scholarly journals Siglec Signaling in the Tumor Microenvironment

2021 ◽  
Vol 12 ◽  
Author(s):  
Eline J. H. van Houtum ◽  
Christian Büll ◽  
Lenneke A. M. Cornelissen ◽  
Gosse J. Adema
Keyword(s):  
Sialic Acid ◽  
Tumor Microenvironment ◽  
Immune Cells ◽  
Current Knowledge ◽  
Surface Distribution ◽  
Tumor Immune Evasion ◽  
Binding Preference ◽  
Ligand Expression ◽  
And Function ◽  
Tumor Types

Sialic acid-binding immunoglobulin-like lectins (Siglecs) are a family of receptors that recognize sialoglycans – sialic acid containing glycans that are abundantly present on cell membranes. Siglecs are expressed on most immune cells and can modulate their activity and function. The majority of Siglecs contains immune inhibitory motifs comparable to the immune checkpoint receptor PD-1. In the tumor microenvironment (TME), signaling through the Siglec-sialoglycan axis appears to be enhanced through multiple mechanisms favoring tumor immune evasion similar to the PD-1/PD-L1 signaling pathway. Siglec expression on tumor-infiltrating immune cells appears increased in the immune suppressive microenvironment. At the same time, enhanced Siglec ligand expression has been reported for several tumor types as a result of aberrant glycosylation, glycan modifications, and the increased expression of sialoglycans on proteins and lipids. Siglec signaling has been identified as important regulator of anti-tumor immunity in the TME, but the key factors contributing to Siglec activation by tumor-associated sialoglycans are diverse and poorly defined. Among others, Siglec activation and signaling are co-determined by their expression levels, cell surface distribution, and their binding preferences for cis- and trans-ligands in the TME. Siglec binding preference are co-determined by the nature of the proteins/lipids to which the sialoglycans are attached and the multivalency of the interaction. Here, we review the current understanding and emerging conditions and factors involved in Siglec signaling in the TME and identify current knowledge gaps that exist in the field.

scholarly journals Mesenchymal Stem Cell: A Friend or Foe in Anti-Tumor Immunity

2021 ◽  
Vol 22 (22) ◽  
pp. 12429
Author(s):  
Carl Randall Harrell ◽  
Ana Volarevic ◽  
Valentin G. Djonov ◽  
Nemanja Jovicic ◽  
Vladislav Volarevic
Keyword(s):  
Stem Cells ◽  
Tumor Microenvironment ◽  
Tumor Cells ◽  
Tumor Immunity ◽  
Immune Cells ◽  
Therapeutic Potential ◽  
Current Knowledge ◽  
Cellular Mechanisms ◽  
Multipotent Stem Cells ◽  
And Function

Mesenchymal stem cells (MSCs) are self-renewable, multipotent stem cells that regulate the phenotype and function of all immune cells that participate in anti-tumor immunity. MSCs modulate the antigen-presenting properties of dendritic cells, affect chemokine and cytokine production in macrophages and CD4+ T helper cells, alter the cytotoxicity of CD8+ T lymphocytes and natural killer cells and regulate the generation and expansion of myeloid-derived suppressor cells and T regulatory cells. As plastic cells, MSCs adopt their phenotype and function according to the cytokine profile of neighboring tumor-infiltrated immune cells. Depending on the tumor microenvironment to which they are exposed, MSCs may obtain pro- and anti-tumorigenic phenotypes and may enhance or suppress tumor growth. Due to their tumor-homing properties, MSCs and their exosomes may be used as vehicles for delivering anti-tumorigenic agents in tumor cells, attenuating their viability and invasive characteristics. Since many factors affect the phenotype and function of MSCs in the tumor microenvironment, a better understanding of signaling pathways that regulate the cross-talk between MSCs, immune cells and tumor cells will pave the way for the clinical use of MSCs in cancer immunotherapy. In this review article, we summarize current knowledge on the molecular and cellular mechanisms that are responsible for the MSC-dependent modulation of the anti-tumor immune response and we discuss different insights regarding therapeutic potential of MSCs in the therapy of malignant diseases.

scholarly journals The Cross-Talk between Mesenchymal Stem Cells and Immune Cells in Tissue Repair and Regeneration

2021 ◽  
Vol 22 (5) ◽  
pp. 2472
Author(s):  
Carl Randall Harrell ◽  
Valentin Djonov ◽  
Vladislav Volarevic
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Immune Cells ◽  
Tissue Repair ◽  
Molecular Mechanisms ◽  
Current Knowledge ◽  
Multipotent Stem Cells ◽  
Tissue Repair And Regeneration ◽  
Almost All ◽  
And Function

