often appear with metastasis, leading to the poor prognosis. Up to date, the extrachromosomal circular DNAs (eccDNAs) have been shown to be involved in cancer genome remodeling but the roles of eccDNAs in metastatic HGSOC are still not clear. Here we explored eccDNA profiles in HGSOC by Circle-Sequencing analysis using four pairs of primary and metastatic tissues of HGSOC patients. Within the differentially expressed eccDNAs screened out by our analysis, eight candidates were validated by outward PCR and qRT-PCR analysis. Among them, DNMT1circle10302690-10302961 was further confirmed by FISH assay and BaseScope assay, as the most significantly down-regulated eccDNA in metastatic tumors of HGSOC. Lower expression of DNMT1circle10302690-10302961 in both primary and metastatic tumors was associated with worse prognosis of HGSOC. Taken together, our finding firstly demonstrated the eccDNAs landscape of primary and metastatic tissues of HGSOC. The eccDNA DNMT1circle10302690-10302961 can be considered as a potential biomarker or a therapeutically clinical target of HGSOC metastasis and prognosis.

DHRS2 inhibits cell growth and metastasis in ovarian cancer by downregulation of CHKα to disrupt choline metabolism

AbstractThe short-chain dehydrogenase/reductase (SDR) superfamily has essential roles in lipid metabolism and redox sensing. In recent years, accumulating evidence highlights the emerging association between SDR family enzymes and cancer. Dehydrogenase/reductase member 2(DHRS2) belongs to the NADH/NADPH-dependent SDR family, and extensively participates in the regulation of the proliferation, migration, and chemoresistance of cancer cells. However, the underlying mechanism has not been well defined. In the present study, we have demonstrated that DHRS2 inhibits the growth and metastasis of ovarian cancer (OC) cells in vitro and in vivo. Mechanistically, the combination of transcriptome and metabolome reveals an interruption of choline metabolism by DHRS2. DHRS2 post-transcriptionally downregulates choline kinase α (CHKα) to inhibit AKT signaling activation and reduce phosphorylcholine (PC)/glycerophosphorylcholine (GPC) ratio, impeding choline metabolism reprogramming in OC. These actions mainly account for the tumor-suppressive role of DHRS2 in OC. Overall, our findings establish the mechanistic connection among metabolic enzymes, metabolites, and the malignant phenotype of cancer cells. This could result in further development of novel pharmacological tools against OC by the induction of DHRS2 to disrupt the choline metabolic pathway.

CircRNF144B/miR-342-3p/FBXL11 axis reduced autophagy and promoted the progression of ovarian cancer by increasing the ubiquitination of Beclin-1

AbstractCircular RNAs (circRNAs) can regulate autophagy and ovarian cancer (OC) progression. However, autophagy-associated circRNAs involved in OC progression are largely unknown. Bioinformatics, RNA sequencing, and qRT-PCR were conducted to detect circRNF144B expression in OC as well as its relationship with patient prognosis. Functional experiments were used to determine the effects of circRNF144B on the proliferation, mobility and autophagy of OC. Double luciferase reporter assays, immunoprecipitation, and ubiquitination detection were performed to determine the molecular mechanisms of circRNF144B in autophagy and OC progression. CircRNF144B was elevated in OC tissues with low autophagy levels, and associated with poor prognosis. CircRNF144B promoted the malignant biological properties of OC cells, and inhibited the autophagy. Mechanistically, circRNF144B acts as a sponge for miR-342-3p and inhibits miR-342-3p-induced degradation of lysine demethylase 2 A (FBXL11) mRNA, leading to elevated FBXL11 protein levels. Elevated FBXL11 promoted the ubiquitination and degradation of Beclin-1, thus inhibiting autophagy. In conclusion, CircRNF144B increased FBXL11 level by sponging miR-342-3p, whereas elevated FBXL11 promoted the ubiquitination and protein degradation of Beclin-1, thus suppressing autophagy flux and promoting OC progression. Thus, circRNF144B may be an effective target for OC therapy.

Olaparib synergizes with arsenic trioxide by promoting apoptosis and ferroptosis in platinum-resistant ovarian cancer

AbstractPoly (ADP-ribose) polymerase (PARP) inhibitors are efficacious in treating platinum-sensitive ovarian cancer (OC), but demonstrate limited efficiency in patients with platinum-resistant OC. Thus, further investigations into combined strategies that enhance the response to PARP inhibitors (PARPi) in platinum-resistant OC are required. The present study aimed to investigate the combined therapy of arsenic trioxide (ATO) with olaparib, a common PARPi, and determine how this synergistic cytotoxicity works in platinum-resistant OC cells. Functional assays demonstrated that the combined treatment of olaparib with ATO significantly suppressed cell proliferation and colony formation, and enhanced DNA damage as well as cell apoptosis in A2780-CIS and SKOV3-CIS cell lines. Results of the present study also demonstrated that a combination of olaparib with ATO increased lipid peroxidation and eventually triggered ferroptosis. Consistently, the combined treatment synergistically suppressed tumor growth in mice xenograft models. Mechanistically, ATO in combination with olaparib activated the AMPK α pathway and suppressed the expression levels of stearoyl-CoA desaturase 1 (SCD1). Collectively, results of the present study demonstrated that treatment with ATO enhanced the effects of olaparib in platinum-resistant OC.

Multiomics characterization implicates PTK7 in ovarian cancer EMT and cell plasticity and offers strategies for therapeutic intervention

AbstractMost patients with ovarian cancer (OC) are diagnosed at a late stage when there are very few therapeutic options and a poor prognosis. This is due to the lack of clearly defined underlying mechanisms or an oncogenic addiction that can be targeted pharmacologically, unlike other types of cancer. Here, we identified protein tyrosine kinase 7 (PTK7) as a potential new therapeutic target in OC following a multiomics approach using genetic and pharmacological interventions. We performed proteomics analyses upon PTK7 knockdown in OC cells and identified novel downstream effectors such as synuclein-γ (SNCG), SALL2, and PP1γ, and these findings were corroborated in ex vivo primary samples using PTK7 monoclonal antibody cofetuzumab. Our phosphoproteomics analyses demonstrated that PTK7 modulates cell adhesion and Rho-GTPase signaling to sustain epithelial-mesenchymal transition (EMT) and cell plasticity, which was confirmed by high-content image analysis of 3D models. Furthermore, using high-throughput drug sensitivity testing (525 drugs) we show that targeting PTK7 exhibited synergistic activity with chemotherapeutic agent paclitaxel, CHK1/2 inhibitor prexasertib, and PLK1 inhibitor GSK461364, among others, in OC cells and ex vivo primary samples. Taken together, our study provides unique insight into the function of PTK7, which helps to define its role in mediating aberrant Wnt signaling in ovarian cancer.

