MiRNA-335-5 p inhibits cell proliferation and invasion through regulating DKK 1 in epithelial ovarian carcinoma

The function of miRNA-335-5p (miR-335-5p) has been reported in many human cancers. However, till now, the expression and role of miR-335-5p in epithelial ovarian carcinoma was unclear. In this study, we aimed to investigate the expression and molecular mechanism of miR-335-5p in EOC development. The expression level of miR-335-5p in EOC tissues and cell lines was measured by using quantitative Real-time PCR. MiR-335-5p mimic and inhibitor were respectively transfected into EOC cell line for further investigation. CKK8 assay was used to detect cell proliferation. Transwell assay was performed to detect cell invasive ability. Dual-luciferase report assay, quantitative real-time PCR, western blot and immunocytochemical analysis were performed to explore the mechanism of miR-335-5p in EOC development by regulating DKK1 protein. Our results showed that miR-335-5p was down-expressed in EOC tissues and negatively correlated with tumor stage (P<0.05). MiR-335-5p mimic could inhibit cell proliferation and invasion, while miR-335-5p inhibitor promoted cell proliferation and invasion (P<0.05). DKK1 was identified as a target of miR-335-5p. The expression of DKK1 protein was inhibited by miR-335-5p mimic while promoted by miR-335-5p inhibitor (P<0.05). Our results showed miR-335-5p played an important role in suppressing the proliferation and invasion of EOC cells by directly targeting DKK1.