Design and Synthesis of a 2-Amino-pyridine Derivative as a Potent CDK8 Inhibitor for Anti-colorectal Cancer Therapy

CDK8 is a transcriptional cyclin-dependent kinase and considered as a potential target in colon cancer therapeutics. Here, a novel selective CDK8 inhibitor was identified against colon cancer in vivo. Specifically, based on the structural information of the sorafenib-bound CDK8 structure, a series of novel 2-amino-pyridine derivatives were designed, synthesized, and evaluated. Among them, compound 29 showed strong inhibitory activity against CDK8 with an IC50 value of 46 nM and favorable selectivity. And there is an apparent interaction between the endogenous or overexpressed CDK8 and biotinylated-29. This compound exhibited antiproliferation potency on colon cancer cell lines with a high CDK8 expression level, suppressed the activation of WNT/β-catenin and transcriptional activity of the TCF family, and induced G1 phase arrested in HCT-116 cells. In addition, this compound showed potent activity against sorafenib-resistant HCT-116 cells. What's more, it exhibited low toxicity and suitable pharmacokinetic (PK) profiles and showed preferable antitumor effects in vivo.