The IFN-?/PD-L1 axis between T cells and tumor microenvironment: hints for glioma anti-PD-1/PD-L1 therapy.
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ABSTRACT: BACKGROUND:PD-L1 is an immune inhibitory receptor ligand that leads to T cell dysfunction and apoptosis by binding to its receptor PD-1, which works in braking inflammatory response and conspiring tumor immune evasion. However, in gliomas, the cause of PD-L1 expression in the tumor microenvironment is not yet clear. Besides, auxiliary biomarkers are urgently needed for screening possible responsive glioma patients for anti-PD-1/PD-L1 therapies. METHODS:The distribution of tumor-infiltrating T cells and PD-L1 expression was analyzed via immunofluorescence in orthotopic murine glioma model. The expression of PD-L1 in immune cell populations was detected by flow cytometry. Data excavated from TCGA LGG/GBM datasets and the Ivy Glioblastoma Atlas Project was used for in silico analysis of the correlation among genes and survival. RESULTS:The distribution of tumor-infiltrating T cells and PD-L1 expression, which parallels in murine orthotopic glioma model and human glioma microdissections, was interrelated. The IFN-? level was positively correlated with PD-L1 expression in murine glioma. Further, IFN-? induces PD-L1 expression on primary cultured microglia, bone marrow-derived macrophages, and GL261 glioma cells in vitro. Seven IFN-?-induced genes, namely GBP5, ICAM1, CAMK2D, IRF1, SOCS3, CD44, and CCL2, were selected to calculate as substitute indicator for IFN-? level. By combining the relative expression of the listed IFN-?-induced genes, IFN-? score was positively correlated with PD-L1 expression in different anatomic structures of human glioma and in glioma of different malignancies. CONCLUSION:Our study identified the distribution of tumor-infiltrating T cells and PD-L1 expression in murine glioma model and human glioma samples. And we found that IFN-? is an important cause of PD-L1 expression in the glioma microenvironment. Further, we proposed IFN-? score aggregated from the expressions of the listed IFN-?-induced genes as a complementary prognostic indicator for anti-PD-1/PD-L1 therapy.
SUBMITTER: Qian J
PROVIDER: S-EPMC6192101 | biostudies-literature | 2018 Oct
REPOSITORIES: biostudies-literature
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