Paris saponin VII extracted from Trillium tschonoskii induces autophagy and apoptosis in NSCLC cells

Trillium tschonoskii Maxim, a perennial herb of the Trilliaceae, has been widely used to treat inflammation, hypertension and cancer. We investigated Paris saponin VII's (PS VII), isolated from Trillium tschonoskii Maxim, function in mediating autophagy and apoptosis in NSCLC cells.We treated various NSCLC cells with different concentrations of PS Ⅶ and then measure the cell apoptosis by using flow cytometry assays and western blot. Autophagy were investigated by using western blot, transmission electron microscopy and immunofluorescence analysis. We also use a xenograft model of nude mice to measure the effect of PS Ⅶ in vivo.Treatment with PS Ⅶ significantly inhibit NSCLC cell growth, especially for A549 (IC50 = 1.53 μM). Moreover, PS VII induces caspase-dependent apoptosis and autophagy through AMPK-ULK1 pathway. After blocking autophagy by 3-methyladenine (3-MA), PS VII induced cell death was significantly increased. In vivo, the co-treatment with PS VII and 3-MA dramatically inhibited A549 tumor growth in immune deficient mice and has similar inhibition rates as cisplatin group.Our results suggest that a combination of PS VII and autophagy inhibitor may be a potential anticancer strategy in the NSCLC therapy.