HMGB1 Mediates Endogenous TLR2 Activation and Brain Tumor Regression
TL;DR: Evidence is provided for the molecular and cellular mechanisms that support the rationale for the clinical implementation of antibrain cancer immunotherapies in combination with tumor killing approaches in order to elicit effective antitumor immune responses, and thus, will impact clinical neuro-oncology practice.
Abstract: Background
Glioblastoma multiforme (GBM) is the most aggressive primary brain tumor that carries a 5-y survival rate of 5%. Attempts at eliciting a clinically relevant anti-GBM immune response in brain tumor patients have met with limited success, which is due to brain immune privilege, tumor immune evasion, and a paucity of dendritic cells (DCs) within the central nervous system. Herein we uncovered a novel pathway for the activation of an effective anti-GBM immune response mediated by high-mobility-group box 1 (HMGB1), an alarmin protein released from dying tumor cells, which acts as an endogenous ligand for Toll-like receptor 2 (TLR2) signaling on bone marrow-derived GBM-infiltrating DCs.
Citations
More filters
TL;DR: A number of distinct features of the brain tumor microenvironment are discussed, including brain-resident cell types, the blood-brain barrier, and various aspects of the immune-suppressive environment.
1,011 citations
Cites background from "HMGB1 Mediates Endogenous TLR2 Acti..."
...For example, in mouse models of glioma, it has been shown that both temozolomide and radiation treatment cause the release of HMGB1 from dying cancer cells into the microenvironment, where it signals via TLR2 on DCs to enhance anti-tumor immunity (Curtin et al., 2009)....
[...]
TL;DR: High-mobility group box 1 (HMGB1), the most abundant and well-studied HMG protein, senses and coordinates the cellular stress response and plays a critical role not only inside of the cell as a DNA chaperone, chromosome guardian, autophagy sustainer, and protector from apoptotic cell death, but also outside thecell as the prototypic damage associated molecular pattern molecule (DAMP).
717 citations
Institut Gustave Roussy1, University of São Paulo2, Katholieke Universiteit Leuven3, University of Burgundy4, Sapienza University of Rome5, Istituto Superiore di Sanità6, Vrije Universiteit Brussel7, University of Manchester8, University of Michigan9, National University of Cuyo10, Pierre-and-Marie-Curie University11, New York University12, University of Salento13, University of Crete14, Charles University in Prague15, University of Erlangen-Nuremberg16, University Hospital Heidelberg17, University of Pittsburgh18, University of Helsinki19, National Institutes of Health20, University of Bonn21, Providence Portland Medical Center22, National University of Singapore23, Ghent University24, University of Milan25, University of Graz26, University of Paris-Sud27, University College London28, Tuscia University29, McMaster University30, Technische Universität München31, Medical University of Vienna32, Karolinska Institutet33, University of Nice Sophia Antipolis34, University of Turin35, QIMR Berghofer Medical Research Institute36, Université de Montréal37, Dow University of Health Sciences38, French Institute of Health and Medical Research39, University of Colorado Denver40, University of Hawaii41, Stony Brook University42, Paris Descartes University43
TL;DR: Strategies conceived to detect surrogate markers of ICD in vitro and to screen large chemical libraries for putative I CD inducers are outlined, based on a high-content, high-throughput platform that was recently developed.