CRMP2 derived from cancer associated fibroblasts facilitates progression of ovarian cancer via HIF-1α-glycolysis signaling pathway

AbstractAs the predominant stroma cells of tumor microenvironment (TME), cancer associated fibroblasts (CAFs) are robust tumor player of different malignancies. However, less is known about the regulatory mechanism of CAFs on promoting progression of ovarian cancer (OvCA). In the present study, the conditioned medium of primary CAFs (CAF-CM) from OvCA was used to culture cell lines of epithelial ovarian cancer (EOC), and showed a potent role in promoting proliferation, migration and invasion of cancer cells. Mass spectrum (MS) analysis identified that Collapsin response mediator protein-2 (CRMP2), a microtubule-associated protein involved in diverse malignancies, derived from CAFs was a key regulator responsible for mediating these cell events of OvCA. In vitro study using recombinant CRMP2 (r-CRMP2) revealed that the protein promoted proliferation, invasion, and migration of OvCA cells through activation of hypoxia-inducible factor (HIF)-1α-glycolysis signaling pathway. The CRMP2 was abundantly expressed in OvCA, with a well correlation with metastasis and poor prognosis, as analyzed from 118 patients’ samples. Inhibition of the CRMP2 derived from CAFs by neutralizing antibodies significantly attenuated the tumor size, weights, and metastatic foci numbers of mice in vivo. Our finding has provided a novel therapeutic clue for OvCA based on TME.

Ct-OATP1B3 promotes high-grade serous ovarian cancer metastasis by regulation of fatty acid beta-oxidation and oxidative phosphorylation

AbstractHigh-grade serous ovarian cancer (HGSOC) is the most lethal gynecologic malignancy mainly due to its extensive metastasis. Cancer-type organic anion transporting polypeptide 1B3 (Ct-OATP1B3), a newly discovered splice variant of solute carrier organic anion transporter family member 1B3 (SLCO1B3), has been reported to be overexpressed in several types of cancer. However, the biological function of Ct-OATP1B3 remains largely unknown. Here, we reveal that Ct-OATP1B3 is overexpressed in HGSOC and promotes the metastasis of HGSOC in vivo and in vitro. Mechanically, Ct-OATP1B3 directly interacts with insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2), an RNA-binding protein, which results in enhancement of the mRNA stability and expression of carnitine palmitoyltransferase 1A (CPT1A) and NADH:Ubiquinone Oxidoreductase Subunit A2 (NDUFA2), leading to increased mitochondrial fatty acid beta-oxidation (FAO) and oxidative phosphorylation (OXPHOS) activities. The increased FAO and OXPHOS activities further facilitate adenosine triphosphate (ATP) production and cellular lamellipodia formation, which is the initial step in the processes of tumor cell migration and invasion. Taken together, our study provides an insight into the function and underlying mechanism of Ct-OATP1B3 in HGSOC metastasis, and highlights Ct-OATP1B3 as a novel prognostic marker as well as therapeutic target in HGSOC.

MEX3A promotes the malignant progression of ovarian cancer by regulating intron retention in TIMELESS

AbstractThe latest research shows that RNA-binding proteins (RBPs) could serve as novel potential targets for cancer therapy. We used bioinformatics analysis to screen and identify the key RBPs in ovarian cancer, from which we found that Mex-3 RNA Binding Family Member A (MEX3A) was intimately associated with the clinical prognosis of ovarian cancer. Nevertheless, little is known about its biological roles in ovarian cancer. In this case, we observed that MEX3A was highly overexpressed in fresh-frozen ovarian cancer tissues. MEX3A knockdown suppressed the development and invasion of ovarian cancer cells, while MEX3A overexpression promoted the proliferation and invasion of ovarian cancer cells. Mechanistically, TIMELESS was the critical downstream target gene of MEX3A, as demonstrated through alternative splicing event analysis based on RNA-seq. MEX3A knockdown resulted in retention of intron twenty-three of TIMELESS mRNA and decreased TIMELESS mRNA owing to stimulation of nonsense-mediated RNA decay (NMD). Additionally, we found that TIMELESS overexpression with MEX3A knockdown partially restored the proliferation ability of ovarian cancer cells. The results of this paper demonstrated that the MEX3A/TIMELESS signaling pathway was a key regulator of ovarian cancer, and MEX3A was a novel possible treatment target for ovarian cancer patients.

Cisplatin resistance can be curtailed by blunting Bnip3-mediated mitochondrial autophagy

AbstractCisplatin (CDDP) is commonly used to treat a multitude of tumors including sarcomas, ovarian and cervical cancers. Despite recent investigations allowed to improve chemotherapy effectiveness, the molecular mechanisms underlying the development of CDDP resistance remain a major goal in cancer research. Here, we show that mitochondrial morphology and autophagy are altered in different CDDP resistant cancer cell lines. In CDDP resistant osteosarcoma and ovarian carcinoma, mitochondria are fragmented and closely juxtaposed to the endoplasmic reticulum; rates of mitophagy are also increased. Specifically, levels of the mitophagy receptor BNIP3 are higher both in resistant cells and in ovarian cancer patient samples resistant to platinum-based treatments. Genetic BNIP3 silencing or pharmacological inhibition of autophagosome formation re-sensitizes these cells to CDDP. Our study identifies inhibition of BNIP3-driven mitophagy as a potential therapeutic strategy to counteract CDDP resistance in ovarian carcinoma and osteosarcoma.

