p53, cancer and the immune response Blagih, Julianna; Buck, Michael D; Vousden, Karen H
Journal of cell science,
03/2020, Letnik:
133, Številka:
5
Journal Article
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The importance of cancer-cell-autonomous functions of the tumour suppressor p53 (encoded by
) has been established in many studies, but it is now clear that the p53 status of the cancer cell also has ...a profound impact on the immune response. Loss or mutation of p53 in cancers can affect the recruitment and activity of myeloid and T cells, allowing immune evasion and promoting cancer progression. p53 can also function in immune cells, resulting in various outcomes that can impede or support tumour development. Understanding the role of p53 in tumour and immune cells will help in the development of therapeutic approaches that can harness the differential p53 status of cancers compared with most normal tissue.
Failure of T cells to protect against cancer is thought to result from lack of antigen recognition, chronic activation, and/or suppression by other cells. Using a mouse sarcoma model, we show that ...glucose consumption by tumors metabolically restricts T cells, leading to their dampened mTOR activity, glycolytic capacity, and IFN-γ production, thereby allowing tumor progression. We show that enhancing glycolysis in an antigenic “regressor” tumor is sufficient to override the protective ability of T cells to control tumor growth. We also show that checkpoint blockade antibodies against CTLA-4, PD-1, and PD-L1, which are used clinically, restore glucose in tumor microenvironment, permitting T cell glycolysis and IFN-γ production. Furthermore, we found that blocking PD-L1 directly on tumors dampens glycolysis by inhibiting mTOR activity and decreasing expression of glycolysis enzymes, reflecting a role for PD-L1 in tumor glucose utilization. Our results establish that tumor-imposed metabolic restrictions can mediate T cell hyporesponsiveness during cancer.
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•Tumor cells and TILs compete for glucose within the tumor niche•Metabolic competition can drive cancer progression•Checkpoint blockade antibodies alter the metabolic balance in a tumor•PD-L1 promotes Akt/mTOR activation and glycolysis in tumor cells
Glucose consumption by antigenic tumors can metabolically restrict T cells, directly dampening their effector function and allowing tumor progression. Checkpoint blockade therapy may correct this resource imbalance through a direct effect in the tumor cells.
Activated effector T (TE) cells augment anabolic pathways of metabolism, such as aerobic glycolysis, while memory T (TM) cells engage catabolic pathways, like fatty acid oxidation (FAO). However, ...signals that drive these differences remain unclear. Mitochondria are metabolic organelles that actively transform their ultrastructure. Therefore, we questioned whether mitochondrial dynamics controls T cell metabolism. We show that TE cells have punctate mitochondria, while TM cells maintain fused networks. The fusion protein Opa1 is required for TM, but not TE cells after infection, and enforcing fusion in TE cells imposes TM cell characteristics and enhances antitumor function. Our data suggest that, by altering cristae morphology, fusion in TM cells configures electron transport chain (ETC) complex associations favoring oxidative phosphorylation (OXPHOS) and FAO, while fission in TE cells leads to cristae expansion, reducing ETC efficiency and promoting aerobic glycolysis. Thus, mitochondrial remodeling is a signaling mechanism that instructs T cell metabolic programming.
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•TM cells have fused mitochondria while TE cells have fissed mitochondria•Mitochondrial fusion protein Opa1 is required for TM cells and not TE cells•Enforcing fusion improves adoptive cellular immunotherapy against tumors•Cristae remodeling via fusion/fission signals metabolic adaptations in T cells
The fate of T cells is in the shape of their mitochondria: remodeling mitochondrial cristae via fusion/fission instructs metabolic adaptations in T cells and can be modulated to enhance antitumor immunity.
