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Immuno-Metabolism: Resisting Resistance to Immuno-Checkpoint Therapy

A special issue of International Journal of Molecular Sciences (ISSN 1422-0067). This special issue belongs to the section "Molecular Immunology".

Deadline for manuscript submissions: closed (31 December 2020) | Viewed by 43618

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GenVivo, 475 Huntington Dr, San Marino, CA 91108, USA
Interests: immunotherapy, myeloid targeting, cell and gene therapy
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Special Issue Information

The cross-talk of myeloid cells with T cells coordinates immune responses that regulate the balance between immune activation and tolerance. Recent progress has focused attention on metabolic regulation of coordinated innate and adaptive immune responses.

The induction of programmed death 1 (PD-1) in T cells, and its ligand, PD-L1, on myeloid cells can limit effector T cell responses and provide protection from immune-mediated tissue damage. This pathway is co-opted by tumors to promote host immune evasion.Selective deletion of PD-1 expression on myeloid bone marrow precursors and myeloid cells switches myelopoiesis to effector-like cells with enhanced antigen-presenting capacity. Ablation of PD-1 in myeloid cells causes them to engage in glycolysis-driven cholesterol metabolism(a pathway critical for progenitor differentiation), enhanced APC function and increased anti-tumor T cell immunity.

Despite important clinical benefits, immune checkpoint blockade is associated with immune-related adverse events (irAEs), that include pneumonitis and cardiovascular artery disease (CAD). IrAEs are discussed to arise from persistent immune activation and to nutrient excess.

Blockade of PD-1 in metabolically predisposed patients or patients with pre-existing inflammatory diseases might lead to excessive nutrient uptake and mitochondrial activity resulting in high levels of intracellular ROS (reactive oxygen species) and oxidized lipids. Lipid accumulation in monocytes and macrophages leads to foam cell formation, key drivers of pneumonitis and CAD. High levels of glucose/lactate or oxidized lipids activate the immunoinhibitory PD-1/PD-L1 pathway, leading to enhanced immunosuppressive activity of MDSC (myeloid-derived suppressor cells) and impaired T cell, DC and NK cell function, promoting the formation of tumor metastases.

Dear Colleagues,

Inhibitory immune checkpoints such as PD‐1/PD‐L1 normally maintain peripheral tolerance by disabling the activation and effector functions of autoreactive T‐cells and avoiding uncontrolled myeloid cell activation, have been found to be co‐opted in cancer. Monoclonal antibodies that neutralize these pathways have represented a significant step forward in incorporating immunotherapy into the fight against cancer.

Unfortunately, observations of acquired resistance and toxicity to immune checkpoint blockade occurring in a substantial proportion of patients enrolled in clinical trials have been reported. As immunotherapy is further incorporated into routine clinical practice, an increase in the number of reported cases of relapse and adverse side effects is to be expected. Therefore, experimental research to identify resistance and toxicity pathways to overcome are required.

Metabolic reprogramming of T and myeloid cells in patients with cancer and autoimmune diseases has been increasingly investigated. Of interest are the functional activities through which myeloid cells instruct T cells. Monocytes and macrophages serve as antigen-presenting cells and fine tune T cell responses. By expressing PD-1/PD-L1, they can also suppress T cell immunity, a functional aspect of importance in tumors with PD-1 or PD-L1hi tumor–associated monocytes and macrophages. Research over the last decade have shown that PD-1/PD-L1 blockade on T or myeloid cells increases glucose and lipid metabolism, metabolic networks critical for inducing efficient anti-tumor immune responses. Significantly, very recent reports show that overnutrition promotes persistent T and myeloid activation and impairs timely resolution of inflammation, resulting in immune-driven tissue damage.

Therefore, harnessing immune cell functions for immune checkpoint therapy and regenerative medicine applications requires an understanding of the metabolic networks that direct the maintenance, heterogeneity, and protective and pathological function of immune cells.