Abstract: Apoptotic cells have long been considered as intrinsically tolerogenic or unable to elicit immune responses specific for dead cell-associated antigens. However, multiple stimuli can trigger a functionally peculiar type of apoptotic demise that does not go unnoticed by the adaptive arm of the immune system, which we named "immunogenic cell death" (ICD). ICD is preceded or accompanied by the emission of a series of immunostimulatory damage-associated molecular patterns (DAMPs) in a precise spatiotemporal configuration. Several anticancer agents that have been successfully employed in the clinic for decades, including various chemotherapeutics and radiotherapy, can elicit ICD. Moreover, defects in the components that underlie the capacity of the immune system to perceive cell death as immunogenic negatively influence disease outcome among cancer patients treated with ICD inducers. Thus, ICD has profound clinical and therapeutic implications. Unfortunately, the gold-standard approach to detect ICD relies on vaccination experiments involving immunocompetent murine models and syngeneic cancer cells, an approach that is incompatible with large screening campaigns. Here, we outline strategies conceived to detect surrogate markers of ICD in vitro and to screen large chemical libraries for putative ICD inducers, based on a high-content, high-throughput platform that we recently developed. Such a platform allows for the detection of multiple DAMPs, like cell surface-exposed calreticulin, extracellular ATP and high mobility group box 1 (HMGB1), and/or the processes that underlie their emission, such as endoplasmic reticulum stress, autophagy and necrotic plasma membrane permeabilization. We surmise that this technology will facilitate the development of next-generation anticancer regimens, which kill malignant cells and simultaneously convert them into a cancer-specific therapeutic vaccine.
665 citations
TL;DR: This review will discuss the current status of TLR2 mediated immune responses by recognition of pathogen-associated molecular patterns (PAMPS) on these organisms and emphasis on whether the inflammation induced by these responses contributes to the disease state or to protection from diseases.
Abstract: Toll-like receptors (TLRs) are recognition molecules for multiple pathogens, including bacteria, viruses, fungi, and parasites. TLR2 forms heterodimers with TLR1 and TLR6, which is the initial step in a cascade of events leading to significant innate immune responses, development of adaptive immunity to pathogens and protection from immune sequelae related to infection with these pathogens. This review will discuss the current status of TLR2 mediated immune responses by recognition of pathogen-associated molecular patterns (PAMPS) on these organisms. We will emphasize both canonical and non-canonical responses to TLR2 ligands with emphasis on whether the inflammation induced by these responses contributes to the disease state or to protection from diseases.
524 citations
TL;DR: The studies suggest that HMGB1 is central to cancer (abnormal wound healing) and many of the findings in normal wound healing as well and therapeutic strategies based on targetingHMGB1 are suggested.
500 citations
References
More filters
Book•
01 Dec 1969TL;DR: The concepts of power analysis are discussed in this paper, where Chi-square Tests for Goodness of Fit and Contingency Tables, t-Test for Means, and Sign Test are used.
Abstract: Contents: Prefaces. The Concepts of Power Analysis. The t-Test for Means. The Significance of a Product Moment rs (subscript s). Differences Between Correlation Coefficients. The Test That a Proportion is .50 and the Sign Test. Differences Between Proportions. Chi-Square Tests for Goodness of Fit and Contingency Tables. The Analysis of Variance and Covariance. Multiple Regression and Correlation Analysis. Set Correlation and Multivariate Methods. Some Issues in Power Analysis. Computational Procedures.
115,069 citations
TL;DR: New insights into innate immunity are changing the way the way the authors think about pathogenesis and the treatment of infectious diseases, allergy, and autoimmunity.
10,685 citations
"HMGB1 Mediates Endogenous TLR2 Acti..." refers background in this paper
...Therefore, our data suggest that the vast majority of CD11cþ-infiltrating immune cells in Ad-Flt3L and Ad-TKtreated brain tumors are bone marrow-derived mDC. TLR2 Expression on BMDC Is Necessary for Tumor Regression To determine if TLRs were involved in mediating the efficacy of the combined antiglioma treatment, we investigated whether Myd88 knockout mice would respond to our therapy, as Myd88 is required for downstream signaling from every TLR except TLR3 [12,50]....
[...]
...To determine if TLRs were involved in mediating the efficacy of the combined antiglioma treatment, we investigated whether Myd88 knockout mice would respond to our therapy, as Myd88 is required for downstream signaling from every TLR except TLR3 [12,50]....
[...]
