The effect of miR-381 on proliferation and prognosis of breast cancer by altering CCNA2 expression

MiR-381 can regulate the expression of cyclin A2 (CCNA2) to inhibit the proliferation and migration of bladder cancer cells, but whether miR-381 has the same function in breast cancer is not well know. The over express or silence miR-381 expressing cell lines were constructed by lentivirus infection to reveal the biological functions of miR-381 <i>in vitro</i>. The expression of miR-381 and CCNA2 in 162 breast cancer patients were detected to further reveal their impact and predictive value on progression-free survival (PFS) and overall survival (OS). After transfection of MDA-MB-231 and MCF-7 cells with miR-381 mimics, the expression of miR-381 was effectively up-regulated and CCNA2 was effectively down-regulated, while the opposite results were observed in tumour cell which transfected with miR-381 inhibitors. After transfection of cell lines with miR-381 mimics, tumour cell activity was significantly reduced, while the opposite results were observed in tumour cell which transfected with miR-381 inhibitors. The area under curves (AUCs) of miRNA-381 and CCNA2 for predicting PFS and OS were 0.711, 0.695, 0.694 and 0.675 respectively. Cox regression analysis showed that miRNA-381 ≥ 1.65 2^−ΔΔCt and CCNA ≥ 2.95 2^−ΔΔCt were the influence factors of PFS and OS, the hazard ratio (HR) values were 0.553, 2.075, 0.462 and 2.089, respectively. miR-381 inhibitors breast cancer cells proliferation and migration by down-regulating the expression of CCNA2, both of them can predict the prognosis of breast cancer. miR-381 can regulate the expression of cyclin A2 and inhibit the proliferation and migration of bladder cancer cells, but whether miR-381 has the same function in breast cancer is not well know. We analysed the levels of miR-381 and cyclin A2 in breast cancer patients and breast cancer cells to reveal the mechanism of miR-381 affecting the expression of cyclin A2. We found miRNA-381 affects the proliferation and migration of breast cancer cells by down-regulating the expression of cyclin A2. The expression of serum miR-381 and cyclin A2 have important values in predicting the prognosis of breast cancer. Our findings provide mechanistic insights into how miR-381 regulates the proliferation and migration of breast cancer, as well as a new target for clinical treatment. Future research may focus on how to improve patient prognosis by up-regulating expression of miR-381 and down-regulating the expression of cyclin A2.