GCN2-IN-6 is a potent and orally available GCN2 inhibitor confirmed by in-house enzymatic (IC50: 1.8 nM) and cellular assays (IC50: 9.3 nM). GCN2-IN-6 is also an eIF2α kinase PERK inhibitor with IC50s of 0.26 nM in enzymatic assay and 230 nM in cells respectively.

GCN2:1.8 nM (IC50, in-house enzymatic), PERK:230 nM (cellular assays), GCN2:9.3 nM (IC50, cellular assays), PERK:0.26 nM (IC50, in-house enzymatic)

The moderate antiproliferative effects achieved by combining asparaginase and GCN2-IN-6 treatment are observed in GCN2-wildtype (WT) mouse embryonic fibroblast (MEF) cells but not in GCN2-knockout (KO) MEF. GCN2-IN-6 demonstrates suppression on p-GCN2, p-eIF2α, and ATF4 activated by asparaginase. To examine the impact of GCN2 inhibition on cancer cell proliferation, acute lymphoblastic leukemia (ALL) CCRFCEM cells are treated with GCN2-IN-6 (Compound 6d) in the presence of asparagine depleting agent asparaginase. Treatment with GCN2-IN-6 greatly sensitizes CCRF-CEM cells to asparaginase.

GCN2-IN-6 ( 0.3-3 mg/kg;oral administration;for 8 hours;mice) treatment at 3 mg/kg suppresses both self-phosphorylation of GCN2 and the downstream effector ATF4 to the basal level following pretreatment with asparaginase.