Identification of 1,5-naphthyridine derivatives as a novel series of potent and selective TGF-beta type I receptor inhibitors.
Gellibert F., Woolven J., Fouchet M.-H., Mathews N., Goodland H., Lovegrove V., Laroze A., Nguyen V.-L., Sautet S., Wang R., Janson C., Smith W., Krysa G., Boullay V., De Gouville A.-C., Huet S., Hartley D.
Optimization of the screening hit 1 led to the identification of novel 1,5-naphthyridine aminothiazole and pyrazole derivatives, which are potent and selective inhibitors of the transforming growth factor-beta type I receptor, ALK5. Compounds 15 and 19, which inhibited ALK5 autophosphorylation with IC50 = 6 and 4 nM, respectively, showed potent activities in both binding and cellular assays and exhibited selectivity over p38 mitogen-activated protein kinase. The X-ray crystal structure of 19 in complex with human ALK5 is described, confirming the binding mode proposed from docking studies.