ABSTRACT
Monoallelic point mutations of isocitrate dehydrogenase type 1 (IDH1) are an early and defining event in the development of a subgroup of gliomas and other types of tumour. They almost uniformly occur in the critical arginine residue (Arg 132) in the catalytic pocket, resulting in a neomorphic enzymatic function, production of the oncometabolite 2-hydroxyglutarate (2-HG), genomic hypermethylation, genetic instability and malignant transformation. More than 70% of diffuse grade II and grade III gliomas carry the most frequent mutation, IDH1(R132H) (ref. 3). From an immunological perspective, IDH1(R132H) represents a potential target for immunotherapy as it is a tumour-specific potential neoantigen with high uniformity and penetrance expressed in all tumour cells. Here we demonstrate that IDH1(R132H) contains an immunogenic epitope suitable for mutation-specific vaccination. Peptides encompassing the mutated region are presented on major histocompatibility complexes (MHC) class II and induce mutation-specific CD4(+) T-helper-1 (TH1) responses. CD4(+) TH1 cells and antibodies spontaneously occurring in patients with IDH1(R132H)-mutated gliomas specifically recognize IDH1(R132H). Peptide vaccination of mice devoid of mouse MHC and transgenic for human MHC class I and II with IDH1(R132H) p123-142 results in an effective MHC class II-restricted mutation-specific antitumour immune response and control of pre-established syngeneic IDH1(R132H)-expressing tumours in a CD4(+) T-cell-dependent manner. As IDH1(R132H) is present in all tumour cells of these slow-growing gliomas, a mutation-specific anti-IDH1(R132H) vaccine may represent a viable novel therapeutic strategy for IDH1(R132H)-mutated tumours.
Subject(s)
Cancer Vaccines/immunology , Cancer Vaccines/therapeutic use , Glioma/immunology , Glioma/therapy , Isocitrate Dehydrogenase/genetics , Isocitrate Dehydrogenase/immunology , Mutant Proteins/immunology , Animals , Antibody Specificity , Antigens, Neoplasm/genetics , Antigens, Neoplasm/immunology , Female , Glioma/enzymology , Glioma/genetics , Histocompatibility Antigens Class II/immunology , Humans , Immunity, Humoral , Immunotherapy/methods , Male , Mice , Mutant Proteins/genetics , Mutation , T-Lymphocytes, Helper-Inducer/immunology , Xenograft Model Antitumor AssaysABSTRACT
Activation of the aryl hydrocarbon receptor (AHR) by environmental xenobiotic toxic chemicals, for instance 2,3,7,8-tetrachlorodibenzo-p-dioxin (dioxin), has been implicated in a variety of cellular processes such as embryogenesis, transformation, tumorigenesis and inflammation. But the identity of an endogenous ligand activating the AHR under physiological conditions in the absence of environmental toxic chemicals is still unknown. Here we identify the tryptophan (Trp) catabolite kynurenine (Kyn) as an endogenous ligand of the human AHR that is constitutively generated by human tumour cells via tryptophan-2,3-dioxygenase (TDO), a liver- and neuron-derived Trp-degrading enzyme not yet implicated in cancer biology. TDO-derived Kyn suppresses antitumour immune responses and promotes tumour-cell survival and motility through the AHR in an autocrine/paracrine fashion. The TDO-AHR pathway is active in human brain tumours and is associated with malignant progression and poor survival. Because Kyn is produced during cancer progression and inflammation in the local microenvironment in amounts sufficient for activating the human AHR, these results provide evidence for a previously unidentified pathophysiological function of the AHR with profound implications for cancer and immune biology.
Subject(s)
Brain Neoplasms/metabolism , Brain Neoplasms/pathology , Glioma/metabolism , Glioma/pathology , Kynurenine/metabolism , Receptors, Aryl Hydrocarbon/metabolism , Animals , Autocrine Communication , Brain Neoplasms/genetics , Brain Neoplasms/immunology , Cell Line, Tumor , Cell Survival , Disease Progression , Gene Expression Regulation, Neoplastic , Glioma/genetics , Glioma/immunology , Humans , Kynurenine/immunology , Kynurenine/pharmacology , Ligands , Mice , Mice, Inbred C57BL , Mice, Nude , Neoplasm Transplantation , Paracrine Communication , Receptors, Aryl Hydrocarbon/immunology , Tryptophan/metabolism , Tryptophan Oxygenase/deficiency , Tryptophan Oxygenase/genetics , Tryptophan Oxygenase/metabolismABSTRACT
The spleen tyrosine kinase family members Syk and Zap-70 are pivotal signal transducers downstream of antigen receptors and exhibit overlapping expression patterns at early lymphocytic developmental stages. To assess their differential kinase fitness in vivo, we generated mice, which carry a Zap-70 cDNA knock-in controlled by intrinsic Syk promoter elements that disrupts wild-type Syk expression. Kinase replacement severely compromised Erk1/2-mediated survival and proper selection of developing B cells at central and peripheral checkpoints, demonstrating critical dependence on BCR signalling quality. Furthermore, ITAM- and hemITAM-mediated activation of platelets and neutrophils was completely blunted, while surprisingly FcγR-mediated phagocytosis in macrophages was retained. The alteration in BCR signalling quality resulted in preferential development and survival of marginal zone B cells and prominent autoreactivity, causing the generation of anti-insulin antibodies and age-related glomerulonephritis. Development of concomitant fasting glucose intolerance in knock-in mice highlights aberrant B cell selection as a potential risk factor for type 1 diabetes, and suggests altered BCR signalling as a mechanism to cause biased cellular and Ig repertoire selection, ultimately contributing to B cell-mediated autoimmune predisposition.
