HDAC-IN-91 is a multiple inhibitor of HDAC (IC50 = 134.22 nM for HDAC1, 66.29 nM for HDAC2), carbonic anhydrase (CA) (Ki = 72.03 nM for CA IX, 50.76 nM for XII), and tubulin polymerization ( IC50 = 2.56 µM). HDAC-IN-91 inhibits PARP1 and increases the Bax/Bcl-2 ratio. HDAC-IN-91 blocks the cell cycle at the G2/M phase and induces apoptosis through a mitochondrial apoptosis activation mechanism. HDAC-IN-91 can exert potent cytotoxic activity through tubulin polymerization inhibition. HDAC-IN-91 can be used in breast, colorectal, cervical and lung cancer research[1].