c-Myc expression in BT474 cells impacts on Bim expression and Mcl-1 dependence. BT474 cells were transfected with control siRNA, Foxo3A siRNA or c-Myc siRNA, as indicated. 48 hours later, western blot analysis was performed to confirm the effect of each siRNA on the expression of the targeted proteins and on Bim (EL), (L-) and (S), as indicated (A-B). In (C), BT474 cells were transfected with control siRNA, c-Myc siRNA, and/or Mcl-1 siRNA as indicated and apoptosis was assessed 48 hours later as described in Figure 1. Data are mean ± se of three independent experiments. They are expressed as a percentage of cell death obtained after Mcl-1 siRNA transfection of cells that had been transfected with control siRNA (42.4% ± 6.8%). p-values were assessed using a Student's t test.