ABSTRACT
Nuclear receptor subfamily 2, group F, member 6 (NR2F6) is an orphan member of the nuclear receptor superfamily. Here, we show that genetic ablation of Nr2f6 significantly improves survival in the murine transgenic TRAMP prostate cancer model. Furthermore, Nr2f6(-/-) mice spontaneously reject implanted tumors and develop host-protective immunological memory against tumor rechallenge. This is paralleled by increased frequencies of both CD4(+) and CD8(+) T cells and higher expression levels of interleukin 2 and interferon γ at the tumor site. Mechanistically, CD4(+) and CD8(+) T cell-intrinsic NR2F6 acts as a direct repressor of the NFAT/AP-1 complex on both the interleukin 2 and the interferon γ cytokine promoters, attenuating their transcriptional thresholds. Adoptive transfer of Nr2f6-deficient T cells into tumor-bearing immunocompetent mice is sufficient to delay tumor outgrowth. Altogether, this defines NR2F6 as an intracellular immune checkpoint in effector T cells, governing the amplitude of anti-cancer immunity.
Subject(s)
CD4-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/immunology , COUP Transcription Factors/genetics , Immunologic Surveillance , Immunotherapy, Adoptive/methods , Prostatic Neoplasms/therapy , Animals , CD4-Positive T-Lymphocytes/cytology , CD4-Positive T-Lymphocytes/transplantation , CD8-Positive T-Lymphocytes/cytology , CD8-Positive T-Lymphocytes/transplantation , COUP Transcription Factors/deficiency , COUP Transcription Factors/immunology , Cell Line, Tumor , Gene Expression Regulation, Neoplastic , Humans , Immunologic Memory , Interferon-gamma/agonists , Interferon-gamma/genetics , Interferon-gamma/immunology , Interleukin-2/agonists , Interleukin-2/genetics , Interleukin-2/immunology , Lymphocyte Activation , Male , Mice , Mice, Inbred C57BL , Neoplasm Transplantation , Prostatic Neoplasms/genetics , Prostatic Neoplasms/immunology , Prostatic Neoplasms/mortality , Repressor Proteins , Signal Transduction , Survival Analysis , Tumor Necrosis Factor-alpha/agonists , Tumor Necrosis Factor-alpha/genetics , Tumor Necrosis Factor-alpha/immunologyABSTRACT
Interleukin-17A (IL-17A) is the signature cytokine produced by Th17 CD4(+) T cells and has been tightly linked to autoimmune pathogenesis. In particular, the transcription factors NFAT and RORγt are known to activate Il17a transcription, although the detailed mechanism of action remains incompletely understood. Here, we show that the nuclear orphan receptor NR2F6 can attenuate the capacity of NFAT to bind to critical regions of the Il17a gene promoter. In addition, because NR2F6 binds to defined hormone response elements (HREs) within the Il17a locus, it interferes with the ability of RORγt to access the DNA. Consistently, NFAT and RORγt binding within the Il17a locus were enhanced in Nr2f6-deficient CD4(+) Th17 cells but decreased in Nr2f6-overexpressing transgenic CD4(+) Th17 cells. Taken together, our findings uncover an example of antagonistic regulation of Il17a transcription through the direct reciprocal actions of NR2F6 versus NFAT and RORγt.
