In vitro activity: Brivanib also inhibits VEGFR1 and FGFR-1 with IC50 of 0.38 μM and 0.148 μM. Brivanib is not sensitive to PDGFRβ, EGFR, LCK, PKCα or JAK-3 with IC50 all above 1900 nM. Brivanib could inhibit the proliferation of VEGF-stimulated HUVECs with IC50 of 40 nM, compared to 276 nM in FGF-stimulated HUVECs. On the other hand, Brivanib exhibits low activity to tumor cell lines.

Kinase Assay: Recombinant proteins containing tyrosine kinases are expressed as GST fusion proteins using baculovirus expression vector system in Sf9 cells. All enzymes are stored at -80 °C. Brivanib is dissolved in DMSO and diluted by water/10% DMSO. The VEGFR2 kinase solution is composed by 8 ng GST-VEGFR2 enzyme, 75 μg/mL substrate, 1 μM ATP, and 0.04 μCi [γ-33P]-ATP in 50 μL buffer: 20 mM Tris (pH 7.0), 25 μg/mL BSA, 1.5 mM MnCl2, 0.5 mM dithiothreitol). Flk-1 kinase solution is composed by 10 ng GST-Flk-1 enzyme, 75 μg/mL substrate, 1 μM ATP, and 0.04 μCi [γ-33P]-ATP in 50 μL buffer: 20 mM Tris, pH 7.0, 25 μg/mL BSA, 4 mM MnCl2, 0.5 mM dithiothreitol). The reactions are incubated for 1 hour at 27 °C and terminated with cold trichloroacetic acid (TCA) to a final concentration of 15%. These TCA precipitates are collected onto unifilter plates and quantitated by liquid scintillation counter.

Cell Assay: The cells are stimulated by VEGF or FGF at a concentration of 8 or 80 ng/mL. These cells are seeded in 96 well plates at a density of 2 × 103and incubated for 24 hours. Brivanib at various dilutions are added to the cells for another 48 hours. Then 0.5 μCi of [3H] thymidine is added for 24 hours. After that the incorporated tritium is quantified using a β-counter.

J Med Chem. 2006 Apr 6;49(7):2143-6; Clin Cancer Res. 2008 Oct 1;14(19):6146-53.