Docetaxel (DTX) induces caspase-dependent death in PC3 cells. A. Caspase-3/7 and -2 activity assays in PC3 cells treated with DTX, TRAIL, or STS in the presence and absence of the pan caspase inhibitor Z-VAD-FMK and the caspase-2 inhibitor Ac-VDVAD-CHO respectively. Cells were pre-treated 1 h prior to drug treatment. Activity was determined by measuring the cleavage of the fluorogenic substrate Ac-DEVD-AMC for caspase-3/7 and Ac-VDVAD-AMC for caspase-2. Fold activation was determined by normalization of the test sample to untreated controls: B. Immunoblotting analysis of PARP and LEDGF/p75 cleavage in DTX-treated PC3 cells in the presence and absence of Z-VAD-FMK: C. Flow cytometric analysis of mitochondrial membrane potential (MMP), using the JC-1 method, in PC3 cells treated with DTX in the presence and absence of Z-VAD-FMK for 48 h. A representative of three independent experiments is shown: D. Cell cycle analysis of PC3 cells treated with DTX in the presence and absence of Z-VAD-FMK for 48 h. Flow cytometric analysis of cells stained with propidium iodide was used to determine the percentage of cells in SubG1 and G2/M. Representative DNA histograms are shown. Error bars in panels A and D represent the standard deviation of at least three independent experiments done in triplicates (* p < 0.05, t-test).