Figure.Figure 1Mouse YUMM1.7 melanoma cells were subcutaneously inoculated into C57BL/6 mice and when tumors reached 100 mm3 mice were treated with vehicle (Ctrl), Nintedanib/BIBF1120 (BIBF), MAPKi (BRAFi, Vemurafenib and MEKi, Trametinib) or BRAFi/MEKi plus BIBF (n=6). Mouse YUMM1.7 melanoma cells were subcutaneously inoculated into C57BL/6 mice and when tumors reached 100 mm3 mice were treated with vehicle (Ctrl), Nintedanib/BIBF1120 (BIBF), MAPKi (BRAFi, Vemurafenib and MEKi, Trametinib) or BRAFi/MEKi plus BIBF (n=6). (B) Representative median graphics showing tumor growth following treatment (n = 6). Two-way ANOVA was used for statistical analysis. ** P≤0.01. Mouse YUMM1.7 melanoma cells were subcutaneously inoculated into C57BL/6 mice and when tumors reached 100 mm3 mice were treated with vehicle (Ctrl), Nintedanib/BIBF1120 (BIBF), MAPKi (BRAFi, Vemurafenib and MEKi, Trametinib) or BRAFi/MEKi plus BIBF (n=6). (C) Kaplan-Meier survival curves of mice treated with the indicated therapies (n = 6). Log rank (Mantel-Cox) statistical test was used for MAPKi vs MAPKi/BIBF1120. ****P≤0.0001. Mouse YUMM1.7 melanoma cells were subcutaneously inoculated into C57BL/6 mice and when tumors reached 100 mm3 mice were treated with vehicle (Ctrl), Nintedanib/BIBF1120 (BIBF), MAPKi (BRAFi, Vemurafenib and MEKi, Trametinib) or BRAFi/MEKi plus BIBF (n=6). (D) Mouse body weight was measured at the indicated times. Data shown are mean±SD (n = 6). Mouse YUMM1.7 melanoma cells were subcutaneously inoculated into C57BL/6 mice and when tumors reached 100 mm3 mice were treated with vehicle (Ctrl), Nintedanib/BIBF1120 (BIBF), MAPKi (BRAFi, Vemurafenib and MEKi, Trametinib) or BRAFi/MEKi plus BIBF (n=6). Tumor sections were stained with picrosirius red and imaged under polarized light. (E) Representative image of collagen fibers network in tumors from mice under the different treatments. Scale bar 200 μm. Mouse YUMM1.7 melanoma cells were subcutaneously inoculated into C57BL/6 mice and when tumors reached 100 mm3 mice were treated with vehicle (Ctrl), Nintedanib/BIBF1120 (BIBF), MAPKi (BRAFi, Vemurafenib and MEKi, Trametinib) or BRAFi/MEKi plus BIBF (n=6). (F) Quantification of collagen fibers thickness (n = 6 for control, BIBF and BRAFi/MEKi groups and n = 5 for BRAFi/MEKi + BIBF group). Two-way ANOVA statistical test was used for statistical analysis of mature collagen fibers thickness quantification. **P≤0.01, ***P≤0.001, ****P≤0.0001. Significance was calculated against the control group. Statistical significance of BIBF vs BIBF + BRAFi/MEKi was also calculated. Mouse YUMM1.7 melanoma cells were subcutaneously inoculated into C57BL/6 mice and when tumors reached 100 mm3 mice were treated with vehicle (Ctrl), Nintedanib/BIBF1120 (BIBF), MAPKi (BRAFi, Vemurafenib and MEKi, Trametinib) or BRAFi/MEKi plus BIBF (n=6). (G) Heatmap showing the differential expression of ECM and myofibroblast/CAF genes in mice treated with MAPK-targeted therapies with or without BIBF compared to control mice (log2 ratio, n = 5). (H) Heatmap and Western Blot showing the expression of ECM, myofibroblast/CAF and phenotype switch markers in human M238R cells compared to the parental M238P cells. Heatmap represents the mean of expression of 3 independent experiments by RT-qPCR. (I) Heatmap showing the expression of ECM, myofibroblast/CAF and phenotype switch markers in human M238R cells treated with BIBF (2 µM, 72 h) or vehicle alone by RT-qPCR (n = 3). (J) Crystal violet viability assay of M238R cells treated with BRAFi/MEKi (BRAFi, Vemurafenib and MEKi, Trametinib) (1 µM), BIBF (2 μM) or with BRAFi/MEKi (1 μM) plus BIBF (2 μM) for 72 h. Paired Student t-test was used for statistical analysis. ****P≤0.0001. Significance was calculated against the control group. Statistical significance of BIBF vs BIBF + BRAFi/MEKi was also calculated. Data is represented as mean ± SD from a triplicate representative of 3 independent experiments.