Journal

Biochemical Pharmacology

Papers (41)

Sulfated glycolipid PG545 induces endoplasmic reticulum stress and augments autophagic flux by enhancing anticancer chemotherapy efficacy in endometrial cancer

The sulfated glycolipid PG545 shows promising antitumor activity in various cancers. This study was conducted to explore the effects and the mechanism of PG545 action in endometrial cancer (EC). PG545 exhibited strong synergy as assessed by the Chou-Talalay-Method in vitro when combined with cisplatin, or paclitaxel in both type I (Hec1B) and type II (ARK2) EC cell lines. While PG545 showed antitumor activity as monotherapy, a combination of PG545 with paclitaxel and cisplatin was highly effective in reducing the tumor burden and significantly prolonged survival of both Hec1B and ARK2 xenograft bearing mice. Mechanistically, PG545 elicits ER stress as an early response with resultant induction of autophagy. Our data demonstrated an increase in pERK, Bip/Grp78, IRE1α, Calnexin and CHOP/GADD153 within 6-24 hrs of PG545 treatment in EC cells. In parallel, PG545 also blocked FGF2 and HB-EGF mediated signaling in EC cells. Moreover, melatonin-mediated ER stress inhibition reduced PG545-mediated autophagy and PG545 in combination with cisplatin further heightened this stress response. Collectively these data indicate that PG545 exhibits strong synergistic effects with chemotherapeutics in vitro and showed promising antitumor activity in vivo. Our preclinical data indicates that in future studies PG545 can be a useful adjunct to chemotherapy in endometrial cancer.

ATR-mediated phosphorylation of RIPK1 inhibits DNA damage-induced necroptosis

Necroptosis induced by DNA damage during chemotherapy is a significant and effective treatment strategy for epithelial ovarian cancer. Ataxia telangiectasia and rad3-related protein (ATR), a key kinase in DNA damage checkpoints, initiates repair by transmitting damage signals to effectors. However, persistent DNA damage may result in cell death. The mechanisms by which ATR regulates necroptosis remain incompletely understood. In this study, we demonstrated that ATR binds to receptor-interacting serine/threonine-protein kinase 1 (RIPK1) and inhibits its activation, thereby suppressing RIPK1-dependent necroptosis triggered by DNA damage. Mechanistically, ATR directly inhibited RIPK1 and downstream necrosome formation through Ser335 phosphorylation following DNA damage, thereby attenuating RIPK1-dependent necroptosis. In the case of the S335A mutation, RIPK1 repression was relieved, leading to enhanced downstream necroptosis. Furthermore, RIPK1 knockout with complementation of wild-type or S335A mutation in ovarian cancer cell lines revealed that ATR phosphorylation of RIPK1 at S335 promoted chemoresistance, while the S335A mutation significantly increased chemosensitivity. This was characterized by heightened necroptosis activation, reduced cell viability, and increased cell death. These findings expand our understanding of the interaction between DNA damage and cell death regulation and may aid in developing therapeutic drugs to enhance DNA damage-induced tumor necroptosis and improve chemosensitivity.

Inhibition of RUNX1 promotes cisplatin-induced apoptosis in ovarian cancer cells

Runt-related transcription factor 1 (RUNX1), one subunit of core-binding factors in hematopoiesis and leukemia, was highly expressed in ovarian cancer (OC), but the role of RUNX1 in OC is largely unknown. Since we found that high expression of RUNX1 is correlated with poor survival in patients with OC through bioinformatic analysis of TCGA database, we developed RUNX1-knockout clones by CRISPR/Cas9 technique and discovered that RUNX1 depletion could promote cisplatin-induced apoptosis in OC cells, which was further confirmed by RUNX1 knockdown and overexpression. We also proved that RUNX1 could elevate the expression of BCL2. We then examined a total of 32 candidate miRNAs that might mediate the regulation between RUNX1 and BCL2, of which three miRNAs from the miR-17~92 cluster were found to be negatively regulated by RUNX1. Consistently, our analysis of data from TCGA database revealed the negative correlation between RUNX1 and the cluster. We further confirmed that miR-17~92 cluster could enhance cisplatin-induced apoptosis by directly targeting BCL2 3'UTR. Since rescue experiments proved that RUNX1 could repress cisplatin-induced apoptosis by up-regulating BCL2 via miR-17~92 cluster, combining RUNX1 inhibitor Ro5-3335 and cisplatin showed synergic effect in triggering OC cell apoptosis. Collectively, these findings show for the first time that combinational treatment of cisplatin and RUNX1 inhibitor could be used to potentiate apoptosis of ovarian cancer cells, and reveal the potential of targeting RUNX1 in ovarian cancer chemotherapy.