...TLR signaling induces production of pro-inflammatory cytokines and upregulation of costimulatory molecules, which result in the activation of the adaptive immune system [12]....
[...]
TL;DR: Recognition of microbial infection and initiation of host defense responses is controlled by multiple mechanisms and recent studies have provided important clues about the mechanisms of TLR-mediated control of adaptive immunity orchestrated by dendritic cell populations in distinct anatomical locations.
Abstract: Recognition of microbial infection and initiation of host defense responses is controlled by multiple mechanisms. Toll-like receptors (TLRs) have recently emerged as a key component of the innate immune system that detect microbial infection and trigger antimicrobial host defense responses. TLRs activate multiple steps in the inflammatory reactions that help to eliminate the invading pathogens and coordinate systemic defenses. In addition, TLRs control multiple dendritic cell functions and activate signals that are critically involved in the initiation of adaptive immune responses. Recent studies have provided important clues about the mechanisms of TLR-mediated control of adaptive immunity orchestrated by dendritic cell populations in distinct anatomical locations.
4,108 citations
"HMGB1 Mediates Endogenous TLR2 Acti..." refers background in this paper
...While TLRs play an important role in detecting and regulating the innate immune response to bacteria, viruses, and/or parasites, TLRs are also necessary for the induction of an adaptive immune response through the activation and maturation of DCs and macrophages [20,21]....
[...]
TL;DR: A model of immunity based on the idea that the immune system is more concerned with entities that do damage than with those that are foreign is outlined.
Abstract: For over 50 years immunologists have based their thoughts, experiments, and clinical treatments on the idea that the immune system functions by making a distinction between self and nonself. Although this paradigm has often served us well, years of detailed examination have revealed a number of inherent problems. This Viewpoint outlines a model of immunity based on the idea that the immune system is more concerned with entities that do damage than with those that are foreign.
4,082 citations
"HMGB1 Mediates Endogenous TLR2 Acti..." refers background in this paper
...[55], soluble CD14 [29,70], and possibly larger hydrophobic molecular complexes (Hyppo's) [71]....
[...]
TL;DR: The methodology for inducing dendritic cell growth that was recently described for mouse blood now has been modified to MHC class II- negative precursors in marrow, and this feature should prove useful for future molecular and clinical studies of this otherwise trace cell type.
Abstract: Antigen-presenting, major histocompatibility complex (MHC) class II-rich dendritic cells are known to arise from bone marrow. However, marrow lacks mature dendritic cells, and substantial numbers of proliferating less-mature cells have yet to be identified. The methodology for inducing dendritic cell growth that was recently described for mouse blood now has been modified to MHC class II-negative precursors in marrow. A key step is to remove the majority of nonadherent, newly formed granulocytes by gentle washes during the first 2-4 d of culture. This leaves behind proliferating clusters that are loosely attached to a more firmly adherent "stroma." At days 4-6 the clusters can be dislodged, isolated by 1-g sedimentation, and upon reculture, large numbers of dendritic cells are released. The latter are readily identified on the basis of their distinct cell shape, ultrastructure, and repertoire of antigens, as detected with a panel of monoclonal antibodies. The dendritic cells express high levels of MHC class II products and act as powerful accessory cells for initiating the mixed leukocyte reaction. Neither the clusters nor mature dendritic cells are generated if macrophage colony-stimulating factor rather than granulocyte/macrophage colony-stimulating factor (GM-CSF) is applied. Therefore, GM-CSF generates all three lineages of myeloid cells (granulocytes, macrophages, and dendritic cells). Since > 5 x 10(6) dendritic cells develop in 1 wk from precursors within the large hind limb bones of a single animal, marrow progenitors can act as a major source of dendritic cells. This feature should prove useful for future molecular and clinical studies of this otherwise trace cell type.
3,852 citations
"HMGB1 Mediates Endogenous TLR2 Acti..." refers methods in this paper
...BMDC were generated as described previously [38] with modifications....
[...]