RESUMO
One-carbon metabolism (1CM), comprising folate metabolism and methionine metabolism, serves as an important mechanism for cellular energy provision and the production of vital signaling molecules, including single-carbon moieties. Its regulation is instrumental in sustaining the proliferation of cancer cells and facilitating metastasis; in addition, recent research has shed light on its impact on the efficacy of T cell-mediated immunotherapy. In this review, we consolidate current insights into how 1CM affects T cell activation, differentiation, and functionality. Furthermore, we delve into the strategies for modulating 1CM in both T cells and tumor cells to enhance the efficacy of adoptively transferred T cells, overcome metabolic challenges in the tumor microenvironment (TME), and maximize the benefits of T cell-mediated immunotherapy.
RESUMO
Lactate influences the behavior of various immune cell types. In a recent Nature Immunology study, Ma et al. revealed that lithium carbonate induces monocarboxylate transporter 1 translocation to mitochondria, enhancing cytoplasmic lactate transport into the mitochondria and increasing lactate mitochondrial metabolism, thereby promoting T cell effector function.
Assuntos
Carbonato de Lítio , Neoplasias , Humanos , Carbonato de Lítio/farmacologia , Linfócitos T , Mitocôndrias , Ácido LácticoRESUMO
Deciphering cellular interactions is essential to both understand the mechanisms underlying a broad range of human diseases, but also to manipulate therapies targeting these diseases. Here, the formation of cell doublets resulting from specific membrane ligand-receptor interactions is discovered. Based on this phenomenon, the study developed DoubletSeeker, a novel high-throughput method for the reliable identification of ligand-receptor interactions. The study shows that DoubletSeeker can accurately identify T cell receptor (TCR)-antigen interactions with high sensitivity and specificity. Notably, DoubletSeeker effectively captured paired TCR-peptide major histocompatibility complex (pMHC) information during a highly complex library-on-library screening and successfully identified three mutant TCRs that specifically recognize the MART-1 epitope. In turn, DoubletSeeker can act as an antigen discovery platform that allows for the development of novel immunotherapy targets, making it valuable for investigating fundamental tumor immunology.
Assuntos
Antígenos , Receptores de Antígenos de Linfócitos T , Humanos , Ligantes , Receptores de Antígenos de Linfócitos T/genética , Receptores de Antígenos de Linfócitos T/metabolismo , Peptídeos , Complexo Principal de HistocompatibilidadeRESUMO
The acidic metabolic byproducts within the tumor microenvironment (TME) hinder T cell effector functions. However, their effects on T cell infiltration remain largely unexplored. Leveraging the comprehensive The Cancer Genome Atlas dataset, we pinpoint 16 genes that correlate with extracellular acidification and establish a metric known as the "tumor acidity (TuAci) score" for individual patients. We consistently observe a negative association between the TuAci score and T lymphocyte score (T score) across various human cancer types. Mechanistically, extracellular acidification significantly impedes T cell motility by suppressing podosome formation. This phenomenon can be attributed to the reduced expression of methyltransferase-like 3 (METTL3) and the modification of RNA N6-methyladenosine (m6A), resulting in a subsequent decrease in the expression of integrin ß1 (ITGB1). Importantly, enforced ITGB1 expression leads to enhanced T cell infiltration and improved antitumor activity. Our study suggests that modulating METTL3 activity or boosting ITGB1 expression could augment T cell infiltration within the acidic TME, thereby improving the efficacy of cell therapy.
Assuntos
Integrina beta1 , Neoplasias , Humanos , Terapia Baseada em Transplante de Células e Tecidos , Concentração de Íons de Hidrogênio , Integrina beta1/genética , Metiltransferases/genética , Linfócitos T , Microambiente TumoralRESUMO
ABSTRACT: The efficacy of adaptive immune responses in cancer treatment relies heavily on the state of the T cells. Upon antigen exposure, T cells undergo metabolic reprogramming, leading to the development of functional effectors or memory populations. However, within the tumor microenvironment (TME), metabolic stress impairs CD8 + T cell anti-tumor immunity, resulting in exhausted differentiation. Recent studies suggested that targeting T cell metabolism could offer promising therapeutic opportunities to enhance T cell immunotherapy. In this review, we provide a comprehensive summary of the intrinsic and extrinsic factors necessary for metabolic reprogramming during the development of effector and memory T cells in response to acute and chronic inflammatory conditions. Furthermore, we delved into the different metabolic switches that occur during T cell exhaustion, exploring how prolonged metabolic stress within the TME triggers alterations in cellular metabolism and the epigenetic landscape that contribute to T cell exhaustion, ultimately leading to a persistently exhausted state. Understanding the intricate relationship between T cell metabolism and cancer immunotherapy can lead to the development of novel approaches to improve the efficacy of T cell-based treatments against cancer.
