scholarly journals 212 CLEC-1 is a novel myeloid immune checkpoint for cancer immunotherapy limiting tumor cells phagocytosis and synergizing with tumor-targeted antibodies

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A231-A231
Author(s):  
Vanessa Gauttier ◽  
Marion Drouin ◽  
Sabrina Pengam ◽  
Javier Saenz ◽  
Bérangère Evrard ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Tumor Cells ◽  
Cell Activation ◽  
Immune Cell ◽  
Myeloid Cells ◽  
Human Tumor ◽  
Carcinoma Cells ◽  
Dead Cell ◽  
Lectin Receptors

BackgroundMyeloid cells represent one of the most abundant immune cell types in solid tumors that impede myeloid phagocytosis by triggering ‘don’t eat me’ and ‘don’t find me’ signals. Recent literature demonstrates that C-type lectin receptors (CLRs) normally constrain immune cell–mediated tissue damage by suppressing myeloid cell activation and then promote tumor immune evasion. We previously identified the orphan (CLRs) CLEC-1 as over-expressed in situation of established immune tolerance and reported that CLEC-1 expression by dendritic cells (DCs) and macrophages is enhanced by TGFβ and tempers downstream T cells responses. Furthermore, we reported that CLEC-1 is highly expressed by myeloid cells purified from human tumor micro-environment significantly more expressed by suppressive macrophages.MethodsAs DCs and macrophages are professional phagocytes of dying/dead cell, we evaluated whether CLEC-1 could be a receptor of damaged cells in the phagocytosis.ResultsWe found that CLEC-1 fusion protein, binds specifically to late apoptotic and secondary necrotic healthy or tumor cells induced by chemotherapy, radiation (UV, X-ray) or culture stress conditions. Importantly, we observed in vivo that CLEC-1 deficient mice, but not wild-type, eradicate MC38 colorectal tumors in combination with cytotoxic and immunogenic chemotherapy (eg. Cyclophosphamide. We then generated, screened and identified different anti-human Clec-1 antagonist monoclonal antibodies (mAbs) with the capacity to block the CLEC-1/CLEC-1L interaction. We discovered that various antagonist CLEC-1 mAbs, but not non-antagonist CLEC-1 control mAbs, increase the phagocytosis of CLEC-1L-positive human tumor cells by human CLEC-1 expressing TGFβ-polarized DCs or macrophages. Indeed, TGFβ-polarized DCs phagocytosed more efficiently Rituximab (anti-CD20 mAb)-opsonized Burkitt lymphoma cells (Raji) as well as bare NSCLC cells (A549) when CLEC-1 is antagonized by antibodies. Furthermore, macrophages more productively engulfed Rituximab-opsonized Raji cells as well in the context of CLEC-1 blockade (2–3 fold increase). Moreover, Cetuximab opsonized colon carcinoma cells (DLD-1; EGFR+) and Trastuzumab opsonized mammary carcinoma cells (SK-BR-3; Her2+) were likewise more phagocytosed by CLEC-1 blocked macrophages.ConclusionsAltogether, these data indicate illustrate that CLEC-1 broadly inhibits tumor-cell phagocytosis and synergized with tumor-targeted cytotoxic monoclonal antibodies in both solid and hematological tumors.

scholarly journals 230 Preclinical efficacy of CLEC-1 antagonist as novel myeloid immune checkpoint therapy for oncology

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A245-A245
Author(s):  
Vanessa Gauttier ◽  
Marion Drouin ◽  
Sabrina Pengam ◽  
Javier Saenz ◽  
Bérangère Evrard ◽  
...  
Keyword(s):  
Tumor Microenvironment ◽  
Tumor Cells ◽  
Immune Cell ◽  
Human Tumor ◽  
Myeloid Cell ◽  
Lectin Receptors ◽  
Knock Out ◽  
Cell Functions ◽  
Preclinical Efficacy