Role of the TLR4-androgen receptor axis and genistein in taxol-resistant ovarian cancer cells

Toll-like receptor 4 (TLR4) is often overexpressed in taxol-resistant cancer cells. Here we used whole-genome transcriptomic analysis to identify 787 upregulated genes in SKOV3 ovarian carcinoma cells that ectopically express TLR4. Using chromatin immunoprecipitation enrichment analysis, we observed that 27.8% of the TLR4-upregulated genes identified were androgen receptor (AR)-regulated genes. Accordingly, AR expression was induced in taxol-resistant SKOV3 cells overexpressing TLR4, whereas depletion of TLR4 by shRNA repressed AR expression. Activation of AR by androgens or silencing of AR using shRNA also regulated expression of AR-related genes. We found that expression of DCDC2, ANKRD18B, ALDH1A1, c14orf105, ITGBL1 and NEB was overexpressed in taxol-resistant cells, suggesting the involvement of these AR-related genes in taxol resistance. Pathway enrichment analysis confirmed that the expression of several upregulated genes enriched in steroid biosynthesis pathways was inducible by androgens, supporting the results of previous studies. We also observed that genistein inhibits AR activation, leading to suppression of AR-driven genes and reduced taxol resistance in ovarian cancer cells. Overall, we identified six TLR4- and AR-regulated genes involved in taxol resistance. Our results reveal that the TLR4/AR axis plays a critical role in taxol resistance and that genistein is a candidate compound to limit chemoresistance and improve cancer treatment in ovarian cancer.

Cytoplasmic expression of EGFR shRNA using a modified T7 autogene-based hybrid mRNA/DNA system induces long-term EGFR silencing and prolongs antitumor effects

Unusual activation or overexpression of epidermal growth factor receptor (EGFR) has been found in various cancers, and therefore down-regulation of EGFR expression is recognized as a promising strategy for cancer treatment. For decades, RNAi has emerged as an effective solution to regulate gene overexpression, but transient effects of exogenous siRNA have limited the development of EGFR-targeting siRNA therapeutics. Recently, we developed T7 autogene-based hybrid mRNA/DNA system as a non-viral vector for shRNA production and reported the feasibility of long-term silencing for RFP expression as a concept of proof. To investigate its therapeutic availability in cancer therapy, we here modified the hybrid system to stably express EGFR shRNA and confirmed the antitumor effects. When autocatalytic production of T7pol protein in cytoplasm was combined with pT7-driven cytoplasmic transcription for EGFR shRNA, a single transfection lead to stable EGFR silencing in SKOV3 cells for more than 13 days. Also, liposomal systemic administration at two-week intervals resulted in significant inhibition of tumor growth in both SKOV3-bearing mice and PDX models, contrast to the conventional siRNA approach. Our results show an efficient strategy to overcome the temporary effects of synthetic EGFR siRNA in cancer treatment and ultimately provide a potential candidate as an anticancer drug.