Assuntos
Linfócitos T CD8-Positivos , Neoplasias , Humanos , Linfócitos T CD8-Positivos/metabolismo , Imunoterapia/métodos , Diferenciação Celular , Neoplasias/terapia , Neoplasias/metabolismo , Microambiente TumoralRESUMO
The discovery and characterization of antigen-specific CD8+ T cell clonotypes typically involves the labor-intensive synthesis and construction of peptide-MHC tetramers. We adapt single-chain trimer (SCT) technologies into a high throughput platform for pMHC library generation, showing that hundreds can be rapidly prepared across multiple Class I HLA alleles. We use this platform to explore the impact of peptide and SCT template mutations on protein expression yield, thermal stability, and functionality. SCT libraries were an efficient tool for identifying T cells recognizing commonly reported viral epitopes. We then construct SCT libraries to capture SARS-CoV-2 specific CD8+ T cells from COVID-19 participants and healthy donors. The immunogenicity of these epitopes is validated by functional assays of T cells with cloned TCRs captured using SCT libraries. These technologies should enable the rapid analyses of peptide-based T cell responses across several contexts, including autoimmunity, cancer, or infectious disease.
Assuntos
Linfócitos T CD8-Positivos , COVID-19 , Humanos , SARS-CoV-2/genética , Antígenos , Epitopos , Peptídeos/genéticaRESUMO
The accumulation of acidic metabolic waste products within the tumor microenvironment inhibits effector functions of tumor-infiltrating lymphocytes (TILs). However, it remains unclear how an acidic environment affects T cell metabolism and differentiation. Here we show that prolonged exposure to acid reprograms T cell intracellular metabolism and mitochondrial fitness and preserves T cell stemness. Mechanistically, elevated extracellular acidosis impairs methionine uptake and metabolism via downregulation of SLC7A5, therefore altering H3K27me3 deposition at the promoters of key T cell stemness genes. These changes promote the maintenance of a 'stem-like memory' state and improve long-term in vivo persistence and anti-tumor efficacy in mice. Our findings not only reveal an unexpected capacity of extracellular acidosis to maintain the stem-like properties of T cells, but also advance our understanding of how methionine metabolism affects T cell stemness.
Assuntos
Acidose , Neoplasias , Animais , Camundongos , Neoplasias/metabolismo , Diferenciação Celular , Microambiente Tumoral , Acidose/metabolismo , CarbonoRESUMO
CD8 + cytotoxic T cell responses against viral infection represent a major element of the adaptive immune response. We describe the development of a peptide antigen - major histompatibility complex (pMHC) library representing the full SARS-CoV-2 viral proteome, and comprised of 634 pMHC multimers representing the A*02.01, A*24.02, and B*07.02 HLA alleles, as well as specific antigens associated with the cytomegalovirus (CMV). These libraries were used to capture non-expanded CD8 + T cells from blood samples collected from 64 infected individuals, and then analyzed using single cell RNA-seq. The discovery and characterization of antigen-specific CD8 + T cell clonotypes typically involves the labor-intensive synthesis and construction of peptide-MHC tetramers. We adapted single-chain trimer (SCT) technologies into a high throughput platform for pMHC library generation, showing that hundreds can be rapidly prepared across multiple Class I HLA alleles. We used this platform to explore the impact of peptide and SCT template mutations on protein expression yield, thermal stability, and functionality. SCT libraries were an efficient tool for identifying T cells recognizing commonly reported viral epitopes. We then constructed SCT libraries designed to capture SARS-CoV-2 specific CD8 + T cells from COVID-19 participants and healthy donors. The immunogenicity of these epitopes was validated by functional assays of T cells with cloned TCRs captured using SCT libraries. These technologies should enable the rapid analyses of peptide-based T cell responses across several contexts, including autoimmunity, cancer, or infectious disease.
