Examining induction of BH3-only proteins, Bak, and Bax to explain the dichotomy in antiapoptotic capacity of the prosurvival Bcl-2 proteins. (A) J16 cells were treated with etoposide (5 µg/mL), daunorubicin (0.25 µg/mL), bortezomib (50 nM), IR (32 Gy), vincristine (5 ng/mL), or roscovitine (100 µM) for 48 hours in the presence of Q-VD-OPH (20 µM) to block apoptosis in order to maintain cell yield. Equal protein amounts of total cell lysates were separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis and subjected to immunoblotting to assess expression of indicated endogenous proapoptotic proteins. Actin detection was used as a measure for equal loading. Numbers below blots indicate signal intensity normalized to the untreated control. Data are representative of 2 independent experiments. (B) J16 T-ALL cells with Dox-inducible expression of tBid-C were transduced to stably express the indicated prosurvival Bcl-2 family members or empty control vector (E.V.). Resulting cell lines were selected on antibiotics, and cell death was assessed by PI uptake 48 hours after the addition of Dox. Q-VD-OPH was taken along as a control for apoptotic cell death (E.V. Q). Data shown are mean values ± SD derived from 3 independent experiments.