Background: Circular RNA (circRNA) has been proven to play a significant role in multiple types of cancer. However, the expression and role of circRNAs in epithelial ovarian cancer (EOC) remains elusive. Methods: CircRNA and mRNA expression profiles of EOC were screened with sequencing analysis. Gene silencing and over-expression were used to study circRNA function. Cell proliferation and Matrigel invasion assays were used to detect cell proliferation and invasion, respectively. The expression of circRNAs, mRNAs and miRNAs was detected using qPCR. The location of circRNAs was detected using FISH. The expression of proteins was detected using western blot and immunohistochemistry. Results: CircMUC16 had increased expression in EOC tissues as compared to healthy ovarian tissues. The expression of circMUC16 was linked to the progression in stage and grade of EOC. Hence, silencing circMUC16 suppressed autophagy flux of SKOV3 cells. In contrast, ectopic expression of circMUC16 promoted autophagy flux of A2780 cells. CircMUC16-mediated autophagy exacerbated EOC invasion and metastasis. Mechanistically, circMUC16 could directly bind to miR-199a-5p and relieve suppression of target Beclin1 and RUNX1. In turn, RUNX1 elevated the expression of circMUC16 via promotion of its transcription. CircMUC16 could directly bind to ATG13 and promote its expression. Conclusion: This study demonstrated that circMUC16 regulated Beclin1 and RUNX1 by sponging miR-199a-5p. The data suggested that circMUC16 could be a potential target for EOC diagnosis and therapy.

Chemotherapy is the preferred therapeutic approach for the therapy of advanced ovarian cancer, but 5-year survival rate remains low due to the development of drug resistance. Increasing evidence has documented that microRNAs (miRNAs) act important roles in drug resistance in a variety types of cancer. However, the roles of miRNA in regulating Taxol resistance in ovarian cancer and the detailed mechanism are less reported. We used Taqman probe stem loop real-time PCR to accurately measure the levels of miR-197 in normal ovarian cells, ovarian cancer cells, and Taxol-resistant ovarian cancer cells and found that miR-197 was significantly increased in Taxol-resistant ovarian cancer cells. Enforced expression of miR-197 can promote Taxol resistance, cell proliferation, and invasion of ovarian cancer cells. Meanwhile, repression of miR-197 in ovarian cancer cells can sensitize its response to Taxol and also induced attenuated cell proliferation and invasion ability. Furthermore, investigation of the detailed mechanism showed that the promotion of miR-197 on drug resistance in ovarian cancer cells was partially mediated by downregulating NLK, a negative regulator of WNT signaling pathway. Taken together, our work first demonstrated that miR-197 can confer drug resistance to Taxol, by regulating tumor suppressor, NLK expression in ovarian cancer cells.

Long stress-induced noncoding transcript 5 (LSINCT5) is a member of the LSINCT family, members of which are expressed during stress-induced cell formation and have also been reported to promote cancer progression. In the present study, the association between LSINCT5 expression and clinical significance was investigated and the biological function of LSINCT5 in epithelial ovarian cancer (EOC) was explored. LSINCT5 expression was examined in EOC tissues by reverse transcription-quantitative polymerase chain reaction and its association with clinicopathological factors was analysed. Cell proliferation, migration and invasion tests were performed to observe the role of LSINCT5 in human ovarian cancer cell lines in vitro. The negative control (NC) and siLSINCT5 SKOV3 cells were treated with chemokine ligand 12 (CXCL12) and their proliferation, migration and invasion activities were examined. LSINCT5 was overexpressed in EOC compared with normal ovarian tissue. LSINCT5 expression was significantly associated with the International Federation of Gynecologists and Obstetricians cancer stage and the presence of lymphatic metastases. Silencing LSINCT5 significantly reduced the expression of chemokine receptor 4 (CXCR4) and inhibited SKOV3 cell proliferation, migration and invasion, however the CXCL12 expression level had no significant change. When NC and siLSINCT5-SKOV3 cells were treated with CXCL12, the proliferation and invasion ability were significantly enhanced. The migration ability of the siLSINCT5-SKOV3 cells was also significantly enhanced. The present study indicated that LSINCT5 serves an important role in ovarian cancer metastasis by regulating the CXCL12/CXCR4 signalling axis, suggesting that this pathway may be a potential target for the treatment of patients with EOC.

Background: Risk stratification of patients with cervical cancer accompanied by positive lymph nodes (stage IIIC) (the 2018 International Federation of Gynecology and Obstetrics [FIGO] new staging system) yields a clinically heterogeneous group. In this study, we investigated the prognostic performance of the 2018 FIGO staging system for stage IIIC cervical cancer. Methods: The study included patients with stage III cervical cancer based on the 2018 FIGO staging system, who visited Chongqing University Cancer Hospital between January 2011 and December 2014. Kaplan-Meier curves were generated to evaluate overall survival (OS), which was compared using the log-rank test. The Cox proportional hazard regression model was used for multivariable analysis. Results: A total of 418 patients were eligible for analysis. The 5-year OS was 54.1% for stage IIIC1, 43.3% for stage IIIA, 40.6% for stage IIIB, and 23.1% for stage IIIC2 ( P < .001). Multivariable analysis revealed that compared with stages IIIA (hazard ratio [HR] 1.432, 95% confidence interval [CI] 0.867-2.366, P = .161) and IIIB (HR 1.261, 95% CI 0.871-1.827, P = .219), stage IIIC1 cancer was not significantly associated with an increased mortality risk. Stage IIIC2 was independently associated with an increased mortality risk compared with stages IIIA (HR 2.958, 95% CI 1.757-4.983, P < .001) and IIIB (HR 2.606, 95% CI 1.752-3.877, P < .001). We stratified patients with stage IIIC1 based on the T stage. The 5-year OS was significantly longer in patients with stage IIIC1 (T1) than in those with stage IIIA ( P = .004) or IIIB ( P < .001). Analysis of multiple factors revealed that the mortality risk was 2.75-fold higher in patients with stage IIIC1pN>2 than in patients with stage IIIC1pN1-2 (HR 2.753, 95% CI 1.527-4.965, P = .001). Conclusions: Patients with stage IIIC1 cervical cancer showed heterogeneous clinical characteristics that reflected variable prognoses, depending on the T stage and the extent of pelvic lymph node metastases.