Generation of CD8+ memory T cells requires metabolic reprogramming that is characterized by enhanced mitochondrial fatty-acid oxidation (FAO). However, where the fatty acids (FA) that fuel this ...process come from remains unclear. While CD8+ memory T cells engage FAO to a greater extent, we found that they acquired substantially fewer long-chain FA from their external environment than CD8+ effector T (Teff) cells. Rather than using extracellular FA directly, memory T cells used extracellular glucose to support FAO and oxidative phosphorylation (OXPHOS), suggesting that lipids must be synthesized to generate the substrates needed for FAO. We have demonstrated that memory T cells rely on cell intrinsic expression of the lysosomal hydrolase LAL (lysosomal acid lipase) to mobilize FA for FAO and memory T cell development. Our observations link LAL to metabolic reprogramming in lymphocytes and show that cell intrinsic lipolysis is deterministic for memory T cell fate.
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•Unlike Teff cells, memory T cells do not acquire substantial amounts of long-chain FA•Glucose supports mitochondrial FAO and OXPHOS in memory T cells•Memory T cells use LAL-mediated cell-intrinsic lipolysis to mobilize FA for FAO•T cell-intrinsic lysosomal lipolysis is important for memory T cell development
CD8+ memory T cells engage fatty-acid oxidation (FAO); however, the source of fatty acids that fuel FAO is unclear. O’Sullivan et al. show that memory T cells rely on glucose, and cell-intrinsic lipolysis to mobilize substrates, for FAO.
In mammals, early resistance to viruses relies on interferons, which protect differentiated cells but not stem cells from viral replication. Many other organisms rely instead on RNA interference ...(RNAi) mediated by a specialized Dicer protein that cleaves viral double-stranded RNA. Whether RNAi also contributes to mammalian antiviral immunity remains controversial. We identified an isoform of Dicer, named antiviral Dicer (aviD), that protects tissue stem cells from RNA viruses-including Zika virus and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-by dicing viral double-stranded RNA to orchestrate antiviral RNAi. Our work sheds light on the molecular regulation of antiviral RNAi in mammalian innate immunity, in which different cell-intrinsic antiviral pathways can be tailored to the differentiation status of cells.
Group 2 innate lymphoid cells (ILC2s) regulate tissue inflammation and repair after activation by cell-extrinsic factors such as host-derived cytokines. However, the cell-intrinsic metabolic pathways ...that control ILC2 function are undefined. Here we demonstrate that expression of the enzyme arginase-1 (Arg1) during acute or chronic lung inflammation is a conserved trait of mouse and human ILC2s. Deletion of mouse ILC-intrinsic Arg1 abrogated type 2 lung inflammation by restraining ILC2 proliferation and dampening cytokine production. Mechanistically, inhibition of Arg1 enzymatic activity disrupted multiple components of ILC2 metabolic programming by altering arginine catabolism, impairing polyamine biosynthesis and reducing aerobic glycolysis. These data identify Arg1 as a key regulator of ILC2 bioenergetics that controls proliferative capacity and proinflammatory functions promoting type 2 inflammation.
How cells adapt metabolism to meet demands is an active area of interest across biology. Among a broad range of functions, the polyamine spermidine is needed to hypusinate the translation factor ...eukaryotic initiation factor 5A (eIF5A). We show here that hypusinated eIF5A (eIF5AH) promotes the efficient expression of a subset of mitochondrial proteins involved in the TCA cycle and oxidative phosphorylation (OXPHOS). Several of these proteins have mitochondrial targeting sequences (MTSs) that in part confer an increased dependency on eIF5AH. In macrophages, metabolic switching between OXPHOS and glycolysis supports divergent functional fates stimulated by activation signals. In these cells, hypusination of eIF5A appears to be dynamically regulated after activation. Using in vivo and in vitro models, we show that acute inhibition of this pathway blunts OXPHOS-dependent alternative activation, while leaving aerobic glycolysis-dependent classical activation intact. These results might have implications for therapeutically controlling macrophage activation by targeting the polyamine-eIF5A-hypusine axis.