Mesenchymal stem cells (MSCs) are self-renewable, rapidly proliferating, multipotent stem cells which reside in almost all post-natal tissues. MSCs possess potent immunoregulatory properties and, in juxtacrine and paracrine manner, modulate phenotype and function of all immune cells that participate in tissue repair and regeneration. Additionally, MSCs produce various pro-angiogenic factors and promote neo-vascularization in healing tissues, contributing to their enhanced repair and regeneration. In this review article, we summarized current knowledge about molecular mechanisms that regulate the crosstalk between MSCs and immune cells in tissue repair and regeneration.

scholarly journals When Cells Suffocate: Autophagy in Cancer and Immune Cells under Low Oxygen

2011 ◽  
Vol 2011 ◽  
pp. 1-13 ◽  
Author(s):  
Katrin Schlie ◽  
Jaeline E. Spowart ◽  
Luke R. K. Hughson ◽  
Katelin N. Townsend ◽  
Julian J. Lum
Keyword(s):  
Tumor Microenvironment ◽  
Cancer Cells ◽  
Immune Cells ◽  
Immune Cell ◽  
Treatment Strategies ◽  
Patient Treatment ◽  
Low Oxygen ◽  
Tumor Environment ◽  
And Function ◽  
The Impact

Hypoxia is a signature feature of growing tumors. This cellular state creates an inhospitable condition that impedes the growth and function of all cells within the immediate and surrounding tumor microenvironment. To adapt to hypoxia, cells activate autophagy and undergo a metabolic shift increasing the cellular dependency on anaerobic metabolism. Autophagy upregulation in cancer cells liberates nutrients, decreases the buildup of reactive oxygen species, and aids in the clearance of misfolded proteins. Together, these features impart a survival advantage for cancer cells in the tumor microenvironment. This observation has led to intense research efforts focused on developing autophagy-modulating drugs for cancer patient treatment. However, other cells that infiltrate the tumor environment such as immune cells also encounter hypoxia likely resulting in hypoxia-induced autophagy. In light of the fact that autophagy is crucial for immune cell proliferation as well as their effector functions such as antigen presentation and T cell-mediated killing of tumor cells, anticancer treatment strategies based on autophagy modulation will need to consider the impact of autophagy on the immune system.

Dietary and Physiological Effects of Zinc on the Immune System

2021 ◽  
Vol 41 (1) ◽  
Author(s):  
Inga Wessels ◽  
Henrike Josephine Fischer ◽  
Lothar Rink
Keyword(s):  
Immune Responses ◽  
Immune Cells ◽  
Immune Cell ◽  
Current Knowledge ◽  
Annual Review ◽  
Publication Date ◽  
Biological Processes ◽  
And Function ◽  
Broad Overview

Evidence for the importance of zinc for all immune cells and for mounting an efficient and balanced immune response to various environmental stressors has been accumulating in recent years. This article describes the role of zinc in fundamental biological processes and summarizes our current knowledge of zinc's effect on hematopoiesis, including differentiation into immune cell subtypes. In addition, the important role of zinc during activation and function of immune cells is detailed and associated with the specific immune responses to bacteria, parasites, and viruses. The association of zinc with autoimmune reactions and cancers as diseases with increased or decreased immune responses is also discussed. This article provides a broad overview of the manifold roles that zinc, or its deficiency, plays in physiology and during various diseases. Consequently, we discuss why zinc supplementation should be considered, especially for people at risk of deficiency. Expected final online publication date for the Annual Review of Nutrition, Volume 41 is September 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

scholarly journals Immunometabolism in the Tumor Microenvironment

2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Dominic G. Roy ◽  
Irem Kaymak ◽  
Kelsey S. Williams ◽  
Eric H. Ma ◽  
Russell G. Jones
Keyword(s):  
Tumor Microenvironment ◽  
Immune Cells ◽  
Cancer Biology ◽  
Antitumor Immunity ◽  
Immune Cell ◽  
Metabolic Reprogramming ◽  
Proper Function ◽  
Annual Review ◽  
Publication Date ◽  
And Function

