Chidamide is an inhibitor of histone deacetylases (HDACs; IC50s = 0.095, 0.160, 0.067, 0.733, 0.078, and 0.432 μM for HDAC1-3, 8, 10, and 11, respectively). It is selective for these HDACs over HDAC4-7 and 9 (IC50s = >30 μM for all). Chidamide also inhibits nicotinamide phosphoribosyltransferase (Nampt; IC50 = 2.1 μM). It inhibits cell growth in a panel of 18 cancer cell lines (GI50s = 0.4-40 μM) but has no effect on the growth of non-cancerous CCC-HEK human fetal kidney or CCC-HEL human liver cells (GI50s = >100 μM). In vivo, tucidinostat (12.5, 25, and 50 mg/kg) reduces tumor growth in HCT-8, A549, BEL-7402, and MCF-7 mouse xenograft models.