In this Special Issue, dedicated to Immuno-metabolism, we present a collection of works that provide insight into this diverse spectrum of metabolic reprogramming of myeloid and T cell activities within the host immune and tissue repair responses, and the contribution of chronic inflammation and metabolic syndrome to resistance and toxicity pathways to immuno-checkpoint therapy.

Dr. Laura Strauss
Guest Editor

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Keywords

  • lipid and glucose metabolism
  • oxidized lipids
  • metabolic reprogramming
  • monocytes/macrophages
  • MDSC
  • bone marrow progenitors
  • T cells
  • PD-1/PD-L1
  • tissue homeostasis
  • fibrosis
  • overnutrition
  • irAEs
  • chronic inflammation.

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Published Papers (7 papers)

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Research

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16 pages, 1512 KiB  
Article
Immunometabolic Modulatory Role of Naltrexone in BV-2 Microglia Cells
by Natalia Kučić, Valentino Rački, Roberta Šverko, Toni Vidović, Irena Grahovac and Jasenka Mršić-Pelčić
Int. J. Mol. Sci. 2021, 22(16), 8429; https://doi.org/10.3390/ijms22168429 - 5 Aug 2021
Cited by 24 | Viewed by 5183
Abstract
Background: Naltrexone is an opioid receptor antagonist commonly used to treat opioid and alcohol dependence. The use of low dose naltrexone (LDN) was found to have anti-inflammatory properties for treatment of diseases such as fibromyalgia, Crohn’s disease, multiple sclerosis and regional pain [...] Read more.
Background: Naltrexone is an opioid receptor antagonist commonly used to treat opioid and alcohol dependence. The use of low dose naltrexone (LDN) was found to have anti-inflammatory properties for treatment of diseases such as fibromyalgia, Crohn’s disease, multiple sclerosis and regional pain syndromes. Related to its anti-neuroinflammatory properties, the mechanism of action is possibly mediated via Toll-like receptor 4 antagonism, which is widely expressed on microglial cells. The aim of the present study was to assess the immunometabolic effects of naltrexone on microglia cells in in vitro conditions. Methods: All experiments were performed in the BV-2 microglial cell line. The cells were treated with naltrexone at 100 μM concentrations corresponding to low dose for 24 h. Cell viability was assessed for every drug dose. To induce additional activation, the cells were pretreated with LPS and IFN-γ. Immunofluorescence was used to analyse the classical microglial activation markers iNOS and CD206, while Seahorse was used for real-time cellular metabolic assessments. mTOR activity measured over the expression of a major direct downstream target S6K was assessed using western blot. Results: LDN induced a shift from highly activated pro-inflammatory phenotype (iNOShighCD206low) to quiescent anti-inflammatory M2 phenotype (iNOSlowCD206high) in BV-2 microglia cells. Changes in the inflammatory profile were accompanied by cellular metabolic switching based on the transition from high glycolysis to mitochondrial oxidative phosphorylation (OXPHOS). LDN-treated cells were able to maintain a metabolically suppressive phenotype by supporting OXPHOS with high oxygen consumption, and also maintain a lower energetic state due to lower lactate production. The metabolic shift induced by transition from glycolysis to mitochondrial oxidative metabolism was more prominent in cells pretreated with immunometabolic modulators such as LPS and IFN-γ. In a dose-dependent manner, naltrexone also modulated mTOR/S6K expression, which underlies the cell metabolic phenotype regulating microglia immune properties and adaptation. Conclusion: By modulating the phenotypic features by metabolic switching of activated microglia, naltrexone was found to be an effective and powerful tool for immunometabolic reprogramming and could be a promising novel treatment for various neuroinflammatory conditions. Full article
(This article belongs to the Special Issue Immuno-Metabolism: Resisting Resistance to Immuno-Checkpoint Therapy)
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Review

