Inhibition of wild type CRAF (unknown origin) assessed as ADP formation measured for 5 hrs by pyruvate kinase/lactate dehydrogenase coupled assay in presence of ATP, MEK1, PEP, NADH
ADP-Glo Kinase Assay: Inhibitor Concentration at 50% enzyme inhibition (IC50) values were calculated by quantifying the end-point ADP production from each kinase reaction using the ADP-Glo Kinase Assay (Promega, Madison, Wis.) as described by the manufacturer. Reactions were performed in Tris buffer (50 mM pH 7.5, RT) containing 20 mM MgCl2 and 0.1% Bovine Serum Albumin. Each assay was performed in 60 uL of the solution in 10x75 mm borosilicate glass test tubes and allowed to continuously shake during the duration of the assay. The total ADP generated was quantified by transferring 25 uL (2x) of each assay to a 96-well luminescence assay plate, followed by the addition of 25 uL of ADP-Glo Reagent (45 min incubation) to remove any remaining ATP. For luminescence readings, 50 uL of Kinase Detection Reagent (45 min incubation) was added to convert the ADP generated from the kinase reaction to ATP, and luminescent intensity was measured using a luciferase/luciferin reaction.
Kinase Assay: Inhibition of kinase activity by test compound disclosed herein was estimated by quantifying the amount of [33P] incorporation of substrate in the presence of test compound. Standard assay conditions were 2 ng of recombinant C-Raf or 5 ng of recombinant B-Raf or 5 ng of recombinant B-Raf (V600E) kinase (Upstate Biotechnology) with 500 ng MEK1(K97R) in assay buffer {8 μM ATP, 0.5 μCi [33P]ATP (specific activity 3000 Ci/mmol, PerkinElmer), 50 mM Tris/HCl (pH7.5), and 1 mM EGTA, 1 mM Na3VO4, 1% 2-mercaptoethanol, 0.1% Brij 35, and 0.2 mg/ml BSA} at a final volume of 25 μL. Reactions were incubated at 30° C. for 30 min and stopped by adding 3% phosphoric acid, harvested onto a 96-well GF/B UniFilter (PerkinElmer) using a unifilter harvester (PerkinElmer), and counted with a TopCount microplate scintillation counter (PerkinElmer). The IC50 values of inhibitors were determined after carrying out assays at 3-fold serially diluted concentrations of each compound in duplication.