Tartary Buckwheat Tea Polysaccharide Induces Mitochondria-Mediated Apoptosis in A549 Human Lung Cancer Cells

Objective: To investigate the effect of tartary buckwheat tea polysaccharide (TBTP) on the apoptosis of A549 human lung cancer cells and its underlying mechanisms. Methods: TBTP was obtained by water extraction. 3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay was used to detect the influence of TBTP on the proliferation of A549 cells. Flow cytometry was applied to determine the effect of TBTP on cell apoptosis in A549 cells.The production of reactive oxygen species (ROS) was assessed by DHE and Mito SOX Red staining. The change of mitochondrial membrane potential was assessed by JC-1 staining. Meanwhile, Western blot analysis was used to evaluate the expression of Bcl-2-associated X protein (Bax), Bcl-2, cleaved caspase-3 and cytochrome c. Results: MTT assay showed a significant inhibitory effect of TBTP on A549 cells proliferation in a dose- and time-dependent manner. After 24 hours'cultivation, TBTP also promoted A549 cells apoptosis in a dose-dependent manner. TBTP treatment promoted mitochondrial ROS production and oxidative stress in A549 cells. The mitochondrial membrane potential of A549 cells also decreased after TBTP administration, accompanied with increased cytochrome c release from mitochondria. Furthermore, TBTP treatment up-regulated the expression of Bax and cleaved caspase-3, and decreased Bcl-2 expression. Conclusion: TBTP exerts a novel anti-proliferative effect through induction of mitochondria-mediated apoptosis in A549 cells. © 2019, China Food Publishing Company. All right reserved.