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15 pages, 1211 KiB  
Review
Impact of BMI on Survival Outcomes of Immunotherapy in Solid Tumors: A Systematic Review
by Alice Indini, Erika Rijavec, Michele Ghidini, Gianluca Tomasello, Monica Cattaneo, Francesca Barbin, Claudia Bareggi, Barbara Galassi, Donatella Gambini and Francesco Grossi
Int. J. Mol. Sci. 2021, 22(5), 2628; https://doi.org/10.3390/ijms22052628 - 5 Mar 2021
Cited by 26 | Viewed by 3061
Abstract
Growing research has focused on obesity as a prognostic factor during therapy with immune-checkpoint inhibitors (ICIs). The role of body-mass index (BMI) in predicting response and toxicity to ICIs is not clear, as studies have shown inconsistent results and significant interpretation biases. We [...] Read more.
Growing research has focused on obesity as a prognostic factor during therapy with immune-checkpoint inhibitors (ICIs). The role of body-mass index (BMI) in predicting response and toxicity to ICIs is not clear, as studies have shown inconsistent results and significant interpretation biases. We performed a systematic review to evaluate the relationship between BMI and survival outcomes during ICIs, with a side focus on the incidence of immune-related adverse events (irAEs). A total of 17 studies were included in this systematic review. Altogether, the current evidence does not support a clearly positive association of BMI with survival outcomes. Regarding toxicities, available studies confirm a superimposable rate of irAEs among obese and normal weight patients. Intrinsic limitations of the analyzed studies include the retrospective nature, the heterogeneity of patients’ cohorts, and differences in BMI categorization for obese patients across different studies. These factors might explain the heterogeneity of available results, and the subsequent absence of a well-established role of baseline BMI on the efficacy of ICIs among cancer patients. Further prospective studies are needed, in order to clarify the role of obesity in cancer patients treated with immunotherapy. Full article
(This article belongs to the Special Issue Immuno-Metabolism: Resisting Resistance to Immuno-Checkpoint Therapy)
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27 pages, 2565 KiB  
Review
Metabolic Factors Affecting Tumor Immunogenicity: What Is Happening at the Cellular Level?
by Rola El Sayed, Yolla Haibe, Ghid Amhaz, Youssef Bouferraa and Ali Shamseddine
Int. J. Mol. Sci. 2021, 22(4), 2142; https://doi.org/10.3390/ijms22042142 - 21 Feb 2021
Cited by 11 | Viewed by 6195
Abstract
Immunotherapy has changed the treatment paradigm in multiple solid and hematologic malignancies. However, response remains limited in a significant number of cases, with tumors developing innate or acquired resistance to checkpoint inhibition. Certain “hot” or “immune-sensitive” tumors become “cold” or “immune-resistant”, with resultant [...] Read more.
Immunotherapy has changed the treatment paradigm in multiple solid and hematologic malignancies. However, response remains limited in a significant number of cases, with tumors developing innate or acquired resistance to checkpoint inhibition. Certain “hot” or “immune-sensitive” tumors become “cold” or “immune-resistant”, with resultant tumor growth and disease progression. Multiple factors are at play both at the cellular and host levels. The tumor microenvironment (TME) contributes the most to immune-resistance, with nutrient deficiency, hypoxia, acidity and different secreted inflammatory markers, all contributing to modulation of immune-metabolism and reprogramming of immune cells towards pro- or anti-inflammatory phenotypes. Both the tumor and surrounding immune cells require high amounts of glucose, amino acids and fatty acids to fulfill their energy demands. Thus, both compete over one pool of nutrients that falls short on needs, obliging cells to resort to alternative adaptive metabolic mechanisms that take part in shaping their inflammatory phenotypes. Aerobic or anaerobic glycolysis, oxidative phosphorylation, tryptophan catabolism, glutaminolysis, fatty acid synthesis or fatty acid oxidation, etc. are all mechanisms that contribute to immune modulation. Different pathways are triggered leading to genetic and epigenetic modulation with consequent reprogramming of immune cells such as T-cells (effector, memory or regulatory), tumor-associated macrophages (TAMs) (M1 or M2), natural killers (NK) cells (active or senescent), and dendritic cells (DC) (effector or tolerogenic), etc. Even host factors such as inflammatory conditions, obesity, caloric deficit, gender, infections, microbiota and smoking status, may be as well contributory to immune modulation, anti-tumor immunity and response to immune checkpoint inhibition. Given the complex and delicate metabolic networks within the tumor microenvironment controlling immune response, targeting key metabolic modulators may represent a valid therapeutic option to be combined with checkpoint inhibitors in an attempt to regain immune function. Full article
