Fig. 6

PGC-1α mediates LMP1 upregulation of PD-L1 to promote immune escape of NPC cells. A CNE1/CM, HNE2/HM, CM-con/CM-shLMP1, and HM-con/HM-shLMP1 cells were cultured in suspension for 48 h, and the protein levels of PD-L1, TNFα and VEGF were detected by Western blotting. B CNE1/CM, HNE2/HM, CM-con/CM-shLMP1, and HM-con/HM-shLMP1 cells were co-cultured with Jurkat cells or T cells for 24 h, and IFN-γ secreted by T cells was detected by ELISA (**p < 0.01, *p < 0.05). C PGC-1α was overexpressed in CNE1 and HNE2 cells or PGC-1α was knocked down in CM and HM cells, and the transcriptional levels of PGC-1α and PD-L1 were detected by real-time fluorescence quantitative PCR (**p < 0.01, *p < 0.05). D PGC-1α was overexpressed in CNE1 and HNE2 cells or PGC-1α was knocked down in CM and HM cells, and the protein expression level of PD-L1 was detected by Western blotting. E CNE1/HNE2 cells were transfected with PGC-1α overexpression plasmid and cultured for 48 h, and then co-cultured with T cells for 24 h, and the apoptotic rate of T cells was detected by flow cytometry. F PGC-1α was overexpressed in CNE1 and HNE2 cells or PGC-1α was knocked down in CM and HM cells. The secretion of IFN-γ by T cells was detected by ELISA (**p < 0.01, *p < 0.05). G PGC-1α was overexpressed in CNE1 and HNE2 cells, and then these cells were co-cultured with Jurkat cells or T cells. NPC cells were treated with sufficient anti-PD-L1 to block PD-L1 activity, and the secretion of IFN-γ in T cells was detected by ELISA (**p < 0.01, *p < 0.05). H PGC-1α was overexpressed in CNE1 and HNE2 cells or PGC-1α was knocked down in CM and HM cells, and the transcriptional levels of transcription factors STAT1, STAT3, and IRF2 were detected by real-time fluorescence quantitative PCR (**p < 0.01, *p < 0.05). I CNE1/CM and HNE2/HM cells were cultured in suspension, and the interaction of PGC-1α-STAT3 was detected by co-immunoprecipitation. J CNE1/CM cells were cultured in suspension, and the interaction of PGC-1α-STAT1 and PGC-1α-IRF2 was detected by co-immunoprecipitation. K Dual luciferase reporter assay was used to detect the effect of STAT3 on the PD-L1 promoter (**p < 0.01, *p < 0.05). L A dual luciferase reporter gene assay was used to detect the effect of PGC-1α and STAT3 on PD-L1 promoter (**p < 0.01, *p < 0.05). M CNE1/HNE2 cells were transfected with STAT3 overexpression plasmid, and the expression of PGC-1α, STAT3, and PD-L1 was detected by Western blotting. N CNE1/HNE2 cells were transfected with a PGC-1α overexpression plasmid and a STAT3 inhibitor was added; and the expression of PGC-1α, STAT3, and PD-L1 was detected by Western blotting