Fig. 3
EpEX regulates gene expression and competes with EGF for binding to EGFR. A Volcano plots of DEGs in Kyse30 and FaDu cells 6 h after EpEX treatment. Numbers of DEGs for each cell line are indicated (|log2FC|> 0.5; adjusted p-value ≤ 0.05). B-C Shared and exclusive DEGs between EpEX, EGFlow, and EGFhigh are depicted in scatter/bar plots with Spearman correlation and p-values. D Schematic representation of the EGF/EpEX competition assay. Cells were incubated with fluorescence-labeled EGF alone or in combination with non-labeled EGF or EpEX in equimolar conditions. E–F Fluorescence of Kyse30 and FaDu cells incubated with fluorescence-labeled EGF and combinations with non-labeled EGF and EpEX was quantified by flow cytometry. E Representative histograms of EGFR staining in a competition assay in Kyse30 and FaDu cells. F Mean values with SD of n = 3 independent experiments are shown. P-values from one-way ANOVA with Tukey´s multiple comparison test. * ≤ 0.05; ** ≤ 0.01; *** ≤ 0.001; **** ≤ 0.0001. Control = unstained cells; EGF-Fluo: fluorescence-labeled EGF; EGF-Fluo + EGF: fluorescence-labeled EGF plus unlabeled EGF; EGF-Fluo + EpEX: fluorescence-labeled EGF plus EpEX