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•The polyamine synthesis pathway and hypusinated eIF5A modulate mitochondrial OXPHOS•Hypusinated eIF5A maintains TCA cycle and ETC integrity in macrophages•Some mitochondrial enzymes depend on eIF5AH for efficient expression•Inhibition of hypusinated eIF5A blunts macrophage alternative activation
Puleston et al. show that polyamine biosynthesis modulates mitochondrial metabolism through eIF5A hypusination (eIF5AH). They find that inhibiting the polyamine-eIF5A-hypusine pathway blocks OXPHOS-dependent macrophage alternative activation, while leaving aerobic glycolysis-dependent macrophage classical activation intact. These results might have implications for therapeutically controlling macrophage activation by targeting the polyamine-eIF5A-hypusine axis.
Greater understanding of the complex host responses induced by type 1 interferon (IFN) cytokines could allow new therapeutic approaches for diseases in which these cytokines are implicated. We found ...that in response to the Toll-like receptor-9 agonist CpGA, plasmacytoid dendritic cells (pDC) produced type 1 IFNs, which, through an autocrine type 1 IFN receptor-dependent pathway, induced changes in cellular metabolism characterized by increased fatty acid oxidation (FAO) and oxidative phosphorylation (OXPHOS). Direct inhibition of FAO and of pathways that support this process, such as fatty acid synthesis, prevented full pDC activation. Type 1 IFNs also induced increased FAO and OXPHOS in non-hematopoietic cells and were found to be responsible for increased FAO and OXPHOS in virus-infected cells. Increased FAO and OXPHOS in response to type 1 IFNs was regulated by PPARα. Our findings reveal FAO, OXPHOS and PPARα as potential targets to therapeutically modulate downstream effects of type 1 IFNs.
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•Type 1 IFNs promote FAO and oxidative phosphorylation (OXPHOS)•In CpG-stimulated pDCs, FAO is enhanced due to autocrine type 1 IFN signaling•Increased FAO induced in pDCs by CpG-stimulation is essential for cellular activation•Type 1 IFN-induced FAO is partly PPARα-dependent and has anti-viral properties
Type 1 IFN cytokines play complex and incompletely understood roles in immunity. Pearce and colleagues have shown that these cytokines upregulate fatty acid oxidation and that this metabolic change plays a critical role in plasmacytoid dendritic cell activation and in anti-viral effects induced by type 1 IFNs.
Competition for nutrients like glucose can metabolically restrict T cells and contribute to their hyporesponsiveness during cancer. Metabolic adaptation to the surrounding microenvironment is ...therefore key for maintaining appropriate cell function. For instance, cancer cells use acetate as a substrate alternative to glucose to fuel metabolism and growth. Here, we show that acetate rescues effector function in glucose-restricted CD8+ T cells. Mechanistically, acetate promotes histone acetylation and chromatin accessibility and enhances IFN-γ gene transcription and cytokine production in an acetyl-CoA synthetase (ACSS)-dependent manner. Ex vivo acetate treatment increases IFN-γ production by exhausted T cells, whereas reducing ACSS expression in T cells impairs IFN-γ production by tumor-infiltrating lymphocytes and tumor clearance. Thus, hyporesponsive T cells can be epigenetically remodeled and reactivated by acetate, suggesting that pathways regulating the use of substrates alternative to glucose could be therapeutically targeted to promote T cell function during cancer.
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•Acetate restores IFN-γ in TILs and T cells under prolonged glucose-restriction•Acetate promotes histone acetylation and chromatin accessibility in T cells•ACSS expression contributes to optimal effector T cell function during cancer
Qiu et al. show that acetate enhances histone acetylation, chromatin accessibility, and effector function in glucose-restricted CD8+ T cells. The authors find that manipulation of acetate-handling pathways influences cytokine production of tumor-infiltrating CD8+ T cells, which could have therapeutic implications for activating CD8+ T cell effector function in the tumor microenvironment.
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