Description

Malignant melanoma,Colorectal cancer

RAF kinase activity measurements

The kinase activities of wild-type RAF and mutants are determined by measuring phosphorylation of biotinylated-BAD protein. For each enzyme (0.01 ng), 20 μL reactions are carried out in 20 mM Hepes (pH 7.0), 10 mM MgCl₂, 1 mM DTT, 0.01% (v/v) Tween-20, 50 nM biotin-BAD protein, and 1 mM ATP at room temperature. Reactions are stopped at 5 min with 5 μL of a solution containing 20 mM Hepes (pH 7.0), 200 mM NaCl, 80 mM EDTA, 0.3% (w/v) bovine serum albumin (BSA). The stop solution also includes phospho-BAD (Ser112) antibody, streptavidin-coated donor beads, and protein A acceptor beads. The antibody and beads are pre-incubated in stop solution in the dark at room temperature for 30 min. The final dilution of antibody is 1/2000 and the final concentration of each bead is 10 μg/mL. The assay plates are incubated at room temperature for one hour and then are read on a PerkinElmer AlphaQuest reader. Mutant activities are the average of two different batches of purified protein assayed in duplicate in three different experiments.

Cell Lines

MALME-3M, Colo829, Colo38, A375, SK-MEL28, and A2058 cells

Concentrations

0–10 μM , dissolved in DMSO

Incubation Time

5 days

Methods

Cellular proliferation is evaluated by MTT assay. Briefly, cells are plated in 96-well microtiter plates at a density of 1000 to 5000 cells per well in a volume of 180 μL. PLX4032 is prepared at 10 times the final assay concentration in media containing 1% DMSO. Twenty-four hours after cell plating, 20 μL of the appropriate dilution of PLX4032 are added to plates in duplicate. The plates are assayed for proliferation 6 days after the cells are plated. Percent inhibition is calculated and the IC50 is determined from the regression of a plot of the logarithm of the concentration versus percent inhibition.

Animal Models

Mice (athymic nude) xenograft models of LOX, Colo829, and A375 cells

Formulation

Formulated as microprecipitated bulk powder (MBP), suspended at the desired concentration in an aqueous vehicle containing 2% Klucel LF, and adjusted to pH 4 with dilute HCl

Doses

12.5 mg/kg–100 mg/kg

Administration

Oral gavage twice daily