Foretinib (GSK1363089)

Kinase inhibition is investigated using one of three assay formats: [³³P]phosphoryl transfer, luciferase-coupled chemiluminescence, or AlphaScreen tyrosine kinase technology. IC50s are calculated by nonlinear regression analysis using XLFit.³³P -Phosphoryl Transfer Kinase Assay Reactions are performed in 384-well white, clear bottom, high-binding microtiter plates (Greiner, Monroe, NC). Plates are coated with 2 μg/well of protein or peptide substrate in a 50 μL volume of coating buffer contained 40 μg/mL substrate (poly(Glu, Tyr) 4:1, 22.5 mM Na2CO₃, 27.5 mM NaHCO₃, 50 mM NaCl and 3 mM NaN ₃. Coated plates are washed once with 50 μL of assay buffer following overnight incubation at room temperature (RT). Test compounds and enzymes are combined with ³³P-γ-ATP (3.3 μCi/nmol) in a total volume of 20 μL. The reaction mixture is incubated at RT for 2 hours and terminated by aspiration. The microtiter plates are subsequently washed 6 times with 0.05% Tween-PBS buffer (PBST). Scintillation fluid (50 μL/well) is added and incorporated ³³P is measured by liquid scintillation spectrometry using a MicroBeta scintillation counter.Luciferase-Coupled Chemiluminescence Assay Reactions are conducted in 384-well white, medium binding microtiter plates (Greiner). In a first step enzyme and compound are combined and incubated for 60 minutes; reactions are initiated by addition of ATP and peptide substrate (poly(Glu, Tyr) 4:1) in a final voume of 20 μL, and incubated at RT for 2-4 hours. Following the kinase reaction, a 20 μL aliquot of Kinase Glo (Promega, Madison, WI) is added and luminescence signal is measured using a Victor plate reader. Total ATP consumption is limited to 50%. AlphaScreenTM Tyrosine Kinase Assay Donor beads coated with streptavidin and acceptor beads coated with PY100 anti-phosphotyrosine antibody are used. Biotinylated poly(Glu,Tyr) 4:1 is used as the substrate. Substrate phosphorylation is measured by addition of donor/acceptor beads by luminescence following donor-acceptor bead complex formation. Kinase and test compounds are combined and preincubated for 60 minutes, followed by addition of ATP, and biotinylated poly(Glu, Tyr) in a total volume of 20 μL in 384-well white, medium binding microtiter plates (Greiner). Reaction mixtures are incubated for 1 hour at room temperature. Reactions are quenched by addition of 10 μL of 15-30 μg/mL AlphaScreen bead suspension containing 75 mM Hepes, pH 7.4, 300 mM NaCl, 120 mM EDTA, 0.3% BSA and 0.03% Tween-20. After 2-16 hours incubation at room temperature plates are read using an AlphaQuest reader.

B16F10, A549, and HT29 cells (1.2× 10³ per well) are mixed with soft agar and seeded in a 96-well plate containing 10% FBS and EXEL-2880 over a base agar layer. For normoxic conditions, the plates are incubated (37°C) for 12 to 14 days in 21% oxygen, 5% CO₂, and 74% nitrogen, whereas incubation (37 °C) under hypoxic conditions is done in a hypoxia chamber in 1% oxygen, 5% CO₂, and 94% nitrogen. The number of colonies is evaluated under each condition following addition of 50% Alamar Blue and fluorescence detection.