FGFR3 phosphorylates EGFR to promote cisplatin-resistance in ovarian cancer

Ovarian cancer is a deadly gynecologic cancer, and the majority of patients with ovarian cancer experience relapse after traditional treatment. Cisplatin (DDP) is a common chemotherapeutic drug for ovarian cancer, but many patients acquire DDP-resistance after treatment with long-term chemotherapy. The mechanisms of drug-resistance in ovarian cancer are not clear, and we thus aim to investigate novel targets for DDP-resistant ovarian cancer. Differential analysis, KEGG pathway enrichment and protein interaction networks were employed to identify the key genes related to DDP-resistance in ovarian cancer. Subsequently, cell viability, apoptosis and migration were measured to assess the effect of fibroblast growth factor receptor 3 (FGFR3) on DDP-resistance. Further, Pearson correlation analysis and co-expression analysis were used to explore the downstream pathways of FGFR3, and the function of FGFR3 and its downstream targets were further demonstrated by in vitro and nude mice experiments. FGFR3 were expressed at high levels in DDP-resistant ovarian cancer cells. FGFR3 silencing suppressed the activation of PI3K/AKT pathway and impeded the drug-resistance and development of tumor cells. Afterwards, we found that FGFR3 was co-expressed with epidermal growth factor receptor (EGFR). FGFR3 overexpression elevated EGFR phosphorylation and activated PI3K/AKT signaling. Furthermore, in nude mice, silencing FGFR3 and inhibiting EGFR phosphorylation were observed to promote the therapeutic effect of DDP. In conclusion, FGFR3 overexpression enhances DDP-resistance of ovarian cancer by promoting EGFR phosphorylation and further activating PI3K/AKT pathway. This study may offer promising targets for DDP-resistant ovarian cancer.

TLR4/IL-6/IRF1 signaling regulates androgen receptor expression: A potential therapeutic target to overcome taxol resistance in ovarian cancer

Ovarian cancer is poorly treatable due, at least in part, to induced drug resistance to taxol- and cisplatin-based chemotherapy. Recent studies showed that ectopic overexpression of toll-like receptor 4 (TLR4) in ovarian cancer cells leads to upregulation of the androgen receptor (AR) and transactivation of taxol resistance genes, thereby causing chemoresistance. In the present study, we examined the signaling pathways involving TLR4 and interleukin 6 (IL-6) that enhance AR expression. Based on transcriptomic analysis, we show that IL-6 functions as a hub gene among the upregulated genes in taxol-treated TLR4-overexpressing ovarian cancer cells. Both the TLR4 activator taxol and IL-6 can induce AKT phosphorylation, whereas TLR4 knockdown or inhibition of the IL-6 signal transducer GP130 abrogates AKT activation. Furthermore, expression of AR and IL-6 is downregulated in TLR4-knockdown, taxol-resistant cells. In addition, TLR4 knockdown inhibits GP130 and IL-6 receptor alpha (IL6Rα) activities, indicating that TLR4 plays a critical role in IL-6 signaling. On the other hand, nuclear translocation of AR is induced by IL-6 treatment, whereas knockdown of endogenous IL-6 reduces AR and TLR4 expression in taxol-resistant ovarian cancer cells. These results indicate that TLR4 and IL-6 play a crucial role in AR gene regulation and function. We also identify interferon regulatory factor 1 (IRF1) as a downstream target of IL-6 signaling and as a regulator of AR expression. Moreover, analysis of clinical samples indicates that high IL-6 expression correlates with poor progression-free survival in ovarian cancer patients treated with taxol. Overall, our findings indicate that the TLR4/IL-6/IRF1 signaling axis represents a potential therapeutic target to overcome AR-based taxol resistance in ovarian cancer.

The role of PICT1 in RPL11/Mdm2/p53 pathway-regulated inhibition of cell growth induced by topoisomerase IIα inhibitor against cervical cancer cell line

Our previous work showed that a podophyllum derivative (D-3F), named 4-N-(2-Amino-3-fluoropyridine) -4-deoxidation-4'-demethylepipofophyllotoxin, inhibits the activity of topoisomerase II (TOPO II) and then results in DNA damage. Also, D-3F increases the expression of p53 to induce cervical cancer HeLa cell apoptosis by enhancing its stability, due to the translocation of RPL11 to interact with Mdm2 and then consequently causing the blockage of the Mdm2-p53 feedback loop. In present study, we further explored the detailed mechanism of the antitumor activity of D-3F against cervical cancer cell line. Firstly, the decreased level of protein interacting with carboxyl terminus 1 (PICT1) in cervical cancer cell lines (HeLa and SiHa) treated with D-3F, exerted its potent inhibitory effect on cellular proliferation, which was dependent on the inhibition of TOPO IIα activity induced by D-3F in vitro. In addition, the downregulation of PICT1 was required to enhancement of p53 stability, resulted from its promoting the nucleoplasmic translocation of RPL11 to bind to Mdm2 following D-3F treatment. Altogether, it demonstrated that the reduction of PICT1 level in HeLa cell line, as well as SiHa exposed to D-3F, a TOPO IIα inhibitor, may play an essential role in the regulation of RPL11/Mdm2/p53 pathway to induce cell apoptosis. Besides, it suggested the potential of this podophyllum derivative (D-3F) as an alternative agent for therapy in cervical cancer.

