KO947 is an ERK inhibitor (IC50 = <50 nM for ERK2). It is greater than 50-fold selective for ERK over a panel of 450 kinases. KO947 reduces phosphorylation of the ERK target p90 ribosomal S6 kinase (RSK) in A375 cancer cells containing constitutively active B-RAFV600E with an IC50 value of less than 250 nM. It inhibits proliferation of A375 cells, as well as mutant K-Ras-expressing HCT116 and H358 cancer cell lines (IC50s = 50-250 nM for all).
