UNC3866

UNC3866 is a potent antagonist of the CBX7-H3 interaction as determined by AlphaScreen (IC₅₀=66±1.2 nM) and is more than 100-fold selective for CBX7 over the other nine members of this methyl-lysine (Kme) reader panel. IC50 & Target: IC50: 66±1.2 nM (CBX7)^[1] In Vitro: UNC3866, a potent antagonist of the methyl-lysine (Kme) reading function of the Polycomb CBX and CDY families of chromodomains. UNC3866 binds the chromodomains of CBX4 and CBX7 most potently with a K_d of 100 nM for each, and is 6- to 18-fold selective versus seven other CBX and CDY chromodomains while being highly selective versus >250 other protein targets. UNC3866 inhibits PC3 cell proliferation, a known CBX7 phenotype, while UNC4219, a methylated negative control compound, has negligible effects. UNC3866 is a potent and cellularly active antagonist of PRC1 chromodomains. UNC3866 is the most potent ligand reported for CBX7 with a K_d of 97±2.4 nM. UNC3866 is equipotent for CBX4, which is most similar to CBX7, while it is 18-, 6- and 12-fold selective for CBX4/7 over CBX2, -6 and -8, respectively. Additionally, UNC3866 is 65-fold selective for CBX4/7 over CDY1 and 9-fold selective for CBX4/7 over CDYL1b and CDYL2^[1].