KCMF1 regulates HRI ubiquitination to inhibit the integrated stress response in ovarian cancer

This study aimed to investigate the biological functions and underlying mechanisms of potassium channel modulatory factor 1 (KCMF1) in ovarian cancer (OC). KCMF1 expression in OC was analyzed using single-cell sequencing, quantitative real-time reverse transcription polymerase chain reaction, immunohistochemistry, and western blot analysis. The effects of KCMF1 on OC progression were evaluated in cell lines and a xenograft mouse model. The effect of KCMF1 on the integrated stress response (ISR) was evaluated by assessing heme-regulated inhibitor (HRI) ubiquitination using Ni-NTA pull-down assays, immunohistochemistry, and western blotting. KCMF1 was highly expressed in OC epithelial cells and was associated with poor prognosis in patients with OC. Overexpression of KCMF1 promoted OC cell proliferation, migration, and invasion and inhibited cell apoptosis. On the other hand, KCMF1 knockdown produced the opposite results and inhibited tumor growth. Knockdown of KCMF1 reduced HRI ubiquitination and promoted the phosphorylation of eukaryotic translation initiation factor 2 subunit alpha (eIF2α), and the expression of activating transcription factor (ATF)4, ATF3, and sestrin 2 (SESN2), while KCMF1 overexpression produced the opposite results. Additionally, an ISR inhibitor reversed the effects of KCMF1 knockdown on OC cell proliferation, migration, and invasion. Plantainoside D was identified as a novel KCMF1 inhibitor that exhibited potent antitumor activity in OC. Overall, KCMF1 regulates HRI ubiquitination to inhibit ISR, thereby promoting tumor growth and progression in OC.

Cinnamaldehyde suppresses ovarian cancer progression by activating ROS-mediated apoptosis and mitophagy

Cinnamaldehyde (CA), a natural bioactive compound derived from Cinnamomum species, has demonstrated broad-spectrum antitumor activity. However, its therapeutic potential and precise mechanisms in ovarian cancer (OC) remain incompletely elucidated. In this study, we systematically investigated the inhibitory effects of CA on OC and the underlying molecular mechanisms through both in vitro and in vivo approaches. In vitro experiments demonstrated that CA significantly induces reactive oxygen species (ROS) accumulation in OC cells, activates mitochondria-mediated apoptosis, and induces mitochondrial autophagy via the AMPK/ULK1/Beclin1 signaling axis. These synergistic effects collectively lead to significant suppression of OC cell proliferation. In a murine xenograft model of OC, CA administration substantially inhibited the growth of heterotransplanted tumors. Further in vivo analyses revealed a significant increase in the number of apoptotic cells and upregulation of the expression of the autophagy markers LC3B, PINK1, and Parkin in tumor tissues. Concurrently, the expression of the autophagic substrate p62 and the mitochondrial membrane protein TOMM20 decreased. These findings consistently corroborated the cellular mechanisms observed in vitro. This study provides the first evidence that CA suppresses OC progression via ROS-mediated dual mechanisms: apoptosis induction and mitophagy activation. Our results underscore the translational potential of CA as a promising therapeutic candidate and provide a robust experimental foundation for its further development against OC.

