ArrayExpress Uploader0human660-69serous3c12160-69serous3c0430-39endometrioid466060-69mucinous1c74860-69serous3c547650-59serous2a1631330-39clear1a1335660-69serous3c31050-59clear1c02350-59serous3b1094170-79serous2c73170-79serous3c252106arrayexpress_sid4PD-L1 suppresses host immunity and promotes tumor growth. We investigated how IFN-γ regulates PD-L1 in the ovarian cancer...E-GEOD-55512/profile/8773/arrayexpressuploader512cancercellepithelial cellgenomelinelymphocyteovarian cancersurfaceDec.12, 2014Falsegene-expression-profiles-of-ovarian-cancer-regardiE-GEOD-55512_A-AFFY-44Gene-expression profiles of ovarian cancer regarding its microenvironmentJul.11, 2014PD-L1 suppresses host immunity and promotes tumor growth. We investigated how IFN-γ regulates PD-L1 in the ovarian cancer microenvironment. In clinical samples, the number of stromal CTLs in peritoneally disseminated tumors was correlated with PD-L1 expression on the tumor cells, and the lymphocyte number was significantly related to the IFN-γ signature score. In mouse models, PD-L1 was induced in peritoneal disseminated tumors, where lymphocytes were prominent, but not in subcutaneous tumors. Depleting IFNGR1 resulted in lower PD-L1 expression and longer survival in peritoneal dissemination model. Injection of IFN-γ into subcutaneous tumors increased PD-L1 expression and tumor size, and PD-L1 depletion abrogated tumor growth. These data suggest that IFN-γ works as a tumor progressor through PD-L1 induction. The source of IFN-γ in ovarian cancer microenvironment and its biological effect to the tumor cells is unclear. The immortalized human ovarian surface epithelial cell line, HOSE-E7/hTERT (HOSE) was treated with IFN-γ and expression microarray analysis was performed, and probes showing significantly higher values in IFN-γ-added group were termed “IFN-γ signature genes (295 probes)”. We then applied this signature to our ovarian cancer microarray data, which included 75 ovarian cancer clinical samples, by means of ss-GSEA. IFN-γ signature score was strongly correlated to the number of infiltrating CD4-positive or CD8-positive lymphocytes in the tumors. These data suggest that the IFN-γ in the ovarian cancer microenvironment is derived from lymphocytes, and an IFN-γ-rich microenvironment is strongly correlated to a lymphocyte-rich microenvironment. Genome-wide transcriptional changes in human ovarian cancer tissue were observed in different tumor immunological microenvironment.http://www.ebi.ac.uk/arrayexpress/experiments/E-GEOD-55512http://www.ebi.ac.uk/arrayexpress/experiments/E-GEOD-55512/samples/