Caspases-dependent apoptosis is mediated by HDACi. Time-course analyses of HDACi-induced apoptosis in SH-EP cells (A), in IMR32 and LAN-1 cells (B). Cells were treated with indicated doses of NaB (mM), SAHA (μM) or TSA (μM). C. The caspases inhibitor zVAD completely prevents HDACi-induced apoptosis. SH-EP and IMR32 cells were treated for 24 h with NaB, SAHA, or TSA, in the presence (white) or in the absence (black) of zVAD. Percentage of sub-G1 apoptotic cells detected by the propidium staining method after stimulation with HDACi are indicated in the histograms (A), or as bare graph (B and C).