RECQL4 as a novel drug target against ovarian cancer

Ovarian cancer is characterized by poor specificity and unfavorable prognosis. Therefore, exploring new mechanisms of ovarian cancer development, identifying specific new targets, and developing effective therapeutic drugs based on these new targets have become the focus of current research. This study collected clinical case tissues from high-grade serous ovarian cancer (HGSC) patients and found that the expression of RecQ-like helicase 4 (RECQL4) was positively correlated with the malignancy of ovarian cancer but negatively correlated with its prognosis. From the chemical library of traditional Chinese medicine and ethnic medicines established by our research group in Guizhou, we screened out an effective target, a fluorinated tanshinone analogue (TC12-1), which can effectively inhibit and bind to RECQL4. In vitro experiments showed that TC12-1 induced apoptosis and inhibited cancer cell invasion and metastasis. Additionally, TC12-1 can induce DNA damage, enhancing replication fork stress and blocking the cell cycle at the S phase in cancer cells. The compound effectively inhibited tumor growth and metastasis in subcutaneous tumor models and in orthotopic ovarian cancer mouse models, showing no significant toxicity to vital organs in tumor animal models. The molecular mechanism of TC12-1 targeting RECQL4 in anti-ovarian epithelial cell carcinoma involves the regulation of key genes such as γ-H2AX, PRPA32, ATM, RAD50, CHK2, P53, P21, Bax, Cyclin E, and CDC2, thereby affecting the cell cycle and DNA replication signaling pathways. The results provide theoretical support for developing specific ovarian cancer therapeutic drugs using RECQL4 as a new target.

WP1066, a small molecule inhibitor of STAT3, chemosensitizes paclitaxel-resistant ovarian cancer cells to paclitaxel by simultaneously inhibiting the activity of STAT3 and the interaction of STAT3 with Stathmin

Paclitaxel is widely used to treat cancer, however, drug resistance limits its clinical utility. STAT3 is constitutively activated in some cancers, and contributes to chemotherapy resistance. Currently, several STAT3 inhibitors including WP1066 are used in cancer clinical trials. However, whether WP1066 reverses paclitaxel resistance and the mechanismremains unknown. Here, we report that in contrast to paclitaxel-sensitive parental cells, the expressions of several pro-survival BCL2 family members such as BCL-2, BCL-XL and MCL-1 are higher in paclitaxel-resistant ovarian cancer cells. Meanwhile, STAT3 is constitutively activated while stathmin loses its activity in paclitaxel-resistant cells. Importantly, WP1066 amplifies the inhibition of cell proliferation, colony-forming ability and apoptosis of ovarian cancer cells induced by paclitaxel. Mechanistically, WP1066, on the one hand, interferes the STAT3/Stathmin interaction, causing unleash of STAT3/Stathmin from microtubule, thus destroying microtubule stability. This process results in reduction of Ac-α-tubulin, further causing MCL-1 reduction. On the other hand, WP1066 inhibits phosphorylation of STAT3 by JAK2, and blocks its nuclear translocation, therefore repressing the transcription of pro-survival targets such as BCL-2, BCL-XL and MCL-1. Finally, the two pathways jointly promote cell death. Our findings reveal a new mechanism wherein WP1066 reverses paclitaxel-resistance of ovarian cancer cells by dually inhibiting STAT3 activity and STAT3/Stathmin interaction, which may layfoundation for WP1066 combined with paclitaxel in treating paclitaxel-resistant ovarian cancer.

Albacarcin V adds EPLIN as a novel and promising target for the treatment of female cancers and pediatric medulloblastoma

Breast and ovarian cancers remain among the most lethal malignancies affecting women worldwide. Despite advances in standard therapies, drug resistance and high relapse rates continue to undermine long-term treatment outcomes. To address these challenges, we re-evaluated five previously identified drug candidates (FLIX1-FLIX5), all of which are effective at nanomolar concentrations in breast and ovarian cancer cell lines. Among them, FLIX3 (Albacarcin V) and FLIX4 exhibited the most potent cytotoxicity, with IC50 values below 50 nM across multiple cell lines. Notably, FLIX3 also exhibited nanomolar-range efficacy in drug-resistant, patient-derived samples from triple-negative breast cancer (TNBC) and ovarian cancer. In a zebrafish model, FLIX3 effectively eliminated cancer cells within its safety window. ATAC-Seq analysis revealed that both compounds induce significant epigenetic alterations. Proteome Integral Solubility Alteration (PISA) and cellular thermal shift assay (CETSA) identified EPLIN (Epithelial Protein Lost in Neoplasm) as the top target of FLIX3 but not FLIX4. EPLIN was previously identified as the primary target of FLIX5. Its re-emergence as the dominant target of FLIX3 highlights its potential as a broadly applicable therapeutic target. Collectively, these findings support the continued development of EPLIN-targeting compounds as promising agents for treating aggressive and drug-resistant breast and ovarian cancers.

