MS-275 is an inhibitor of histone deacetylases (HDACs) that preferentially inhibits HDAC1 (IC50 = 300 nM) over HDAC3 (IC50 = 8 μM). However, it does not inhibit HDAC8 (IC50 > 100 μM). MS-275 induces cyclin-dependent kinase inhibitor 1A (p21/CIP1/WAF1), slowing cell growth, differentiation, and tumor development in vivo. Recent studies suggest that MS-275 may be particularly useful as an antineoplastic agent when combined with other drugs, like adriamycin, inhibitors of poly (ADP-ribose) polymerase (PARP), or inhibitors of heat shock protein 90 (Hsp90).
