GSK2656157 is a highly specific and ATP-competitive PERK inhibitor (IC50: 0.9 nM) in a cell-free assay. The selectivty is 500-fold higher against a panel of 300 kinases.

MLK2:2796 nM, KHS:1764 nM, MEKK3:954 nM, MEKK3:2847 nM, c-MER:3431 nM, ROCK1:7244 nM, EIF2AK1 (HRI):460 nM, PI3Kγ:3802 nM, JAK2:24547 nM, BRK:905 nM, AXL:9808 nM, LCK:2344 nM, WNK3:5951 nM, Aurora B:1259 nM, NEK1:9807 nM, LRRK2:6918 nM, EIF2AK2 (PKR):905 nM, MLCK2:3039 nM, MSK1:8985 nM, PERK:0.9 nM, ALK5:3020 nM, EIF2AK4(GCN2):3162 nM

GSK2656157可抑制小鼠体内多种人移植瘤生长.GSK2656157（50 mg/kg,p.o.）处理8 h后,完全抑制phospho-PERK Thr980. GSK2656157（50/150 mg/kg,2次/天）剂量依赖性地抑制小鼠体内四种肿瘤模型生长,150 mg/kg可抑制54-114%肿瘤生长.

GSK2656157（1 mM）可进行UPR诱导,并抑制de novo蛋白合成。GSK2656157下调6%的UPR相关基因（PPP1R15A,HERPUD1,DDIT3,C/EBP-β和ERN1）,且有超过4倍的下调。GSK2656157预处理细胞可抑制PERK活化,且可使下游底物、phospho-eIF2a、ATF4和 CHOP减少（IC50：10-30 nM）。在无外源UPR诱导剂时,GSK2656157则不影响这些细胞的生长（IC50：6-25 mM）。

Kinase assay: Inhibitory potency of GSK2656157 is measured using recombinant GST-PERK (536–1116 amino acids) with 6-His-full-length human eIF2a as a substrate. Kinase selectivity is evaluated using 27 kinases at GSK as well as a panel of 300 kinases.

Antiproliferative activity of GSK2656157 against multiple human tumor cell lines as well as primary human microvascular endothelial cells is evaluated in a 3-day proliferation assay using standard culture medium. In the absence of exogeneous UPR inducers, GSK2656157 has no significant effect on the growth of any of these cells with IC50 range of 6–25 mM. (Only for Reference)