Partitioning defective 6 homolog alpha (PARD6A) promotes epithelial–mesenchymal transition via integrin β1-ILK-SNAIL1 pathway in ovarian cancer

AbstractPartitioning-defective protein 6 (Par6) family proteins have been demonstrated to be closely associated with the occurrence and development of cancers. It is well accepted that dysregulation of epithelial–mesenchymal transition (EMT) greatly contributes to carcinogenesis and metastases of ovarian cancer. So far, the roles of Par6 in EMT of ovarian cancer are not clear. Functional experiments were carried out to study the roles of PARD6A in EMT of ovarian cancer in vitro and in vivo, and EMT pathways potentially affected by PARD6A expression were screened. We found that PARD6A was significantly highly expressed in tissues of ovarian cancer patients in III-IV stages, poorly differentiated or with lymphatic metastases versus I-II stages, moderately or well differentiated, or without lymphatic metastases, respectively. PARD6A knockdown suppressed EMT of SKOV3 and A2780 cells in vitro and ovarian cancer metastasis in vivo, while overexpression of PARD6A promoted EMT in HO8910 and OVCAR8 cells. It was indicated that PARD6A affected EMT of ovarian cancer cells through SNAIL1 signaling pathway and subsequently modulated the expression of VIMENTIN and E-cadherin, which was further confirmed by knockdown and overexpression of SNAIL1 experiments. PARD6A was also demonstrated to regulate expression of SNAIL1 by modulating integrin β1 and ILK proteins, specifically it was shown that the transcription of SNAIL1 was regulated by ILK in this study. In addition, expression of ILK in ovarian cancer tissues was demonstrated to be correlated with tumor stages and lymphatic metastases clinically. In this study, we identified a novel role of PARD6A as an inducer of cell migration and invasion, which is likely to play an important role in metastasis of ovarian cancer. The molecular pathways of EMT mediated by PARD6A-Integrin β1-ILK-SNAIL1 and finally implemented by E-cadherin and VIMENTIN may provide a novel strategy for drug development for ovarian cancer therapy in the near future.

HMGB3 promotes PARP inhibitor resistance through interacting with PARP1 in ovarian cancer

AbstractPoly (ADP-ribose) polymerase (PARP) inhibitor (PARPi) resistance remains a therapeutic challenge in ovarian cancer. High-mobility group box 3 (HMGB3) plays significant roles in the development of drug resistance of many cancers. However, the function of HMGB3 in PARPi resistance is poorly understood. In the current study, we clarified that HMGB3 was aberrantly overexpressed in high-grade serous ovarian carcinoma (HGSOC) tissues, and high HMGB3 levels indicated shorter overall survival and drug resistance in HGSOC. The overexpression of HMGB3 increased the insensitivity of ovarian cancer to PARPi, whereas HMGB3 knockdown reduced PARPi resistance. Mechanistically, PARP1 was identified as a novel interaction partner of HMGB3, which could be blocked using olaparib and was enhanced upon DNA damage conditions. We further showed that loss of HMGB3 induced PARP1 trapping at DNA lesions and inhibited the PARylation activity of PARP1, resulting in an increased DNA damage response and cell apoptosis. The PARPi-resistant role of HMGB3 was also verified in a xenograft mouse model. In conclusion, HMGB3 promoted PARPi resistance via interacting with PARP1, and the targeted inhibition of HMGB3 might overcome PARPi resistance in ovarian cancer therapy.

SF3B4 promotes ovarian cancer progression by regulating alternative splicing of RAD52

AbstractMany studies have proven that splicing factors are crucial for human malignant tumor development. However, as a classical splicing factor, the expression of SF3B4 is not clear, and its biological function needs to be further clarified in ovarian cancer (OC). We determined that SF3B4 was obviously upregulated and its high expression was associated with poor prognosis in OC patients. In vitro and in vivo assays suggested that SF3B4 overexpression promoted OC cell proliferation and mobility, and downregulation of SF3B4 had the opposite effect. Further studies found that miR-509–3p decreased SF3B4 mRNA expression by binding to the 3’ -UTR of SF3B4 directly. Importantly, we revealed that RAD52 was a potential target of SF3B4 through alternative splicing events analysis. Loss of SF3B4 led to decreased expression of RAD52, owing to intron 8 retention and generation of premature termination codons. Moreover, decreased expression of RAD52 partially counteracted the tumor-promoting effect of SF3B4 overexpression. In conclusion, our results suggested that SF3B4, negatively regulated by miR-509–3p, promoted OC progression through effective splicing of RAD52. Therefore, SF3B4 may be a promising biomarker and effective therapeutic target for OC.

PHY34 inhibits autophagy through V-ATPase V0A2 subunit inhibition and CAS/CSE1L nuclear cargo trafficking in high grade serous ovarian cancer

AbstractPHY34 is a synthetic small molecule, inspired by a compound naturally occurring in tropical plants of the Phyllanthus genus. PHY34 was developed to have potent in vitro and in vivo anticancer activity against high grade serous ovarian cancer (HGSOC) cells. Mechanistically, PHY34 induced apoptosis in ovarian cancer cells by late-stage autophagy inhibition. Furthermore, PHY34 significantly reduced tumor burden in a xenograft model of ovarian cancer. In order to identify its molecular target/s, we undertook an unbiased approach utilizing mass spectrometry-based chemoproteomics. Protein targets from the nucleocytoplasmic transport pathway were identified from the pulldown assay with the cellular apoptosis susceptibility (CAS) protein, also known as CSE1L, representing a likely candidate protein. A tumor microarray confirmed data from mRNA expression data in public databases that CAS expression was elevated in HGSOC and correlated with worse clinical outcomes. Overexpression of CAS reduced PHY34 induced apoptosis in ovarian cancer cells based on PARP cleavage and Annexin V staining. Compounds with a diphyllin structure similar to PHY34 have been shown to inhibit the ATP6V0A2 subunit of V(vacuolar)-ATPase. Therefore, ATP6V0A2 wild-type and ATP6V0A2 V823 mutant cell lines were tested with PHY34, and it was able to induce cell death in the wild-type at 246 pM while the mutant cells were resistant up to 55.46 nM. Overall, our data demonstrate that PHY34 is a promising small molecule for cancer therapy that targets the ATP6V0A2 subunit to induce autophagy inhibition while interacting with CAS and altering nuclear localization of proteins.

ASF1B promotes cervical cancer progression through stabilization of CDK9

AbstractCervical cancer (CC) is one of the most deadly cancers in women, its current treatments still result in poor outcomes and developing the novel targets and therapeutic strategies are urgently needed. Recent studies have shown that anti-silencing function 1B (ASF1B) might be used as a new proliferation marker for cancer diagnosis and prognosis. However, the expression and function of ASF1B in cervical cancer remain unclear. Here, we induced ASF1B knockdown and overexpression in cervical cancer cell lines and detected the biological behavior changes in vitro. Furthermore, we established two murine models using stable ASF1B-shRNA HeLa cells or normal HeLa cells following AAV-shRNA-ASF1B administration to evaluate how suppression of ASF1B affects tumor growth. We showed that ASF1B functions as an oncogene in cervical cancer cells. Silence of ASF1B suppressed cervical cancer cell growth in vitro and in vivo, while, ASF1B overexpression accelerated cancer cell proliferation. Furthermore, ASF1B deficiency induced cell cycle arrest and apoptosis. Mechanistically, we found that ASF1B formed stable complexes with cyclin-dependent kinase 9 (CDK9), and positively regulated CDK9 stabilization. Taken together, tumorigenic ASF1B could be targeted to suppress cervical cancer tumor growth by inducing apoptotic cell death.

