PCI-24781, a Novel Hydroxamic Acid HDAC Inhibitor, Exerts Cytotoxicity and Histone Alterations via Caspase-8 and FADD in Leukemia Cells
The exposure of PCI-24781 induces caspase-dependent apoptosis in leukemic cells. (a) DNA fragmentation was assessed in Jurkat cells treated with 5 M of PCI-24781 (PCI), with or without 30 minutes of zVAD-fmk pretreatment, incubated for 24 hours, dyed with PI reagent, and assessed on the flow cytometer. (b) Jurkat cells were treated with 0.5 M and 5 M PCI-24781, with or without 30 minutes of zVAD-fmk pretreatment, and incubated for 16 hours. Incubated cells were lysed and stained with DEVD-amc to measure caspase-3-like activity. The release of amc was measured on a spectrofluorometer using an excitation of 355 nm and an emission of 460 nm. (c) In protein lysates from cells treated with 5 M PCI-24781 for 16 hours, procaspase 3, cleaved caspase 3, and actin were measured by western blot. (d) CEM cells were pretreated with 5 M QVD-OPH for 2 hours and treated with 0.5 M PCI-24781 for 30 hours. Percentage cells positive with Annexin V/PI staining was measured for both. Error bars ((a), (b), and (d)) represent the means S.D. of three independent experiments. ((a) and (b)) *P < .05 relative to 5 M PCI-24781.