Fig. 4: Paracrine effects of FGF1.

a Sensitivity towards vemurafenib in presence of FGF1 and FGF inhibitor AZD4547. Cells were treated with vemurafenib (2 µM) in absence or presence of FGF1 (100 ng/ml) and AZD4547 (100 ng/ml) for 5 days. Medium was changed every 2 days. After 5 days, cells were counted. Data are derived from three independent experiments (One-way ANOVA: p < 0.05, post hoc test: t test, unpaired). b Viability of M14 melanoma cells, treated with control- or vemurafenib (0.5 µM)-conditioned supernatant of A375 cells for 2 days. Left image: scheme of the experimental setup. Right: corresponding quantification. Where indicated, FGFR inhibitor AZD (100 ng/µl) was added. (One-way ANOVA: p < 0.05, post hoc test: t test, unpaired). c MTT assay of MainUro fibroblasts and normal human dermal fibroblasts (NHDF) after treatment with recombinant FGF1 (100 ng/ml) for 5 days. Cells were starved in medium containing 2% FCS before FGF1 treatment. 1 × 10³ cells were seeded per 96 well and medium with the recombinant ligand was changed after 48 h. Significant differences are referred to the respective untreated control, which was set as 100%. d Real-time PCR of HGF in MainUro fibroblasts treated with FGF1, FGF7, FGF17 or a combination of these (100 ng/ml, 8 h). Data are normalized to the untreated controls and are derived from four independent experiments. e HGF secretion of MainUro cells after FGF1 treatment (100 ng/ml, 2 days), as measured by ELISA. Data are derived from three independent experiments. f Analysis of HGF secretion of MainUro fibroblasts in response to conditioned supernatant from melanoma cells. Left: Scheme of the experimental setup. Middle: HGF expression in MainUro cells treated for 2 days with conditioned control medium (ctrl) or vemurafenib-conditioned medium from A375 cells (vem) (see also Fig. 1). Where indicated, AZD4547 (100 nM) was added to MainUro cells (at the same time as vemurafenib-conditioned medium was applied). Right: Corresponding HGF secretion, as determined by ELISA. Data are derived from three independent experiments. Statistical analysis was done using One-way ANOVA (p < 0.0001; post hoc test: t test). *p < 0.05; **p < 0.01, ***p < 0.001