ABSTRACT
The combination of radiotherapy/chemoradiotherapy and immune checkpoint blockade can result in poor outcomes in patients with locally advanced head and neck squamous cell carcinoma (HNSCC). Here, we show that combining ATR inhibition (ATRi) with radiotherapy (RT) increases the frequency of activated NKG2A+PD-1+ T cells in animal models of HNSCC. Compared with the ATRi/RT treatment regimen alone, the addition of simultaneous NKG2A and PD-L1 blockade to ATRi/RT, in the adjuvant, post-radiotherapy setting induces a robust antitumour response driven by higher infiltration and activation of cytotoxic T cells in the tumour microenvironment. The efficacy of this combination relies on CD40/CD40L costimulation and infiltration of activated, proliferating memory CD8+ and CD4+ T cells with persistent or new T cell receptor (TCR) signalling, respectively. We also observe increased richness in the TCR repertoire and emergence of numerous and large TCR clonotypes that cluster based on antigen specificity in response to NKG2A/PD-L1/ATRi/RT. Collectively, our data point towards potential combination approaches for the treatment of HNSCC.
Subject(s)
Ataxia Telangiectasia Mutated Proteins , B7-H1 Antigen , Immunotherapy , Squamous Cell Carcinoma of Head and Neck , Tumor Microenvironment , Tumor Microenvironment/immunology , Tumor Microenvironment/radiation effects , Animals , Humans , Mice , Squamous Cell Carcinoma of Head and Neck/immunology , Squamous Cell Carcinoma of Head and Neck/radiotherapy , Squamous Cell Carcinoma of Head and Neck/therapy , Squamous Cell Carcinoma of Head and Neck/pathology , Immunotherapy/methods , B7-H1 Antigen/antagonists & inhibitors , B7-H1 Antigen/metabolism , Ataxia Telangiectasia Mutated Proteins/metabolism , Ataxia Telangiectasia Mutated Proteins/antagonists & inhibitors , Head and Neck Neoplasms/immunology , Head and Neck Neoplasms/therapy , Head and Neck Neoplasms/radiotherapy , Cell Line, Tumor , Immune Checkpoint Inhibitors/pharmacology , Immune Checkpoint Inhibitors/therapeutic use , NK Cell Lectin-Like Receptor Subfamily C/metabolism , Programmed Cell Death 1 Receptor/antagonists & inhibitors , Programmed Cell Death 1 Receptor/metabolism , CD8-Positive T-Lymphocytes/immunology , Female , T-Lymphocytes, Cytotoxic/immunology , CD4-Positive T-Lymphocytes/immunology , CD4-Positive T-Lymphocytes/radiation effects , Mice, Inbred C57BL , CD40 Antigens/metabolism , CD40 Antigens/immunology , CD40 Antigens/antagonists & inhibitorsABSTRACT
Receptor-interacting serine/threonine-protein kinase 1 (RIPK1) functions as a critical stress sentinel that coordinates cell survival, inflammation, and immunogenic cell death (ICD). Although the catalytic function of RIPK1 is required to trigger cell death, its non-catalytic scaffold function mediates strong pro-survival signaling. Accordingly, cancer cells can hijack RIPK1 to block necroptosis and evade immune detection. We generated a small-molecule proteolysis-targeting chimera (PROTAC) that selectively degraded human and murine RIPK1. PROTAC-mediated depletion of RIPK1 deregulated TNFR1 and TLR3/4 signaling hubs, accentuating the output of NF-κB, MAPK, and IFN signaling. Additionally, RIPK1 degradation simultaneously promoted RIPK3 activation and necroptosis induction. We further demonstrated that RIPK1 degradation enhanced the immunostimulatory effects of radio- and immunotherapy by sensitizing cancer cells to treatment-induced TNF and interferons. This promoted ICD, antitumor immunity, and durable treatment responses. Consequently, targeting RIPK1 by PROTACs emerges as a promising approach to overcome radio- or immunotherapy resistance and enhance anticancer therapies.