Gambogic acid induces GSDME dependent pyroptotic signaling pathway via ROS/P53/Mitochondria/Caspase-3 in ovarian cancer cells

Gambogic acid (GA) is a naturally active compound extracted from the Garcinia hanburyi with various anticancer activities. However, whether GA induces pyroptosis (a newly discovered inflammation-mediated programmed cell death mechanism) in ovarian cancer (OC) has not yet been reported. This study revealed that GA treatment reduced cell viability by inducing pyroptosis in OC cell lines. Typical pyroptosis morphological manifestations such as cell swelling with large bubbles and loss of cell membrane integrity, were observed. Cleaved caspase-3 and GSDME-N levels increased after GA treatment, and knocking out GSDME or using a caspase-3 inhibitor could switch GA-induced cell death from pyroptosis to apoptosis, indicating GA induced caspase-3/GSDME-dependent pyroptosis. Furthermore, this research indicated that GA significantly increased reactive oxygen species (ROS) and p53 phosphorylation. OC cells pretreated with ROS inhibitor N-Acetylcysteine (NAC) and the specific p53 inhibitor pifithrin-μ could completely reverse the pyroptosis post-treatment. Elevated p53 and phosphorylated p53 reduced mitochondrial membrane potential (MMP) and Bcl-2, increase the expression of Bax, and damage mitochondria by releasing cytochrome c to activate the downstream pyroptosis pathway. Different doses of GA inhibited tumor growth in ID8 tumor-bearing mice, and high-dose GA increased in tumor-infiltrating lymphocytes CD3, CD4, and CD8 were detected in tumor tissues. Notably, the expressions of GSDME-N, cleaved caspase-3 and other proteins were increased in tumor tissues with high-dose GA groups. These findings demonstrate that GA-treated OC cells could induce GSDME-mediated pyroptosis through the ROS/p53/mitochondria signaling pathway and caspase-3/-9 activation. Thus, GA is a promising therapeutic agent for OC treatment.

Sensitization of cancer cells to paclitaxel-induced apoptosis by canagliflozin

Cancer cells consume more glucose and usually overexpress glucose transporters which have become potential targets for the development of anticancer drugs. It has been demonstrated that selective SGLT2 inhibitors, such as canagliflozin and dapagliflozin, display anticancer activity. Here we demonstrated that canagliflozin and dapagliflozin synergistically enhanced the growth inhibitory effect of paclitaxel in cancer cells including ovarian cancer and oral squamous cell carcinoma cells. Canagliflozin also inhibited glucose uptake via GLUTs. The combination of paclitaxel and WZB117, a GLUT inhibitor, exhibited a strong synergy, supporting the notion that inhibition of GLUTs by canagliflozin may also account for the synergy between canagliflozin and paclitaxel. Mechanistic studies in ES-2 ovarian cancer cells revealed that canagliflozin potentiated paclitaxel-induced apoptosis and DNA damaging effect. Paclitaxel in the nanomolar range elevated abnormal mitotic cells as well as aneuploid cells, and canagliflozin further enhanced this effect. Furthermore, canagliflozin downregulated cyclin B1 and phospho-BUBR1 upon spindle assembly checkpoint (SAC) activation by paclitaxel, and may consequently impair SAC. Thus, paclitaxel disturbed microtubule dynamics and canagliflozin compromised SAC activity, together they may induce premature mitotic exit, accumulation of aneuploid cells with DNA damage, and ultimately apoptosis.

Bavachinin exerts anti-tumor effects by activating TLR4/STING axis-dependent PANoptosis and synergistically enhances chemosensitivity in endometrial cancer