(This article belongs to the Special Issue Immuno-Metabolism: Resisting Resistance to Immuno-Checkpoint Therapy)
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25 pages, 1986 KiB  
Review
Immuno-Metabolism: The Role of Cancer Niche in Immune Checkpoint Inhibitor Resistance
by Chao-Yuan Weng, Cheng-Xiang Kao, Te-Sheng Chang and Yen-Hua Huang
Int. J. Mol. Sci. 2021, 22(3), 1258; https://doi.org/10.3390/ijms22031258 - 27 Jan 2021
Cited by 19 | Viewed by 4470
Abstract
The use of immune checkpoint inhibitors (ICI) in treating cancer has revolutionized the approach to eradicate cancer cells by reactivating immune responses. However, only a subset of patients benefits from this treatment; the majority remains unresponsive or develops resistance to ICI therapy. Increasing [...] Read more.
The use of immune checkpoint inhibitors (ICI) in treating cancer has revolutionized the approach to eradicate cancer cells by reactivating immune responses. However, only a subset of patients benefits from this treatment; the majority remains unresponsive or develops resistance to ICI therapy. Increasing evidence suggests that metabolic machinery in the tumor microenvironment (TME) plays a role in the development of ICI resistance. Within the TME, nutrients and oxygen are scarce, forcing immune cells to undergo metabolic reprogramming to adapt to harsh conditions. Cancer-induced metabolic deregulation in immune cells can attenuate their anti-cancer properties, but can also increase their immunosuppressive properties. Therefore, targeting metabolic pathways of immune cells in the TME may strengthen the efficacy of ICIs and prevent ICI resistance. In this review, we discuss the interactions of immune cells and metabolic alterations in the TME. We also discuss current therapies targeting cellular metabolism in combination with ICIs for the treatment of cancer, and provide possible mechanisms behind the cellular metabolic rewiring that may improve clinical outcomes. Full article
(This article belongs to the Special Issue Immuno-Metabolism: Resisting Resistance to Immuno-Checkpoint Therapy)
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32 pages, 806 KiB  
Review
Resisting Resistance to Immune Checkpoint Therapy: A Systematic Review
by Yolla Haibe, Ziad El Husseini, Rola El Sayed and Ali Shamseddine
Int. J. Mol. Sci. 2020, 21(17), 6176; https://doi.org/10.3390/ijms21176176 - 27 Aug 2020
Cited by 28 | Viewed by 6087
Abstract
The treatment landscape in oncology has witnessed a major revolution with the introduction of checkpoint inhibitors: anti-PD1, anti-PDL1 and anti-CTLA-4. These agents enhance the immune response towards cancer cells instead of targeting the tumor itself, contrary to standard chemotherapy. Although long-lasting durable responses [...] Read more.
The treatment landscape in oncology has witnessed a major revolution with the introduction of checkpoint inhibitors: anti-PD1, anti-PDL1 and anti-CTLA-4. These agents enhance the immune response towards cancer cells instead of targeting the tumor itself, contrary to standard chemotherapy. Although long-lasting durable responses have been observed with immune checkpoints inhibitors, the response rate remains relatively low in many cases. Some patients respond in the beginning but then eventually develop acquired resistance to treatment and progress. Other patients having primary resistance never respond. Multiple studies have been conducted to further elucidate these variations in response in different tumor types and different individuals. This paper provides an overview of the mechanisms of resistance to immune checkpoint inhibitors and highlights the possible therapeutic approaches under investigation aiming to overcome such resistance in order to improve the clinical outcomes of cancer patients. Full article
(This article belongs to the Special Issue Immuno-Metabolism: Resisting Resistance to Immuno-Checkpoint Therapy)
