Paris polyphylla saponins II inhibits invasive, migration and epithelial-mesenchymal transition of melanoma cells through activation of autophagy

Malignant melanoma is a kind of malignant tumor derived from normal epidermal melanocytes or original nevus cells. It has a high degree of malignancy, rapid progress, dangerous condition, and poor prognosis. In recent years, the innovation of traditional Chinese medicine has broadened the scope and effect of tumor treatment. It is a hotspot and breakthrough to find new anti-tumor invasion and migration drugs from natural plants or traditional Chinese medicine. This study explored the role of PPII in promoting autophagy to inhibit EMT of melanoma cells, the role of the PI3K/Akt signaling pathway in the invasion and migration of melanoma cells induced by PPII. We found that PPII effectively inhibited the proliferation, invasion and migration of melanoma B16 and B16F10 in vitro, and induced autophagy. We also established the xenograft tumor and metastatic tumor model of C57BL/6 mice with B16F10 cells. Results showed that PPII effectively inhibited the growth of transplanted tumors, induced autophagy and inhibited the expression level of EMT related protein; Metastasis experiment showed that PPII inhibited the invasion and migration of B16F10, the effect of inhibiting lung metastasis is the most significant. Further mechanism studies showed that the inhibition of PPII on melanoma invasion and migration is related to its induction of autophagy and then inhibition of EMT.