The incidence and mortality rates of endometrial cancer (EC), a malignancy originating from endometrium, have been increasing globally. Currently, there are no effective therapeutic options for patients with recurrent, chemoresistant, and metastatic forms of this disease. Through compound library screening, we identified that bavachinin (BVC) has a killing effect on EC cells. BVC is a bioactive small molecule with potential pharmacological effects derived from the traditional Chinese herb Proralea corylifolia L, but the specific mechanisms are unclear. We first discovered that BVC induces ZBP1 (Z-DNA binding protein 1)-mediated PANoptosis in EC cells, characterized by activating of pyroptosis, apoptosis, and necroptosis. BVC promoted reactive oxygen species (ROS) production, mitochondrial membrane potential (MMP, ΔΨm) collapse, and ATM-CHK2 mediated DNA damage, which activated cGAS-STING pathway in EC cells. Mechanistically, network pharmacology, molecular docking, cellular thermal shift assays (CESTA), and drug affinity responsive target stability (DARTS) experiments revealed that BVC induced PANoptosis in EC cells by directly interacting with toll-like receptor 4 (TLR4), thereby triggering mitochondrial ROS generation, activating the cGAS-STING pathway. Notably, TLR4 knockdown inhibited STING-TBK1-IRF3 pathway and ZBP1-mediated PANoptosis. In addition, low-dose BVC combined with cisplatin increased phosphorylated H2AX expression, suggesting that BVC enhances the sensitivity of EC cells to cisplatin. In vivo studies demonstrated that BVC induced PANoptosis in EC, and BVC in combination with cisplatin had effective anti-tumor effect without injuring vital organs. These novel findings provide compelling evidence to support the clinical application of BVC and PANoptosis-based therapy for treating EC.

Strategies to synergize PD-1/PD-L1 targeted cancer immunotherapies to enhance antitumor responses in ovarian cancer

Anti-programmed cell death 1/programmed cell death ligand 1 (anti-PD-1/PD-L1) antibodies have developed rapidly but exhibited modest activity in ovarian cancer (OC), achieving a clinical response rate ranging from 5.9% to 19%. Current evidence indicate that the establishment of an integrated cancer-immunity cycle is a prerequisite for anti-PD-1/PD-L1 antibodies. Any impairment in this cycle, including lack of cancer antigens release, impaired antigen-presenting, decreased T cell priming and activation, less T cells that are trafficked or infiltrated in tumor microenvironment (TME), and low tumor recognition and killings, will lead to decreased infiltrated cytotoxic T cells to tumor bed and treatment failure. Therefore, combinatorial strategies aiming to modify cancer-immunity cycle and reprogram tumor immune microenvironment are of great interest. By far, various strategies have been studied to enhance responsiveness to PD-1/PD-L1 inhibitors in OC. Platinum-based chemotherapy increases neoantigens release; poly (ADP-ribose) polymerase (PARP) inhibitors (PARPis) improve the function of antigen-presenting cells and promote the trafficking of T cells into tumors; epigenetic drugs help to complete the immune cycle by affecting multiple steps; immunotherapies like anti-cytotoxic T lymphocyte antigen 4 (CTLA-4) antibodies reactivate T cells, and other treatment strategies like radiotherapy helps to increase the expression of tumor antigens. In this review, we will summarize the preclinical studies by analyzing their contribution in modifying the cancer immunity cycle and remodeling tumor environment, and we will also summarize recent progress in clinical trials and discuss some perspectives to improve these treatment strategies.

Curcumin reduces paclitaxel resistance in ovarian carcinoma cells by upregulating SNIP1 and inhibiting NFκB activity

The therapeutic activity of paclitaxel against ovarian carcinoma is relatively low due to the frequent occurrence of chemoresistance and disease recurrence. We found earlier that a combination of curcumin and paclitaxel reduces cell viability and promotes apoptosis in paclitaxel-resistant (i.e., taxol-resistant, Txr) ovarian cancer cells. In the present study, we first used RNA sequencing (RNAseq) analysis to identify genes that are upregulated in Txr cell lines but downregulated by curcumin in ovarian cancer cells. The nuclear factor kappa B (NFκB) signaling pathway was shown to be upregulated in Txr cells. Furthermore, based on the protein interaction database BioGRID, we found that Smad nuclear interacting protein 1 (SNIP1) may be involved in regulating the activity of NFκB in Txr cells. Accordingly, curcumin upregulated SNIP1 expression, which in turn downregulated the pro-survival genes Bcl-2 and Mcl-1. Using shRNA-guided gene silencing, we found that SNIP1 depletion reversed the inhibitory effect of curcumin on NFκB activity. Moreover, we identified that SNIP1 enhanced NFκB protein degradation, thereby suppressing NFκB/p65 acetylation, which is involved in the inhibitory effect of curcumin on NFκB signaling. The transcription factor early growth response protein 1 (EGR1) was shown to represent an upstream transactivator of SNIP1. Consequently, we show that curcumin inhibits NFκB activity by modulating the EGR1/SNIP1 axis to attenuate p65 acetylation and protein stability in Txr cells. These findings provide a new mechanism to account for the effects of curcumin in inducing apoptosis and reducing paclitaxel resistance in ovarian cancer cells.

