Transcriptome analysis of U87 cells under different treatments to identify IDO1-regulated genes Indoleamine 2, 3-dioxygenase 1 (IDO1) is a tryptophan (Trp) catabolic enzyme that converts Trp into downstream kynurinine (Kyn). Many studies have indicated that IDO1 is a critical suppressive immune checkpoint molecule invovled in various types of cancer. Canonically, the underlying mechanism of IDO1 immunosuppressive role is related with its enzyme activity, that is the depletion of Trp and accumulation of Kyn lead to increased tumor infiltrating suppressive regulatory T cells. Recent studies, however, challenged this hypothesis and imply that tumor cell-derived IDO1 can mediate immunosuppression independent of its enzyme activity. In this study, we aim to identify genes that are regulated by IDO1 in human glioblastoma cells, a gene expression regulatory function of IDO1 that is indepent of its enzyme activity.
Overall design
U87 cells were either non-treated or treated with 20 nM human IDO1-specific siRNA for 16-18 hours, followed by human IFN-g (100 ng/ml) treatment for another 24 hours. Human IDO1 overexpressing U87 (O/E) cells were either non-treated or treated with 20 nM human IDO1-siRNA for 24 hours. At the end of experiment, total RNAs were extracted from the following 6 groups: 1) U87 NT; 2) U87 + IFNg; 3) U87 + siRNA; 4) U87 + siRNA + IFNg; 5) IDO1-O/E U87 NT; 6) IDO1-O/E U87 + siRNA and subject to microarray analysis. Each treatment group has two replicates. Experiment was repeated 3 times. Totally 36 samples were analyzed.
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