(−)-Gossypol induces a caspase-dependent type of cell death in bladder cancer cells that is attenuated in gemcitabine- and cisplatin-resistant cells. 5637, 5637rGEMCI20, 5637rCDDP1000, RT4, RT4rGEMCI20 and RT4rCDDP1000 cells were pre-treated with pan-caspase inhibitor z-VAD (100 μM) for 1 h followed by treatment with 10 μM of pan Bcl-2 inhibitor (−)-gossypol for 48 h. Total cell death and early apoptotis cell were quantified by flow cytometric analysis. *, P < 0,05 compared with the control. #, P > 0.05 compared to with or without z-VAD. §, P > 0.05 compared to the parental cell (A and B). Representative data from the experiment B in 5637, 5637rGEMCI20 and 5637rCDDP1000 exhibited as FACS dot plot profiles (C). Western blot analysis of the expression of pro-survival and pro-apoptotic Bcl-2 family members and LC-3 I and LC-3 II in 5637 parental (PAR), 5637rGEMCI20, 5637rCDDP1000, RT4 parental, RT4rGEMCI20 and RT4rCDDP1000cells. GAPDH served as a loading control (D).