Advances in immunotherapy have underscored the importance of antitumor immune responses in controlling cancer. However, the tumor microenvironment (TME) imposes several obstacles to the proper function of immune cells, including a metabolically challenging and immunosuppressive microenvironment. The increased metabolic activity of tumor cells can lead to the depletion of key nutrients required by immune cells and the accumulation of byproducts that hamper antitumor immunity. Furthermore, the presence of suppressive immune cells, such as regulatory T cells and myeloid-derived suppressor cells, and the expression of immune inhibitory receptors can negatively impact immune cell metabolism and function. This review summarizes the metabolic reprogramming that is characteristic of various immune cell subsets, discusses how the metabolism and function of immune cells is shaped by the TME, and highlights how therapeutic interventions aimed at improving the metabolic fitness of immune cells and alleviating the metabolic constraints in the TME can boost antitumor immunity. Expected final online publication date for the Annual Review of Cancer Biology, Volume 5 is March 4, 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

scholarly journals PTEN Function at the Interface between Cancer and Tumor Microenvironment: Implications for Response to Immunotherapy

2020 ◽  
Vol 21 (15) ◽  
pp. 5337 ◽  
Author(s):  
Fabiana Conciatori ◽  
Chiara Bazzichetto ◽  
Italia Falcone ◽  
Ludovica Ciuffreda ◽  
Gianluigi Ferretti ◽  
...  
Keyword(s):  
Tumor Microenvironment ◽  
Current Knowledge ◽  
Predictive Biomarkers ◽  
Point Of View ◽  
Solid Cancer ◽  
Host Immune System ◽  
Phosphatase And Tensin Homolog ◽  
Tensin Homolog ◽  
And Function ◽  
Promising Development

Mounting preclinical and clinical evidence indicates that rewiring the host immune system in favor of an antitumor microenvironment achieves remarkable clinical efficacy in the treatment of many hematological and solid cancer patients. Nevertheless, despite the promising development of many new and interesting therapeutic strategies, many of these still fail from a clinical point of view, probably due to the lack of prognostic and predictive biomarkers. In that respect, several data shed new light on the role of the tumor suppressor phosphatase and tensin homolog on chromosome 10 (PTEN) in affecting the composition and function of the tumor microenvironment (TME) as well as resistance/sensitivity to immunotherapy. In this review, we summarize current knowledge on PTEN functions in different TME compartments (immune and stromal cells) and how they can modulate sensitivity/resistance to different immunological manipulations and ultimately influence clinical response to cancer immunotherapy.

scholarly journals Macrophages and Extracellular Matrix in Breast Cancer: Partners in Crime or Protective Allies?

2021 ◽  
Vol 11 ◽  
Author(s):  
Claire Deligne ◽  
Kim S. Midwood
Keyword(s):  
Breast Cancer ◽  
Immune Response ◽  
Extracellular Matrix ◽  
Tumor Growth ◽  
Immune Cells ◽  
Current Knowledge ◽  
Immune Surveillance ◽  
Tumor Stroma ◽  
The Matrix ◽  
And Function

Solid cancers such as breast tumors comprise a collection of tumor, stromal and immune cells, embedded within a network of tumor-specific extracellular matrix. This matrix is associated with tumor aggression, treatment failure, chemo- and radio-resistance, poor survival and metastasis. Recent data report an immunomodulatory role for the matrix in cancer, via the creation of niches that control the migration, localization, phenotype and function of tumor-infiltrating immune cells, ultimately contributing to escape of immune surveillance. Macrophages are crucial components of the immune infiltrate in tumors; they are associated with a poor prognosis in breast cancer and contribute to shaping the anti-tumor immune response. We and others have described how matrix molecules commonly upregulated within the tumor stroma, such as tenascin-C, fibronectin and collagen, exert a complex influence over macrophage behavior, for example restricting or enhancing their infiltration into the tumor, and driving their polarization towards or away from a pro-tumoral phenotype, and how in turn macrophages can modify matrix production in the tumor to favor tumor growth and metastasis. Targeting specific domains of matrix molecules to reinstate an efficient anti-tumor immune response, and effectively control tumor growth and spread, is emerging as a promising field offering a new angle for cancer therapy. Here, we review current knowledge on the interactions between tumor-associated macrophages and matrix molecules that occur within the tumor microenvironment of breast cancer, and discuss how these pathways can be targeted for new immunotherapies for hard to treat, desmoplastic tumors.

scholarly journals Metabolic Cancer-Macrophage Crosstalk in the Tumor Microenvironment

Biology ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 380
Author(s):  
Kyra E. de de Goede ◽  
Amber J. M. Driessen ◽  
Jan Van den Bossche
Keyword(s):  
Tumor Microenvironment ◽  
Tumor Progression ◽  
Cancer Cell ◽  
Immune Cells ◽  
Cell Metabolism ◽  
Cancer Therapies ◽  
Macrophage Phenotype ◽  
Cancer Cell Growth ◽  
Metabolic Conditions ◽  
And Function

