EPZ5676 is a potent inhibitor of DOT1L histone methyltransferase, according to X-ray crystallographic analysis, that occupies the S-adenosyl methionine (SAM) binding pocket of DOT1L and induces conformational changes in DOT1L resulting in the opening of a hydrophobic pocket beyond the amino acid portion of SAM. EPZ5676 selectively inhibits DOTIL with a value of 50% inhibition concentration IC50 of 0.8 nM, which is 37000-fold greater in selectivity than other methyltransferases, including CARM1, EHMT1/2, EZH1/2, PRMT1/2/5/6/8, SETD7, SMYD2/3, and WHSC1/1L1. EPZ5676 has been investigated for the treatment of MLL-rearranged leukemia in multiple studies where results have shown that EPZ5676 inhibits H3K79 methylation and the expression of MLL-fusion target gene and potently kills acute leukemia cell lines bearing MLL translocation.
Reference
Daigle SR, Olhava EJ, Therkelsen CA, Basavapathruni A, Jin L, Boriack-Sjodin PA, Allain CJ, Klaus CR, Raimondi A, Scott MP, Waters NJ, Chesworth R, Moyer MP, Copeland RA, Richon VM, Pollock RM. Potent inhibition of DOT1L as treatment of MLL-fusion leukemia. Blood. 2013 Aug 8;122(6):1017-1025.