Purity >98%. GSK923295 is a potent inhibitor of centromere-associated protein E (CENP-E; Ki = 3.2 nM), a kinesin motor protein involved in mitotic checkpoint signaling. GSK923295 causes mitotic cell cycle delay, leading to apoptosis in various cancer cell lines. It induces apoptosis in cancer cells in mice bearing xenografts of COLO 205 cells. GSK923295 can be used with AZ3146, an inhibitor of the spindle checkpoint kinase Mps1, to generate aneuploidy in cells.