UNC 1999

The histone H3 lysine 27 (H3K27) methyltransferase EZH2 plays an important role in regulating gene expression, and its aberrant activity is linked to the onset and progression of cancer. UNC1999 is a cell-permeable EZH2 inhibitor (IC50 = 2 nM) that is 22-fold selective over EZH1 and >1,000-fold selective over other histone methytranferases. UNC1999 has been shown to inhibit H3K27 methylation in MCF10A cells with an IC50 value of 124 nM.[Cayman Chemical]

The polycomb repressive complex 2 (PRC2), which represses gene expression through methylation of histone H3 on lysine 27 (H3K27), contains either EZH1 or EZH2 as its catalytic subunit, with EZH1 being found in both dividing and non-dividing cells, whereas EZH2 is only found in actively dividing cells. UNC1999 is an orally bioavaliable selective inhibitor of both EZH2 and EZH1 lysine methyltransferases with IC50 < 10 nM for EZH2 and 45 nM for EZH1. UNC1999 potently inhibited both wild-type and mutant Y641N EZH2 methyltransferase activity with less than a 5-fold difference in potency, and selectively killed diffused large B cell lymphoma (DLBCL) cells bearing Y641 point mutations. It was selective for EZH2 and EZH1 over 15 other lysine, arginine and DNA methyltransferases. UNC1999 is competitive with the cofactor S-adenosylmethionine (SAM) and non-competitive with the peptide substrate. Because it inhibits both EZH2 and EZH1, UNC1999 has potential advantages over EZH2 selective inhibitors in the disease settings where both PRC2 – EZH2 and PRC2 – EZH1 contribute to the methylation of H3K27. For full characterization details, please visit the UNC1999 probe summary on the Structural Genomics Consortium (SGC) website.UNC2400 is the negative control for the active probe, UNC1999. To request a sample of the negative control from the SGC, click here.To learn about other SGC chemical probes for epigenetic targets, visit sigma.com/sgc