Harmine inhibits ovarian cancer migration and invasion and epithelial-mesenchymal transition (EMT) by inhibiting HDAC7 to restore RECK expression

Harmine, a β-carboline alkaloid derived from Peganum harmala L., exhibits potent anticancer properties, including the suppression of ovarian cancer (OC) cell proliferation and metastasis. However, the underlying molecular mechanisms remain incompletely understood. This study demonstrates that harmine significantly inhibits OC cell migration, invasion, and epithelial-mesenchymal transition (EMT) both in vitro and in vivo. Transcriptome sequencing revealed that harmine downregulates histone deacetylase 7 (HDAC7) while upregulating the reversion-inducing cysteine-rich protein with Kazal motifs (RECK), a tumor suppressor gene frequently silenced in cancers. Functional assays showed that harmine treatment dose- and time-dependently reduced OC cell viability, migration, and invasion, concomitant with elevated RECK expression and suppression of matrix metalloproteinases (MMP2, MMP9) and mesenchymal markers (N-cadherin, Snail, Vimentin), alongside increased E-cadherin levels. Knockdown of RECK abolished these antitumor effects, confirming its pivotal role in harmine-mediated metastasis inhibition. Mechanistically, harmine suppressed HDAC7 expression, and conversely, HDAC7 overexpression reversed harmine's anti-metastatic effects by repressing RECK. Further analysis revealed that HDAC7 binds to transcription factor SP1. Chromatin immunoprecipitation (ChIP) assays confirmed that harmine disrupts this interaction, liberating SP1 to bind the RECK promoter and activate its transcription. Collectively, these findings elucidate a novel HDAC7/RECK/SP1 axis through which harmine exerts its anti-metastatic effects in OC, highlighting its potential as a therapeutic agent for OC treatment.

H1.0 modulates IL-6 expression and paclitaxel resistance via HDAC5 in ovarian cancer cells

Chemoresistance is a significant challenge and major obstacle to achieving cancer remission during chemotherapy, primarily due to the risk of recurrence and metastasis. This study reveals that linker histone H1.0 plays a crucial role in paclitaxel resistance (TXR) in ovarian cancer cells by regulating Histone deacetylase 5 (HDAC5), which deacetylates core histones and represses gene transactivation. Transcriptomic profile analysis revealed that cytokine signaling networks are enriched pathways that correlate with H1.0 expression. Advanced clustering analysis identified interleukin 6 (IL-6) as a key molecule connecting these enriched H1.0-related pathways. Furthermore, gain- and loss-of-H1.0 expression experiments showed that H1.0 controls IL-6 mRNA and protein expression in ovarian cancer cells. Additionally, our findings indicate that HDAC5 expression is downregulated in SKOV3/Txr cells compared with parental cells. H1.0 silencing in TXR cells increases HDAC5 levels, suggesting an antagonistic effect between H1.0 and HDAC5. Cell viability assays showed that HDAC5 overexpression markedly inhibited cell survival. Furthermore, ectopic HDAC5 overexpression reduced IL-6 mRNA and protein expression, which was increased by H1.0. This effect was associated with reduced H3K9Ac core histone acetylation and decreased NF-κB binding on the IL-6 promoter, as demonstrated by chromatin immunoprecipitation assays. Further analysis revealed that HDAC5 is downregulated in several tumor types. Furthermore, high H1.0 and IL-6 expression, coupled with low HDAC5 levels, was exclusively observed in ovarian carcinoma. Together, our results demonstrate an interplay between H1.0, HDAC5, and IL-6 in modulating paclitaxel resistance in ovarian cancer cells, highlighting new therapeutic targets to overcome chemoresistance.

Publisher

Elsevier BV

ISSN

0006-2952