Camellia nitidissima Chi Extract Potentiates the Sensitivity of Gastric Cancer Cells to Paclitaxel via the Induction of Autophagy and Apoptosis

BACKGROUND: Camellia nitidissima Chi (CNC) has been applied as a traditional folk medicine for the effective treatment of various diseases. However, there is little research regarding the mechanism of CNC on pharmaceutical function including anticancer effect. MATERIALS AND METHODS: JHC-4 is a n-butanol extract from CNC. The anti-proliferation effect was evaluated by MTT assays. Monodansylcadaverine (MDC) staining, Western blotting and autophagy inhibitors (CQ and BafA1) were applied to determine whether JHC-4 induced autophagy. The synergistic anticancer effect was evaluated by MTT assays, flow cytometry, Western blotting and autophagy inhibitors. Western blotting was used to explore the influence of PI3K/Akt/mTOR signaling pathway induced by drug treatment. RESULTS: JHC-4 caused significant growth inhibition and induced autophagy in human gastric cancer cells. Moreover, JHC-4 as an autophagy agonist synergistically potentiated the sensitivity of gastric cancer cells to paclitaxel. Meanwhile, JHC-4 could significantly enhance the growth inhibition effect of paclitaxel by the induction of autophagy and apoptosis. Finally, we demonstrated that the PI3K/Akt/mTOR signaling pathway was involved in the synergistic anti-proliferation effect of JHC-4 and paclitaxel. CONCLUSION: All these data indicated that JHC-4 was a novel autophagy inducer when combination with paclitaxel for gastric cancer, which provided the scientific evidence for the use of this Chinese traditional medicine against cancer.