scholarly journals Correlation of suppressor cell development in parental and F1 hybrid mouse strains with the growth of a parental tumor in vivo.

1976 ◽  
Vol 144 (5) ◽  
pp. 1363-1368 ◽  
Author(s):  
R B Levy ◽  
S D Waksal ◽  
G M Shearer
Keyword(s):  
Tumor Growth ◽  
Tumor Response ◽  
Tumor Regression ◽  
Suppressor Cells ◽  
Suppressor Cell ◽  
Mouse Strains ◽  
Immune Responsiveness ◽  
F1 Hybrid ◽  
Parental Tumor

Parental AKR/J, and AKB6F1 and AKD2F1 hybrid mice were injected subcutaneously with a spontaneously arising AKR/J tumor. The highly responsive AKB6F1 strain never exhibited any depression of immune functioning during the course of tumor growth and regression. The (AKR/J) intermediately responsive strain, while able to generate a successful anti-tumor response, did display a transient reduction of immunological capability, but only during the period tumor growth and not during tumor regression. Cells able to suppress antibody, but not cell-mediated responses, were found. The unresponsive AKD2F1 strain was characterized by both a marked depression of immune responsiveness, as well as the generation of suppressor cells to both antibody, and later, cell-mediated responses. Depression of immune responsiveness, and the generation of suppressor cells, appeared to correlate with the strength or weakness of the anti-tumor response in these strains of mice.

scholarly journals The critical immunosuppressive effect of MDSC-derived exosomes in the tumor microenvironment

2020 ◽  
Author(s):  
Mohammad H. Rashid ◽  
Thaiz F. Borin ◽  
Roxan Ara ◽  
Raziye Piranlioglu ◽  
Bhagelu R. Achyut ◽  
...  
Keyword(s):  
T Cells ◽  
Tumor Microenvironment ◽  
Tumor Growth ◽  
Cd8 T Cells ◽  
Suppressor Cells ◽  
Cell Types ◽  
Biological Macromolecules

AbstractMyeloid-derived suppressor cells (MDSCs) are an indispensable component of the tumor microenvironment (TME), and our perception regarding the role of MDSCs in tumor promotion is attaining extra layer of intricacy in every study. In conjunction with MDSC’s immunosuppressive and anti-tumor immunity, they candidly facilitate tumor growth, differentiation, and metastasis in several ways that yet to be explored. Alike any other cell types, MDSCs also release a tremendous amount of exosomes or nanovesicles of endosomal origin and partake in intercellular communications by dispatching biological macromolecules. There has not been any experimental study done to characterize the role of MDSCs derived exosomes (MDSC exo) in the modulation of TME. In this study, we isolated MDSC exo and demonstrated that they carry a significant amount of proteins that play an indispensable role in tumor growth, invasion, angiogenesis, and immunomodulation. We observed higher yield and more substantial immunosuppressive potential of exosomes isolated from MDSCs in the primary tumor area than those are in the spleen or bone marrow. Our in vitro data suggest that MDSC exo are capable of hyper activating or exhausting CD8 T-cells and induce reactive oxygen species production that elicits activation-induced cell death. We confirmed the depletion of CD8 T-cells in vivo by treating the mice with MDSC exo. We also observed a reduction in pro-inflammatory M1-macrophages in the spleen of those animals. Our results indicate that immunosuppressive and tumor-promoting functions of MDSC are also implemented by MDSC-derived exosomes which would open up a new avenue of MDSC research and MDSC-targeted therapy.

scholarly journals Atovaquone Suppresses Triple-Negative Breast Tumor Growth by Reducing Immune-Suppressive Cells

2021 ◽  
Vol 22 (10) ◽  
pp. 5150
Author(s):  
Nehal Gupta ◽  
Shreyas Gaikwad ◽  
Itishree Kaushik ◽  
Stephen E. Wright ◽  
Maciej M. Markiewski ◽  
...  
Keyword(s):  
Tumor Growth ◽  
Cancer Progression ◽  
Breast Tumor ◽  
Triple Negative ◽  
Immune Surveillance ◽  
Suppressor Cells ◽  
Myeloid Derived Suppressor Cells ◽  
In Vivo Models ◽  
Ribosomal Protein S19

