Beihua Kong

SNRPB-mediated regulation of DDX39A splicing promotes ovarian cancer progression by regulating α6 integrin subunit expression

Dysfunction or aberrant expression of DEAD-box RNA helicases might play a role in the initiation and progression of human cancers. Nevertheless, the key regulator and underlying molecular mechanism have yet to be fully elucidated in ovarian cancer. This study identified DDX39A as one of the prominently upregulated genes in ovarian cancer through a systematic analysis of RNA helicase expression profiles using the CPTAC and TCGA ovarian cancer datasets. High expression of DDX39A was confirmed in paraffin-embedded ovarian cancer samples. Specifically, elevated DDX39A expression was found to be associated with poor overall survival in ovarian cancer patients. Antisense oligonucleotide-mediated DDX39A silencing led to a decrease in the proliferation capacity of a CDX model and a PDX model. Furthermore, DDX39A expression is regulated by the splicing factor SNRPB. SNRPB depletion or DDX39A knockdown induced the retention of DDX39A introns 6 and 8 to generate the noncoding transcript DDX39A-209, which yielded premature termination codons and resulted in nonsense-mediated RNA decay and decreased expression of the DDX39A protein. DDX39A silencing reduced the proliferative and metastatic capacities of SNRPB-overexpressing cells, indicating that DDX39A mediates the oncogenic function of SNRPB in ovarian cancer cells. In addition, RNA-Seq data analysis revealed that DDX39A promotes the proliferation and metastasis of ovarian cancer cells through the regulation of exon skipping of ITGA6 to produce the oncogenic ITGA6A transcript. These findings suggest that the SNRPB/DDX39A/ITGA6 axis plays critically important role in the progression of ovarian cancer, which increases our understanding of the role of DEAD-box RNA helicases and provides a viable therapeutic target for ovarian cancer.

Development and validation of a prediction model for lymph node metastasis based on molecular typing in clinically early-stage endometrial carcinoma

To develop and externally validate a machine learning-based preoperative model integrating molecular typing and clinical features to predict lymph node metastasis (LNM) in patients with early-stage endometrial carcinoma (EC). This retrospective study included 465 patients with clinically early-stage EC treated at Qilu Hospital of Shandong University. Tumors were classified into molecular subtypes using The Cancer Genome Atlas-based methods. Least Absolute Shrinkage and Selection Operator regression identified five preoperative predictors: molecular typing (CN-H vs. non-CN-H), histological subtype, depth of myometrial invasion, neutrophil-to-lymphocyte ratio, and CA125 levels. Multiple machine learning algorithms were evaluated, and logistic regression (LR) was selected based on optimal discrimination and clinical applicability. Model performance was assessed using area under the curve (AUC), calibration plots, and decision curve analysis (DCA). A web-based nomogram was developed for clinical use. The LR model demonstrated excellent discrimination, with AUCs of 0.843 in the training cohort and 0.809 in the testing cohort. The CN-H subtype was significantly associated with increased LNM risk. The model enabled effective risk stratification and calibration curves and DCA confirmed the model's accuracy and clinical utility. By integrating molecular and preoperative clinical features, this model offers accurate LNM risk stratification for early-stage EC. It supports clinical decision-making and has been implemented as a user-friendly online tool. Further prospective multicenter validation is warranted.

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.

Age-specific clinical performance of HPV-based vs. cytology-based cervical cancer screening in China

Cervical cancer remains a significant health burden, and effective screening is essential, yet the age-specific performance of HPV primary screening is rarely studied. This multicenter study evaluates age-specific performance of primary human papillomavirus (HPV) testing as cross-sectional and longitudinal screening for cervical cancer among 28,501 Chinese women. At baseline, HPV screening with cytology triage demonstrates higher sensitivity (96.9% vs. 79.7%) but slightly lower specificity (88.8% vs. 92.7%) than cytology with HPV triage for cervical intraepithelial neoplasia grade 2 or worse (CIN2+). HPV sensitivities remain high across age groups (≤35: 100.0%; 36-45: 96.4%; >45: 96.8%), consistently exceeding the corresponding cytology sensitivities (66.7%, 75.7%, and 84.9%). Over a three-year follow-up, HPV screening maintains superior sensitivity (93.1% vs. 58.1%) and slightly lower specificity (89.6% vs. 92.4%) compared with cytology. Age-stratified analyses in the longitudinal setting reveal trends similar to those observed in the cross-sectional analyses. Women positive for HPV16/18 have a 43.0% three-year risk of CIN2+, compared with 0.2% for HPV-negative women. These findings support the durable protection of HPV-based screening and the feasibility of extending screening intervals.

