HDACi activate the caspases cascade. A. Cells were untreated (no) or treated with 20 mM NaB, 20 μM SAHA or 5 μM TSA for SH-EP, or with 10 mM of NaB, 2.5 μM of SAHA or 1.5 μM of TSA for IMR32 during 48 h. Whole cell extracts were analysed by immunoblotting for the cleavage of caspases-2, -3, -7 and -9. β-actin was used as loading control. B. Caspase-3-like activities are induced by HDACi. Hydrolysis of DEVD-pNA was measured in SH-EP or IMR32 cells unstimulated (no) or stimulated with NaB (mM), SAHA (μM), or TSA (μM) for 48 h as indicated. The caspase-3-like activities of stimulated cells, relative to unstimulated cells are indicated.