Fig. 6.

Sorafenib and doxorubicin regulate PD-L1 expression in OS cells via the ERK pathway. The ERK1/2-specific inhibitor PD98059 was used to confirm the correlation between the phosphorylation of ERK1/2 (Thr202/Tyr204) and PD-L1 expression. PD-L1 expression in OS cells and phosphorylation levels of the ERK1/2 (Thr202/Tyr204) in MG63 and K7 OS cells were analyzed by Western blotting (A) and flow cytometry (C, E). Quantification of western blotting results (B) and flow cytometry results (D, F) were shown, respectively. All data were obtained from at least three independent experiments. All data are presented as the means ± SD. *p < 0.05, **p < 0.01, ***p < 0.001, and ****p < 0.0001