IFN-γ诱导A549细胞表达PD-L1的机制研究

Study on the action mechanism of IFN-γ-induced PD-L1 expression in A549 cells The study on the mechanism of IFN-γinduced the expression of PD-L1 in A549 cells

目的探讨IFN-γ诱导非小细胞肺癌A549细胞表达PD-L1的分子机制。方法IFN-γ刺激体外培养的非小细胞肺癌A549细胞,或加入信号通路抑制剂预先孵育1 h后再行刺激,流式细胞术检测PD-L1的表达水平。分选CD+3 T细胞与A549细胞共培养,检测CD+3 T细胞的增殖情况。结果与未刺激组A549细胞表达的PD-L1水平[(39.6±5.8)%]比较,IFN-γ刺激的A549细胞显著上调PD-L1的蛋白水平[(94.3±4.9)%],二者比较差异有统计学意义(P<0.01)。加入STAT1抑制剂后,IFN-γ上调PD-L1的效果受到显著抑制,差异有统计学意义(P<0.01)。而STAT3抑制剂、STAT5抑制剂、STAT6抑制剂和NF-κB抑制剂无明显影响。与未刺激组比较,IFN-γ刺激组A549细胞能够显著抑制CD+3 T细胞的增殖能力。结论IFN-γ可通过STAT1信号诱导A549细胞上调PD-L1的表达,从而促进肺癌的免疫逃逸。

Objective To investigate the molecular mechanism of IFN-γ-induced PD-L1 expression in non-small cell lung cancer(NSCLC)A549 cells.Methods NSCLC A549 cells were cultured with IFN-γin vitro,or signal pathway inhibitor was used for pre-incubation for 1 h before IFN-γwas added.Flow cytometry was used to detect the expression of PD-L1.CD+3 T cells were sorted and co-cultured with A549 cells,to detect the proliferation of CD+3 T cells.Results As compared with those(39.6±5.8)%,the protein levels(94.3±4.9)%of PD-L1 in A549 cells cultured with IFN-γwere significantly up-regulated,there were significant significances(P<0.01).After incubation with STAT1 inhibitor,the effects of IFN-γup-regulating PD-L1 were significantly inhibited,and the differences were statistically significant(P<0.01).However,such effects were not detected when A549 cells were incubated with STAT3 inhibitors,STAT5 inhibitors,STAT6 inhibitors and NF-κB inhibitors.Compared with the control group,A549 cells cultured with IFN-γcould significantly inhibit the proliferation of CD+3 T cells.Conclusion IFN-γcan induce up-regulation of the expression of PD-L1 in A549 cells through STAT1 signal,thereby promoting the immune escape of lung cancer.