BackgroundC-type lectin receptors (CLRs) are powerful pattern recognition receptors shaping immune cell-mediated tissue damage by positively or negatively regulating myeloid cell functions and hence tumor elimination or evasion. We previously reported that the orphan CLR CLEC-1 expressed by dendritic cells (DCs) tempers T cell’s responses in vivo by limiting antigen cross-presentation by cDC1. Furthermore, we observed that CLEC-1 is highly expressed by myeloid cells purified from human tumor microenvironment, in particular tumor-associated macrophages.MethodsMacrophages were generated from monocytes of healthy volunteers for phagocytosis assays. MC38 and Hepa 1.6 murine tumor cells were implanted in Clec1a KO or KI mice for immunotherapeutic treatment evaluation.ResultsUsing newly developed anti-human CLEC-1 monoclonal antibodies (mAbs), we found that antagonist anti-CLEC-1 mAbs with the capacity to block CLEC-1/CLEC-1Ligand interaction, as opposed to non-antagonist CLEC-1 mAbs, increase the phagocytosis of CLEC-1Ligand-positive human tumor cells by human macrophages, in particular when opsonized by tumor-associated antigen mAbs (Rituximab, Cetuximab, Trastuzumab) or with anti-CD47 mAb (Magrolimab). In-vivo, CLEC-1 knock-out (KO) mice (n=19) display significant prolonged survival in monotherapy as compared to wild-type littermates (n=12) in an orthotopic hepatocellular carcinoma (HCC) model and anti-tumor memory responses was demonstrated by tumor rechallenge in cured mice. CLEC1 KO mice also illustrate significant eradication of MC38 colorectal tumors in combination with chemotherapy promoting CLEC-1Ligand expression by tumor cells (n=16 with Gemcitabine or n=11 with Cyclophosphamide). HCC tumor microenvironment analysis after 2 weeks of tumor implantation shows significantly higher number of CD8+ and memory CD8+ T cells with reduced PD1 expression in CLEC1 KO animals (n=16 versus n=12 for KO vs WT mice respectively). Finally, we recently generated human CLEC-1 knock-in mice expressing the extracellular human CLEC1 domain fused to the intracellular mouse CLEC1 tail and confirmed preclinical efficacy in vivo with anti-human CLEC1 antagonist mAb in monotherapy in the orthotopic HCC model.ConclusionsThese data illustrate that CLEC-1 inhibition represents a novel therapeutic target for immuno-oncology modifying T cell immune responses and tumor cell phagocytosis by macrophages.

scholarly journals Subtractive immunization yields monoclonal antibodies that specifically inhibit metastasis

1993 ◽  
Vol 122 (6) ◽  
pp. 1351-1359 ◽  
Author(s):  
PC Brooks ◽  
JM Lin ◽  
DL French ◽  
JP Quigley
Keyword(s):  
Monoclonal Antibodies ◽  
Tumor Cells ◽  
Human Tumor ◽  
Fold Increase ◽  
Antigenic Determinants ◽  
Human Tumor Cells ◽  
Isolation And Characterization ◽  
Metastatic Variant

Subtractive immunization allowed the isolation and characterization of monoclonal antibodies that specifically inhibit metastasis but not proliferation of highly metastatic human tumor cells. The tolerizing agent cyclophosphamide was used to suppress the immune system in mice to dominant immunodeterminants present on a non-metastatic variant (M-) of the human epidermoid carcinoma cell line (HEp3). Mice were then inoculated with a highly metastatic variant (M+) of HEp3 to enhance an immune response to antigenic determinants present on metastatic cells. Hybridomas were generated and screened by ELISA for differential reactivity to M+ HEp3 over M- HEp3 cells. This experimental approach, termed subtractive immunization (S.I.), was compared to a control immunization protocol, which eliminated the cyclophosphamide treatment. The S.I. protocol resulted in an eight-fold increase in the proportion of mAbs that react with molecules enriched on the surface of the M+ HEp3 cells. Two of the mAbs derived from the S.I. protocol, designated DM12-4 and 1A5, were purified and examined for their effect in a metastasis model system in which chick embryos are transplanted with primary HEp3 tumors. Purified mAbs DM12-4 and 1A5, inoculated i.v. into the embryos, inhibited spontaneous metastasis of HEp3 cells by 86 and 90%, respectively. The mAbs are specifically anti-metastatic in that they have no effect on the growth of HEp3 cells in vitro nor did they inhibit primary tumor growth in vivo. The mAbs recognize M+ HEp3 cell surface molecules of 55 kD and 29 kD, respectively. These data demonstrate that the S.I. protocol can be used for the development of unique mAbs that are reactive with antigenic determinants whose expression is elevated on metastatic human tumor cells and which function mechanistically in the metastatic cascade.

The cytosolic DNA sensor cGAS recognizes neutrophil extracellular traps

2021 ◽  
Vol 14 (673) ◽  
pp. eaax7942
Author(s):  
Falko Apel ◽  
Liudmila Andreeva ◽  
Lorenz Sebastian Knackstedt ◽  
Robert Streeck ◽  
Christian Karl Frese ◽  
...  
Keyword(s):  
Cell Activation ◽  
Immune Cell ◽  
Myeloid Cells ◽  
Neutrophil Extracellular Traps ◽  
Type I Interferons ◽  
Type I ◽  
Immune Cell Activation ◽  
Extracellular Traps ◽  
Regulated Cell Death

Neutrophil extracellular traps (NETs) are structures consisting of chromatin and antimicrobial molecules that are released by neutrophils during a form of regulated cell death called NETosis. NETs trap invading pathogens, promote coagulation, and activate myeloid cells to produce type I interferons (IFNs), proinflammatory cytokines that regulate the immune system. Here, we showed that macrophages and other myeloid cells phagocytosed NETs. Once in phagosomes, NETs translocated to the cytosol, where the DNA backbones of these structures activated the innate immune sensor cyclic GMP-AMP synthase (cGAS) and induced type I IFN production. The NET-associated serine protease neutrophil elastase (NE) mediated the activation of this pathway. We showed that NET induction in mice treated with the lectin concanavalin A, a model of autoimmune hepatitis, resulted in cGAS-dependent stimulation of an IFN response, suggesting that NETs activated cGAS in vivo. Thus, our findings suggest that cGAS is a sensor of NETs, mediating immune cell activation during infection.

