Specific Direct Small Molecule p300/β-Catenin Antagonists Maintain Stem Cell Potency.

Despite their high degree of identity and even higher homology, the two Kat3 transcriptional coactivators, CBP and p300, have distinct functions, particularly within the Wnt/β-catenin signaling cascade. ICG-001, by directly binding to CBP but not p300, inhibits CBP/β-catenin transcription and has served as an invaluable chemical genomic tool to dissect the Wnt signaling cascade and the divergent roles of these two coactivators. However, to date no direct antagonist of the p300/β-catenin interaction has been reported. We now report the identification and validation of the first highly specific, direct p300/β-catenin antagonists, YH249/250 and their ability to maintain pluripotency in ESC.