Abstract
MicroRNA-425-5p (miR-425-5p) has been reported to be involved in the tumorigenesis of several tumors, but its function in breast cancer is still unknown. In this study, miR-425-5p was found significantly upregulated in breast cancer cells, and predicted a poor prognosis for breast cancer patients. Overexpression of miR-425-5p could significantly promote breast cancer cell growth. Further studies showed that overexpression of miR-425-5p upregulated the protein levels of Cyclin D1, Cyclin D3, CDK4, and CDK6. However, inhibiting miR-425-5p downregulated their expression and induced cell cycle arrest at G0/G1 phase. In mechanism, overexpression of miR-425-5p increased the phosphorylation of PI3K p85 and AKT, but inhibiting miR-425-5p displayed opposite effects. Moreover, miR-425-5p bound to the 3'UTR of PTEN mRNA, and downregulated the expression levels of PTEN in both mRNA and protein levels in breast cancer cells. Collectively, the results above demonstrated that miR-425-5p was involved in the tumorigenesis of breast cancer by inducing PI3K/AKT signaling and indicated that miR-425-5p could be as a potential target for breast cancer therapy in the future.