MC2625 is a potent pyridine-containing histone deacetylase ( HDAC ) inhibitor. MC2625 show selective HDAC3 and HDAC6 inhibition with IC 50 s of 80 nM and 11 nM. MC2625 increases acetyl-H3 and acetyl-tubulin levels and inhibits cancer stem cells (CSCs) growth by apoptosis induction.