Abrogating tumor angiogenesis by inhibiting vascular endothelial growth factor 
receptor-2 (VEGFR2) has been established as a therapeutic strategy for treating 
cancer. However, because of their low selectivity, most small molecule 
inhibitors of VEGFR2 tyrosine kinase show unexpected adverse effects and limited 
anticancer efficacy. In the present study, we detailed the pharmacological 
properties of anlotinib, a highly potent and selective VEGFR2 inhibitor, in 
preclinical models. Anlotinib occupied the ATP-binding pocket of VEGFR2 tyrosine 
kinase and showed high selectivity and inhibitory potency (IC50 <1 nmol/L) for 
VEGFR2 relative to other tyrosine kinases. Concordant with this activity, 
anlotinib inhibited VEGF-induced signaling and cell proliferation in HUVEC with 
picomolar IC50 values. However, micromolar concentrations of anlotinib were 
required to inhibit tumor cell proliferation directly in vitro. Anlotinib 
significantly inhibited HUVEC migration and tube formation; it also inhibited 
microvessel growth from explants of rat aorta in vitro and decreased vascular 
density in tumor tissue in vivo. Compared with the well-known tyrosine kinase 
inhibitor sunitinib, once-daily oral dose of anlotinib showed broader and 
stronger in vivo antitumor efficacy and, in some models, caused tumor regression 
in nude mice. Collectively, these results indicate that anlotinib is a 
well-tolerated, orally active VEGFR2 inhibitor that targets angiogenesis in 
tumor growth, and support ongoing clinical evaluation of anlotinib for a variety 
of malignancies.