Fig. 4

GLUT4 promotes HNSCC metastasis. a Relative fluorescence units after GLUT4 overexpression in FaDu (left panel) and HSC-3 cells (right panel) with or without ritonavir treatment. b The migration and invasion abilities of FaDu cells and HSC-3 cells were demonstrated after the overexpression of the exogenous GLUT4 gene, with and without the addition of ritonavir or indinavir. The data were the average of three independent experiments and are presented as the mean ± SEM. The significance of the difference was analyzed using the nonparametric Mann–Whitney U test. The blue and green columns represent cellular migration and invasion abilities, respectively. c The glucose uptake abilities of FaDu cells and HSC-3 cells were demonstrated after the overexpression of the exogenous GLUT4 gene, with and without the addition of ritonavir or indinavir. The data were the average of three independent experiments and are presented as the mean ± SEM. The significance of the difference was analyzed using the nonparametric Mann–Whitney U test. The black and red columns represent ritonavir and indinavir treatment, respectively