Interactions between tumor-derived proteins and Toll-like receptors

AbstractDamage-associated molecular patterns (DAMPs) are danger signals (or alarmins) alerting immune cells through pattern recognition receptors (PRRs) to begin defense activity. Moreover, DAMPs are host biomolecules that can initiate a noninflammatory response to infection, and pathogen-associated molecular pattern (PAMPs) perpetuate the inflammatory response to infection. Many DAMPs are proteins that have defined intracellular functions and are released from dying cells after tissue injury or chemo-/radiotherapy. In the tumor microenvironment, DAMPs can be ligands for Toll-like receptors (TLRs) expressed on immune cells and induce cytokine production and T-cell activation. Moreover, DAMPs released from tumor cells can directly activate tumor-expressed TLRs that induce chemoresistance, migration, invasion, and metastasis. Furthermore, DAMP-induced chronic inflammation in the tumor microenvironment causes an increase in immunosuppressive populations, such as M2 macrophages, myeloid-derived suppressor cells (MDSCs), and regulatory T cells (Tregs). Therefore, regulation of DAMP proteins can reduce excessive inflammation to create an immunogenic tumor microenvironment. Here, we review tumor-derived DAMP proteins as ligands of TLRs and discuss their association with immune cells, tumors, and the composition of the tumor microenvironment.

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Targeting of the Cancer-Associated Fibroblast—T-Cell Axis in Solid Malignancies

Journal of Clinical Medicine ◽

10.3390/jcm8111989 ◽

2019 ◽

Vol 8 (11) ◽

pp. 1989 ◽

Cited By ~ 11

Author(s):

Tom J. Harryvan ◽

Els M. E. Verdegaal ◽

James C. H. Hardwick ◽

Lukas J. A. C. Hawinkels ◽

Sjoerd H. van der Burg

Keyword(s):

T Cells ◽

T Cell ◽

Tumor Microenvironment ◽

T Cell Activation ◽

Cell Activation ◽

Suppressor Cells ◽

T Cell Response ◽

Cytotoxic T Cell ◽

Cell Axis ◽

Wide Range

The introduction of a wide range of immunotherapies in clinical practice has revolutionized the treatment of cancer in the last decade. The majority of these therapeutic modalities are centered on reinvigorating a tumor-reactive cytotoxic T-cell response. While impressive clinical successes are obtained, the majority of cancer patients still fail to show a clinical response, despite the fact that their tumors express antigens that can be recognized by the immune system. This is due to a series of other cellular actors, present in or attracted towards the tumor microenvironment, including regulatory T-cells, myeloid-derived suppressor cells and cancer-associated fibroblasts (CAFs). As the main cellular constituent of the tumor-associated stroma, CAFs form a heterogeneous group of cells which can drive cancer cell invasion but can also impair the migration and activation of T-cells through direct and indirect mechanisms. This singles CAFs out as an important next target for further optimization of T-cell based immunotherapies. Here, we review the recent literature on the role of CAFs in orchestrating T-cell activation and migration within the tumor microenvironment and discuss potential avenues for targeting the interactions between fibroblasts and T-cells.

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Antibodies to ILT3 abrogate myeloid immunosuppression and enable tumor killing

10.1101/2021.12.18.472552 ◽

2021 ◽

Author(s):

Philip E Brandish ◽

Anthony Palmieri ◽

Gulesi Ayanoglu ◽

Jeanne Baker ◽

Raphael Bueno ◽

...

Keyword(s):

T Cell ◽

Tumor Microenvironment ◽

T Cell Activation ◽

Cell Activation ◽

Suppressor Cells ◽

Myeloid Cell ◽

Soluble Form ◽

Myeloid Suppressor Cells ◽

Wide Range ◽

Tumor Killing

Tumor myeloid suppressor cells impede response to T cell checkpoint immunotherapy. Immunoglobulin-like transcript 3 (ILT3, gene name, LILRB4) expressed on dendritic cells (DCs) promotes antigen-specific tolerance. Circulating monocytic MDSCs that express ILT3 have been linked to clinical outcomes and a soluble form of ILT3 is elevated in certain cancers. We find that LILRB4 expression is correlated with Gene Expression Profile of T-cell inflamed tumor microenvironment shown to be significantly associated with response to the anti-PD1 antibody pembrolizumab across several tumor types. A potent and selective anti-ILT3 mAb effectively antagonized IL-10 polarization of DCs and enabled T cell priming. In an MLR assay anti-ILT3 combined with pembrolizumab afforded greater CD8+ T cell activation compared to either agent alone. Anti-ILT3 antibodies impaired the acquisition of a suppressive phenotype of monocytes co-cultured with SK-MEL-5 cancer cells, accompanied by a reduction in surface detection of peptidase inhibitor 16, a cis interaction candidate for ILT3. Growth of myeloid cell-abundant SK-MEL-5 tumors was abrogated by ILT3 blockade and remodeling of the immune tumor microenvironment was evident by CyTOF. These data support the testing of anti-ILT3 antibodies for the treatment of a wide range of solid tumors replete with myeloid cells.

