Targeting mTOR by CZ415 Suppresses Cell Proliferation and Promotes Apoptosis via Lipin-1 in Cervical Cancer In Vitro and In Vivo.

CZ415, a novel inhibitor of mammalian target of rapamycin (mTOR) kinase, has demonstrated anti-tumor activity in several types of cancer. However, its biological function and underlying mechanism of action in cervical cancer (CC) have not been fully studied. Two CC cell lines (Hela and Siha) were treated with increasing concentrations of CZ415. Cell viability was tested with the CCK-8 assay, cell proliferation was determined by Edu staining and the colony formation assay, and apoptosis was determined by flow cytometry and Hoechst 33342 staining. Protein expression was evaluated by western blotting. A nude mouse xenograft model was used to confirm the anti-tumor activity of CZ415 in vivo. Hematoxylin and eosin (H&E) and immunohistochemistry (IHC) staining were performed on samples of tumor tissue. Results showed that CZ415 inhibited CC cell survival in a dose- and time-dependent manner, and 100 nanomolar and 48 h were the optimal conditions. In vitro and in vivo experiments showed that treatment with CZ415 significantly inhibited spheroid formation, cell proliferation, and tumor growth. Further studies showed that the anti-cancer effects of CZ415 were due to an induction of apoptosis, which was accompanied by an upregulation of Bax and downregulation of Bcl-2 through Lipin-1. CZ415 also reduced the levels of mTOR/STAT3 expression. However, these phenotypic changes were reversed by overexpression of Lipin-1. Our results suggest that the novel mTOR inhibitor CZ415 mediates tumor malignancy via Lipin-1 and might be useful for treating CC.