Belinostat (PXD101) is a novel HDAC (histone deacetylase) inhibitor with IC50 of 27 nM. Belinostat inhibits the growth of tumor cells (A2780, HCT116, HT29, WIL, CALU-3, MCF7, PC3 and HS852) with IC50 from 0.2-0.66 μM. PD101 shows low activity in A2780/cp70 and 2780AD cells. Belinostat inhibits bladder cancer cell growth, especially in 5637 cells, which shows accumulation of G0-G1 phase, decrease in S phase, and increase in G2-M phase. Belinostat also shows enhanced tubulin acetylation in ovarian cancer cell lines. A recent study shows that Belinostat activates PKA (protein kinase A) in a TGF-β signaling-dependent mechanism and decreases survivin mRNA. Belinostat is an inhibitor of HDAC3 (histone deacetylase 3).