Fig. 4
BH3 mimetics induce apoptosis even in the absence of BH3-only proteins in HCT116 cells. a HCT116 cells, wild-type (WT) and deficient in 8 different pro-apoptotic BH3-only proteins (8KO), were exposed to A-1331852 (100 nM) in combination with increasing concentrations of S63845 for 4 h and assessed for PS externalization. b Same as (a) but the experiments were carried out with HCT116 WT cells or cells deficient in BAX, BAK or both (DKO). c Immunoprecipitation of MCL-1, BCL-XL and active-BAX in the indicated cells exposed to a combination of S63845 (100 nM) and A-1331852 (100 nM), following a 0.5 h pre-treatment with z-VAD.FMK (30 μM), were performed to assess BAX interaction. d The level of mitochondrial BAX in WT and 8KO cells following S63845 and A-1331852 treatment (both 100 nM) for 4 h was assessed by immunocytochemistry using an anti-BAX antibody. e Western blots of different molecular weight fractions from FPLC showing BAX oligomerization in HCT116 WT and 8KO cells upon exposure to S63845 (100 nM) and A-1331852 (100 nM) for 2 h. f Quantification and representative images of cytochrome c release in the indicated cell lines, from three independent experiments, following exposure to S63845 (100 nM) and A-1331852 (100 nM) for 4 h in the indicated cells. Error bars = Mean ± SEM (standard error of the mean); *p ≤ 0.05; **p ≤ 0.01; ***p ≤ 0.001
