A pan-HDAC inhibitor (IC50 = 77 nM in an in vitro HDAC1 activity assay) that prevents proliferation of ovarian (A2780), colon (COLO 205 and HCT116), and prostate cancer (PC-3) cell lines at IC50 values of 0.48, 0.56, 0.48, and 0.34 μM, respectively; binds all HDAC isozymes with similar affinity (Kis = 16-28 nM) with the exception of HDAC6 and 7 (Kis = 247 and 104 nM, respectively).