Compound a2 induced mitochondria-dependent apoptosis in gastric cancer cells. MGC-803 cells were treated with a2 at indicated concentrations for 24 h (A and B) and 48 h (C and D), cells were then stained by PI and Annexin V-FITC and analyzed by flow cytometry. (E and F) MGC-803 cells were treated with a2 for 24 h, cells were then stained by JC-1 and analyzed by flow cytometry. (G) MGC-803 cells were treated with a2 for 24 h with illustrated concentrations, indicated proteins were tested by Western blot. (H) MGC-803 cells were treated with a2 alone or in combination with the indicated agents for 72 h, cell viability was then tested by SRB assay. Data are presented as the mean ± SD (n = 3) from three independent experiments with biological duplicates in (B, D, F, H). Statistics differences were analyzed by two-way ANOVA analysis (B, D, H) or one-way ANOVA analysis (F): ∗P < 0.05, ∗∗P < 0.01, ∗∗∗∗P < 0.001 vs. the control (B, D, F). ∗∗P < 0.01, ∗∗∗P < 0.005, ∗∗∗∗P < 0.001 vs. the a2 treated samples (H).