RESUMO
Different subsets of tumor-infiltrating dendritic cells (DCs) influence immune response and tolerance in cancer settings. Duong et al. discovered that conventional DC2 subset (cDC2s) can differentiate into stimulatory interferon-stimulated gene (ISG)+ DCs by type I interferon (IFN-I) produced in regressor tumors and acquire and present tumor-derived peptide-MHC (pMHC) class I complexes to increase the protective antitumor CD8+ T cell response.
Assuntos
Linfócitos T CD8-Positivos , Células Dendríticas , Bandagens , Humanos , Tolerância ImunológicaRESUMO
The persistent antigen stimulation during chronic infections and cancer results in CD8+ T cell exhaustion. The exhausted T (Tex) cells within the tumor microenvironment (TME) are characterized by increased expression of multiple co-inhibitory receptors simultaneously, progressive loss of effector function, poor proliferation and self-renewal capacity, and dysregulated metabolic activity. Emerging insights into molecular mechanisms underlying T cell exhaustion have proposed potential approaches to improve the efficacy of cancer immunotherapy via restoring the effector function of Tex cells. In this review, we summarize the fundamental characteristics (e.g., inhibitory receptors and transcriptional factors) regarding Tex cell differentiation and discuss in particular how those exhaustion features are acquired and shaped by key factors within the TME. Additionally, we discuss the progress and limitations of current cancer immunotherapeutic strategies targeting Tex cells in clinical setting.
Assuntos
Linfócitos T CD8-Positivos/imunologia , Imunoterapia/métodos , Neoplasias/terapia , Microambiente Tumoral , Diferenciação Celular , Humanos , Transcrição GênicaRESUMO
Two recent studies published in Nature Immunology map out the link between dysregulated mitochondrial metabolism and terminal exhaustion of tumor-infiltrating T lymphocytes. Yu et al. (2020) and Vardhana et al. (2020) show that defective mitophagy or impaired oxidative phosphorylation triggers mitochondrial reactive oxygen species production, which in turn promotes a T cell exhaustion program, limiting T cell proliferation and self-renewal.
Assuntos
Fosforilação Oxidativa , Linfócitos T , Mitocôndrias/metabolismo , Mitofagia , Espécies Reativas de Oxigênio/metabolismoRESUMO
The determination of individual cell trajectories through a high-dimensional cell-state space is an outstanding challenge for understanding biological changes ranging from cellular differentiation to epigenetic responses of diseased cells upon drugging. We integrate experiments and theory to determine the trajectories that single BRAFV600E mutant melanoma cancer cells take between drug-naive and drug-tolerant states. Although single-cell omics tools can yield snapshots of the cell-state landscape, the determination of individual cell trajectories through that space can be confounded by stochastic cell-state switching. We assayed for a panel of signaling, phenotypic, and metabolic regulators at points across 5 days of drug treatment to uncover a cell-state landscape with two paths connecting drug-naive and drug-tolerant states. The trajectory a given cell takes depends upon the drug-naive level of a lineage-restricted transcription factor. Each trajectory exhibits unique druggable susceptibilities, thus updating the paradigm of adaptive resistance development in an isogenic cell population.
Assuntos
Tolerância a Medicamentos , Genômica , Melanoma/tratamento farmacológico , Análise de Célula Única , Linhagem Celular Tumoral , Genes Reporter , Proteínas de Fluorescência Verde/metabolismo , Humanos , Metabolômica , Fator de Transcrição Associado à Microftalmia , Modelos Moleculares , Proteômica , Proteínas Proto-Oncogênicas B-raf/genética , Reprodutibilidade dos TestesRESUMO
Immunotherapies are yielding effective treatments for several previously untreatable cancers. Still, the identification of suitable antigens specific to the tumour that can be targets for cancer vaccines and T cell therapies is a challenge. Alternative processing of mRNA, a phenomenon that has been shown to alter the proteomic diversity of many cancers, may offer the potential of a broadened target space. Here, we discuss the promise of analysing mRNA processing events in cancer cells, with an emphasis on mRNA splicing, for the identification of potential new targets for cancer immunotherapy. Further, we highlight the challenges that must be overcome for this new avenue to have clinical applicability.