Subject(s)
Immunogenic Cell Death , Proteolysis , Receptor-Interacting Protein Serine-Threonine Kinases , Signal Transduction , Receptor-Interacting Protein Serine-Threonine Kinases/metabolism , Humans , Animals , Mice , Proteolysis/drug effects , Cell Line, Tumor , Signal Transduction/drug effects , Immunogenic Cell Death/drug effects , Necroptosis/drug effects , Necroptosis/immunology , Neoplasms/immunology , Neoplasms/drug therapy , Mice, Inbred C57BL , Antineoplastic Agents/pharmacology , Immunotherapy/methodsABSTRACT
BACKGROUNDPhase 1 study of ATRinhibition alone or with radiation therapy (PATRIOT) was a first-in-human phase I study of the oral ATR (ataxia telangiectasia and Rad3-related) inhibitor ceralasertib (AZD6738) in advanced solid tumors.METHODSThe primary objective was safety. Secondary objectives included assessment of antitumor responses and pharmacokinetic (PK) and pharmacodynamic (PD) studies. Sixty-seven patients received 20-240 mg ceralasertib BD continuously or intermittently (14 of a 28-day cycle).RESULTSIntermittent dosing was better tolerated than continuous, which was associated with dose-limiting hematological toxicity. The recommended phase 2 dose of ceralasertib was 160 mg twice daily for 2 weeks in a 4-weekly cycle. Modulation of target and increased DNA damage were identified in tumor and surrogate PD. There were 5 (8%) confirmed partial responses (PRs) (40-240 mg BD), 34 (52%) stable disease (SD), including 1 unconfirmed PR, and 27 (41%) progressive disease. Durable responses were seen in tumors with loss of AT-rich interactive domain-containing protein 1A (ARID1A) and DNA damage-response defects. Treatment-modulated tumor and systemic immune markers and responding tumors were more immune inflamed than nonresponding.CONCLUSIONCeralasertib monotherapy was tolerated at 160 mg BD intermittently and associated with antitumor activity.TRIAL REGISTRATIONClinicaltrials.gov: NCT02223923, EudraCT: 2013-003994-84.FUNDINGCancer Research UK, AstraZeneca, UK Department of Health (National Institute for Health Research), Rosetrees Trust, Experimental Cancer Medicine Centre.
Subject(s)
Morpholines , Neoplasms , Pyrimidines , Sulfonamides , Humans , Neoplasms/drug therapy , Neoplasms/genetics , Neoplasms/pathology , Indoles , Inflammation/drug therapy , Genomics , Ataxia Telangiectasia Mutated Proteins/geneticsABSTRACT
Radiotherapy is one of the most effective and frequently used treatments for a wide range of cancers. In addition to its direct anti-cancer cytotoxic effects, ionising radiation can augment the anti-tumour immune response by triggering pro-inflammatory signals, DNA damage-induced immunogenic cell death and innate immune activation. Anti-tumour innate immunity can result from recruitment and stimulation of dendritic cells (DCs) which leads to tumour-specific adaptive T-cell priming and immunostimulatory cell infiltration. Conversely, radiotherapy can also induce immunosuppressive and anti-inflammatory mediators that can confer radioresistance. Targeting the DNA damage response (DDR) concomitantly with radiotherapy is an attractive strategy for overcoming radioresistance, both by enhancing the radiosensitivity of tumour relative to normal tissues, and tipping the scales in favour of an immunostimulatory tumour microenvironment. This two-pronged approach exploits genomic instability to circumvent immune evasion, targeting both hallmarks of cancer. In this review, we describe targetable DDR proteins (PARP (poly[ADP-ribose] polymerase); ATM/ATR (ataxia-telangiectasia mutated and Rad3-related), DNA-PKcs (DNA-dependent protein kinase, catalytic subunit) and Wee1 (Wee1-like protein kinase) and their potential intersections with druggable immunomodulatory signalling pathways, including nucleic acid-sensing mechanisms (Toll-like receptors (TLR); cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) and retinoic acid-inducible gene-I (RIG-I)-like receptors), and how these might be exploited to enhance radiation therapy. We summarise current preclinical advances, recent and ongoing clinical trials and the challenges of therapeutic combinations with existing treatments such as immune checkpoint inhibitors.
ABSTRACT
BACKGROUND: Combination herpes simplex virus (HSV) oncolytic virotherapy and BRAF inhibitors (BRAFi) represent promising immunogenic treatments for BRAF mutant melanoma, but an improved understanding of the immunobiology of combinations is needed to improve on the benefit of immune checkpoint inhibitors (ICI). METHODS: Using a BRAFV600E-driven murine melanoma model, we tested the immunogenicity of HSV/BRAFi in immunocompetent C57BL mice. In addition to standard FACS analysis, we used the 'Timer of Cell Kinetics and Activity' system, which can analyze the temporal dynamics of different T cell subsets. This immune data was used to inform the selection of ICI for triple combination therapy, the effects of which were then further characterized using transcriptomics. RESULTS: Adding BRAFi treatment to HSV improved anti-tumor effects in vivo but not in vitro. Immune characterization showed HSV or dual therapy led to fewer intratumoral Treg, although with a more activated phenotype, together with more effector CD8 +T cells. Tocky analysis further showed that HSV/BRAFi dual treatment reduced the Tocky signal (reflecting engagement with cognate antigen), in both Treg and conventional subsets of CD4+, but not in CD8 +cells. However, a higher percentage of Treg than of conventional CD4 +maintained frequent engagement with antigens on treatment, reflecting a predominance of suppressive over effector function within the CD4 +compartment. The only T cell subset which correlated with a reduction in tumor growth was within Tocky signal positive conventional CD4+, supporting their therapeutic role. Targeting CD25 high, antigen-engaged Treg with a depleting anti-CD25 ICI, achieved complete cures in 100% of mice with triple therapy. Transcriptomic analysis confirmed reduction in Foxp3 on addition of anti-CD25 to HSV/BRAFi, as well as increases in expression of genes reflecting interferon signaling and cytotoxic activity. CONCLUSIONS: Combination HSV/BRAFi is an immunogenic therapy for BRAF mutant melanoma, but cannot fully control tumors. Dual therapy results in changes in T cell dynamics within tumors, with relatively maintained antigen signaling in Treg compared with conv CD4+. Antigen-engaged CD4 +effectors correlate with tumor growth control, and depletion of Treg by addition of an anti-CD25 ICI, releasing suppression of conventional CD4 +effectors by Treg, enhances survival and activates immune signaling within tumors.
