FIGURE 3 from Dabrafenib Alters MDSC Differentiation and Function by Activation of GCN2

Activation of MAPK by dabrafenib is not responsible for phenotypic changes during differentiation. Western blot analysis (A) and relative quantification (B) of ERK1/2 phosphorylation (p-ERK) versus total protein at increasing doses of DAB in bone marrow–derived MDSC cultures on day 4 of differentiation with IL6+GMCSF. Western blot analysis of p-ERK (C) and total cell counts (D) of bone marrow cells differentiated with indicated cytokines ± 1.5 µmol/L DAB for 4 days. For D, P values were determined by two-way ANOVA with Šidák correction post-test. Significance considered P E) and total cell counts (F) of MDSC differentiated in presence of increasing doses of MEK inhibitor Trametinib (TRAB) ± 1.5 µmol/L DAB for 4 days. For F, P values were determined by two-way ANOVA with Šidák correction post-test. Significance considered P G, Representative contour plot of Ly6C and Ly6G expression in CD11b+MHCIIneg cells expanded in presence of 1.5 µmol/L DAB and/or 3 nmol/L TRAB. For all panels, experiments were repeated three times with similar results. DAB = dabrafenib.