Discovery of Novel 7-Azaindole Derivatives as Selective Covalent Fibroblast Growth Factor Receptor 4 Inhibitors for the Treatment of Hepatocellular Carcinoma.

Fibroblast growth factor receptor 4 (FGFR4) has been identified as a potential target for the treatment of hepatocellular carcinoma (HCC) with aberrant FGFR4 signaling because of its important role in HCC progression and development. Several FGFR4 inhibitors are under clinical development. Using a 7-azaindole scaffold, we discovered a series of novel selective and covalent FGFR4 inhibitors by performing a structure-based design approach. Representative compounds and exhibited potent FGFR4 inhibition and high selectivity among kinases. Western blot analysis showed that compounds and significantly inhibited the FGF19/FGFR4 signaling pathway in HuH-7 cells and effectively suppressed the proliferation of HuH-7 HCC cells and MDA-MB-453 breast cancer cells. Moreover, compound exhibited significant in vivo antitumor activity in a mouse HuH-7 xenograft model. Thus, compound and the 7-azaindole scaffold can be applied to develop anticancer agents for the treatment of cancers characterized by aberrant FGFR4 signaling.