Abstract 736: DJ4, a novel ROCK and MRCK inhibitor, potently inhibits migration and invasion of cancer cells

Abstract

Rho-associated coiled-coil containing protein kinase (Rho kinase/ROCK) and myotonic dystrophy kinase-related Cdc42-binding kinase (MRCK) are involved in the aggressive migration of cancer cells. These are the key proteins involved in the formation of stress fibers that confer contractility to cancer cells during migration and invasion. ROCK and MRCK are primarily involved in amoeboid and mesenchymal type of migration of cancer cells respectively. Earlier studies reported that combined inhibition/silencing of ROCK and MRCK has more pronounced effect than inhibition of the individual kinases suggesting a more effective therapeutic strategy to combat metastatic cancers. With this hypothesis in mind, we developed a series of novel multikinase inhibitors and identified DJ4 as a potent ATP competitive inhibitor of ROCK1, ROCK2 and MRCKβ. DJ4 effectively inhibits the kinase activity of ROCK (ROCK1 and ROCK2) and MRCK in a cell-free system and multiple human non-small cell lung cancer cell lines. In cellular functional assays DJ4 inhibited migration of human melanoma, lung, pancreatic and breast cancer cells in a concentration-dependent manner. In live cell imaging over 20h by time-lapse microscopy, DJ4 (2.5µM ) reduced the migration rate of lung-and breast-cancer cells by 2.7 and 5.5 times compared to control cells respectively. DJ4 (5µM) also inhibited invasion of MDA-MB-231 breast cancer cells by ∼70%. Fluorescent microscopic observation also revealed that inhibition of activity of these kinases, by DJ4, causes reduction in stress fibers which leads to inhibition of cell contractility and migration. In summary, our studies demonstrate that DJ4 is a potent ATP competitive inhibitor of ROCK and MRCK, and effectively inhibits migration and invasion of multiple cancers in vitro. Together these results indicate that DJ4 has a strong potential to be an anti-metastatic drug against multiple cancer types. Citation Format: Vijaykumar P. Kale, Dhimant Desai, Taryn Dick, Katherine Choe, Ashley Colledge, Shantu Amin, Jeremy Hengst, Jong Yun. DJ4, a novel ROCK and MRCK inhibitor, potently inhibits migration and invasion of cancer cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 736. doi:10.1158/1538-7445.AM2014-736