An inhibitor of caspase-2, -3, and -7 (Kis = 3.5, 1, and 7.5 nM, respectively); inhibits caspase-2 and -3 in cell-based assays (IC50s = 1,334 and 346 nM, respectively); inhibits increases in alkaline phosphatase and caspase-2 and -3 activity induced by human BMP4 in MC3T3-E1 cells at 3 μM; inhibits BMP4-induced cell cycle arrest at the G0/G1 phase in MC3T3-E1 cells