SGC707 is a selective, potent, low molecular weight (MW = 298) and cell-active allosteric inhibitor of protein arginine N-methyltransferase 3 (PRMT3). PRMT3, one of the four type I protein arginine N-methyltransferases, has been implicated in ribosomal biosynthesis via catalyzing the formation of asymmetric (type I) mono- and dimethylarginine. PRMT3 has also been involved in cancer via interaction with the DAL-1 tumor suppressor protein [1]. SGC707 inhibits the activity of PRMT3 by targeting the dimerization interface of PRMT3[2].

In vitro: The IC50 and KD value of SGC707 against PRMT3was 31 ± 2 nM and 53 ± 2 nM respectively. SGC707 showed an outstanding selectivity for PRMT3 against 31 other methyltransferases and a broad range of 250 non-epigenetic targets, G protein-coupled receptors (GPCRs), ion channels, and transporters. The residence time of SGC707 was 9.7 min. In both HEK293 and A549 cells, SGC707 stabilized PRMT3 with EC50 values of 1.3 μM and 1.6 μM, respectively. SGC707 treatment at high concentrations 50 and 100 mM for 72 h lead to some toxicity [1].

In vivo: In CD-1 male mice, intraperitoneal injection of SGC707 at 30 mg/kg for over 6 h showed good plasma exposure with the peak plasma level of 38 μM. After injection 6 h, the plasma level of SGC707 decreased to 208 nM. The half-life of SGC707 was about 1 h. The 30 mg/kg dose was well tolerated in the tested mouse model [1].

References:
Kaniskan H, Szewczyk M M, Yu Z, et al.  A Potent, Selective and Cell‐Active Allosteric Inhibitor of Protein Arginine Methyltransferase 3 (PRMT3)[J]. Angewandte Chemie International Edition, 2015, 54(17): 5166-5170.
Luo M.  Inhibitors of protein methyltransferases as chemical tools[J]. Epigenomics, 2015, 7(8): 1327-1338.