Histone Demethylase Inhibition

N-Methylation of histone lysine residues is an “epigenetic modification” that can be either transcriptionally activating or deactivating, depending on the position of the lysine, its methylation state and the presence of other modifications. The largest family of demethylases, the JmjC enzymes, employ 2-oxoglutarate (2OG) as a cosubstrate (Figure 1a). Some JmjC demethylases are targeted for cancer treatment and inflammatory diseases. There are 5 JmjC demethylase subfamilies, targeting histone lysines (H3K= histone 3 lysine-residue) including at H3K4, H3K9, H3K27, and H3K36 (Figure 1b). The factors determining JmjC selectivities are emerging, and involve both catalytic and non-catalytic domains. Although there are reports of JmjC inhibitors, to date there are no reported compounds that are selective for subfamilies/isoforms. Here we report that a strategy involving binding to both the 2OG and substrate binding sites leads to selective and potent inhibitors of the JMJD2 subfamily. There are predicted to be four human JMJD2 enzymes (A to D) and a “pseudogene” product JMJD2E. JMJD2A–C accept both H3K9me3/me2 and H3K36me3/me2, whereas JMJD2D–E only accept H3K9me3/me2. Most, if not all, reported JmjC inhibitors are 2OG analogues with limited or undetermined selectivity, and with the exception of some peptide-based inhibitors, have not, at least rationally, exploited the histone binding pocket. We reasoned that “two-component inhibitors” that bind to 2OG and histone