Study on promotion of A549 cells apoptosis by steroid saponin YB16 of Ypsilandra thibetica and its mechanism / 中草药

ABSTRACT

Objective: To observe the effects of steroidal saponin YB16 of Ypsilandra thibetica on cell apoptosis of A549 human lung cancer cells, and explore the mechanism of apoptosis. Methods: Cells were cultured in vitro and treated with different concentration of YB16; The proliferation of A549 cells was examined by MTT method; Cells fluorescence changes of A549 were examined by acridine orange (AO) and JC-1 staining; PI, Annexin V-FITC/PI double staining, and JC-1 staining were examined by flow cytometry. Intracellular level of reactive oxygen (ROS) was determined by DCFH-DA assay, the expression of YB16 on apoptosis-related proteins was examined by Western blotting. Results: Steroidal saponin YB16 of Y. thibetica could inhibit A549 cells growth significantly with dose-effect relationship (P < 0.05); With the increasing of drug concentration, cell morphology changed significantly compared with the control group; Cell apoptosis rate increased with the different concentration of YB16 (P < 0.05); Mitochondrial membrane potential decreased significantly; ROS level of cells was increased with a significant difference (P < 0.05). Apoptotic protein, such as Bcl-2 expression of anti-apoptotic protein, was decreased, and the expression of pro-apoptotic protein Bax and cleaved caspase-3 was increased treated by YB16 after 24 h (P < 0.05). Conclusion: Steroidal saponin YB16 of Y. thibetica could inhibit the cell proliferation, reduce the mitochondrial membrane potential, enhance ROS level of A549 cells, and promote apoptosis. Therefore, it has a good anti-tumor activity.