A Novel Inhibitor of c-Met and VEGF Receptor Tyrosine Kinases with a Broad Spectrum of In Vivo Antitumor Activities

Abstract

The c-Met receptor tyrosine kinase and its ligand, hepatocyte growth factor (HGF), are dysregulated in a wide variety of human cancers and are linked with tumorigenesis and metastatic progression. VEGF also plays a key role in tumor angiogenesis and progression by stimulating the proangiogenic signaling of endothelial cells via activation of VEGF receptor tyrosine kinases (VEGFR). Therefore, inhibiting both HGF/c-Met and VEGF/VEGFR signaling may provide a novel therapeutic approach for treating patients with a broad spectrum of tumors. Toward this goal, we generated and characterized T-1840383, a small-molecule kinase inhibitor that targets both c-Met and VEGFRs. T-1840383 inhibited HGF-induced c-Met phosphorylation and VEGF-induced VEGFR-2 phosphorylation in cancer epithelial cells and vascular endothelial cells, respectively. It also inhibited constitutively activated c-Met phosphorylation in c-met-amplified cancer cells, leading to suppression of cell proliferation. In addition, T-1840383 potently blocked VEGF-dependent proliferation and capillary tube formation of endothelial cells. Following oral administration, T-1840383 showed potent antitumor efficacy in a wide variety of human tumor xenograft mouse models, along with reduction of c-Met phosphorylation levels and microvessel density within tumor xenografts. These results suggest that the efficacy of T-1840383 is produced by direct effects on tumor cell growth and by an antiangiogenic mechanism. Furthermore, T-1840383 showed profound antitumor activity in a gastric tumor peritoneal dissemination model. Collectively, our findings indicate the therapeutic potential of targeting both c-Met and VEGFRs simultaneously with a single small-molecule inhibitor for the treatment of human cancers.