TP-064, a potent and selective small molecule inhibitor of PRMT4 for multiple myeloma

// Kazuhide Nakayama 1, * , Magdalena M. Szewczyk 2, * , Carlo dela Sena 2, * , Hong Wu 2 , Aiping Dong 2 , Hong Zeng 2 , Fengling Li 2 , Renato Ferreira de Freitas 2 , Mohammad S. Eram 2 , Matthieu Schapira 2, 3 , Yuji Baba 1 , Mihoko Kunitomo 1 , Douglas R. Cary 1 , Michiko Tawada 4 , Akihiro Ohashi 1 , Yasuhiro Imaeda 1 , Kumar Singh Saikatendu 5 , Charles E. Grimshaw 6 , Masoud Vedadi 2, 3 , Cheryl H. Arrowsmith 2, 7 , Dalia Barsyte-Lovejoy 2 , Atsushi Kiba 1 , Daisuke Tomita 1 and Peter J. Brown 2 1 Oncology Drug Discovery Unit, Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, Fujisawa, Kanagawa 251-8555, Japan 2 Structural Genomics Consortium, University of Toronto, Toronto, Ontario M5G 1L7, Canada 3 Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario M5S 1A8, Canada 4 Medicinal Chemistry Research Laboratory, Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, Fujisawa, Kanagawa 251-8555, Japan 5 Structiural Biology, Takeda California Inc., 10410 Science Center Drive, San Diego, CA 92121, USA 6 Enzymology and Biophysical Chemistry, Takeda California Inc., 10410 Science Center Drive, San Diego, CA 92121, USA 7 Princess Margaret Cancer Centre and Department of Medical Biophysics, University of Toronto, Toronto, Ontario M5G 2M9, Canada * These authors have contributed equally to this work Correspondence to: Kazuhide Nakayama, email: kazuhide.nakayama@takeda.com Peter J. Brown, email: peterj.brown@utoronto.ca Keywords: PRMT4; small molecule inhibitor; TP-064; crystal structure; multiple myeloma Received: November 11, 2017      Accepted: March 06, 2018      Published: April 06, 2018 ABSTRACT Protein arginine methyltransferase (PRMT) 4 (also known as coactivator-associated arginine methyltransferase 1; CARM1) is involved in a variety of biological processes and is considered as a candidate oncogene owing to its overexpression in several types of cancer. Selective PRMT4 inhibitors are useful tools for clarifying the molecular events regulated by PRMT4 and for validating PRMT4 as a therapeutic target. Here, we report the discovery of TP-064, a potent, selective, and cell-active chemical probe of human PRMT4 and its co-crystal structure with PRMT4. TP-064 inhibited the methyltransferase activity of PRMT4 with high potency (half-maximal inhibitory concentration, IC 50 < 10 nM) and selectivity over other PRMT family proteins, and reduced arginine dimethylation of the PRMT4 substrates BRG1-associated factor 155 (BAF155; IC 50 = 340 ± 30 nM) and Mediator complex subunit 12 (MED12; IC 50 = 43 ± 10 nM). TP-064 treatment inhibited the proliferation of a subset of multiple myeloma cell lines, with affected cells arrested in G1 phase of the cell cycle. TP-064 and its negative control (TP-064N) will be valuable tools to further investigate the biology of PRMT4 and the therapeutic potential of PRMT4 inhibition.