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Pyroptotic and Necroptotic Cell Death in the Tumor Microenvironment and Their Potential to Stimulate Anti-Tumor Immune Responses

Frontiers in Oncology ◽

10.3389/fonc.2021.731598 ◽

2021 ◽

Vol 11 ◽

Author(s):

Allan Scarpitta ◽

Ulrich T. Hacker ◽

Hildegard Büning ◽

Olivier Boyer ◽

Sahil Adriouch

Keyword(s):

Cell Death ◽

Tumor Microenvironment ◽

Immune Responses ◽

Immune Cells ◽

Immunogenic Cell Death ◽

Chemotherapeutic Drugs ◽

Immune Functions ◽

Molecular Patterns ◽

Dying Cells ◽

Damage Associated Molecular Patterns

Cancer remains the second most common cause of death worldwide affecting around 10 million patients every year. Among the therapeutic options, chemotherapeutic drugs are widely used but often associated with side effects. In addition, toxicity against immune cells may hamper anti-tumor immune responses. Some chemotherapeutic drugs, however, preserve immune functions and some can even stimulate anti-tumor immune responses through the induction of immunogenic cell death (ICD) rather than apoptosis. ICD stimulates the immune system by several mechanisms including the release of damage-associated molecular patterns (DAMPs) from dying cells. In this review, we will discuss the consequences of inducing two recently characterized forms of ICD, i.e., pyroptosis and necroptosis, in the tumor microenvironment (TME) and the perspectives they may offer to increase the immunogenicity of the so-called cold tumors and to stimulate effective anti-tumor immune responses.

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Neutrophil plasticity in the tumor microenvironment

Blood ◽

10.1182/blood-2018-11-844548 ◽

2019 ◽

Vol 133 (20) ◽

pp. 2159-2167 ◽

Cited By ~ 59

Author(s):

Morgan A. Giese ◽

Laurel E. Hind ◽

Anna Huttenlocher

Keyword(s):

Tumor Microenvironment ◽

T Cell Activation ◽

Cell Activation ◽

Suppressor Cells ◽

Polymorphonuclear Neutrophil ◽

Specific Cell ◽

First Line ◽

Tumor Associated Neutrophils ◽

Specific Cell Surface ◽

Functional Phenotype

Abstract Neutrophils act as the body’s first line of defense against infection and respond to diverse inflammatory cues, including cancer. Neutrophils display plasticity, with the ability to adapt their function in different inflammatory contexts. In the tumor microenvironment, neutrophils have varied functions and have been classified using different terms, including N1/N2 neutrophils, tumor-associated neutrophils, and polymorphonuclear neutrophil myeloid–derived suppressor cells (PMN-MDSCs). These populations of neutrophils are primarily defined by their functional phenotype, because few specific cell surface markers have been identified. In this review, we will discuss neutrophil polarization and plasticity and the function of proinflammatory/anti-inflammatory and protumor/antitumor neutrophils in the tumor microenvironment. We will also discuss how neutrophils with the ability to suppress T-cell activation, referred to by some as PMN-MDSCs, fit into this paradigm.

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High potency STING agonists engage unique myeloid pathways to reverse pancreatic cancer immune privilege

Journal for ImmunoTherapy of Cancer ◽

10.1136/jitc-2021-003246 ◽

2021 ◽

Vol 9 (8) ◽

pp. e003246

Author(s):

Casey R Ager ◽

Akash Boda ◽

Kimal Rajapakshe ◽

Spencer Thomas Lea ◽

Maria Emilia Di Francesco ◽

...

Keyword(s):

Flow Cytometry ◽

Pancreatic Adenocarcinoma ◽

T Cell Activation ◽

Cell Activation ◽

Suppressor Cells ◽

Intratumoral Injection ◽

Immune Checkpoint Blockade ◽

Checkpoint Blockade ◽

High Potency

BackgroundIntratumoral injection of cyclic dinucleotide (CDN) agonists of the stimulator of interferon genes (STING) pathway engages innate immune activation and priming of adaptive immune effectors to foster local and distal tumor clearance. Despite proven therapeutic efficacy in preclinical models, a thorough understanding of how CDNs reprogram suppressive myeloid stroma in mouse and man is lacking.MethodsHere, we perform deep transcript-level and protein-level profiling of myeloid-derived suppressor cells and M2 macrophages following stimulation with CDNs of ascending potency. Additionally, we leverage orthotopic Kras+/G12DTP53+/R172HPdx1-Cre (KPC) derived models of pancreatic adenocarcinoma (PDAC) to determine the capacity for locally administered CDNs to sensitize PDAC to immune checkpoint blockade. We use bioluminescent in vivo imaging and 30-parameter flow cytometry to profile growth kinetics and remodeling of the tumor stroma post-therapy.ResultsHighly potent synthetic STING agonists repolarize suppressive myeloid populations of human and murine origin in part through inhibition of Myc signaling, metabolic modulation, and antagonism of cell cycle. Surprisingly, high-potency synthetic agonists engage qualitatively unique pathways as compared with natural CDNs. Consistent with our mechanistic observations, we find that intratumoral injection of the highest activity STING agonist, IACS-8803, into orthotopic pancreatic adenocarcinoma lesions unmasks sensitivity to checkpoint blockade immunotherapy. Dimensionality reduction analyses of high parameter flow cytometry data reveals substantial contributions of both myeloid repolarization and T cell activation underlying the in vivo therapeutic benefit of this approach.ConclusionsThis study defines the molecular basis of STING-mediated myeloid reprogramming, revealing previously unappreciated and qualitatively unique pathways engaged by CDNs of ascending potency during functional repolarization. Furthermore, we demonstrate the potential for high potency CDNs to overcome immunotherapy resistance in an orthotopic, multifocal model of PDAC.