Assuntos
Processamento Alternativo , Imunoterapia/métodos , Neoplasias/terapia , Apresentação de Antígeno , Humanos , Neoplasias/genética , Neoplasias/imunologia , Receptores de Antígenos de Linfócitos T/imunologiaRESUMO
MicroRNAs (miRNAs) are small non-coding RNAs that play a wide variety of critical roles in different biological processes by post-transcriptionally regulating gene expression. They access diverse regulatory pathways during various stages of cellular differentiation, growth, and apoptosis, and can contribute to both normal and diseased functions. One important family of miRNAs involved in these functions is the miR-125 family (miR-125a and miR-125b). Investigations have been made to increasingly uncover the mechanisms by which the miR-125 family regulates normal homeostasis and growth in a variety of cell types including immune cells, and how dysregulation of miR-125a and miR-125b can lead to disease pathogenesis and tumorigenesis. In this review, we summarize what is currently known about miR-125a and miR-125b, mainly focusing on their roles in immune cell development and function as well as tumor suppression and promotion.
Assuntos
MicroRNAs/genética , MicroRNAs/imunologia , Neoplasias/genética , Neoplasias/imunologia , Animais , Humanos , Imunidade/genéticaRESUMO
Immunotherapy treatments harnessing the patient's immune system herald a new era of personalized medicine, offering hope for curative responses in patients with serious illnesses. Cell-mediated immunity can eliminate cancer cells and provide durable remissions. This often relies on repurposing cytotoxic T cell activity through modified T cell receptors or chimeric antigen receptors. Furthermore, synthetic biology has expanded the cell engineering toolkit to provide immune cells with more functionality, including disease targeting, potency, and safety. We focus on T cell-based immunotherapy, highlighting discoveries of genetic engineering and therapeutic use. We also examine emerging paths that could be undertaken to improve this novel class of drugs, and discuss the challenges of toxicities as well as other limitations of cellular immunotherapy.
Assuntos
Imunoterapia , Neoplasias/terapia , Medicina de Precisão , Animais , Humanos , Neoplasias/imunologiaRESUMO
CD8+ T cells recognize and eliminate tumors in an antigen-specific manner. Despite progress in characterizing the antitumor T cell repertoire and function, the identification of target antigens remains a challenge. Here we describe the use of chimeric receptors called signaling and antigen-presenting bifunctional receptors (SABRs) in a cell-based platform for T cell receptor (TCR) antigen discovery. SABRs present an extracellular complex comprising a peptide and major histocompatibility complex (MHC), and induce intracellular signaling via a TCR-like signal after binding with a cognate TCR. We devised a strategy for antigen discovery using SABR libraries to screen thousands of antigenic epitopes. We validated this platform by identifying the targets recognized by public TCRs of known specificities. Moreover, we extended this approach for personalized neoantigen discovery.
Assuntos
Apresentação de Antígeno , Receptores de Antígenos de Linfócitos T/metabolismo , Transdução de Sinais , Células Apresentadoras de Antígenos/citologia , Antígenos/química , Antígenos CD/metabolismo , Antígenos de Diferenciação de Linfócitos T/metabolismo , Linfócitos T CD8-Positivos/citologia , Clonagem Molecular , Técnicas de Cocultura , Epitopos/química , Reações Falso-Positivas , Biblioteca Gênica , Proteínas de Fluorescência Verde/metabolismo , Células HEK293 , Humanos , Imunoterapia/métodos , Células Jurkat , Células K562 , Lectinas Tipo C/metabolismo , Complexo Principal de Histocompatibilidade , Oligonucleotídeos/genética , Peptídeos/químicaRESUMO
T cell receptor (TCR) ligand discovery is essential for understanding and manipulating immune responses to tumors. We developed a cell-based selection platform for TCR ligand discovery that exploits a membrane transfer phenomenon called trogocytosis. We discovered that T cell membrane proteins are transferred specifically to target cells that present cognate peptide-major histocompatibility complex (MHC) molecules. Co-incubation of T cells expressing an orphan TCR with target cells collectively presenting a library of peptide-MHCs led to specific labeling of cognate target cells, enabling isolation of these target cells and sequencing of the cognate TCR ligand. We validated this method for two clinically employed TCRs and further used the platform to identify the cognate neoepitope for a subject-derived neoantigen-specific TCR. Thus, target cell trogocytosis is a robust tool for TCR ligand discovery that will be useful for studying basic tumor immunology and identifying new targets for immunotherapy.