Abstract: Objective To explore the effects of micro RNA 502-3p (miR-502-3p) on the proliferation and apoptosis of ovarian cancer cells by targeting Casitas B-cell lymphoma ( CBL). Methods The ovarian cancer related datasets GSE66957, GSE119056 and TCGA _ OV were downloaded and the relationship between ovarian cancer and miR-502-3p or CBL was analyzed. The SKOV3 and HO8910 cell lines with overexpressed miR-502-3p or/ and CBL were constructed. The cell proliferation and apoptosis were detected by cell counting kit 8 (CCK-8), clone formation assay and flow cytometry. The effect of CBL overexpression on tumor growth was observed in tumor bearing nude mice. The targeting relationship between miR-502-3p and CBL was verified. Results Bioinformatics analysis showed that the expression level of CBL in ovarian cancer tissues was higher than that in para-cancerous tissues, while the expression level of miR-502-3p was lower in cancer tissues than in para-cancerous tissues (P < 0. 05). The expression level of CBL was related to the prognosis of ovarian cancer and the expression of cell proliferation-related genes (P < 0. 05). There was a targeting relationship between miR-502-3p and CBL. The volume and weight of tumors were significantly increased in the CBL group compared with the vector group (P< 0. 05). The expression level of CBL protein, cell viability and number of clones formed in SKOV3 and HO8910 cell lines were significantly decreased and the apoptosis rate was significantly increased in the miR-502-3p group compared with the miR-NC group (P < 0. 05). However, CBL overexpression could reverse the above changes. Conclusion miR-502-3p can inhibit the proliferation and induce the apoptosis of ovarian cancer cells by down-regulating CBL.

Key words: ovarian cancer, miR-502-3p, Casitas B-cell lymphoma, cell proliferation, apoptosis