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Development and characterization of a HCMV multiantigen therapeutic vaccine for GBM using the UNITE platform.

Journal of Clinical Oncology ◽

10.1200/jco.2021.39.15_suppl.e14565 ◽

2021 ◽

Vol 39 (15_suppl) ◽

pp. e14565-e14565

Author(s):

Amit Adhikari ◽

Juliete Macauley ◽

Yoshimi Johnson ◽

Mike Connolly ◽

Tim Coleman ◽

...

Keyword(s):

Flow Cytometry ◽

T Cells ◽

T Cell ◽

Tumor Microenvironment ◽

Mouse Model ◽

T Cell Activation ◽

Cell Activation ◽

Cd8 T Cell ◽

T Cell Response

e14565 Background: Glioblastoma (GBM) is an aggressive form of brain cancer with a median survival of 15 months which has remained unchanged despite technological advances in the standard of care. GBM cells specifically express human cytomegalovirus (HCMV) proteins providing a unique opportunity for targeted therapy. Methods: We utilized our UNITE (UNiversal Intracellular Targeted Expression) platform to develop a multi-antigen DNA vaccine (ITI-1001) that codes for the HCMV proteins- pp65, gB and IE-1. The UNITE platform involves lysosomal targeting technology, fusing lysosome-associated protein 1 (LAMP1) with target antigens resulting in increased antigen presentation by MHC-I and II. ELISpot, flow cytometry and ELISA techniques were used to evaluate the vaccine immunogenicity and a syngeneic, orthotopic GBM mouse model that expresses HCMV proteins was used for efficacy studies. The tumor microenvironment studies were done using flow cytometry and MSD assay. Results: ITI-1001 vaccination showed a robust antigen-specific CD4 and CD8 T cell response in addition to a strong humoral response. Using GBM mouse model, therapeutic treatment of ITI-1001 vaccine resulted in ̃56% survival with subsequent long-term immunity. Investigating the tumor microenvironment showed significant CD4 T cell infiltration as well as enhanced Th1 and CD8 T cell activation. Regulatory T cells were also upregulated upon ITI-1001 vaccination and would be an attractive target to further improve this therapy. In addition, tumor burden negatively correlated with number of activated CD4 T cells (CD4 IFNγ+) reiterating the importance of CD4 activation in ITI-1001 efficacy and potentially identifying treatment responders and non-responders. Further characterization of these two groups showed high infiltration of CD3+, CD4+ and CD8+ T cells in responders compared with non- responders along with higher CD8 T cell activation. Conclusions: Thus, we show that vaccination with HCMV antigens using the ITI-1001-UNITE platform generates strong cellular and humoral immune responses, triggering significant anti-tumor activity that leads to enhanced survival in mice with GBM.

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Microglia Purinoceptor P2Y6: An Emerging Therapeutic Target in CNS Diseases

Cells ◽

10.3390/cells9071595 ◽

2020 ◽

Vol 9 (7) ◽

pp. 1595 ◽

Cited By ~ 2

Author(s):

Shehata Anwar ◽

Vincent Pons ◽

Serge Rivest

Keyword(s):

Immune Cells ◽

Neurological Disorders ◽

Cell Activation ◽

Purinergic Receptor ◽

Biochemical Pathways ◽

Current Review ◽

Radiation Induced ◽

Pathological Environment ◽

Dying Cells ◽

Pro Inflammatory Cytokines

The purinergic receptor P2Y6 is expressed in immune cells, including the microglia that are implicated in neurological disorders. Its ligand, UDP, is a signaling molecule that can serve as an “find-me” signal when released in significant quantities by damaged/dying cells. The binding of UDP by P2Y6R leads to the activation of different biochemical pathways, depending on the disease context and the pathological environment. Generally, P2Y6R stimulates phagocytosis. However, whether or not phagocytosis coincides with cell activation or the secretion of pro-inflammatory cytokines needs further investigation. The current review aims to discuss the various functions of P2Y6R in some CNS disorders. We present evidence that P2Y6R may have a detrimental or beneficial role in the nervous system, in the context of neurological pathologies, such as ischemic stroke, Alzheimer’s disease, Parkinson’s disease, radiation-induced brain injury, and neuropathic pain.

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