Pim-1 inhibitor SMI-4a suppresses tumor growth in non-small cell lung cancer via PI3K/AKT/mTOR pathway

Background: In the present study, we aimed to investigate the effect of proviral integration site for moloney murine leukemia virus-1 (Pim-1) inhibitor (SMI-4a) on the progression of non-small cell lung cancer (NSCLC). Materials and methods: The effects of SMI-4a on proliferation, apoptosis, and cell cycle of NSCLC cells were examined by in vitro experiments using human NSCLC cell lines (A549 and Ltep-a-2). The pathway regulated by SMI-4a was detected using Western blot. Furthermore, we performed in vivo experiments to assess the effects of SMI-4a on tumor growth using mouse models with NSCLC. Results: Our data demonstrated that SMI-4a could inhibit the proliferation of A549 and Ltep-a-2 cells markedly in a dose-dependent manner (P<0.05). Treatment with 80 μmol/L of SMI-4a for 48 h significantly induced the apoptosis rate of NSCLC cells (P<0.05), and blocked the cell cycle of NSCLC cells in G2/M phase (P<0.05). The phosphorylation levels of PI3K, AKT, and mTOR in NSCLC cells were significantly downregulated by SMI-4a (P<0.05). Result from in vivo experiments demonstrated that SMI-4a could suppress the tumor growth in mouse models with NSCLC (P<0.05). Conclusions: SMI-4a suppresses the progression of NSCLC by blocking the PI3K/AKT/mTOR pathway.