Fig. 3
BRAF p.V504_R506dup mutation activates MAPK signaling and confers resistance to MEK inhibitors. a Relative expression of BRAF mutants (p.V504_R506dup and V600E) and wild type (WT) in transfected HEK293T cells. b Kinase activity of cells containing the WT or the mutants (p.V504_R506dup, V600) BRAF. The activity is measured by western blot (left) and Luminex phosphorylation measurements (right) using ERK1/2 as substrates. The total immunoprecipitated BRAF (BRAF), the phosphorylated level of ERK1/2 (pERK1/2) and the total level of ERK1/2 are shown. c Morphological examination of HEK293T cells 24 h after transfection with the empty vector or expressing BRAF-WT, BRAF p.V504_R506dup, or V600E. d BRAF p.V504_R506dup. Changes in pERK in HEK293T cells expressing the BRAF-WT and the mutants (p.V504_R506dup, V600E) after 18 h treatment with 3 µM of DMSO, 3 µM of vemurafenib, 3 µM of sorafenib or 1 µM of trametinib. Each sample was assayed in triplicate and error bars are used to indicate the standard deviations from the means. Similar results were obtained in two-independent transfections. * indicates a P-value <0.01 according to Student’s t-distribution
