Tivozanib (KRN951) is an orally bioavailable inhibitor of vascular endothelial growth factor receptors (VEGFRs) 1, 2 and 3 with potential antiangiogenic and antineoplastic activities.

VEGFR2:6.5 nM, PDGFRα:40 nM, EphB2:24 nM, VEGFR1:30 nM, VEGFR3:15 nM

Kinase Assays: Cell-free kinase assays are done in quadruplicate with 1 μM ATP to determine the IC50 values of AV-951 against a variety of recombinant receptor and nonreceptor tyrosine kinases including VEGFR1, VEGFR2, VEGFR3, c-Kit, PDGFRβ, Flt-3 and FGFR1.

Human umbilical vein endothelial cells (HUVEC) and normal human dermal fibroblasts-based assays are done to determine the ability of AV-951 to inhibit ligand-dependent phosphorylation of tyrosine kinase receptors. The cells are starved overnight in appropriate basic medium containing 0.5% fetal bovine serum (FBS). The cells are incubated for 1 hour following the addition of AV-951 or 0.1% DMSO, and then stimulated with the cognate ligand at 37 °C. Receptor phosphorylation is induced for 5 minutes except for VEGFR3 (10 minutes), c-Met (10 minutes), and c-Kit (15 minutes). All the ligands used in the assays are human recombinant proteins, except for VEGF-C, a rat recombinant protein. Following cell lysis, receptors are immunoprecipitated with appropriate antibodies and subjected to immunoblotting with phosphotyrosine. Quantification of the blots and calculation of IC50 values are carried ou(Only for Reference)