Tumors consist of a wide variety of cells, including immune cells, that affect tumor progression. Macrophages are abundant innate immune cells in the tumor microenvironment (TME) and are crucial in regulating tumorigenicity. Specific metabolic conditions in the TME can alter the phenotype of tumor-associated macrophages (TAMs) in a direction that supports their pro-tumor functions. One of these conditions is the accumulation of metabolites, also known as oncometabolites. Interactions of oncometabolites with TAMs can promote a pro-tumorigenic phenotype, thereby sustaining cancer cell growth and decreasing the chance of eradication. This review focuses on the metabolic cancer-macrophage crosstalk in the TME. We discuss how cancer cell metabolism and oncometabolites affect macrophage phenotype and function, and conversely how macrophage metabolism can impact tumor progression. Lastly, we propose tumor-secreted exosome-mediated metabolic signaling as a potential factor in tumorigenesis. Insight in these processes may contribute to the development of novel cancer therapies.

scholarly journals Tumor Microenvironment Autophagic Processes and Cachexia: The Missing Link?

2021 ◽  
Vol 10 ◽  
Author(s):  
Renata de Castro Gonçalves ◽  
Paula Paccielli Freire ◽  
Dario Coletti ◽  
Marilia Seelaender
Keyword(s):  
Tumor Microenvironment ◽  
Systemic Inflammation ◽  
Immune Cells ◽  
Cancer Cachexia ◽  
Tumor Antigens ◽  
Cytokine Production ◽  
Peripheral Tissues ◽  
Inflammatory Phenotype ◽  
And Function ◽  
Treatment Tolerance

Cachexia is a syndrome that affects the entire organism and presents a variable plethora of symptoms in patients, always associated with continuous and involuntary degradation of skeletal muscle mass and function loss. In cancer, this syndrome occurs in 50% of all patients, while prevalence increases to 80% as the disease worsens, reducing quality of life, treatment tolerance, therapeutic response, and survival. Both chronic systemic inflammation and immunosuppression, paradoxically, correspond to important features in cachexia patients. Systemic inflammation in cachexia is fueled by the interaction between tumor and peripheral tissues with significant involvement of infiltrating immune cells, both in the peripheral tissues and in the tumor itself. Autophagy, as a process of regulating cellular metabolism and homeostasis, can interfere with the metabolic profile in the tumor microenvironment. Under a scenario of balanced autophagy in the tumor microenvironment, the infiltrating immune cells control cytokine production and secretion. On the other hand, when autophagy is unbalanced or dysfunctional within the tumor microenvironment, there is an impairment in the regulation of immune cell’s inflammatory phenotype. The inflammatory phenotype upregulates metabolic consumption and cytokine production, not only in the tumor microenvironment but also in other tissues and organs of the host. We propose that cachexia-related chronic inflammation can be, at least, partly associated with the failure of autophagic processes in tumor cells. Autophagy endangers tumor cell viability by producing immunogenic tumor antigens, thus eliciting the immune response necessary to counteract tumor progression, while preventing the establishment of inflammation, a hallmark of cachexia. Comprehensive understanding of this complex functional dichotomy may enhance cancer treatment response and prevent/mitigate cancer cachexia. This review summarizes the recent available literature regarding the role of autophagy within the tumor microenvironment and the consequences eliciting the development of cancer cachexia.

scholarly journals Interleukin (IL)-9 Supports the Tumor-Promoting Environment of Chronic Lymphocytic Leukemia

Cancers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 6301
Author(s):  
Laura Patrussi ◽  
Nagaja Capitani ◽  
Cosima T. Baldari
Keyword(s):  
Tumor Microenvironment ◽  
Chronic Lymphocytic Leukemia ◽  
Immune Responses ◽  
Immune Cells ◽  
Molecular Mechanisms ◽  
Current Knowledge ◽  
Hematologic Malignancies ◽  
Lymphocytic Leukemia ◽  
Soluble Factor ◽  
Growth And Survival

Interleukin (IL)-9 is a soluble factor secreted by immune cells into the microenvironment. Originally identified as a mediator of allergic responses, IL-9 has been detected in recent years in several tumor niches. In solid tumors, it mainly promotes anti-tumor immune responses, while in hematologic malignancies, it sustains the growth and survival of neoplastic cells. IL-9 has been recently implicated in the pathogenesis of chronic lymphocytic leukemia; however, the molecular mechanisms underlying its contribution to this complex neoplasia are still unclear. Here, we summarize the current knowledge of IL-9 in the tumor microenvironment, with a focus on its role in the pathogenesis of chronic lymphocytic leukemia.

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