Fig. 4

OPN enhances gefitinib-activated FAK signalling by up-regulating integrin αVβ3 expression. a Under gefitinib treatment, OPN expression was detected by qRT-PCR, western blot analysis and ELISA. b, c Western blot analysis was used to detect the effect of gefitinib treatment on p-EGFR, p-FAK, p-AKT and p-ERK in PC9 cells at different concentrations and times. d Under gefitinib treatment, p-FAK, p-AKT and p-ERK levels in PC9 cells transfected with si-OPN or si-NC were detected by western blot analysis. e The effect of single-drug or combined treatment of rOPN and VS-6063 on p-FAK in PC9 cells. f Expression of integrin αV was detected by western blot and immunofluorescence after PC9 cells were treated with different concentrations of rOPN. g, h Under gefitinib treatment, p-FAK in PC9 cells transfected with si-ITGAV or si-ITGB3 was detected by western blot analysis (*P < 0.05; ***P < 0.001)