Subject(s)
Herpes Simplex , Melanoma , Oncolytic Viruses , Animals , CD4-Positive T-Lymphocytes , Humans , Immunity , Melanoma/drug therapy , Mice , Mice, Inbred C57BL , Oncolytic Viruses/physiology , Protein Kinase Inhibitors/therapeutic use , Proto-Oncogene Proteins B-raf/geneticsABSTRACT
BACKGROUND: Despite therapeutic gains from immune checkpoint inhibitors (ICI) in many tumor types, new strategies are needed to extend treatment benefits, especially in patients failing to mount effective antitumor T-cell responses. Radiation and drug therapies can profoundly affect the tumor immune microenvironment. Here, we aimed to identify immunotherapies to increase the antitumor response conferred by combined ataxia telangiectasia and Rad3-related kinase inhibition and radiotherapy. METHODS: Using the human papillomavirus (HPV)-negative murine oral squamous cell carcinoma model, MOC2, we assessed the nature of the antitumor response following ataxia telangiectasia and Rad3-related inhibitor (ATRi)/radiotherapy (RT) by performing RNA sequencing and detailed flow cytometry analyses in tumors. The benefit of immunotherapies based on T cell immunoreceptor with Ig and ITIM domains (TIGIT) and Programmed cell death protein 1 (PD-1) immune checkpoint blockade following ATRi/RT treatment was assessed in the MOC2 model and confirmed in another HPV-negative murine oral squamous cell carcinoma model called SCC7. Finally, immune profiling was performed by flow cytometry on blood samples in patients with head and neck squamous cell carcinoma enrolled in the PATRIOT clinical trial of combined ATRi/RT. RESULTS: ATRi enhances radiotherapy-induced inflammation in the tumor microenvironment, with natural killer (NK) cells playing a central role in maximizing treatment efficacy. We demonstrated that antitumor activity of NK cells can be further boosted with ICI targeting TIGIT and PD-1. Analyses of clinical samples from patients receiving ATRi (ceralasertib) confirm the translational potential of our preclinical studies. CONCLUSION: This work delineates a previously unrecognized role for NK cells in the antitumor immune response to radiotherapy that can be augmented by small-molecule DNA damage-response inhibitors and immune checkpoint blockade.
