Subcellular localization of Bax in drug-treated HCT116 cells and the p53-/- derivatives. Panel A: HCT116 and HCT116 p53-/- cultures were treated with 100 μM resveratrol (+) or mock-treated (-) and, after 24 h, stained with the mitochondria-specific dye Mitotracker Red (MT-red) and anti-Bax N-20 antibody (1:100). Note the punctuate, cytoplasmic stain with perinuclear concentration produced by the anti-Bax antibody in cells exposed to the drug, resembling the pattern produced by MT-red. Panel B: Confocal microscopy of HCT116 cells treated with resveratrol for 24 h confirmed the co-localization of part of the Bax-produced fluorescence with the MT-red fluorescence. Panel C: Immunoblot analysis on 15 μg of total protein from the high membrane (mitochondrial) fraction of cells mock-treated (-) or drug-treated (+) for 24 h. Staining with Bax and cytochrome b (control) antibody (1:500) revealed the increase in Bax levels in the mitochondria fraction of resveratrol-treated cells. The co-localization of Bax with the mitochondria was not dependent on the presence of p53.