ACY-241 is an inhibitor of histone deacetylase 6 (HDAC6; IC50 = 2.6 nM). It is selective for HDAC6 over HDAC1-3, HDAC7, and HDAC9 (IC50s = 35, 45, 46, 7,300, and 137 nM, respectively), as well as HDAC4, HDAC5, and HDAC9 (IC50 = >20,000 nM for all). It reduces proliferation of A2780, TOV-21G, and MDA-MB-231 cells when used at a concentration of 3 μM and completely inhibits it and induces apoptosis at a concentration of 10 μM. ACY-241, when used in combination with paclitaxel , inhibits proliferation in MiaPaCa-2, TOV-21G, and T47D cells. It also reduces tumor growth in a MiaPaCa-2 mouse xenograft model when administered at a dose of 50 mg/kg in combination with paclitaxel. ACY-241, in combination with the somatostatin receptor agonist pasireotide , reduces hepatorenal cystogenesis in a rat model of polycystic liver disease.
