Protein handling, modification and folding in the endoplasmic reticulum (ER) are tightly regulated processes that determine cell function, fate and survival. In several tumour types, diverse ...oncogenic, transcriptional and metabolic abnormalities cooperate to generate hostile microenvironments that disrupt ER homeostasis in malignant and stromal cells, as well as infiltrating leukocytes. These changes provoke a state of persistent ER stress that has been demonstrated to govern multiple pro-tumoural attributes in the cancer cell while dynamically reprogramming the function of innate and adaptive immune cells. Aberrant activation of ER stress sensors and their downstream signalling pathways have therefore emerged as key regulators of tumour growth and metastasis as well as response to chemotherapy, targeted therapies and immunotherapy. In this Review, we discuss the physiological inducers of ER stress in the tumour milieu, the interplay between oncogenic signalling and ER stress response pathways in the cancer cell and the profound immunomodulatory effects of sustained ER stress responses in tumours.
Malignant cells utilize diverse strategies that enable them to thrive under adverse conditions while simultaneously inhibiting the development of anti-tumor immune responses. Hostile ...microenvironmental conditions within tumor masses, such as nutrient deprivation, oxygen limitation, high metabolic demand, and oxidative stress, disturb the protein-folding capacity of the endoplasmic reticulum (ER), thereby provoking a cellular state of “ER stress.” Sustained activation of ER stress sensors endows malignant cells with greater tumorigenic, metastatic, and drug-resistant capacity. Additionally, recent studies have uncovered that ER stress responses further impede the development of protective anti-cancer immunity by manipulating the function of myeloid cells in the tumor microenvironment. Here, we discuss the tumorigenic and immunoregulatory effects of ER stress in cancer, and we explore the concept of targeting ER stress responses to enhance the efficacy of standard chemotherapies and evolving cancer immunotherapies in the clinic.
The activation of ER stress pathways endows cancer cells with metastatic and drug-resistance capacities through a number of distinct mechanisms. Targeting these pathways offers potential opportunities to enhance the efficacy of chemotherapy and immunotherapies in the clinic.
Dendritic Cell Metabolism and Function in Tumors Giovanelli, Paolo; Sandoval, Tito A.; Cubillos-Ruiz, Juan R.
Trends in immunology,
August 2019, 2019-08-00, 20190801, Letnik:
40, Številka:
8
Journal Article
Recenzirano
Odprti dostop
Dendritic cells (DCs) are fundamental for the initiation and maintenance of immune responses against malignant cells. Despite the unique potential of DCs to elicit robust anticancer immunity, the ...tumor microenvironment poses a variety of challenges that hinder competent DC function and consequently inhibit the development of protective immune responses. Here, we discuss recent studies uncovering new molecular pathways and metabolic programs that tumors manipulate in DCs to disturb their homeostasis and evade immune control. We also examine certain state-of-the-art strategies that seek to improve DC function and elicit antitumor responses in hosts with cancer. Understanding and modulating DC metabolism and activity within tumors might help improve the efficacy of T cell-centric immunotherapies.
Tumors can disrupt normal DC functions to evade immune control.Adverse conditions and factors in the tumor milieu modulate specific transcriptional programs and metabolic processes in infiltrating DCs to inhibit their immunogenic activity.Cancer-associated DCs with altered mitochondrial and lipid metabolism demonstrate reduced capacity to elicit T cell-based responses against tumors.Targeting metabolic pathways in intratumoral DCs might be used to elicit durable anticancer immunity and enhance the efficacy of T cell-based immunotherapies.
Protective anti-tumor immune responses are mediated by effector molecules that enable successful elimination of malignant cells. As the site where transmembrane and secreted proteins are generated, ...the endoplasmic reticulum (ER) of immune cells plays a key role in this process. Recent studies have indicated that adverse conditions within tumors perturb ER homeostasis in infiltrating immune cells, which can impede the development of effective anti-cancer immunity. Here, we describe how the tumor microenvironment induces ER stress in immune cells, and discuss the detrimental consequences of persistent ER stress responses in intratumoral immune populations. We also explore the concept of targeting ER stress responses to reinvigorate endogenous anti-tumor immunity and enhance the efficacy of various forms of cancer immunotherapy.
The tumor microenvironment can disturb the protein-folding capacity of the ER in infiltrating immune cells, thereby causing persistent ER stress.
