protein arginine methyltransferase 5 inhibitor PRT543

An orally available small molecule inhibitor of protein arginine methyltransferase 5 (PRMT5), with potential antiproliferative and antineoplastic activities. Although the exact mechanism of action has not been completely determined, upon oral administration, PRMT5 inhibitor PRT543 selectively binds to the substrate recognition site of PRMT5 and inhibits its methyltransferase activity. This decreases the levels of both monomethylated and dimethylated arginine residues in histones H2A, H3 and H4 and modulates the expression of genes involved in several cellular processes, including cellular proliferation. As a result, PRT543 may increase the expression of antiproliferative genes and/or decrease the expression of genes that promote cell proliferation, which may lead to decreased growth of rapidly proliferating cells, including cancer cells. PRTM5, an arginine methyltransferase that catalyzes the formation of both omega-N monomethylarginine (MMA) and symmetric dimethylarginine (sDMA) on histones and a variety of other protein substrates, is overexpressed in several neoplasms.