– NH-23-C2 (Caspase-2 inhibitor NH-23-C2) is a potent, selective and cell-permeable endogenous caspase-2 inhibitor, does not block caspase-3 or caspase-8.NH-23-C2 displays off-reactivity with cysteine and threonine proteases (cathepsins B, L, V, S).HCT116 cells were preincubated with NH-23-C2 inhibitor, MDM-2 cleavage was inhibited in a concentration-dependent manner (IC50 =3.11 ?M).NH-23-C2 selectively block caspase-2 activity and caspase-2-mediated MDM-2 cleavage.