Severe ER stress responses in intratumoral leukocytes can cripple anticancer immunity in murine models of disease.
Soluble factors from patient-derived cancer specimens can inhibit metabolic pathways and alter human T cell effector functions by inducing ER stress responses.
Disabling ER stress sensors or controlling the UPR can enhance anti-tumor immune responses in certain preclinical models of cancer.
Targeting ER stress-related components in immune cells may be useful for improving the efficacy of cancer immunotherapies, although further studies are warranted.
Dendritic cells (DCs) are required to initiate and sustain T cell-dependent anti-cancer immunity. However, tumors often evade immune control by crippling normal DC function. The endoplasmic reticulum ...(ER) stress response factor XBP1 promotes intrinsic tumor growth directly, but whether it also regulates the host anti-tumor immune response is not known. Here we show that constitutive activation of XBP1 in tumor-associated DCs (tDCs) drives ovarian cancer (OvCa) progression by blunting anti-tumor immunity. XBP1 activation, fueled by lipid peroxidation byproducts, induced a triglyceride biosynthetic program in tDCs leading to abnormal lipid accumulation and subsequent inhibition of tDC capacity to support anti-tumor T cells. Accordingly, DC-specific XBP1 deletion or selective nanoparticle-mediated XBP1 silencing in tDCs restored their immunostimulatory activity in situ and extended survival by evoking protective type 1 anti-tumor responses. Targeting the ER stress response should concomitantly inhibit tumor growth and enhance anti-cancer immunity, thus offering a unique approach to cancer immunotherapy.
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•DCs in the tumor microenvironment exhibit ER stress and robust IRE1α/XBP1 activation•DC-intrinsic XBP1 drives primary and metastatic ovarian cancer progression•XBP1 regulates lipid metabolism and antigen presentation by tDCs•Silencing XBP1 in tDC extends host survival by enhancing T cell anti-tumor immunity
Aggressive tumors inhibit protective T cell responses by triggering ER stress-driven lipid metabolism in dendritic cells, thereby impairing antigen presentation and limiting the ability of the immune system to eliminate malignant cells. Relieving ER stress in immune cells may offer a new approach to cancer immunotherapy.
A recent study published in Nature by Canale et al. (2021) shows that engineered probiotic bacteria can be used to augment the availability of nutrients required for optimal immune cell function in ...tumors. This approach enhances anti-tumor immunity and improves the efficacy of immunotherapy in mouse models of cancer.
A recent study published in Nature by Canale et al. (2021) shows that engineered probiotic bacteria can be used to augment the availability of nutrients required for optimal immune cell function in tumors. This approach enhances anti-tumor immunity and improves the efficacy of immunotherapy in mouse models of cancer.
Dendritic cells (DCs) are critical for bridging innate and adaptive immunity. They do so by presenting antigens to T cells, and by expressing diverse molecules that further promote T cell activation, ...differentiation and memory formation. During this process, intracellular and extracellular factors can perturb the protein-folding capacity of endoplasmic reticulum (ER) and induce a cellular state of "ER stress," which is controlled and resolved by the unfolded protein response (UPR). Interestingly, various studies have shown that DCs can activate UPR-related pathways even in the absence of global ER stress, and that this process can modulate their normal activity. In other settings, such as cancer, adverse microenvironmental conditions have been demonstrated to evoke severe ER stress and persistent activation of the UPR in tumor-infiltrating DCs. This process disrupts their metabolism and local antigen-presenting capacity, hence impeding the initiation and maintenance of anti-cancer immunity. Here, we review recent findings on how canonical and non-canonical UPR activation impacts DC immunobiology at the steady-state, upon activation via pattern recognition receptors, and under diverse pathological conditions. We also discuss the potential therapeutic implications that targeting the UPR in DCs may have in the context of cancer and in other pathologies such as graft-versus-host disease.
