Abstract 2377: Design, synthesis, and characterization of 4-aminopyrazole quinazolines as potent inhibitors of G protein-coupled receptor kinase GRK6 for the potential treatment of multiple myeloma

Abstract

Abstract Multiple myeloma (MM) is one of the most common hematological malignancies, but current therapeutic options are limited to high-dose chemotherapy or high-risk stem-cell transplantation. In a kinome-wide RNAi study by Tiedemann and colleagues (2010), the G-protein coupled receptor kinase GRK6 was identified as a critical kinase required for survival of MM cells. This study also suggests that MM cells, but not other cell types, are dependent on GRK6; and that gene silencing by shRNA or siRNA of GRK6, but not other members of the GRK family, results in decreased survival. Through gene silencing techniques, we determined that a functional GRK6 kinase domain is required for survival of MM cells. These findings helped validate that the kinase domain of GRK6 is a promising target for MM, and therefore encouraged us to embark on an effort to identify potent small molecule kinase inhibitors of GRK6. Toward that end, by screening a focused kinase-directed library of small molecule inhibitors, compounds with moderate potency against GRK6 in biochemical assays were identified. Through this exercise, we discovered that two structurally distinct aminopyrazoles AZ-960 and ASC-082 had modest inhibition of GRK6. By combining structural features of these hits and further optimization we identified the quinazoline analogue OICR9945, a potent GRK6 inhibitor with good selectivity against a panel of diverse kinases and anti-proliferative activity against MM cell lines. Herein, we describe the design, synthesis and early pharmacological characterization of OICR9945 along with structure activity relationships (SAR) of this series against GRK6 and other kinases. Citation Format: David Uehling, Babu Joseph, Carly Griffin, Ratheesh Subramaniam, Ayome Abibi, Richard Marcellus, Michael Prakesch, Gennadiy Poda, Methvin Isaac, Chungyee Leung-Hagesteijn, Rodger Tiedemann, Rima Al-awar. Design, synthesis, and characterization of 4-aminopyrazole quinazolines as potent inhibitors of G protein-coupled receptor kinase GRK6 for the potential treatment of multiple myeloma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2377.