Subject(s)
Ataxia Telangiectasia , Carcinoma, Squamous Cell , Head and Neck Neoplasms , Mouth Neoplasms , Papillomavirus Infections , Animals , Carcinoma, Squamous Cell/drug therapy , Carcinoma, Squamous Cell/radiotherapy , DNA Damage , Humans , Immune Checkpoint Inhibitors/pharmacology , Immune Checkpoint Inhibitors/therapeutic use , Mice , Programmed Cell Death 1 Receptor , Receptors, Immunologic , Squamous Cell Carcinoma of Head and Neck/drug therapy , Squamous Cell Carcinoma of Head and Neck/radiotherapy , Tumor MicroenvironmentABSTRACT
BACKGROUND: The aggressive clinical behavior of poorly differentiated and anaplastic thyroid cancers (PDTC and ATC) has proven challenging to treat, and survival beyond a few months from diagnosis is rare. Although 30%-60% of these tumors contain mutations in the BRAF gene, inhibitors designed specifically to target oncogenic BRAF have shown limited and only short-lasting therapeutic benefits as single agents, thus highlighting the need for improved treatment strategies, including novel combinations. METHODS: Using a BRAFV600E-driven mouse model of ATC, we investigated the therapeutic efficacy of the combination of BRAF inhibition and oncolytic herpes simplex virus (oHSV). Analyses of samples from tumor-bearing mice were performed to immunologically characterize the effects of different treatments. These immune data were used to inform the incorporation of immune checkpoint inhibitors into triple combination therapies. RESULTS: We characterized the immune landscape in vivo following BRAF inhibitor treatment and detected only modest immune changes. We, therefore, hypothesized that the addition of oncolytic virotherapy to BRAF inhibition in thyroid cancer would create a more favorable tumor immune microenvironment, boost the inflammatory status of tumors and improve BRAF inhibitor therapy. First, we showed that thyroid cancer cells were susceptible to infection with oHSV and that this process was associated with activation of the immune tumor microenvironment in vivo. Next, we showed improved therapeutic responses when combining oHSV and BRAF inhibition in vivo, although no synergistic effects were seen in vitro, further confirming that the dominant effect of oHSV in this context was likely immune-mediated. Importantly, both gene and protein expression data revealed an increase in activation of T cells and natural killer (NK) cells in the tumor in combination-treated samples. The benefit of combination oHSV and BRAF inhibitor therapy was abrogated when T cells or NK cells were depleted in vivo. In addition, we showed upregulation of PD-L1 and CTLA-4 following combined treatment and demonstrated that blockade of the PD-1/PD-L1 axis or CTLA-4 further improved combination therapy. CONCLUSIONS: The combination of oHSV and BRAF inhibition significantly improved survival in a mouse model of ATC by enhancing immune-mediated antitumor effects, and triple combination therapies, including either PD-1 or CTLA-4 blockade, further improved therapy.
Subject(s)
Oncolytic Virotherapy/methods , Proto-Oncogene Proteins B-raf/metabolism , Thyroid Neoplasms/genetics , Animals , Cell Line, Tumor , Disease Models, Animal , Female , Herpesvirus 1, Human/pathogenicity , Humans , Male , Mice , Thyroid Neoplasms/pathologyABSTRACT
The development of immune checkpoint inhibitors (ICIs) is revolutionizing the way we think about cancer treatment. Even so, for most types of cancer, only a minority of patients currently benefit from ICI therapies. Intrinsic and acquired resistance to ICIs has focused research towards new combination therapy approaches that seek to increase response rates, the depth of remission and the durability of benefit. In this Review, we describe how radiotherapy, through its immunomodulating effects, represents a promising combination partner with ICIs. We describe how recent research on DNA damage response (DDR) inhibitors in combination with radiotherapy may be used to augment this approach. Radiotherapy can kill cancer cells while simultaneously triggering the release of pro-inflammatory mediators and increasing tumour-infiltrating immune cells - phenomena often described colloquially as turning immunologically 'cold' tumours 'hot'. Here, we focus on new developments illustrating the key role of tumour cell-autonomous signalling after radiotherapy. Radiotherapy-induced tumour cell micronuclei activate cytosolic nucleic acid sensor pathways, such as cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING), and propagation of the resulting inflammatory signals remodels the immune contexture of the tumour microenvironment. In parallel, radiation can impact immunosurveillance by modulating neoantigen expression. Finally, we highlight how tumour cell-autonomous mechanisms might be exploited by combining DDR inhibitors, ICIs and radiotherapy.
Subject(s)
Neoplasms/etiology , Neoplasms/pathology , Tumor Microenvironment , Animals , Antigen Presentation/immunology , Antigen Presentation/radiation effects , Biomarkers, Tumor , Caspases/metabolism , DNA Repair , Disease Susceptibility , Exosomes/metabolism , Humans , Membrane Proteins/metabolism , Molecular Targeted Therapy , Neoplasms/radiotherapy , Nucleotidyltransferases/metabolism , Protein Processing, Post-Translational , Radiotherapy/adverse effects , Radiotherapy/methods , Signal Transduction , Tumor Microenvironment/immunology , Tumor Microenvironment/radiation effectsABSTRACT
Interleukin-7 (IL-7) is a critical cytokine in B- and T-lymphocyte development and maturation. Recent evidence suggests that IL-7 is a preferential homeostatic and survival factor for RORγt+ innate T cells such as natural killer T (NKT) cells, γδT cells, and mucosal-associated invariant T (MAIT) cells in the periphery. Given the important contribution of these populations in antibacterial immunity at barrier sites, we questioned whether IL-7 could be instrumental in boosting the local host immune response against respiratory bacterial infection. By using a cytokine-monoclonal antibody approach, we illustrated a role for topical IL-7 delivery in increasing the pool of RORγt+ IL-17A-producing innate T cells. Prophylactic IL-7 treatment prior to Streptococcus pneumoniae infection led to better bacterial containment, a process associated with increased neutrophilia and that depended on γδT cells and IL-17A. Last, combined delivery of IL-7 and α-galactosylceramide (α-GalCer), a potent agonist for invariant NKT (iNKT) cells, conferred an almost total protection in terms of survival, an effect associated with enhanced IL-17 production by innate T cells and neutrophilia. Collectively, we provide a proof of concept that IL-7 enables fine-tuning of innate T- cell functions. This might pave the way for considering IL-7 as an innovative biotherapeutic against bacterial infection.
