Fig. 4

circPRDM4 overexpression boosts PD-L1 expression and inhibits the CD8⁺ T cell-mediated anti-tumor immune response under hypoxic conditions. A The overexpression efficiency of circPRDM4 in Hep3B cells. B The overexpression efficiency of circPRDM4 in HepG2 cells. C Expression levels of PRDM4 mRNA in circPRDM4-overexpressing Hep3B and HepG2 cells. D Expression levels of CD274 mRNA in circPRDM4-overexpressing HCC cells under hypoxia. E Expression levels of PD-L1 protein in circPRDM4-overexpressing HCC cells under hypoxia. F Cell surface PD-L1 expression levels in circPRDM4-overexpressing HCC cells under hypoxia. G T cell-mediated cancer cell-killing assay results of circPRDM4-overexpressing HCC cells. H LDH release assay results showing the cytotoxicity in circPRDM4-overexpressing HCC cells under hypoxia. I ELISA assays showing secreted TNF-α and IFN-γ from T cells cocultured with circPRDM4-overexpressing Hep3B and HepG2 cells under hypoxia. Data are shown as mean ± SEM. **, P < 0.01; ***, P < 0.001; ns, no significance