Dayue Liu, Haoming Xia, Fang Wang, Cui Chen, Jianting Long

In this study, we investigated the functional correlation between microRNA-210 (miR-210) and gene of F-box protein 31 (FBXO31) in regulating breast cancer. Dual-luciferase assay and quantitative real-time polymerase chain reaction were used to investigate the binding of miR-210 with FBXO31 and their expression patterns in breast cancer. miR-210 was inhibited in breast cancer T47D and MCF-7 cells to assess its effect on cancer proliferation, cell cycle progression, and migration. FBXO31 was also downregulated in breast cancer cells to examine its effect on miR-210-mediated breast cancer regulation. The interaction between miR-210 and FBXO31 was further investigated by examining the effect of overexpressing miR-210 on FBXO31-induced suppression of breast cancer proliferation. FBXO31 was the downstream target gene of miR-210 in breast cancer. miR-210 and FBXO31 are inversely expressed in breast cancer cell lines. miR-210 downregulation reduced cancer progression, induced cell cycle arrest, and inhibited cancer migration in T47D and MCF-7 cells. Tumor suppression by miR-210 downregulation was reversed by downregulating FBXO31. In FBXO31-overexpressed breast cancer cells, upregulating miR-210 also reversed the tumor-suppressive effect of FBXO31 on breast cancer proliferation. Our work demonstrated that the expression pattern and tumor regulatory functions of miR-210 and FBXO31 are inversely correlated in breast cancer.