Subject(s)
Immunotherapy/methods , Interleukin-17/metabolism , Interleukin-7/metabolism , Natural Killer T-Cells/metabolism , Neutrophils/immunology , Pneumococcal Infections/immunology , Respiratory Tract Infections/immunology , Streptococcus pneumoniae/physiology , Animals , Antibodies, Blocking/metabolism , Cells, Cultured , Galactosylceramides/immunology , Humans , Immunity, Innate , Interleukin-7/administration & dosage , Mice , Mice, Inbred C57BL , Mice, Knockout , Natural Killer T-Cells/immunology , Nuclear Receptor Subfamily 1, Group F, Member 3/metabolismABSTRACT
PURPOSE: ATR inhibitors (ATRi) are in early phase clinical trials and have been shown to sensitize to chemotherapy and radiotherapy preclinically. Limited data have been published about the effect of these drugs on the tumor microenvironment.Experimental Design: We used an immunocompetent mouse model of HPV-driven malignancies to investigate the ATR inhibitor AZD6738 in combination with fractionated radiation (RT). Gene expression analysis and flow cytometry were performed posttherapy. RESULTS: Significant radiosensitization to RT by ATRi was observed alongside a marked increase in immune cell infiltration. We identified increased numbers of CD3+ and NK cells, but most of this infiltrate was composed of myeloid cells. ATRi plus radiation produced a gene expression signature matching a type I/II IFN response, with upregulation of genes playing a role in nucleic acid sensing. Increased MHC I levels were observed on tumor cells, with transcript-level data indicating increased antigen processing and presentation within the tumor. Significant modulation of cytokine gene expression (particularly CCL2, CCL5, and CXCL10) was found in vivo, with in vitro data indicating CCL3, CCL5, and CXCL10 are produced from tumor cells after ATRi + RT. CONCLUSIONS: We show that DNA damage by ATRi and RT leads to an IFN response through activation of nucleic acid-sensing pathways. This triggers increased antigen presentation and innate immune cell infiltration. Further understanding of the effect of this combination on the immune response may allow modulation of these effects to maximize tumor control through antitumor immunity.
Subject(s)
Ataxia Telangiectasia Mutated Proteins/antagonists & inhibitors , Neoplasms/etiology , Neoplasms/metabolism , Protein Kinase Inhibitors/pharmacology , Tumor Microenvironment/drug effects , Animals , Ataxia Telangiectasia Mutated Proteins/genetics , Ataxia Telangiectasia Mutated Proteins/metabolism , Cell Line, Tumor , Cytokines/metabolism , Disease Models, Animal , Humans , Lymphocytes, Tumor-Infiltrating/drug effects , Lymphocytes, Tumor-Infiltrating/immunology , Lymphocytes, Tumor-Infiltrating/metabolism , Lymphocytes, Tumor-Infiltrating/pathology , Mice , Myeloid Cells/drug effects , Myeloid Cells/immunology , Myeloid Cells/metabolism , Neoplasms/drug therapy , Neoplasms/pathology , Radiation, Ionizing , Tumor Microenvironment/genetics , Tumor Microenvironment/immunology , Xenograft Model Antitumor AssaysABSTRACT
Historically, our understanding of the cytotoxicity of radiation has centred on tumour cell-autonomous mechanisms of cell death. Here, tumour cell death occurs when a threshold number of radiation-induced non-reparable double-stranded DNA breaks is exceeded. However, in recent years, the importance of immune mechanisms of cell death has been increasingly recognised, as well as the impact of radiotherapy on non-malignant cellular components of the tumour microenvironment. Conserved antiviral pathways that detect foreign nucleic acid in the cytosol and drive downstream interferon (IFN) responses via the cyclic guanosine monophosphate-adenosine monophosphate synthase/stimulator of IFN genes (cGAS/STING) pathway are key components of the immune response to radiation-induced DNA damage. In preclinical models, acute induction of a type 1 IFN response is important for both direct and abscopal tumour responses to radiation. Inhibitors of the DNA damage response show promise in augmenting this inflammatory IFN response. However, a substantial proportion of tumours show chronic IFN signalling prior to radiotherapy, which paradoxically drives immunosuppression. This chronic IFN signalling leads to treatment resistance, and heterotypic interactions between stromal fibroblasts and tumour cells contribute to an aggressive tumour phenotype. The effect of radiotherapy on myeloid cell populations, particularly tumour-associated macrophages, has an additional impact on the immune tumour microenvironment. It is not yet clear how the above preclinical findings translate into a human context. Human tumours show greater intratumoural genomic heterogeneity and more variable levels of chromosomal instability than experimental murine models. High-quality translational studies of immunological changes occurring during radiotherapy that incorporate intrinsic tumour biology will enable a better understanding of the immunological consequences of radiation-induced DNA damage in patients. Copyright © 2019 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Subject(s)
