Project description:Cancer cells evade T-cell-mediated killing through poorly understood mechanisms of tumour–immune interactions. Dendritic cells (DCs), especially type-1 conventional DCs (cDC1), mediate T-cell priming and therapeutic efficacy against tumours. Besides pattern recognition receptors (PRRs), how DC functions are shaped by other environmental cues remains incompletely defined. Nutrients are emerging mediators of adaptive immunity, but whether nutrients impact DC function or innate–adaptive cell communication is largely unresolved. Here, we establish glutamine as an intercellular metabolic checkpoint to mediate tumour–cDC1 crosstalk and license cDC1 functionality for activating cytotoxic T cells. Intratumoral glutamine supplementation inhibits tumour growth by augmenting cDC1-mediated CD8+ T-cell immunity, and also overcomes therapeutic resistance to checkpoint blockade and T-cell-mediated immunotherapies. Mechanistically, tumour cells and cDC1 compete for glutamine uptake via transporter SLC38A2 to tune anti-tumour immunity. Nutrient screening and integrative analyses show that glutamine is the dominant amino acid for promoting cDC1 function, by signalling via FLCN to impinge upon TFEB function. Loss of FLCN in DCs selectively impairs cDC1 function in vivo in a TFEB-dependent manner, and phenocopies SLC38A2 deficiency by abrogating anti-tumour therapeutic effect of glutamine supplementation. Our findings establish glutamine-mediated intercellular metabolic crosstalk between tumour cells and cDC1 that underpins tumour immunoevasion, and reveal glutamine acquisition and signalling in cDC1 as limiting events for DC activation and putative targets for cancer treatment.
Project description:Cancer cells evade T-cell-mediated killing through poorly understood mechanisms of tumour–immune interactions. Dendritic cells (DCs), especially type-1 conventional DCs (cDC1), mediate T-cell priming and therapeutic efficacy against tumours. Besides pattern recognition receptors (PRRs), how DC functions are shaped by other environmental cues remains incompletely defined. Nutrients are emerging mediators of adaptive immunity, but whether nutrients impact DC function or innate–adaptive cell communication is largely unresolved. Here, we establish glutamine as an intercellular metabolic checkpoint to mediate tumour–cDC1 crosstalk and license cDC1 functionality for activating cytotoxic T cells. Intratumoral glutamine supplementation inhibits tumour growth by augmenting cDC1-mediated CD8+ T-cell immunity, and also overcomes therapeutic resistance to checkpoint blockade and T-cell-mediated immunotherapies. Mechanistically, tumour cells and cDC1 compete for glutamine uptake via transporter SLC38A2 to tune anti-tumour immunity. Nutrient screening and integrative analyses show that glutamine is the dominant amino acid for promoting cDC1 function, by signalling via FLCN to impinge upon TFEB function. Loss of FLCN in DCs selectively impairs cDC1 function in vivo in a TFEB-dependent manner, and phenocopies SLC38A2 deficiency by abrogating anti-tumour therapeutic effect of glutamine supplementation. Our findings establish glutamine-mediated intercellular metabolic crosstalk between tumour cells and cDC1 that underpins tumour immunoevasion, and reveal glutamine acquisition and signalling in cDC1 as limiting events for DC activation and putative targets for cancer treatment.
Project description:Cancer cells evade T-cell-mediated killing through poorly understood mechanisms of tumour–immune interactions. Dendritic cells (DCs), especially type-1 conventional DCs (cDC1), mediate T-cell priming and therapeutic efficacy against tumours. Besides pattern recognition receptors (PRRs), how DC functions are shaped by other environmental cues remains incompletely defined. Nutrients are emerging mediators of adaptive immunity, but whether nutrients impact DC function or innate–adaptive cell communication is largely unresolved. Here, we establish glutamine as an intercellular metabolic checkpoint to mediate tumour–cDC1 crosstalk and license cDC1 functionality for activating cytotoxic T cells. Intratumoral glutamine supplementation inhibits tumour growth by augmenting cDC1-mediated CD8+ T-cell immunity, and also overcomes therapeutic resistance to checkpoint blockade and T-cell-mediated immunotherapies. Mechanistically, tumour cells and cDC1 compete for glutamine uptake via transporter SLC38A2 to tune anti-tumour immunity. Nutrient screening and integrative analyses show that glutamine is the dominant amino acid for promoting cDC1 function, by signalling via FLCN to impinge upon TFEB function. Loss of FLCN in DCs selectively impairs cDC1 function in vivo in a TFEB-dependent manner, and phenocopies SLC38A2 deficiency by abrogating anti-tumour therapeutic effect of glutamine supplementation. Our findings establish glutamine-mediated intercellular metabolic crosstalk between tumour cells and cDC1 that underpins tumour immunoevasion, and reveal glutamine acquisition and signalling in cDC1 as limiting events for DC activation and putative targets for cancer treatment.
