Effects of various drugs on caspase activation and cell death with or without caspase inhibitors. OCI-AML3 cells were treated with 2 μM Ara-C, 500 ng/mL Dox, 10 ng/mL vincristine (Vinc), or 50 ng/mL paclitaxel for up to 48 hours, with or without the caspase inhibitor IDN-1529 (Inh I) or IDN-1965 (Inh II) (20 μM). (A) Caspases-3, -9, -8, -7, and -2 processing at 48 hours, measured by immunoblotting. (B) Immunoblotting analysis of caspase-dependent PARP cleavage at 48 hours. (C) DNA fragmentation assay at 48 hours. (D) Cell counts at 48 hours. (E) Annexin V analysis at 48 hours. Results are expressed as mean ± SE. cntl indicates control.