DNA Damage/radiation effects , Animals , Antigens, Neoplasm/genetics , Antigens, Neoplasm/immunology , CD8-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/radiation effects , Cancer-Associated Fibroblasts/immunology , Chromosomal Instability/genetics , Chromosomal Instability/immunology , Combined Modality Therapy , DNA Damage/immunology , Disease Models, Animal , Humans , Immune Tolerance/immunology , Immunologic Factors/therapeutic use , Interferon Type I/biosynthesis , Interferon Type I/radiation effects , Mice , Myeloid Cells/immunology , Myeloid Cells/radiation effects , Neoplasms/immunology , Neoplasms/radiotherapy , Radiation Dosage , Signal Transduction/immunologyABSTRACT
Over the last decade, invasive fungal infections have emerged as a growing threat to human health worldwide and novel treatment strategies are urgently needed. In this context, investigations into host-pathogen interactions represent an important and promising field of research. Antigen presenting cells such as macrophages and dendritic cells are strategically located at the frontline of defence against potential invaders. Importantly, these cells express germline encoded pattern recognition receptors (PRRs), which sense conserved entities from pathogens and orchestrate innate immune responses. Herein, we review the latest findings regarding the biology and functions of the different classes of PRRs involved in pathogenic fungal recognition. We also discuss recent literature on PRR collaboration/crosstalk and the mechanisms involved in inhibiting/regulating PRR signalling. Finally, we discuss how the accumulated knowledge on PRR biology, especially Dectin-1, has been used for the design of new immunotherapies against fungal infections.
Subject(s)
Host-Pathogen Interactions/immunology , Immunity, Innate/genetics , Invasive Fungal Infections/genetics , Receptors, Pattern Recognition/genetics , Dendritic Cells/immunology , Dendritic Cells/microbiology , Fungi/immunology , Fungi/pathogenicity , Germ Cells/immunology , Germ Cells/microbiology , Humans , Invasive Fungal Infections/immunology , Invasive Fungal Infections/microbiology , Macrophages/immunology , Macrophages/microbiology , Receptors, Pattern Recognition/immunologyABSTRACT
γδT cells comprise a unique T cell sublineage endowed with a wide functional repertoire, which allow them to play important-sometimes opposite-roles in many immune responses associated with infection, cancer, and inflammatory processes. This is largely dependent on the existence of pre-programmed discrete functional subsets that differentiate within the thymus at specific temporal windows of life. Since they represent a major early source of interleukin-17A in many models of immune responses, the γδT17 cell population has recently gained considerable interest. Thus, a better dissection of the developmental program of this effector γδT subset appears critical in understanding their associated immune functions. Several recent reports have provided new exciting insights into the developmental mechanisms that control γδT cell lineage commitment and differentiation. Here, we review the importance of thymic cues and intrinsic factors that shape the developmental program of γδT17 cells. We also discuss the potential future areas of research in γδT17 cell development especially in regards to the recently provided data from deep RNA sequencing technology. Pursuing our understanding into this complex mechanism will undoubtedly provide important clues into the biology of this particular T cell sublineage.
Subject(s)
Cell Lineage , Immunity, Innate , Interleukin-17/genetics , Intraepithelial Lymphocytes/immunology , Thymus Gland/immunology , Animals , Cell Differentiation , Cytokines/immunology , High-Throughput Nucleotide Sequencing , Humans , Interleukin-17/immunology , Mice , Thymus Gland/cytologyABSTRACT
The protumoral activity of γδT17 cells has recently emerged in a wide variety of solid malignancies, including breast cancer. These cells exert their detrimental functions by promoting tumor growth, angiogenesis, and subsequent metastasis development. However, the intratumoral factors that regulate the biology of γδT17cells within the tumor microenvironment are less well understood. Here, using two experimental models of breast cancer, we reinforced the concept that tumor-infiltrating γδT17 cells are endowed with protumoral functions, which promote tumor progression and metastasis development. More importantly, we demonstrated a critical role for type I IFN signaling in controlling the preferential accumulation in the tumor bed of a peculiar subset of γδT17 cells displaying a CD27- CD3bright phenotype (previously associated with the invariant Vγ6Vδ1+ TCR). Interestingly, this effect was indirect and partially relied on the IFNAR1-dependent control of IL7 secretion, a factor that triggers proliferation and activating functions of deleterious γδT17 cells. Our work therefore identifies a key role of the type I IFN/IL7 axis in the regulation of intratumoral γδT17-cell functions and in the development of primary breast tumor growth and metastasis.Significance: Tumor-derived IL7 can represent a therapeutic target to prevent accumulation of immune cells endowed with potent protumoral activities. Cancer Res; 78(1); 195-204. ©2017 AACR.