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 splicing factor SNRPB promotes ovarian cancer progression through regulating aberrant exon skipping of POLA1 and BRCA2

Splicing factors play a crucial role in the initiation and development of various human cancers. SNRPB, a core spliceosome component, regulates pre-mRNA alternative splicing. However, its function and underlying mechanism in ovarian cancer remain unclear. This study identified SNRPB as a critical driver of ovarian cancer through TCGA and CPTAC database analysis. SNRPB was highly upregulated in fresh frozen ovarian cancer tissues compared with normal fallopian tubes. Immunohistochemistry revealed that SNRPB expression was increased in formalin-fixed, paraffin-embedded ovarian cancer sections and was positively correlated with a poor prognosis for ovarian cancer. Functionally, SNRPB knockdown suppressed ovarian cancer cell proliferation and invasion, and overexpression exerted opposite effects. SNRPB expression increased after cisplatin treatment, and silencing SNRPB sensitized ovarian cancer cells to cisplatin. KEGG pathway analysis revealed that the differentially expressed genes (DEGs) were mainly enriched in DNA replication and homologous recombination, and almost all DEGs related to DNA replication and homologous recombination were downregulated after SNRPB knockdown according to RNA-seq. Exon 3 skipping of the DEGs DNA polymerase alpha 1 (POLA1) and BRCA2 was induced by SNRPB silencing. Exon 3 skipping of POLA1 yielded premature termination codons and led to nonsense-mediated RNA decay (NMD); exon 3 skipping of BRCA2 led to loss of the PALB2 binding domain, which is necessary for homologous recombination, and increased ovarian cancer cell cisplatin sensitivity. POLA1 or BRCA2 knockdown partially impaired the increased malignancy of SNRPB-overexpressing ovarian cancer cells. Moreover, miR-654-5p was found to reduce SNRPB mRNA expression by directly binding to the SNRPB 3'-UTR. Overall, SNRPB was identified as an important oncogenic driver that promotes ovarian cancer progression by repressing exon 3 skipping of POLA1 and BRCA2. Thus, SNRPB is a potential treatment target and prognostic marker for ovarian cancer.

Fertility and prognosis assessment between bleomycin/etoposide/cisplatin and paclitaxel/carboplatin chemotherapy regimens in the conservative treatment of malignant ovarian germ cell tumors: a multicenter and retrospective study

To evaluate the impact of bleomycin/etoposide/cisplatin (BEP) and paclitaxel/carboplatin (PC) chemotherapy regimens on the fertility and prognostic outcomes in malignant ovarian germ cell tumor (MOGCT) patients who underwent fertility-sparing surgery (FSS). A propensity score matching algorithm was performed between the BEP and PC groups. The χ² test and the Kaplan-Meier method were used to compare the fertility outcome, disease-free survival (DFS) and overall survival (OS). The Cox proportional hazards regression analysis was used to identify risk factor of DFS. We included 213 patients, 185 (86.9%) underwent BEP chemotherapy, and 28 (13.1%) underwent PC chemotherapy. The median age was 22 years (range, 8-44 years), and the median follow-up period was 63 months (range, 2-191 months). Fifty-one (29.3%) patients had a pregnancy plan, and 35 (85.4%) delivered successfully. In the before and after propensity score matching cohorts, there were no significant differences in spontaneous abortion, selective termination of pregnancy, during-pregnancy status, and live birth between the BEP and PC groups (p>0.05). Fourteen (6.6%) patients experienced recurrence, including 11 (5.9%) in the BEP group and 3 (10.7%) in the PC group. Four (1.9%) patients in the BEP group died. Kaplan-Meier analysis revealed no significant differences in DFS (p=0.328) and OS (p=0.446) between the BEP and PC groups, and the same survival results were observed in the after matching cohort. The PC regimen is as safe as the BEP regimen for MOGCT patients with fertility preservation treatment, and no differences were observed in fertility and clinical prognosis.

MiR-509-3 augments the synthetic lethality of PARPi by regulating HR repair in PDX model of HGSOC

Abstract Background PARP inhibitors have been the most promising target drugs with widely proven benefits among ovarian cancer patients. Although platinum-response, HR-related genes, or HRD genomic scar detection are acceptably used in assessment of Olaparib response, there are still evident limitations in the present approaches. Therefore, we aim to investigate more accurate approaches to predict Olaparib sensitivity and effective synergistic treatment strategies. Methods We probed two databases (TCGA and Qilu Hospital) in order to quest novel miRNAs associated with platinum-sensitivity or HR-related genes. Cellular experiments in vitro or in vivo and PDX models were utilized to validate their role in tumor suppression and Olaparib sensitizing. Furthermore, HR gene mutation was analyzed through WES to explore the relation between HR gene mutation and Olaparib response. Results High miR-509-3 expression indicated better response to platinum and longer progression-free and overall survival in two independent ovarian cancer patient cohorts (high vs. low miR-509-3 expression; PFS: TCGA P < 0.05, Qilu P < 0.05; OS: TCGA P < 0.05, Qilu P < 0.01). MiR-509-3 could impair the proliferation, migration, and invasion ability but enhance the sensitivity to Olaparib of ovarian cancer cell in vitro and in vivo by directly targeting HMGA2 and RAD51. In two PDX cases (PDX1 and PDX9), miR-509-3 could significantly increase the sensitivity to Olaparib along with the decrease of RAD51 positive rate (mean tumor weight NC + Olaparib vs. miR-509 + Olaparib; PDX1 P < 0.05, PDX9 P < 0.05). Additionally, in PDX8, miR-509-3 treatment dramatically reversed the Olaparib insensitivity (P < 0.05) by downregulating RAD51 expression. RAD51 functional detection revealed that all Olaparib sensitive cases exhibited low RAD51 positive rate (lesser than 50%) in treated groups. Furthermore, among the four HR gene mutation patients, three harbored HR core gene mutation and were sensitive to Olaparib while the remaining one with non-HR core gene mutation did not respond well to Olaparib. Conclusions MiR-509-3 can sensitize ovarian cancer cells to Olaparib by impeding HR, which makes it a potential target in PARPi synergistic treatment. HR core gene analysis and RAD51 functional detection are prospectively feasible in prediction of PARPi response.