High expression of PTPRM predicts poor prognosis and promotes tumor growth and lymph node metastasis in cervical cancer

AbstractThe prognosis for cervical cancer (CCa) patients with lymph node metastasis (LNM) is dismal. Elucidation of the molecular mechanisms underlying LNM may provide clinical therapeutic strategies for CCa patients with LNM. However, the precise mechanism of LNM in CCa remains unclear. Herein, we demonstrated that protein tyrosine phosphatase receptor type M (PTPRM), identified from TCGA dataset, was markedly upregulated in CCa with LNM and correlated with LNM. Moreover, PTPRM was an independent prognostic factor of CCa patients in multivariate Cox′s proportional hazards model analysis and associated with poor prognosis. Furthermore, through gain-of-function and loss-of-function approaches, we found that PTPRM promoted CCa cells proliferation, migration, invasion, lymphangiogenesis, and LNM. Mechanistically, PTPRM promoted epithelial–mesenchymal transition (EMT) via Src-AKT signaling pathway and induced lymphangiogenesis in a VEGF-C dependent manner, resulting in LNM of CCa. Importantly, knockdown of PTPRM dramatically reduced LNM in vivo, suggesting that PTPRM plays an important role in the LNM of CCa. Taken together, our findings uncover a novel molecular mechanism in the LNM of CCa and identify PTPRM as a novel prognostic factor and potential therapeutic target for LNM in CCa.

Circular RNA circNRIP1 promotes migration and invasion in cervical cancer by sponging miR-629-3p and regulating the PTP4A1/ERK1/2 pathway

AbstractEmerging evidence indicates that circRNAs play essential roles in tumorigenesis and development. However, the role of circRNAs in cervical cancer (CC) remains unclear. CircRNA microarrays performed on the immortal cervical cell line H8 and the cervical cancer cell line SiHa were used to identify a circRNA, termed circNRIP1 (hsa_circ_0004771), which was upregulated in SiHa. QRT-PCR confirmed that circNRIP1 was upregulated in CC tissues, where its expression was correlated with lymphovascular space invasion. Besides, both in vitro and in vivo experiments demonstrated that circNRIP1 promotes cell proliferation, migration, and invasion. Additionally, we found that miR-629-3p induced tumor suppression by regulating PTP4A1 and the ERK1/2 pathway. Finally, we confirmed that circNRIP1 exerts its effect, at least partially, by sponging miR-629-3p and thereby regulating the PTP4A1/ERK1/2 pathway. Therefore, circNRIP1 may be useful as a potential prognostic biomarker and therapeutic target in CC patients.

HOXA5 inhibits the proliferation and neoplasia of cervical cancer cells via downregulating the activity of the Wnt/β-catenin pathway and transactivating TP53

AbstractHOXA5 is considered a regulator involved in embryonic development and cellular differentiation and a tumor suppressor. Nevertheless, its biological role in cervical carcinoma is still unclear. In the present study, immunohistochemistry showed that HOXA5 expression gradually decreased as the degree of cervical lesions deepened. Ectopic expression of HOXA5 restrained cell proliferation, decreased cell viability, and inhibited tumor formation in vitro and in vivo. Furthermore, the expression of HOXA5 could arrest cell cycle from G0/G1 to S phase. RNA-seq revealed that p21 and cyclinD1 were involved in this process. Moreover, the gene set enrichment analysis and the TOP/FOP reporter assay both suggested that HOXA5 could restrain the activity of the Wnt/β-catenin pathway. Further study using dual-luciferase reporter assay and quantitative chromatin immunoprecipitation assay demonstrated that HOXA5 could directly bind to the TAAT motif within the promoter of TP53 by its HD domain and transactivate TP53, which can upregulate p21. Altogether, our data suggest that HOXA5 inhibits the proliferation and neoplasia via repression activity of the Wnt/β-catenin pathway and transactivating TP53 in cervical cancer.

A novel function of IMPA2, plays a tumor-promoting role in cervical cancer

AbstractDiscovery of genes and molecular mechanism involved in cervical cancer development would promote the prevention and treatment. By comparing gene expression profiles of cervical carcinoma in situ (CCIS) and adjacent normal tissues, we identified a potential cancer-promoting gene, IMPA2. This study aimed to elucidate the role of IMPA2 and underlying molecular mechanisms in cervical cancer progression. To do this expression of IMPA2 was compared between human cervical cancer and corresponding adjacent normal cervical tissues firstly. CCK-8 assay, clone formation assay, wound healing assay, transwell assay, and tumor formation in nude mice were performed to demonstrate the effect of IMPA2 in cervical cancer proliferation and metastasis. Further proteomic profiling and western blotting explored the molecular pathway involved in the IMPA2-regulating process. The results showed that IMPA2 gene expression was upregulated in cervical cancer. Consistently, silencing of IMPA2 suppressed tumor formation in BALB/c nude mice. Short hairpin RNA (shRNA)-mediated IMPA2 silencing significantly inhibited proliferation and colony-forming abilities of cervical cancer cells, while IMPA2 overexpression had little impact. Also, IMPA2 silencing suppressed cellular migration, but overexpression promoted migration. Proteomics analysis revealed the involvement of mitogen-activated protein kinase (MAPK) pathway in tumor-promoting action of IMPA2. Significantly, the inhibition of IMPA2 activated ERK phosphorylation, and its inhibitory effects can be restored by using selective ERK inhibitor, FR180204. In conclusion, IMPA2 acts as an oncogene in the proliferation and migration of cervical cancer. IMPA2 downregulated ERK phosphorylation to promote cervical cancer. These findings identify a new mechanism underlying cervical cancer and suggest a regulating effect of IMPA2 in MAPK signaling pathway.