Subject(s)
Breast Neoplasms/immunology , Interleukin-17/metabolism , Interleukin-7/metabolism , Receptor, Interferon alpha-beta/metabolism , T-Lymphocyte Subsets/immunology , Animals , Breast Neoplasms/metabolism , Breast Neoplasms/pathology , Female , Interleukin-17/genetics , Lymphocytes, Tumor-Infiltrating/metabolism , Lymphocytes, Tumor-Infiltrating/pathology , Mice, Inbred BALB C , Mice, Inbred C57BL , Receptor, Interferon alpha-beta/genetics , Receptor, Interferon alpha-beta/immunology , Receptors, Antigen, T-Cell, gamma-delta/metabolism , Signal Transduction , T-Lymphocyte Subsets/metabolism , Tumor Necrosis Factor Receptor Superfamily, Member 7/genetics , Tumor Necrosis Factor Receptor Superfamily, Member 7/metabolismABSTRACT
The macrophage-inducible C-type lectin (Mincle) is an innate immune receptor on myeloid cells sensing diverse entities including pathogens and damaged cells. Mincle was first described as a receptor for the mycobacterial cell wall glycolipid, trehalose-6,6'-dimycolate, or cord factor, and the mammalian necrotic cell-derived alarmin histone deacetylase complex unit Sin3-associated protein 130. Upon engagement by its ligands, Mincle induces secretion of innate cytokines and other immune mediators modulating inflammation and immunity. Since its discovery more than 25 years ago, the understanding of Mincle's immune function has made significant advances in recent years. In addition to mediating immune responses to infectious agents, Mincle has been linked to promote tumor progression, autoimmunity, and sterile inflammation; however, further studies are required to completely unravel the complex role of Mincle in these distinct host responses. In this review, we discuss recent findings on Mincle's biology with an emphasis on its diverse functions in immunity.
ABSTRACT
The causative agent of tuberculosis, Mycobacterium tuberculosis (M. tuberculosis), contains an abundant cell wall glycolipid and a crucial virulence factor, trehalose-6,6'-dimycolate (TDM). TDM causes delay of phagosome maturation and thus promotes survival of mycobacteria inside host macrophages by a not fully understood mechanism. TDM signals through the Monocyte-INducible C-type LEctin (Mincle), a recently identified pattern recognition receptor. Here we show that recruitment of Mincle by TDM coupled to immunoglobulin (Ig)G-opsonised beads during Fcγ receptor (FcγR)-mediated phagocytosis interferes with phagosome maturation. In addition, modulation of phagosome maturation by TDM requires SH2-domain-containing inositol polyphosphate 5' phosphatase (SHP-1) and the FcγRIIB, which strongly suggests inhibitory downstream signalling of Mincle during phagosome formation. Overall, our study reveals important mechanisms contributing to the virulence of TDM.
Subject(s)
Lectins, C-Type/metabolism , Membrane Proteins/metabolism , Phagosomes/drug effects , Protein Tyrosine Phosphatase, Non-Receptor Type 6/metabolism , Receptors, IgG/metabolism , Signal Transduction , Trehalose/pharmacology , Animals , Cell Line , Mice , Mice, Inbred C57BL , Mice, Knockout , Phagosomes/metabolismABSTRACT
The global tuberculosis epidemic is the most common cause of death after infectious disease worldwide. Increasing numbers of infections with multi- and extensively drug-resistant variants of the Mycobacterium tuberculosis complex, resistant even to newly discovered and last resort antibiotics, highlight the urgent need for an efficient vaccine. The protective efficacy to pulmonary tuberculosis in adults of the only currently available vaccine, M. bovis BCG, is unsatisfactory and geographically diverse. More importantly, recent clinical studies on new vaccine candidates did not prove to be better than BCG, yet. Here, we propose and discuss novel strategies to improve efficacy of existing anti-tuberculosis vaccines. Modulation of innate immune responses upon vaccination already provided promising results in animal models of tuberculosis. For instance, neutrophils have been shown to influence vaccine efficacy, both, positively and negatively, and stimulate specific antibody secretion. Modulating immune regulatory properties after vaccination such as induction of different types of innate immune cell death, myeloid-derived suppressor or regulatory T cells, production of anti-inflammatory cytokines such as IL-10 may have beneficial effects on protection efficacy. Incorporation of lipid antigens presented via CD1 molecules to T cells have been discussed as a way to enhance vaccine efficacy. Finally, concepts of dendritic cell-based immunotherapies or training the innate immune memory may be exploitable for future vaccination strategies against tuberculosis. In this review, we put a spotlight on host immune networks as potential targets to boost protection by old and new tuberculosis vaccines.
