EAPB0203-induced apoptosis is caspase dependent in human T-cell lines. (A) Effect of EAPB0203 on the cleavage of PARP in HTLV-I–positive and –negative cells. Cells were treated for 24 hours with EAPB0203 at the indicated concentrations. Total SDS protein lysates (50-100 μg/lane) were prepared and immunoblotted against PARP. (B) Effect of EAPB0203 on the cleavage of pro-caspases 3, 8, and 9. (C) Effect of the general caspase inhibitor z-VAD (50 μM) on the growth inhibition induced by EAPB0203 in CEM and HuT-102 cells. Cell growth was assayed in triplicate wells with the CellTiter 96 nonradioactive cell proliferation kit. Results are expressed as percentage of control plus or minus SD.