Circ_0007444 Inhibits the Progression of Ovarian Cancer via Mediating the miR-570-3p/PTEN Axis

PURPOSE: Some circular RNAs have been found to be effective therapeutic targets for OC. However, the biological function of circ_0007444 in OC is still unknown. Thus, this study investigated the role of circ_0007444 in OC progression. METHODS: circ_0007444 expression was monitored in 87 OC patients and OC cells by quantitative real-time polymerase chain reaction. An in vitro study was performed to research the biological function of circ_0007444, including cell counting kit-8 assay, flow cytometry, wound healing assay, and transwell experiment. Luciferase reporter gene assay and RNA immunoprecipitation assay were used to reveal the interaction between circ_0007444, miR-570-3p, and PTEN. PTEN protein expression was determined by Western blot. In vivo study was performed using nude mice. Ki67, PTEN expression, and apoptosis in xenograft tumors was respectively researched by immunohistochemistry and Tunel assay. RESULTS: circ_0007444 was down-regulated in 87 OC patients, which was related to advanced tumor stage and grade, large tumor size, and low 60-month percent survival (P<0.05 or P<0.01). circ_0007444 inhibited proliferation, migration, and invasion, and promoted apoptosis of OC cells (P<0.01). circ_0007444 promoted PTEN expression via sponging miR-570-3p. miR-570-3p up-regulation and PTEN down-regulation reversed the inhibitory effect of circ_0007444 on OC cells malignant phenotype (P<0.01). circ_0007444 inhibited OC growth in vivo. In xenograft tumor, circ_0007444 decreased Ki67 expression but increased PTEN expression and apoptosis. CONCLUSION: circ_0007444 is a tumor suppressor in OC, which inhibits OC progression by mediating the miR-570-3p/PTEN. circ_0007444 can be a potential candidate for targeted therapy of OC.