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.

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.

PBK drives PARP inhibitor resistance through the TRIM37/NFκB axis in ovarian cancer

AbstractResistance to PARP inhibitors (PARPi) remains a therapeutic challenge in ovarian cancer patients. PDZ-binding kinase (PBK) participates in the chemoresistance of many malignancies. However, the role of PBK in PARPi resistance of ovarian cancer is obscure. In the current study, we demonstrated that overexpression of PBK contributed to olaparib resistance in ovarian cancer cells. Knockdown of PBK sensitized olaparib-resistant SKOV3 cells to olaparib. Inhibition of PBK using a specific inhibitor enhanced the therapeutic efficiency of olaparib. Mechanically, PBK directly interacted with TRIM37 to promote its phosphorylation and nuclear translocation. which subsequently activates the NFκB pathway. Additionally, PBK enhanced olaparib resistance of ovarian cancer by regulating the NFκB/TRIM37 axis in vitro and in vivo. In conclusion, PBK confers ovarian cancer resistance to PARPi through activating the TRIM37-mediated NFκB pathway, and targeted inhibition of PBK provided the new therapy to improve PARPi treatment outcomes for ovarian cancer patients.

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.

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.

PBK promotes aggressive phenotypes of cervical cancer through ERK/c‐Myc signaling pathway

AbstractCervical cancer is the fourth most frequent cancer in women worldwide. PDZ‐binding kinase (PBK) is proven to promote the malignant behaviors of various carcinomas. However, its functional roles and oncogenic mechanisms in cervical cancer are poorly understood. In this study, we reported that PBK was highly expressed in cervical cancer tissues. PBK promoted the proliferation, metastasis, and cisplatin resistance of cervical cancer cells. OTS514, a specific PBK inhibitor, could significantly suppress proliferation and metastasis of cervical cancer cells in vitro and in a xenograft model. Besides, OTS514 could enhance cisplatin‐based chemosensitivity in cervical cancer cells. Mechanistically, PBK promoted the expression and stabilization of c‐Myc through phosphorylating ERK1/2. OTS514 suppressed the phosphorylation of ERK1/2 and the transcriptional activity of c‐Myc. Furthermore, inhibition of the ERK signal pathway by U0126 reversed the increased proliferation and metastasis induced by overexpression of PBK. Exogenous expression of c‐Myc counteracted the decreased proliferation and metastasis evoked by knockdown of PBK. In conclusion, PBK promoted the malignant progression of cervical cancer through ERK/c‐Myc signal pathway. PBK might be a promising molecular target for cervical cancer treatment.

Association between tumor laterality and prognosis across different ovarian cancer subtypes: Results from SEER database and a Chinese multicenter cohort

To investigate the association between tumor laterality and prognosis across different histological subtypes of ovarian cancer. In this study, we enrolled patients with ovarian serous cancer (SC), endometrioid cancer (EC), mucinous cancer (MC), clear cell cancer (CCC), sex cord-stromal tumor (SCST) and malignant germ cell tumor (MGCT) from the Surveillance, Epidemiology, and End Results (SEER) database between 1988 and 2017. Additionally, we enrolled MGCT patients from a Chinese multi-institutional registry between 2003 and 2020 for complementary analyses. The primary outcomes were cancer-specific survival (CSS) and disease-free survival (DFS) in the SEER cohort and Chinese cohort, respectively. Multivariate Cox regression and Kaplan-Meier analyses were used to assess the association of tumor laterality with prognosis. In the SEER cohort with 13597 ovarian cancer patients, the fully-adjusted multivariate Cox regression model showed the right-sided tumor was significantly associated with a better CSS than the left-sided tumor (hazard ratio [HR] 0.51, 95 % confidence interval [CI]: 0.27-0.97; P = 0.041) among MGCT patients, whereas no significant association between tumor laterality and CSS was found among patients with SC, EC, MC, CCC and SCST (all P > 0.05). Furthermore, among the 288 MGCT patients in the Chinese cohort, the significant association of right-sided disease with better DFS (HR: 0.18, 95 % CI: 0.05-0.68; P = 0.011) was also observed. Similar results were found in the Kaplan-Meier analyses. Patients with right-sided tumor had a better prognosis than those with left-sided tumor in MGCT, but not in other ovarian cancer subtypes. Our findings suggested that personalized treatment strategies based on the tumor laterality might be necessary among MGCT patients.