Tumours evade immune control by creating hostile microenvironments that perturb T cell metabolism and effector function
. However, it remains unclear how intra-tumoral T cells integrate and interpret ...metabolic stress signals. Here we report that ovarian cancer-an aggressive malignancy that is refractory to standard treatments and current immunotherapies
-induces endoplasmic reticulum stress and activates the IRE1α-XBP1 arm of the unfolded protein response
in T cells to control their mitochondrial respiration and anti-tumour function. In T cells isolated from specimens collected from patients with ovarian cancer, upregulation of XBP1 was associated with decreased infiltration of T cells into tumours and with reduced IFNG mRNA expression. Malignant ascites fluid obtained from patients with ovarian cancer inhibited glucose uptake and caused N-linked protein glycosylation defects in T cells, which triggered IRE1α-XBP1 activation that suppressed mitochondrial activity and IFNγ production. Mechanistically, induction of XBP1 regulated the abundance of glutamine carriers and thus limited the influx of glutamine that is necessary to sustain mitochondrial respiration in T cells under glucose-deprived conditions. Restoring N-linked protein glycosylation, abrogating IRE1α-XBP1 activation or enforcing expression of glutamine transporters enhanced mitochondrial respiration in human T cells exposed to ovarian cancer ascites. XBP1-deficient T cells in the metastatic ovarian cancer milieu exhibited global transcriptional reprogramming and improved effector capacity. Accordingly, mice that bear ovarian cancer and lack XBP1 selectively in T cells demonstrate superior anti-tumour immunity, delayed malignant progression and increased overall survival. Controlling endoplasmic reticulum stress or targeting IRE1α-XBP1 signalling may help to restore the metabolic fitness and anti-tumour capacity of T cells in cancer hosts.
We characterized the initiation and evolution of the immune response against a new inducible p53-dependent model of aggressive ovarian carcinoma that recapitulates the leukocyte infiltrates and ...cytokine milieu of advanced human tumors. Unlike other models that initiate tumors before the development of a mature immune system, we detect measurable anti-tumor immunity from very early stages, which is driven by infiltrating dendritic cells (DCs) and prevents steady tumor growth for prolonged periods. Coinciding with a phenotypic switch in expanding DC infiltrates, tumors aggressively progress to terminal disease in a comparatively short time. Notably, tumor cells remain immunogenic at advanced stages, but anti-tumor T cells become less responsive, whereas their enduring activity is abrogated by different microenvironmental immunosuppressive DCs. Correspondingly, depleting DCs early in the disease course accelerates tumor expansion, but DC depletion at advanced stages significantly delays aggressive malignant progression. Our results indicate that phenotypically divergent DCs drive both immunosurveillance and accelerated malignant growth. We provide experimental support for the cancer immunoediting hypothesis, but we also show that aggressive cancer progression after a comparatively long latency period is primarily driven by the mobilization of immunosuppressive microenvironmental leukocytes, rather than loss of tumor immunogenicity.
Activation of unfolded protein responses (UPRs) in cancer cells undergoing endoplasmic reticulum (ER) stress promotes survival. However, how UPR in tumor cells impacts anti-tumor immune responses ...remains poorly described. Here, we investigate the role of the UPR mediator pancreatic ER kinase (PKR)-like ER kinase (PERK) in cancer cells in the modulation of anti-tumor immunity. Deletion of PERK in cancer cells or pharmacological inhibition of PERK in melanoma-bearing mice incites robust activation of anti-tumor T cell immunity and attenuates tumor growth. PERK elimination in ER-stressed malignant cells triggers SEC61β-induced paraptosis, thereby promoting immunogenic cell death (ICD) and systemic anti-tumor responses. ICD induction in PERK-ablated tumors stimulates type I interferon production in dendritic cells (DCs), which primes CCR2-dependent tumor trafficking of common-monocytic precursors and their intra-tumor commitment into monocytic-lineage inflammatory Ly6C+CD103+ DCs. These findings identify how tumor cell-derived PERK promotes immune evasion and highlight the potential of PERK-targeting therapies in cancer immunotherapy.
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•Kinase PERK in melanoma cells restricts protective tumor-specific T cell immunity•PERK targeting drives immunogenic melanoma cell death via SEC61β-linked paraptosis•PERK-null tumors promote the expansion of immune competent monocyte-derived DCs•Stroma-originated type I IFN reprograms myelopoiesis in PERK-null tumors via STAT1
How adaptation to endoplasmic reticulum (ER) stress in cancer cells modulates anti-tumor immunity remains elusive. Mandula et al. demonstrate that elimination of the ER stress-related kinase, PERK, in melanoma cells activates protective T cell responses through paraptosis-mediated immunogenic cell death, which primes expansion of monocytic-lineage inflammatory DCs via type-I IFN-STAT1.
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