Circular RNA CDR1as acts as a sponge of miR-135b-5p to suppress ovarian cancer progression

He Chen,1 Min Mao,2 Jing Jiang,1 Daling Zhu,2 Peiling Li11Department of Obstetrics and Gynecology, The Second Affiliated Hospital of Harbin Medical University, Harbin 150086, People’s Republic of China; 2Department of Biopharmaceutical Sciences, Harbin Medical University, Daqing 163319, People’s Republic of ChinaBackground and objectives: Ovarian cancer is the most fatal primary malignancy among gynecological cancers. Circular RNAs (circRNAs) play an important role in the development of various cancers, but the functions of circRNAs in ovarian cancer development have not been studied. We aim to explore the function and mechanism of CDR1as in the progression of ovarian cancer and to provide a new target for the diagnosis and treatment of ovarian cancer.Methods: Ovarian cancer cell proliferation was assessed according to proliferating cell nuclear antigen (PCNA) and Ki67 protein expression levels and MTT and CCK8 assays. The migration ability of cells was detected by scratch-wound assays, and the invasion ability of the cells was determined by Transwell® assays. qRT-PCR and Western blotting were used to verify miRNA and protein expression.Results: CDR1as expression in ovarian tissues was significantly lower in ovarian cancer patients than in patients without ovarian cancer. CDR1as overexpression inhibited the proliferation, invasion and migration of ovarian cancer cells. Silencing CDR1as increased the expression of miR-135b-5p and decreased the expression of hypoxia-inducible factor 1-alpha inhibitor (HIF1AN), thus increasing the proliferation capacity of ovarian cancer cells.Conclusions: CDR1as, acting as a sponge of miR-135b-5p, promotes the expression of HIF1AN and therefore plays a role in tumor inhibition.Keywords: circular RNAs, CDR1as, ovarian cancer, miR-135b-5p, HIF1A