PMID: 30270002

Authors:

Beyett TS, Gan X, Reilly SM, Gomez AV, Chang L, Tesmer JJG, Saltiel AR, Showalter HD

Title:

Design, synthesis, and biological activity of substituted 2-amino-5-oxo-5H-chromeno[2,3-b]pyridine-3-carboxylic acid derivatives as inhibitors of the inflammatory kinases TBK1 and IKKepsilon for the treatment of obesity.

Journal:

Bioorg Med Chem. 2018 Nov 1;26(20):5443-5461. doi: 10.1016/j.bmc.2018.09.020., Epub 2018 Sep 20.

Abstract:

The non-canonical IkappaB kinases TANK-binding kinase 1 (TBK1) and inhibitor of nuclear factor kappa-B kinase epsilon (IKKepsilon) play a key role in insulin-independent pathways that promote energy storage and block adaptive energy expenditure during obesity. Utilizing docking calculations and the x-ray structure of TBK1 bound to amlexanox, an inhibitor of these kinases with modest potency, a series of analogues was synthesized to develop a structure activity relationship (SAR) around the A- and C-rings of the core scaffold. A strategy was developed wherein R7 and R8 A-ring substituents were incorporated late in the synthetic sequence by utilizing palladium-catalyzed cross-coupling reactions on appropriate bromo precursors. Analogues display IC50 values as low as 210nM and reveal A-ring substituents that enhance selectivity toward either kinase. In cell assays, selected analogues display enhanced phosphorylation of p38 or TBK1 and elicited IL-6 secretion in 3T3-L1 adipocytes better than amlexanox. An analogue bearing a R7 cyclohexyl modification demonstrated robust IL-6 production in 3T3-L1 cells as well as a phosphorylation marker of efficacy and was tested in obese mice where it promoted serum IL-6 response, weight loss, and insulin sensitizing effects comparable to amlexanox. These studies provide impetus to expand the SAR around the amlexanox core toward uncovering analogues with development potential.