MTA2 silencing attenuates the metastatic potential of cervical cancer cells by inhibiting AP1-mediated MMP12 expression via the ASK1/MEK3/p38/YB1 axis

AbstractMetastasis-associated protein 2 (MTA2) is a transcription factor that is highly associated with matrix metalloproteinase 12 (MMP12). Thus, we hypothesized that MTA2 may regulate MMP12 expression and is involved in cervical cancer metastasis. Results showed that MTA2 and MMP12 were highly expressed in cervical cancer cells, and MTA2 knockdown reduced MMP12 expression and inhibited the metastasis of cervical cancer cells in xenograft mice. MMP12 knockdown did not influence the viability of cervical cancer cells but clearly inhibited cell migration and invasion both in vitro and in vivo. MMP12 was highly expressed in cervical tumor tissues and correlated with the poor survival rate of patients with cervical cancer. Further investigations revealed that p38 mitogen-activated protein kinase (p38), mitogen-activated protein kinase kinase 3 (MEK3), and apoptosis signal-regulating kinase 1 (ASK1) were involved in MMP12 downregulation in response to MTA2 knockdown. Results also demonstrated that p38-mediated Y-box binding protein1 (YB1) phosphorylation disrupted the binding of AP1 (c-Fos/c-Jun) to the MMP12 promoter, thereby inhibiting MMP12 expression and the metastatic potential of cervical cancer cells. Collectively, targeting both MTA2 and MMP12 may be a promising strategy for the treatment of cervical cancer.

ARNTL-mediated INO80-DHX15 axis reprograms the glycolytic metabolism and augments the progression of endometrial carcinoma

Abstract Immune evasion is a major mechanism responsible for tumor cell survival and dissemination. This study aims to explore key molecules involved in immunosuppression and metastasis of endometrial carcinoma (EC). Primary and metastatic tumors were collected from four patients with EC for array analysis. Metastatic tumors exhibited increased macrophage infiltration, while decreased CD8+ T cell infiltration, and aryl hydrocarbon receptor nuclear translocator-like (ARNTL) was identified as a key factor involved. High ARNTL expression was linked to poor tumor differentiation, advanced stage, and increased metastasis in another cohort of 300 EC patients. ARNTL knockout (ARNTL-KO) in EC cells reduced cell proliferation, migration, and invasion, and increased cell death in vitro, and it blocked the tumorigenicity and metastatic activity of cells in mice. The ARNTL-KO EC cells reduced the M2 polarization of macrophages and induced CD8+ T cell proliferation both in vitro and in vivo. ARNTL activated the transcription of INO80 complex ATPase subunit (INO80), a chromatin remodeler, which further promoted the transcription of DEAH-box helicase 15 (DHX15) through histone acetylation modifications. Overexpression of either INO80 or DHX15 increased glycolytic activity and immunosuppression in ARNTL-KO EC cells. Collectively, this study suggests that the ARNTL-mediated INO80-DHX15 axis induces glycolysis and immunosuppression during EC progression.

Lactobacillus spp. create a protective micro-ecological environment through regulating the core fucosylation of vaginal epithelial cells against cervical cancer

AbstractVaginal dysbiosis often occurs in patients with cervical cancer. The fucosylation of mucosal epithelial cells is closely related to microbial colonization, and play an important role in protecting the vaginal mucosal epithelial cells. However, no reports on the relationship between vaginal dysbiosis and abnormal mucosal epithelial cell fucosylation, and their roles in the occurrence and development of cervical cancer are unavailable. Here we report that core fucosylation levels were significantly lower in the serum, exfoliated cervical cells and tumor tissue of cervical cancer patients. Core fucosyltransferase gene (Fut8) knockout promoted the proliferation and migration of cervical cancer cells. In patients with cervical cancer, the vaginal dysbiosis, and the abundance ofLactobacillus, especiallyL. iners, was significantly reduced. Meanwhile, the abundance ofL.inerswas positively correlated with core fucosylation levels. TheL. inersmetabolite lactate can activate the Wnt pathway through the lactate-Gpr81 complex, which increases the level of core fucosylation in epidermal cells, inhibiting the proliferation and migration of cervical cancer cells, and have application prospects in regulating the vaginal microecology and preventing cervical cancer.

Cdc25A inhibits autophagy-mediated ferroptosis by upregulating ErbB2 through PKM2 dephosphorylation in cervical cancer cells

AbstractCervical cancer is the leading cause of cancer-related deaths in women, and treatment for cervical cancer is very limited. Emerging evidence suggests that targeting ferroptosis is a promising way to treat cancer. Here, we investigated the role of ferroptosis in cervical cancer, with a focus on the Cdc25A/PKM2/ErbB2 axis. Cervical cancer cells were treated with sorafenib to induce ferroptosis. Cellular MDA/ROS/GSH/iron detection assays were used to measure ferroptosis. MTT assays were performed to assess cell viability. qRT-PCR, western blot, and immunostaining assays were performed to measure the levels of proteins. Autophagy was monitored by fluorescence microscopy. Nuclear and cytosolic fractions were isolated to examine the location of PKM2 modifications. Co-IP experiments were conducted to determine the Cdc25A/PKM2 interaction. ChIP assays were performed to measure the binding affinity between H3K9Ac and the ErbB3 promoter, and a dual luciferase assay was performed to examine the transcriptional activity of ErbB2. A nude mouse xenograft model was used to examine the effects of the Cdc25A/ErbB2 axis on tumour growth in vivo. Cdc25A was elevated in human cervical cancer tissues but was reduced during sorafenib-induced ferroptosis of cervical cancer cells. Overexpression of Cdc25A inhibited sorafenib-induced ferroptosis by dephosphorylating nuclear PKM2 and suppressing autophagy. Cdc25A regulated autophagy-induced ferroptosis by increasing ErbB2 levels via the PKM2–pH3T11–H3K9Ac pathway. Cdc25A increased the resistance of cervical cancer to sorafenib, while knockdown of ErbB2 blocked these effects. Cdc25A suppressed autophagy-dependent ferroptosis in cervical cancer cells by upregulating ErbB2 levels through the dephosphorylation of PKM2. These studies revealed that Cdc25A/PKM2/ErbB2 pathway-regulated ferroptosis could serve as a therapeutic target in cervical cancer.

