GSK2656157

GSK2656157 is an ATP-competitive and highly selective inhibitor of PERK with IC50 of 0.9 nM in a cell-free assay, 500-fold greater against a panel of 300 kinases.(In Vitro):GSK2656157 results in inhibition of PERK activation as well as decreases in the downstream substrates, phospho-eIF2α, ATF4, and CHOP with an IC50 in the range of 10-30 nM in the BxPC3 pancreatic tumor cell line. Cells that are exposed to 1 μM GSK2656157 before UPR induction are able to block this effect on de novo protein synthesis. GSK2656157 causes the activation of another eIF2α kinase to compensate for the loss of PERK activity in HT1080 cells. GSK2656157 inhibits the growth of the HT1080 cells. GSK2656157 inhibits LPS-induced IL-1β production, LPS-induced Caspase 1 activation and LPS-induced eIF-2α phosphorylation, but does not inhibit LPS-induced TNF-α production.(In Vivo):GSK2656157 (1.5-150 mg/kg, p.o.) results in dose-dependent inhibition of phospho-PERK Thr980, with more than 80% inhibition at 50 and 150 mg/kg. GSK2656157 (50-150 mg/kg, p.o.) results in dose-dependent inhibition of tumor growth in human tumor xenograft models.