Fig. 6

Pharmacological inhibition of specific EMT-associated kinases reduces FGFRi-induced resistance. A Drug cell viability screen in non-irradiated (left panel) and irradiated (right panel) UM-SCC 10a cells upon monotherapy with selected kinase inhibitors alone (y-axis) versus dual therapy with selected kinase inhibitors plus FGFRi (x-axis). Corresponding annotated cell viability data are presented in Fig. S8 (n = 3; two-way ANOVA; Dunnett’s multiple comparison test to corresponding single FGFRi treatment). B Venn diagram of significant kinase inhibitor effectiveness shown in Fig. 6A (right panel). Underlying data and statistics are presented in Fig. S8. C Effects on cell viabilities of irradiated UM-SCC 10a cells upon exposure to concentration-optimized kinase inhibitors listed in Fig. 6B. The inhibitors RSKi and EGFR_2 were added to the panel (inhibitor names, cell viability data of non-irradiated cells and applied concentrations are displayed in Fig. S9A). Bars and bottom annotation table display mean cell viability (n = 3; two-way ANOVA; Tukey multiple comparison test; ***p ≤ 0.001, **p ≤ 0.01, *p ≤ 0.05). D Representative focus-stacked images of colony formation of 3D lrECM UM-SCC 10a cell cultures upon indicated treatments. Quantitative analysis is presented in Fig. S9B-C. E Comparative testing of cell viability in one FGFRi sensitive versus three FGFRi resistant 3D HNSCC cell models upon indicated mono- and combination treatments relative to corresponding controls (inhibitor names, cell viability data of non-irradiated cells and applied concentrations are displayed in Fig. S10A; cell viability data of irradiated cells normalized to non-irradiated controls are shown in Fig. S10B). Bars represent mean cell viability (n = 3; two-way ANOVA; Tukey multiple comparison test; ***p ≤ 0.001, **p ≤ 0.01). ‘S’ indicates synergy calculated by the Bliss independence model. F Comparison of FGFRi responsiveness in 3D lrECM cell models and HNSCC organoids in absence and presence of 6 Gy X-rays. Bars represent mean enhancement ratio of three biological replicates per cell model (2 µM FGFRi) and six technical replicates per organoid (1.5 µM FGFRi). Corresponding cell viability data are listed in Fig. S3A-B and Fig. S4A-B for cell models and Fig. S11B-C for HNSCC organoids. G Combinatory effectiveness plots of three kinase inhibitors (EGFRi, PAK1-3i, PKCi) together with FGFRi in indicated HNSCC organoids. Results are presented according to the highest-single agent (HSA) combination index, where scores > 1 indicate a potential additive to synergistic effect. Corresponding cell viability data are shown in Fig. S11B-C