Objective To investigate the effect of circ_0000592/miR-515-5p axis on the proliferation, migration and invasion of breast cancer cells.

Methods The cancer tissues and adjacent tissues of 57 breast cancer patients were collected, and the expressions of circ_0000592 and miR-515-5p in the tissues were detected by qRT-PCR. Human breast epithelial cells HMEpiC and breast cancer MCF-7 cells were cultured in vitro. qRT- PCR method was used to detect the expression of circ_0000592 and miR-515-5p in the cells. The dual luciferase reporter gene experiment verified the regulatory relationship between circ_0000592 and miR-515-5p. MCF-7 cells were transfected with circ_0000592 small interfering RNA or miR-515-5p inhibitor, and then CCK-8 assay, clone formation test and Transwell assay were used to detect the cell viability, clone number, migration number and invasion number. The protein expression of E-cadherin and N-cadherin in cells were detected by Western blotting.

Results In breast cancer tissues, the expression of circ_0000592 was increased (P < 0.05), and the expression of miR-515-5p was decreased (P < 0.05). The expression of circ_0000592 in breast cancer MCF-7 cells was higher than that in HMEpiC cells (P < 0.05), but the expression of miR-515-5p was lower than that in HMEpiC cells (P < 0.05). Circ_0000592 could negatively regulate miR-515-5p in MCF-7 cells. After down-regulating circ_0000592, the survival rate, clone number, migration number, invasion number of MCF-7 cells and the expression of N-cadherin protein in the cells were all decreased (P < 0.01), but the expression of E-cadherin protein was increased (P < 0.01). Down-regulation of miR-515-5p partially restored the effectd of down-regulation of circ_0000592 on proliferation, migration and invasion of MCF-7 cells.

Conclusions The expression of circ_0000592 is elevated in breast cancer tissues and cell lines, which promotes breast cancer cell proliferation, migration and invasion through the negative regulation of miR-515-5p.