Overexpression of DTL enhances cell motility and promotes tumor metastasis in cervical adenocarcinoma by inducing RAC1-JNK-FOXO1 axis

AbstractCervical adenocarcinoma is an important disease that affects young women and it has a high mortality and poor prognosis. Denticleless E3 ubiquitin protein ligase homolog (DTL) gene with oncogenic function has been evaluated in several cancers. Through this study, we aimed to clarify the clinical and molecular characteristics of cervical adenocarcinoma involving overexpression of DTL and elucidate its molecular mechanism. Bioinformatics analysis was performed through multiple databases. RNA sequencing was used to obtain differentially expressed genes after DTL was overexpressed in cells. The role of DTL in cervical adenocarcinoma was explored through in vitro and in vivo experiments. We found that DTL has an unfavorable prognostic implication for patients with cervical adenocarcinoma. Overexpression of DTL induced the migration and invasion of tumor cells in vitro and promoted intra-pulmonary metastasis in vivo. In addition, DTL activated JNK through RAC1 and upregulated FOXO1 to induce epithelial–mesenchymal transition, and the migration and invasion of tumor cells. Therefore, we conclude that overexpression of DTL enhanced cell motility and promoted tumor metastasis of cervical adenocarcinoma by regulating the RAC1-JNK-FOXO1 axis. These results suggest that DTL may become a potential therapeutic target for antitumor metastasis of cervical adenocarcinoma.

Circular RNA hsa_circ_0043280 inhibits cervical cancer tumor growth and metastasis via miR-203a-3p/PAQR3 axis

AbstractCircular RNAs (circRNAs) are known to act as key regulators in a variety of malignancies. However, the role of circRNAs in cervical cancer (CCa) remains largely unknown. Herein, we demonstrated that a circRNA derived from the TADA2A gene (hsa_circ_0043280) was significantly downregulated in CCa and that this reduction in expression was correlated with a poor prognosis. Furthermore, our results demonstrated that hsa_circ_0043280 functions as a tumor suppressor to inhibit tumor growth and metastasis in CCa. Mechanistically, hsa_circ_0043280 competitively sponges miR-203a-3p and prevents miR-203a-3p from reducing the levels of PAQR3. Collectively, our results demonstrate that hsa_circ_0043280 plays a pivotal role in the development and metastasis of CCa, thus suggesting that hsa_circ_0043280 has significant potential as a prognostic biomarker and a therapeutic target for CCa.

HOXB4 inhibits the proliferation and tumorigenesis of cervical cancer cells by downregulating the activity of Wnt/β-catenin signaling pathway

AbstractHomeobox B4 (HOXB4), which belongs to the homeobox (HOX) family, possesses transcription factor activity and has a crucial role in stem cell self-renewal and tumorigenesis. However, its biological function and exact mechanism in cervical cancer remain unknown. Here, we found that HOXB4 was markedly downregulated in cervical cancer. We demonstrated that HOXB4 obviously suppressed cervical cancer cell proliferation and tumorigenic potential in nude mice. Additionally, HOXB4-induced cell cycle arrest at the transition from the G0/G1 phase to the S phase. Conversely, loss of HOXB4 promoted cervical cancer cell growth both in vitro and in vivo. Bioinformatics analyses and mechanistic studies revealed that HOXB4 inhibited the activity of the Wnt/β-catenin signaling pathway by direct transcriptional repression of β-catenin. Furthermore, β-catenin re-expression rescued HOXB4-induced cervical cancer cell defects. Taken together, these findings suggested that HOXB4 directly transcriptional repressed β-catenin and subsequently inactivated the Wnt/β-catenin signaling pathway, leading to significant inhibition of cervical cancer cell growth and tumor formation.

Endothelial cell-specific molecule 1 drives cervical cancer progression

AbstractThe expression, biological functions and underlying molecular mechanisms of endothelial cell-specific molecule 1 (ESM1) in human cervical cancer remain unclear. Bioinformatics analysis revealed that ESM1 expression was significantly elevated in human cervical cancer tissues, correlating with patients’ poor prognosis. Moreover, ESM1 mRNA and protein upregulation was detected in local cervical cancer tissues and various cervical cancer cells. In established and primary cervical cancer cells, ESM1 shRNA or CRISPR/Cas9-induced ESM1 KO hindered cell proliferation, cell cycle progression, in vitro cell migration and invasion, and induced significant apoptosis. Whereas ESM1 overexpression by a lentiviral construct accelerated proliferation and migration of cervical cancer cells. Further bioinformatics studies and RNA sequencing data discovered that ESM1-assocaited differentially expressed genes (DEGs) were enriched in PI3K-Akt and epithelial-mesenchymal transition (EMT) cascades. Indeed, PI3K-Akt cascade and expression of EMT-promoting proteins were decreased after ESM1 silencing in cervical cancer cells, but increased following ESM1 overexpression. Further studies demonstrated that SYT13 (synaptotagmin 13) could be a primary target gene of ESM1. SYT13 silencing potently inhibited ESM1-overexpression-induced PI3K-Akt cascade activation and cervical cancer cell migration/invasion. In vivo, ESM1 knockout hindered SiHa cervical cancer xenograft growth in mice. In ESM1-knockout xenografts tissues, PI3K-Akt inhibition, EMT-promoting proteins downregulation and apoptosis activation were detected. In conclusion, overexpressed ESM1 is important for cervical cancer growth in vitro and in vivo, possibly by promoting PI3K-Akt activation and EMT progression. ESM1 represents as a promising diagnostic marker and potential therapeutic target of cervical cancer.

LncRNA SFTA1P promotes cervical cancer progression by interaction with PTBP1 to facilitate TPM4 mRNA degradation

AbstractLong non-coding RNAs (lncRNAs) play key roles in cancer development and progression. However, the biological function and clinical significance of most lncRNAs in cervical cancer remain elusive. In this study, we explore the function and mechanism of lncRNA surfactant associated 1 (SFTA1P) in cervical cancer. We firstly identified SFTA1P by analyzing the RNA sequencing data of cervical cancer from our previous study and from The Cancer Genome Atlas (TCGA). We then verified SFTA1P expression by qRT-PCR. The cell proliferation and migration capacity of SFTA1P was assessed by using CCK-8, colony formation, transwell and wound healing assays. RNA pull-down, RNA immunoprecipitation (RIP), RNA stability and western blot assays were used to reveal potential mechanisms. Athymic nude mice were used to evaluate tumorigenicity and metastasis in vivo. SFTA1P is upregulated in cervical tumor tissues and its high expression is associated with poor prognosis. Biologically, knockdown of SFTA1P inhibited the proliferation, migration, and invasion of cervical cancer cells in vitro, as well as tumorigenesis and metastasis in vivo. Mechanistically, SFTA1P was shown to interact with polypyrimidine tract binding protein 1 (PTBP1) to regulate the stability of tropomyosin 4 (TPM4) mRNA, thereby resulting in malignant cell phenotypes. TPM4 knockdown could attenuate the suppression of cell progression induced by either SFTA1P or PTBP1 knockdown. Our findings demonstrate that SFTA1P can promote tumor progression by mediating the degradation of TPM4 mRNA through its interaction with PTBP1 protein. This provides a potential therapeutic strategy to target the SFTA1P-PTBP1-TPM4 axis in cervical cancer.

