Metapristone (RU486 metabolite) suppresses NSCLC by targeting EGFR-mediated PI3K/AKT pathway

Therapies targeting epidermal growth factor receptor (EGFR) can effectively treat with non-small cell lung cancer (NSCLC), but NSCLC's drug resistance makes it intractable. Herein, we showed that RU486 metabolite metapristone inhibited the proliferation of various NSCLC cell lines with either wild (A549, H1299, H520) or mutated EGFR (H1975, HCC827). The suppression was resulted from inhibition by metapristone of EGFR signaling pathways through down-regulating the EGFR, PTEN, as well as AKT and ERK proteins. In addition, metapristone inhibited anti-apoptotic marker BcI-2, and activated pro-apoptotic key signaling proteins caspase-3, and poly (ADP-ribose) polymerase. Metapristone induced A549 and H1975 cell cycle via arrest at the GO-G1 stage. What's more, metapristone inhibited the growth of NSCLC xenografts in BALB/c nude mice through decreasing the expression of tumor growth biomarkers PCNA and EGFR. Taken together, the present study demonstrated that metapristone suppressed NSCLC proliferation by promoting apoptosis via decrease the cellular EGFR-mediated PI3K/AKT pathways. The results suggest metapristone a new treatment for EGFR-overexpressed NSCLC.