ANTITUMOR EFFECT OF COLLOIDAL SILVER BISILICATE IN EXPERIMENTAL IN VITRO AND IN VIVO STUDIES

2019 ◽  
Vol 65 (5) ◽  
pp. 760-765
Author(s):  
Margarita Tyndyk ◽  
Irina Popovich ◽  
A. Malek ◽  
R. Samsonov ◽  
N. Germanov ◽  
...  
Keyword(s):  
Antitumor Activity ◽  
Tumor Growth ◽  
Tumor Cells ◽  
Human Tumor ◽  
Significant Inhibition ◽  
In Vivo Studies ◽  
Ehrlich Carcinoma ◽  
In Vivo Experiments

The paper presents the results of the research on the antitumor activity of a new drug - atomic clusters of silver (ACS), the colloidal solution of nanostructured silver bisilicate Ag6Si2O7 with particles size of 1-2 nm in deionized water. In vitro studies to evaluate the effect of various ACS concentrations in human tumor cells cultures (breast cancer, colon carcinoma and prostate cancer) were conducted. The highest antitumor activity of ACS was observed in dilutions from 2.7 mg/l to 5.1 mg/l, resulting in the death of tumor cells in all studied cell cultures. In vivo experiments on transplanted Ehrlich carcinoma model in mice consuming 0.75 mg/kg ACS with drinking water revealed significant inhibition of tumor growth since the 14th day of experiment (maximally by 52% on the 28th day, p < 0.05) in comparison with control. Subcutaneous injections of 2.5 mg/kg ACS inhibited Ehrlich's tumor growth on the 7th and 10th days of the experiment (p < 0.05) as compared to control.

scholarly journals MLN8054, an Inhibitor of Aurora A Kinase, Induces Senescence in Human Tumor Cells Both In vitro and In vivo

2010 ◽  
Vol 8 (3) ◽  
pp. 373-384 ◽  
Author(s):  
Jessica J. Huck ◽  
Mengkun Zhang ◽  
Alice McDonald ◽  
Doug Bowman ◽  
Kara M. Hoar ◽  
...  
Keyword(s):  
Tumor Cells ◽  
Human Tumor ◽  
Aurora A Kinase ◽  
Aurora A ◽  
Human Tumor Cells

CSIG-17. IMMUNE MODULATORY ROLE OF TYPE I INTERFERON IN SYNGENEIC MOUSE GLIOMA MODELS

2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi36-vi37
Author(s):  
Evelina Blomberg ◽  
Manuela Silginer ◽  
Michael Weller
Keyword(s):  
Tumor Cells ◽  
Immune Cell ◽  
Synergistic Effects ◽  
Xenograft Model ◽  
Prolonged Survival ◽  
Type I ◽  
Syngeneic Mouse ◽  
Glioma Initiating Cells ◽  
Glioma Growth

Abstract Glioblastoma is characterized by a poor prognosis and a challenging phenotype for drug development. Although multimodal treatment, including surgery, radio- and chemotherapy is applied, the overall survival remains just above one year. Numerous clinical trials have studied targeted therapies against commonly deregulated pathways, but an efficient targeted drug is yet to be discovered. Likewise, immunotherapy has not been shown to be active. A subset of glioma tumor cells demonstrates stem-like properties; these cells are commonly referred to as glioma initiating cells (GIC). These types of cells are pluripotent and can by definition initiate and recapitulate glioma growth in experimental animals in vivo. Furthermore, these cells are often resistant to conventional therapies. Interferon β (IFN-β) is an immunomodulatory molecule with anti-cancer properties. We have previously shown that IFN-β greatly reduces sphere-formation capability of GIC. It was also confirmed that IFN-β sensitized resistant GIC to irradiation or the chemotherapeutic agent, temozolomide (TMZ). IFN-β treatment significantly prolonged survival in a xenograft model with GIC cells. In the current project, we want to use syngeneic mouse models to study the immunomodulatory effects of type I IFNs. Preliminary results indicate that abrogation of IFN signalling in tumor cells by CRISPR/Cas9 technology prolonged survival in mice only in cell lines which have substantial baseline autocrine IFN signalling. On the contrary, we did not observe a difference in survival when wild-type tumor cells were implanted in either IFNAR1 deficient or proficient hosts. Flow cytometry analysis will elucidate changes in immune cell recruitment and infiltration upon IFN signalling disruption. Moreover, we explore different treatments in combination with IFN-β as there are indications that TMZ or radiotherapy can have synergistic effects with stimulation of interferon type I signalling.

