GSK-923295

The first potent, allosteric inhibitor of CENP-E kinesin motor ATPase activity with Ki of 3.2 nM; shows excellent selectivity against a panel of mitotic human kinesins; exhibits inhibition of cell proliferation in a broad panel of human cancer cell lines and induces mitotic arrest leading to apoptosis and cell death (SKOV-3 IC50=22 nM; Colo205 IC50=22 nM) ; induces tumor regressions in vivo.Solid Tumors Phase 1 Clinical (In Vitro) :GSK-923295 (GSK923295) is a first-in-class, specific, allosteric inhibitor of CENP-E kinesin motor function. GSK923295 is uncompetitive with both ATP and MT, inhibiting CENP-E MT-stimulated ATPase activity with a Ki of 3.2±0.2 nM and 1.6±0.1 nM for human and canine, respectively. GSK923295 inhibits release of inorganic phosphate and stabilized CENP-E motor domain interaction with microtubules. GSK923295 has broad growth inhibitory activity in a panel of 237 cancer cell lines and produces significant tumor growth-delay in 8 of the 11 mouse xenograft tumor models with IC50s of 17.2 nM, 55.6 nM, 42 nM, and 51.9 nM for SW48, RKO (BRAF mutant), SW620 (KRAS mutant), and HCT116 (KRAS mutant), respectively. GSK923295 is a potent and selective small molecule inhibitor of human CENPE with a Ki of 3.2 nM. GSK923295 demonstrates broad efficacy against a panel of 19 human neuroblastoma derived cell lines with an average growth IC50 of 41 nM. (In Vivo) :Xenografts of mice treated with GSK-923295 (GSK923295) shows significant tumor growth delay compared to the control arm (NB-EBc1 p<0.0001; NB-1643 p=0.018; NB-1691 p=0.0018) .