Fig. 2

IGFBP3 transcriptionally regulates PD-L1 expression in GBM cells. A Immunoblotting analysis of IGFBP3 and PD-L1 expression in U251 and U118 cells treated with different concentrations of exogenous IGFBP3 (0, 25, 50, and 100 ng/mL) for 24 h. B Immunoblotting was performed to determine the expression of IGFBP3 and PD-L1 in U251 and U118 cells stimulated with 100 ng/mL of IGFBP3 for 0, 12, 24, and 48 h. C QRT-PCR analysis of IGFBP3 and PD-L1 mRNA expression levels in U251 and U118 cells infected with overexpressing IGFBP3 and empty vector lentivirus. D Immunoblotting assay of IGFBP3 and PD-L1 protein expression in U251 and U118 cells infected with overexpressing IGFBP3 and empty vector lentivirus. E Representative immunofluorescence images of DAPI (blue), IGFBP3 (red), PD-L1 (green) in U251-vector and U251-IGFBP3 cells. F Immunoblotting was performed to examine the expression of IGFBP3 and PD-L1 in LN229 and T98G cells transfected with si-RNA targeting IGFBP3 (si-IGFBP3) and negative control (si-NC). G Immunoblotting analysis of IGFBP3 and PD-L1 expression in LN229 and T98G cells infected with lentivirus of targeting IGFBP3 (sh-IGFBP3) and control (sh-con). Data are expressed as mean ± SD. **P < 0.01; ***P < 0.001, Student t test