Subject(s)
Autoimmune Diseases/genetics , Prediabetic State/genetics , Proto-Oncogene Proteins c-bcr/physiology , Animals , B-Lymphocytes/immunology , B-Lymphocytes/metabolism , B-Lymphocytes/physiology , Cells, Cultured , Gene Knock-In Techniques , Gene Rearrangement, B-Lymphocyte/genetics , Genetic Predisposition to Disease , Humans , Intracellular Signaling Peptides and Proteins/genetics , Mice , Mice, Inbred C57BL , Mice, Transgenic , Protein-Tyrosine Kinases/genetics , Proto-Oncogene Proteins c-bcr/genetics , Proto-Oncogene Proteins c-bcr/metabolism , Signal Transduction/genetics , Syk Kinase , ZAP-70 Protein-Tyrosine Kinase/geneticsABSTRACT
For a targeted cancer vaccine to be effective, the antigen of interest needs to be naturally processed and presented on MHC by the target cell or an antigen-presenting cell (APC) in the tumor stroma. The presence of these characteristics is often assumed based on animal models, evaluation of antigen-overexpressing APCs in vitro, or assays of material-consuming immune precipitation from fresh solid tissue. Here, we evaluated the use of an alternative approach that uses the proximity ligation assay (PLA) to identify the presentation of an MHC class II-restricted antigen in paraffin-embedded tissue sections from patients with brain tumors. This approach required a specific antibody directed against the epitope that was presented. We used an antibody that specifically binds an epitope of mutated isocitrate dehydrogenase type 1 (IDH1R132H), which is frequently expressed in gliomas and other types of tumors. In situ PLA showed that the IDH1R132H epitope colocalizes with MHC class II in IDH1R132H-mutated glioma tissue. Moreover, PLA demonstrated colocalization between the class II epitope-containing melanoma antigen New York esophageal 1 and MHC class II. Collectively, our data suggest that PLA may be a useful tool to acquire information on whether an antigen is presented in situ, and this technique has potential to guide clinical studies that use antigen-specific cancer immunotherapy.
Subject(s)
Antigen Presentation , Antigen-Presenting Cells/immunology , Brain Neoplasms/immunology , Glioma/immunology , Immunohistochemistry/methods , Isocitrate Dehydrogenase/immunology , Mutation, Missense , Adult , Aged , Aged, 80 and over , Antigen-Presenting Cells/metabolism , Antigen-Presenting Cells/pathology , Brain Neoplasms/enzymology , Brain Neoplasms/pathology , Cancer Vaccines/genetics , Cancer Vaccines/immunology , Cancer Vaccines/metabolism , Cancer Vaccines/pharmacology , Cell Line, Tumor , Epitopes/genetics , Epitopes/immunology , Epitopes/metabolism , Female , Glioma/enzymology , Glioma/genetics , Glioma/pathology , Histocompatibility Antigens Class II/genetics , Histocompatibility Antigens Class II/immunology , Histocompatibility Antigens Class II/metabolism , Humans , Isocitrate Dehydrogenase/genetics , Isocitrate Dehydrogenase/metabolism , Male , Middle AgedABSTRACT
The discovery of driver mutations in cancers has raised interest in their suitability as immunotherapeutic targets. A recent study demonstrates that a point mutation in isocitrate dehydrogenase 1 (IDH1R132H), expressed in gliomas and other tumors, is presented on human MHC class II and induces a mutation-specific CD4+ antitumor T cell response in patients and a syngeneic tumor model in MHC-humanized mice.
ABSTRACT
3,4-dimethoxycinnamonyl-anthranilic acid (tranilast) is an orally available anti-allergic drug with structural and functional homologies to immunosuppressive catabolites of the essential amino acid tryptophan and broad anti-inflammatory properties. It has recently been shown to be effective in animal models of multiple sclerosis and rheumatoid arthritis, two autoimmune diseases that are mediated by auto-aggressive Th1-polarized CD4+ T lymphocytes. Here we demonstrate potent suppressive effects of tranilast on the function of naïve human CD4+ T cells. Tranilast inhibited inhibits activation and proliferation of purified CD4+ T cells stimulated through the T cell receptor with an EC50 of less than 10 µM, a concentration that is well below plasma levels achieved after oral administration of approved doses of 200-600 mg in humans. The antiproliferative effects were less potent on naïve CD8+ T cells. Suppression of CD4+ and CD8+ T cell proliferation was associated with an inhibition of T cell activation. Cytokine analyses of naïve CD4+ T cells revealed that tranilast interferes with the production of cyto- and chemokines driven by signal transducer and activator of transcription 1 (STAT1), notably chemokine (C-X-C motif) ligands (CXCL) 9 and 10. Tranilast limited STAT1 phosphorylation in activated T cells and supplementation of CXCL9 or CXCL10 reversed the anti-proliferative effects of tranilast. These data imply CXCL9 and CXCL10 as novel therapeutic targets of tranilast in Th1-mediated autoimmune diseases and identify phospho-STAT1 and its target chemokines CXCL9 and CXCL10 as potential markers for monitoring the bioactivity of tranilast in humans.