Project description:Cancer cells evade T-cell-mediated killing through poorly understood mechanisms of tumour–immune interactions. Dendritic cells (DCs), especially type-1 conventional DCs (cDC1), mediate T-cell priming and therapeutic efficacy against tumours. Besides pattern recognition receptors (PRRs), how DC functions are shaped by other environmental cues remains incompletely defined. Nutrients are emerging mediators of adaptive immunity, but whether nutrients impact DC function or innate–adaptive cell communication is largely unresolved. Here, we establish glutamine as an intercellular metabolic checkpoint to mediate tumour–cDC1 crosstalk and license cDC1 functionality for activating cytotoxic T cells. Intratumoral glutamine supplementation inhibits tumour growth by augmenting cDC1-mediated CD8+ T-cell immunity, and also overcomes therapeutic resistance to checkpoint blockade and T-cell-mediated immunotherapies. Mechanistically, tumour cells and cDC1 compete for glutamine uptake via transporter SLC38A2 to tune anti-tumour immunity. Nutrient screening and integrative analyses show that glutamine is the dominant amino acid for promoting cDC1 function, by signalling via FLCN to impinge upon TFEB function. Loss of FLCN in DCs selectively impairs cDC1 function in vivo in a TFEB-dependent manner, and phenocopies SLC38A2 deficiency by abrogating anti-tumour therapeutic effect of glutamine supplementation. Our findings establish glutamine-mediated intercellular metabolic crosstalk between tumour cells and cDC1 that underpins tumour immunoevasion, and reveal glutamine acquisition and signalling in cDC1 as limiting events for DC activation and putative targets for cancer treatment.
Project description:CD4 T cells are thought to help promote anti-tumour responses by ‘licensing’ antigen presenting cells (APCs) that activate CD8 T cells. Conventional type 1 dendritic cells (cDC1s) are responsible for cross-presentation of tumour-derived antigens to CD8 T cells. Prevailing models presume that the cDC1 is licensed by CD4 T cells that are themselves activated by a distinct cDC subset, the cDC2. The recent finding that neoantigens presented by major histocompatibility complex (MHC) class II molecules can promote rejection of tumours that lack MHC class II (MHC-II) surface expression is consistent with an indirect action of CD4 T cells, such as cDC1 licensing. However, no study has directly identified the APC that primes the CD4 T cells responsible for licensing or clearly identified the target of CD4 licensing in vivo. Here, we generated cDC1-specific Cre expressing mouse strain to inactivate or induce expression of MHC-I, MHC-II, or CD40 specifically within the cDC1 lineage. Using a tumour model that relies on CD8 T cells and CD4 T cells for rejection, we discovered that early priming of CD4 T cells against tumour-derived antigens, in contrast to soluble antigens, relied overwhelmingly on the cDC1 and not the cDC2. cDC1 do not simply transport antigen to lymph nodes for processing by cDC2, since lack of MHC-II expression on cDC1 prevented CD4 T cell priming. We also found that CD40 signaling not only affects licensing of cDC1 for CD8 T cell priming, but is also critical for the activation of CD4 T cells. Thus, in the setting of tumour-derived antigens, cDC1 can function as an autonomous platform, capable of priming both CD4 and CD8 T cells and orchestrating their cross-talk required for optimal anti-tumour immunity.