Compound a2 induced ferroptosis via decreasing GPX4. MGC-803 (A) and MKN-45 (B) cells were treated with a2 at indicated doses for 24 h, indicated mRNAs were then determined by qRT-PCR. (C) MGC-803 and MKN-45 cells were treated with a2 for 24 h, indicated proteins were measured. GPX4 were overexpressed in MGC-803 (D) and MKN-45 (E) cells, relative inhibitory rates of a2 in indicated cells for 24 h were tested. MGC-803 (F) and MKN-45 (G) cells were treated with a2 alone or combined with IKE for 72 h, cells were then examined by SRB assay. Data are presented as the mean ± SD (n = 3) from three independent experiments with biological duplicates in (A–B, D–G). Statistics differences were analyzed by one-way ANOVA analysis (A and B) or two-way ANOVA analysis (D–G): ∗P < 0.05, ∗∗P < 0.01, ∗∗∗∗P < 0.001 vs. the control (A–B, D–E). ∗P < 0.05, ∗∗∗P < 0.005, ∗∗∗∗P < 0.001 vs. the a2 treated samples (F and G).