ABSTRACT
Candida spp. elicit cytokine production downstream of various pathogen recognition receptors, including C-type lectin-like receptors, TLRs, and nucleotide oligomerization domain (NOD)-like receptors. IL-12 family members IL-12p70 and IL-23 are important for host immunity against Candida spp. In this article, we show that IL-27, another IL-12 family member, is produced by myeloid cells in response to selected Candida spp. We demonstrate a novel mechanism for Candida parapsilosis-mediated induction of IL-27 in a TLR7-, MyD88-, and NOD2-dependent manner. Our data revealed that IFN-ß is induced by C. parapsilosis, which in turn signals through the IFN-α/ß receptor and STAT1/2 to induce IL-27. Moreover, IL-27R (WSX-1)-deficient mice systemically infected with C. parapsilosis displayed enhanced pathogen clearance compared with wild-type mice. This was associated with increased levels of proinflammatory cytokines in the serum and increased IFN-γ and IL-17 responses in the spleens of IL-27R-deficient mice. Thus, our data define a novel link between C. parapsilosis, TLR7, NOD2, IFN-ß, and IL-27, and we have identified an important role for IL-27 in the immune response against C. parapsilosis Overall, these findings demonstrate an important mechanism for the suppression of protective immune responses during infection with C. parapsilosis, which has potential relevance for infections with other fungal pathogens.
Subject(s)
Candida/physiology , Candidiasis/immunology , Interleukin-27/metabolism , Myeloid Cells/immunology , Toll-Like Receptor 7/metabolism , Animals , Cells, Cultured , Cytokines/metabolism , Immune Evasion , Inflammation Mediators/metabolism , Interferon-beta/metabolism , Interleukin-27/genetics , Mice , Mice, Inbred C57BL , Mice, Knockout , Nod2 Signaling Adaptor Protein/genetics , Nod2 Signaling Adaptor Protein/metabolism , Receptors, Cytokine/genetics , Receptors, Interleukin , Signal TransductionABSTRACT
The role of macrophage-inducible C-type lectin (Mincle) in anti-inflammatory responses has not yet been fully characterized. Herein, we show that engagement of Mincle by trehalose-dimycolate or mycobacteria promotes IL-10 production in macrophages, which causes down-regulation of IL-12p40 secretion. Thus, Mincle mediates both pro- as well as anti-inflammatory responses.
Subject(s)
Lectins, C-Type/metabolism , Macrophages/immunology , Membrane Proteins/metabolism , Mycobacteriaceae/immunology , Mycobacterium bovis/immunology , Tuberculosis, Pulmonary/immunology , Animals , Cells, Cultured , Cord Factors/metabolism , Gene Expression Regulation , Humans , Immunity, Innate , Interleukin-10/genetics , Interleukin-10/metabolism , Interleukin-12 Subunit p40/genetics , Interleukin-12 Subunit p40/metabolism , Lectins, C-Type/genetics , Macrophages/microbiology , Membrane Proteins/genetics , Mice , Mice, Inbred C57BL , Mice, Knockout , Toll-Like Receptor 2/genetics , Toll-Like Receptor 2/metabolismABSTRACT
Following pathogen recognition by macrophages, the causative agent of human tuberculosis, Mycobacterium tuberculosis, is internalized by receptor-mediated phagocytosis. Phagosomes containing nonpathogenic bacteria usually follow a stepwise maturation process to phagolysosomes where bacteria are eliminated. However, as a hallmark of M. tuberculosis virulence, pathogenic mycobacteria inhibit phagosome maturation in order to generate an intracellular niche for persistence and replication in resting macrophages. In contrast, activation by interferon gamma and tumor necrosis alpha activates microbicidal effectors of macrophages such as nitric oxide synthase, NO-mediated apoptosis and LRG-47-linked autophagy, which drives M. tuberculosis into phagolysosomes. Glycolipid compounds of the mycobacterial cell wall have been suggested as virulence factors and several studies revealed their contribution to mycobacterial interference with phagosome maturation. To study their effect on phagosome maturation and to characterize phagosomal protein and lipid compositions, we developed a reductionist mycobacterial lipid-coated bead model. Here, we provide protocols to "infect" macrophages with lipid-coated magnetic beads for subsequent purification and characterization of bead phagosomes. This model has been successfully employed to characterize the virulence properties of trehalose dimycolate, as one of the cell wall glycolipids essential for inhibition of phagosome maturation.