In vitro and in vivo antitumor and anti-inflammatory capabilities of the novel GSK3 and CDK9 inhibitor ABC1183s

Abstract

Glycogen synthase kinase-3s (GSK3a and GSK3b) are consti-tutively active protein kinases that target over 100 substrates, incorporate into numerous protein complexes, and regulate such vital cellular functions as proliferation, apoptosis, and inflammation. Cyclin-dependent kinase 9 (CDK9) regulates RNA production as a component of positive transcription elongation factor b and promotes expression of oncogenic and inflammatory genes. Simultaneous inhibition of these signaling nodes is a promising approach for drug discovery, although previous compounds exhibit limited selectivity and clinical efficacy. The novel diaminothiazole ABC1183 is a selective GSK3a/b and CDK9 inhibitor and is growth-inhibitory against a broad panel of cancer cell lines. ABC1183 treatment decreases cell survival through G2/M arrest and modulates oncogenic signaling through changes in GSK3, glycogen synthase, and b-catenin phosphorylation and MCL1 expression. Oral administration, which demonstrates no organ or hematologic toxicity, suppresses tumor growth and inflammation-driven gastrointestinal disease symptoms, owing in part to downregulation of tumor necrosis factor a and interleukin-6 proinflammatory cytokines. Therefore, ABC1183 is strategically poised to effectively mitigate multiple clinically relevant diseases.