MicroRNA-181a suppresses progestin-promoted oncogenic transformation of breast epithelial cells through interfering PGRMC1 signalling pathway

Background: Studies have demonstrated that hormone therapy may increase the risk of breast cancer (BC), and the synthetic progestins may play a critical role in this event. Progesterone receptor membrane component 1 (PGRMC1) plays a major role in the development of BC, especially with hormone therapy using progestins. Nonetheless, the mechanism of progestin-promoted carcinogenesis of human normal breast epithelial cell has not yet been elaborated. Moreover, the deregulation of microRNA-181a (miR-181a) is often associated with BC and miR-181a shows strong anti-BC effect. This study is designed to dissect whether miR-181a suppresses the effect of progestin on human breast epithelial cells, and the mechanisms underlying the function of miR-181a during hormone therapy.