Development of a Potent, Specific CDK8 Kinase Inhibitor Which Phenocopies CDK8/19 Knockout Cells.
ACS Med Chem Lett 2016;
7:223-8. [PMID:
26985305 DOI:
10.1021/acsmedchemlett.5b00278]
[Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 01/06/2016] [Indexed: 12/30/2022] Open
Abstract
Beginning with promiscuous COT inhibitors, which were found to inhibit CDK8, a series of 6-aza-benzothiophene containing compounds were developed into potent, selective CDK8 inhibitors. When cocrystallized with CDK8 and cyclin C, these compounds exhibit an unusual binding mode, making a single hydrogen bond to the hinge residue A100, a second to K252, and a key cation-π interaction with R356. Structure-based drug design resulted in tool compounds 13 and 32, which are highly potent, kinase selective, permeable compounds with a free fraction >2% and no measurable efflux. Despite these attractive properties, these compounds exhibit weak antiproliferative activity in the HCT-116 colon cancer cell line. Further examination of the activity of 32 in this cell line revealed that the compound reduced phosphorylation of the known CDK8 substrate STAT1 in a manner identical to a CDK8 knockout clone, illustrating the complex effects of inhibition of CDK8 kinase activity in proliferation in these cells.
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