RacGAP1 promotes the malignant progression of cervical cancer by regulating AP-1 via miR-192 and p-JNK

Abstract Cervical cancer (CC) is the most frequently diagnosed genital tract cancer in females worldwide. Rac GTPase-activating protein 1 (RacGAP1) is one of the specific GTPase-activating proteins. As a novel tumor protooncogene, overexpression of RacGAP1 was related to the occurrence of various tumors, but its function in CC is still unclear. In this study, bioinformatics analyses showed that RacGAP1 might be a key candidate gene in the progression of CC. RacGAP1 was significantly overexpressed in CC tissues. High RacGAP1 expression was positively associated with poor prognosis. Downregulating RacGAP1 significantly inhibited the proliferation, migration, and invasion of CC cells, while overexpressing RacGAP1 had the opposite effects. Further research showed that miR-192, which plays as a tumor suppressor in CC, was identified as a downstream target of RacGAP1 in CC cells. miR-192 inhibition could partially rescue the decrease in cell proliferation, migration, and invasion caused by RacGAP1 downregulation. In opposite, miR-192 overexpression could decrease the promotion of malignant progression caused by RacGAP1 upregulation. Mechanism studies revealed that RacGAP1 could regulate the expression and phosphorylation of c-Jun, which was the component of AP-1, via miR-192 and p-JNK separately. These findings suggested that RacGAP1 promoted tumorigenicity, migration, and invasion of CC. Therefore, it represented a potential novel prognostic marker in CC and may probably be a therapeutic target.

FASN promotes lymph node metastasis in cervical cancer via cholesterol reprogramming and lymphangiogenesis

AbstractCervical cancer (CC) patients with lymph node metastasis (LNM) have a poor prognosis. Clarification of the detailed mechanisms underlying LNM may provide potential clinical therapeutic targets for CC patients with LNM. However, the molecular mechanism of LNM in CC is unclear. In the present study, we demonstrated that fatty acid synthase (FASN), one of the key enzymes in lipid metabolism, had upregulated expression in the CC samples and was correlated with LNM. Moreover, multivariate Cox proportional hazards analysis identified FASN as an independent prognostic factor of CC patients. Furthermore, gain-of-function and loss-of-function approaches showed that FASN promoted CC cell migration, invasion, and lymphangiogenesis. Mechanistically, on the one hand, FASN could regulate cholesterol reprogramming and then activate the lipid raft-related c-Src/AKT/FAK signaling pathway, leading to enhanced cell migration and invasion. On the other hand, FASN induced lymphangiogenesis by secreting PDGF-AA/IGFBP3. More importantly, knockdown of FASN with FASN shRNA or the inhibitors C75 and Cerulenin dramatically diminished LNM in vivo, suggesting that FASN plays an essential role in LNM of CC and the clinical application potential of FASN inhibitors. Taken together, our findings uncover a novel molecular mechanism in LNM of CC and identify FASN as a novel prognostic factor and potential therapeutic target for LNM in CC.

Oncogenic circTICRR suppresses autophagy via binding to HuR protein and stabilizing GLUD1 mRNA in cervical cancer

AbstractCircular RNAs (circRNAs) are critical regulators in the occurrence and development of numerous cancers, in which abnormal autophagy plays a key role. However, the potential involvement of circRNAs in autophagy is largely unknown. Here, we identified the overexpression of circTICRR, a circular RNA, in cervical cancer. In vitro experiments showed that knockdown of circTICRR activated autophagy, and consequently promoted apoptosis and inhibited proliferation in cervical cancer cells, and vice versa. CircTICRR interacted with HuR protein via binding to F287/F289 in the RRM3 domain of HuR, stabilizing GLUD1 mRNA and elevating the level of GLUD1 protein. In vivo experiments revealed that knockdown of circTICRR suppressed the growth of transplanted tumors. An inhibitory peptide specific to the binding site between circTICRR and HuR protein promoted autophagy, induced apoptosis, suppressed proliferation in cervical cancer cells, and inhibited the growth of xenografts. Our findings suggest that circTICRR acts as an oncogene in cervical cancer and the interaction between circTICRR and HuR protein may be a potential target in cervical cancer therapeutics.

ROR1-PI3K/AKT signaling drives adaptive resistance to cell cycle blockade in TP53 mutated ovarian cancer

Abstract Drug resistance remains a major challenge to durable responses in ovarian cancer, the fifth leading cause of cancer-related death among women. In this study, we developed long-term resistant (lt-res, several months) pre-clinical models of two drugs inducing mitotic arrest in TP53 -mutated cells: adavosertib (ADA), an investigational WEE1 inhibitor targeting the DNA damage response and currently evaluated in clinical trials, and paclitaxel (PTX), a widely used chemotherapeutic agent in cancer care targeting microtubules. Through integrated multi-omics functional profiling, we identify a shared PI3K/AKT-regulated signaling node that governs drug adaptation across all lt-res models. This node modulates the activity of DNA-damage responses and genotoxic stress to toggle between two adaptive states: activated PI3K/AKT driving a proliferative “fast-bypass” program with sustained cell cycle progression and mitotic evasion, or reduced PI3K/AKT signaling initiating a “slow-repair” state characterized by DNA damage checkpoint engagement, replication slowdown, and increased drug efflux. Notably, upregulation of receptor tyrosine kinases, such as ROR1, was observed in both ADA and PTX lt-res models with activated PI3K/AKT signaling. Targeting ROR1 with zilovertamab-vedotin, a monoclonal antibody-drug conjugate, resulted in enhanced cytotoxicity, demonstrating a new approach against recurrent drug-resistant ovarian cancer.