scholarly journals Erratum: Bisphosphonate-induced differential modulation of immune cell function in gingiva and bone marrow in vivo: Role in osteoclast-mediated NK cell activation

Oncotarget ◽  
2015 ◽  
Vol 6 (38) ◽  
pp. 41398-41398 ◽  
Author(s):  
Han-Ching Tseng ◽  
Keiichi Kanayama ◽  
Kawaljit Kaur ◽  
So-Hyun Park ◽  
Sil Park ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Cell Activation ◽  
Cell Function ◽  
Immune Cell ◽  
Nk Cell ◽  
Differential Modulation ◽  
Immune Cell Function

IMMU-13. COMBINED MODULATION OF THE TGF-Β PATHWAY AND GITR IMMUNE CHECKPOINT SIGNALING PROMOTES ANTI-TUMOR IMMUNITY IN SYNGENEIC GLIOMA MODELS

2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi94-vi94
Author(s):  
Daniela Lorizio ◽  
Michael Weller ◽  
Manuela Silginer ◽  
Alan Epstein ◽  
Patrick Roth
Keyword(s):  
T Cell Activation ◽  
Immune Checkpoint ◽  
Cell Activation ◽  
Transforming Growth Factor ◽  
Immune Cell ◽  
Single Agent ◽  
Underlying Mechanism ◽  
T Effector Cells ◽  
Promising Therapeutic Approach

Abstract The profound local immunosuppressive microenvironment is one hallmark of glioblastoma, which results in resistance to most immunotherapeutic strategies that have been explored so far. Reverting this condition in order to reinvigorate anti-glioma immunity might be a promising therapeutic approach. Transforming growth factor (TGF)-β signaling is deregulated in different cancer types and contributes to the malignant phenotype of glioma cells. Glioma-derived TGF-β is also a major immunosuppressive factor in the tumor microenvironment. Furthermore, intratumoral regulatory T (Treg) cells and activated T effector cells express high levels of the co-stimulatory immune checkpoint glucocorticoid-induced tumor necrosis factor receptor (GITR). Agonistic anti-GITR antibodies have been explored in preclinical tumor models and are under investigation in clinical trials for the treatment of solid tumors. We evaluated the effect of TGF-β and GITR targeting on anti-tumor immune responses in syngeneic mouse glioma models. In co-culture settings, GITR modulation with a GITR ligand (GITRL)-Fc fusion protein, given alone or in combination with a pharmacological TGF-β receptor inhibitor, led to increased T cell activation. Furthermore, the combined targeting of the two pathways resulted in significantly higher immune cell-mediated tumor cell killing than either treatment alone. In vivo, TGF-β inhibition and GITR signaling modulation resulted in a higher fraction of long-term surviving glioma-bearing mice than single-agent treatment. Surviving mice were resistant to tumor re-challenge, suggesting adaptive immunity as an underlying mechanism. These data support the assumption that combined immunotherapeutic strategies may represent a promising approach for the treatment of glioma.

scholarly journals Administration of cardiac mesenchymal cells modulates innate immunity in the acute phase of myocardial infarction in mice

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Yi Kang ◽  
Marjan Nasr ◽  
Yiru Guo ◽  
Shizuka Uchida ◽  
Tyler Weirick ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Innate Immunity ◽  
Mechanism Of Action ◽  
Cell Activation ◽  
Cell Function ◽  
Immune Cell ◽  
Mesenchymal Cell ◽  
Cell Types

Abstract Although cardiac mesenchymal cell (CMC) therapy mitigates post-infarct cardiac dysfunction, the underlying mechanisms remain unidentified. It is acknowledged that donor cells are neither appreciably retained nor meaningfully contribute to tissue regeneration—suggesting a paracrine-mediated mechanism of action. As the immune system is inextricably linked to wound healing/remodeling in the ischemically injured heart, the reparative actions of CMCs may be attributed to their immunoregulatory properties. The current study evaluated the consequences of CMC administration on post myocardial infarction (MI) immune responses in vivo and paracrine-mediated immune cell function in vitro. CMC administration preferentially elicited the recruitment of cell types associated with innate immunity (e.g., monocytes/macrophages and neutrophils). CMC paracrine signaling assays revealed enhancement in innate immune cell chemoattraction, survival, and phagocytosis, and diminished pro-inflammatory immune cell activation; data that identifies and catalogues fundamental immunomodulatory properties of CMCs, which have broad implications regarding the mechanism of action of CMCs in cardiac repair.

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