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31 pages, 1317 KiB  
Review
Lipid Metabolism and Cancer Immunotherapy: Immunosuppressive Myeloid Cells at the Crossroad
by Augusto Bleve, Barbara Durante, Antonio Sica and Francesca Maria Consonni
Int. J. Mol. Sci. 2020, 21(16), 5845; https://doi.org/10.3390/ijms21165845 - 14 Aug 2020
Cited by 62 | Viewed by 7436
Abstract
Cancer progression generates a chronic inflammatory state that dramatically influences hematopoiesis, originating different subsets of immune cells that can exert pro- or anti-tumor roles. Commitment towards one of these opposing phenotypes is driven by inflammatory and metabolic stimuli derived from the tumor-microenvironment (TME). [...] Read more.
Cancer progression generates a chronic inflammatory state that dramatically influences hematopoiesis, originating different subsets of immune cells that can exert pro- or anti-tumor roles. Commitment towards one of these opposing phenotypes is driven by inflammatory and metabolic stimuli derived from the tumor-microenvironment (TME). Current immunotherapy protocols are based on the reprogramming of both specific and innate immune responses, in order to boost the intrinsic anti-tumoral activity of both compartments. Growing pre-clinical and clinical evidence highlights the key role of metabolism as a major influence on both immune and clinical responses of cancer patients. Indeed, nutrient competition (i.e., amino acids, glucose, fatty acids) between proliferating cancer cells and immune cells, together with inflammatory mediators, drastically affect the functionality of innate and adaptive immune cells, as well as their functional cross-talk. This review discusses new advances on the complex interplay between cancer-related inflammation, myeloid cell differentiation and lipid metabolism, highlighting the therapeutic potential of metabolic interventions as modulators of anticancer immune responses and catalysts of anticancer immunotherapy. Full article
(This article belongs to the Special Issue Immuno-Metabolism: Resisting Resistance to Immuno-Checkpoint Therapy)
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22 pages, 1918 KiB  
Review
Immuno-Metabolism and Microenvironment in Cancer: Key Players for Immunotherapy
by Gaia Giannone, Eleonora Ghisoni, Sofia Genta, Giulia Scotto, Valentina Tuninetti, Margherita Turinetto and Giorgio Valabrega
Int. J. Mol. Sci. 2020, 21(12), 4414; https://doi.org/10.3390/ijms21124414 - 21 Jun 2020
Cited by 108 | Viewed by 9882
Abstract
Immune checkpoint inhibitors (ICIs) have changed therapeutic algorithms in several malignancies, although intrinsic and secondary resistance is still an issue. In this context, the dysregulation of immuno-metabolism plays a leading role both in the tumor microenvironment (TME) and at the host level. In [...] Read more.
Immune checkpoint inhibitors (ICIs) have changed therapeutic algorithms in several malignancies, although intrinsic and secondary resistance is still an issue. In this context, the dysregulation of immuno-metabolism plays a leading role both in the tumor microenvironment (TME) and at the host level. In this review, we summarize the most important immune-metabolic factors and how they could be exploited therapeutically. At the cellular level, an increased concentration of extracellular adenosine as well as the depletion of tryptophan and uncontrolled activation of the PI3K/AKT pathway induces an immune-tolerant TME, reducing the response to ICIs. Moreover, aberrant angiogenesis induces a hypoxic environment by recruiting VEGF, Treg cells and immune-suppressive tumor associated macrophages (TAMs). On the other hand, factors such as gender and body mass index seem to affect the response to ICIs, while the microbiome composition (and its alterations) modulates both the response and the development of immune-related adverse events. Exploiting these complex mechanisms is the next goal in immunotherapy. The most successful strategy to date has been the combination of antiangiogenic drugs and ICIs, which prolonged the survival of patients with non-small-cell lung cancer (NSCLC) and hepatocellular carcinoma (HCC), while results from tryptophan pathway inhibition studies are inconclusive. New exciting strategies include targeting the adenosine pathway, TAMs and the microbiota with fecal microbiome transplantation. Full article
(This article belongs to the Special Issue Immuno-Metabolism: Resisting Resistance to Immuno-Checkpoint Therapy)
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