PRDM1 restricts bladder cancer progression and enhances chemosensitivity by suppressing OTUD6A-mediated deubiquitination of CDC6

Abstract PR domain zinc finger protein 1 (PRDM1) functions as a critical transcriptional repressor. The role of PRDM1 in various tumors is controversial, and its specific mechanism in bladder cancer (BCa) remains unclear. In the present study, we demonstrated that PRDM1 expression is downregulated in both human BCa tissues and BBN-induced mouse models of BCa. Gain- and loss-of-function experiments revealed that PRDM1 delays cell cycle progression, suppresses BCa cell proliferation, and enhances chemosensitivity, whereas PRDM1 knockdown promotes cell proliferation and induces chemoresistance. Ovarian tumor deubiquitinase 6 A (OTUD6A) is a deubiquitinating enzyme that prevents the proteasomal degradation of CDC6. PRDM1 directly binds to the OTUD6A promoter and suppresses its transcription, thereby reducing CDC6 deubiquitination and promoting its degradation. Knockdown of CDC6 or OTUD6A abrogates the protective effects of PRDM1 both in vitro and in vivo. Consistently, PRDM1 expression is negatively correlated with CDC6 and OTUD6A expression in BCa tissues. Collectively, these findings demonstrate that PRDM1 acts as a tumor suppressor in BCa by inhibiting OTUD6A transcription and promoting CDC6 degradation. We propose a PRDM1‒OTUD6A‒CDC6 axis model, providing novel insights into PRDM1 as a potential therapeutic target in BCa.

Transglutaminase 2 exacerbates ovarian cancer survival by directly inactivating GSK3β

Abstract Elevated expression of transglutaminase 2 (TGase 2, EC 2.3.2.13, protein-glutamine γ-glutamyltransferase, gene name TGM2 ) is known as one of the most upregulated genes during epithelial-mesenchymal transition (EMT) in ovarian cancer. Despite initial complete responses to conventional chemotherapy, ovarian cancer often recurs with metastasis, presenting a significant clinical challenge. Drug-resistant ovarian cancer cells exhibit markedly higher levels of TGase 2 compared to normal ovarian epithelium, which is associated with EMT activation, enabling them to evade chemotherapy effects. Intracellular TGase 2 is recognized as a key factor in maintaining the mesenchymal phenotype. Therefore, while EMT expression can be effectively reversed by inhibiting TGase 2, the underlying mechanism of this effect remains unclear. We found that TGase 2 promotes EMT by directly binding to glycogen synthase kinase-3β (GSK3β), promoting the stabilization of β-catenin. Domain mapping revealed that the N-terminus of TGase 2 interacts with the mid-region of GSK3β, leading to the autophagic degradation of GSK3β. Pharmacological disruption of this N-terminal interaction by streptonigrin, in combination with standard chemotherapy, extended overall survival in a xenograft model of ovarian cancer. This study identified TGase 2 as a pivotal regulator of EMT-driven metastasis and drug resistance.

Aberrant VEGFR2 supports tumor growth by extracellular matrix remodeling

Abstract The extracellular matrix shapes tumor architecture, cell behavior and therapy response. Here, we identify aberrant activation of the receptor tyrosine kinase VEGFR2 as a driver of tumor-promoting ECM remodeling in melanoma and ovarian cancer. ECM alterations in terms of composition and organization were observed in Sk-Mel-31 melanoma xenografts expressing the oncogenic VEGFR2 R1032Q and in ovarian tumors with VEGFR2 hyperactivation. Down-modulation of VEGFR2 normalized ECM architecture. Decellularized ECM from VEGFR2 R1032Q melanoma cells directly modified the behavior of VEGFR2 WT tumor cells, increasing monolayer fluidity and mitochondrial activation. Transcriptomic profiling revealed a dysregulation of genes involved in ECM structure and remodeling, mediated by the PI3K-AKT and ERK pathways. Pharmacological inhibition of VEGFR2 with tyrosine kinase inhibitors, such as lenvatinib, partially reverted ECM alterations in vitro and in vivo, reducing matrix deposition and modifying its organization. These data identify VEGFR2 as a regulator of tumor ECM dynamics and suggest that its inhibition may restore ECM organization, offering a therapeutic strategy to reprogram the tumor microenvironment and limit cancer progression.

PLK1 or WEE1 inhibition targets homologous recombination repair proficiency in BRCA1/2 wild-type high-grade serous ovarian cancer

Abstract High-grade serous ovarian cancer (HGSOC) is a poor prognostic disease, especially in BRCA1 / 2 wild-type (BRCA-WT) patients with homologous recombination (HR) proficiency. These patients often show limited response to both platinum-based chemotherapy and PARP inhibitors. HR and non-homologous end joining (NHEJ) are the two major DNA double-strand break (DSB) repair pathways. HR is a precise repair mechanism for DSBs but is limited to S and G2 phases. In contrast, NHEJ functions more broadly throughout the cell cycle, including G1. We investigated whether inhibiting the G2/M checkpoint kinases PLK1 or WEE1 individually could disrupt mitotic control and expose therapeutic vulnerabilities in BRCA-WT/HR-proficient HGSOC cells. We evaluated cell cycle–targeted strategies to overcome HR-proficient chemoresistance using either volasertib (a selective PLK1 inhibitor) or adavosertib (a potent WEE1 inhibitor) in BRCA-WT/HR-proficient and BRCA-mutant/HR-deficient HGSOC models. Both agents induced DNA damage, impaired HR repair (reduced RAD51 foci), and triggered mitotic catastrophe—a form of cell death caused by defective mitosis and unresolved DNA damage—in BRCA-WT cells. Volasertib caused polyploidy and abnormal spindle formation, indicating mitotic slippage and cytokinesis failure, whereas adavosertib abrogated the G2/M checkpoint, forcing premature mitotic entry. In contrast, BRCA-mutant cells were resistant to either volasertib or adavosertib, consistent with sustained and functional NHEJ activity. This resistance was restored by the pharmacological or genetic inhibition of DNA-PKcs (DNA-dependent protein kinase, catalytic subunit), a prominent component of NHEJ. Functional and xenograft models confirmed selective vulnerability of BRCA-WT tumors to either PLK1 or WEE1 inhibition. Our work highlights a mechanistic framework linking cell cycle checkpoint inhibition to DNA repair pathway selectivity, providing a rationale for targeting mitotic regulators in HR-proficient ovarian cancer—a subgroup with high clinical unmet need.