A major contributing factor in triple-negative breast cancer progression is its ability to evade immune surveillance. One mechanism for this immunosuppression is through ribosomal protein S19 (RPS19), which facilitates myeloid-derived suppressor cells (MDSCs) recruitment in tumors, which generate cytokines TGF-β and IL-10 and induce regulatory T cells (Tregs), all of which are immunosuppressive and enhance tumor progression. Hence, enhancing the immune system in breast tumors could be a strategy for anticancer therapeutics. The present study evaluated the immune response of atovaquone, an antiprotozoal drug, in three independent breast-tumor models. Our results demonstrated that oral administration of atovaquone reduced HCC1806, CI66 and 4T1 paclitaxel-resistant (4T1-PR) breast-tumor growth by 45%, 70% and 42%, respectively. MDSCs, TGF-β, IL-10 and Tregs of blood and tumors were analyzed from all of these in vivo models. Our results demonstrated that atovaquone treatment in mice bearing HCC1806 tumors reduced MDSCs from tumor and blood by 70% and 30%, respectively. We also observed a 25% reduction in tumor MDSCs in atovaquone-treated mice bearing CI66 and 4T1-PR tumors. In addition, a decrease in TGF-β and IL-10 in tumor lysates was observed in atovaquone-treated mice with a reduction in tumor Tregs. Moreover, a significant reduction in the expression of RPS19 was found in tumors treated with atovaquone.

Standardized pathologic evaluation of the esophagus after neoadjuvant chemoradiation.

2012 ◽  
Vol 30 (4_suppl) ◽  
pp. 136-136
Author(s):  
Christina T. Muijs ◽  
Justin K. Smit ◽  
Arend Karrenbeld ◽  
Jannet C Beukema ◽  
Johannes A. Langendijk ◽  
...  
Keyword(s):  
Lymph Nodes ◽  
Tumor Response ◽  
Tumor Regression ◽  
Neoadjuvant Chemoradiation ◽  
Reference Points ◽  
Adjuvant Chemoradiation ◽  
Pathologic Evaluation ◽  
Radiation Induced ◽  
Complete Tumor

136 Background: The main objective of this study was to develop and validate a method to reconstruct the gross and clinical tumor volume (GTV and CTV) on the esophageal specimen in order to facilitate a good pathologic examination of the original tumor area after neo-adjuvant chemoradiation (CRT). Methods: The GTV and CTV borders of 25 patients were defined by a radiation oncologist on the planning CT in relation to 5 anatomical reference points. After CRT, the GTV and CTV borders were marked in vivo on the esophagus during surgical resection. Finally, the pathologist evaluated the presence of macroscopic and microscopic tumor in- and outside the GTV and CTV. The radiation tumor response was scored according to the standardized 5-tier Mandard classification. Radiation induced side effects were scored as well. Results: The Mandard classification could be scored on basis of the GTV alone in 68% of the cases (N=17). For the other patients (N=8), the GTV and the CTV should both be incorporated for correct evaluation of the tumor response. Five patients (20%) showed complete tumor response (Mandard 1), 68% (N=17) showed partial response (Mandard 2-3) and 12% (N=3) showed hardly any response (Mandard 4-5). In the partial responders, macroscopic tumor was found within the delineated GTV and microscopic tumor remained within the CTV both in 100% of the cases. In two patients (40%) with hardly any response, microscopic tumor was also found outside the CTV. This might be caused by tumor growth during the neo-adjuvant treatment or by geographical miss. Nine patients turned out to have positive lymph nodes. On average 18 (range 8-30) lymph nodes were evaluated per patients. Giant cell reactions, lymphocyte infiltration, and fibrosis, which indicate tumor regression were seen in the CTV and GTV, and were most pronounced in the GTV. Conclusions: This study suggested that demarcation of the GTV and CTV on the esophagus in vivo is important for standardized pathologic evaluation of the esophagus after neo-adjuvant chemoradiation. Furthermore using this method we determined microscopic tumor outside the CTV in 40% of the cases (N=2) of the bad responders (Mandard 4-5), illustrating the importance of our method in this patient category.

Demonstration of the efficacy of compound CFAK-C4 targeting FAK-VEGFR3 protein-protein interaction in gastric cancer.

2013 ◽  
Vol 31 (15_suppl) ◽  
pp. e22143-e22143
Author(s):  
Elena V. Kurenova ◽  
Sartaj Singh Sanghera ◽  
Jianqun Liao ◽  
Michael Yemma ◽  
William G. Cance
Keyword(s):  
Gastric Cancer ◽  
Tumor Growth ◽  
Tumor Progression ◽  
Colony Formation ◽  
Tumor Regression ◽  
Cancer Therapeutics ◽  
Scaffolding Protein ◽  
Dependent Manner ◽  
Gastric Cancer Cells

e22143 Background: While the emerging data strongly suggest that FAK is an excellent target for developmental therapeutics of cancer, kinase inhibitors of FAK have shown crossreactivity with other protein kinases and toxicity in preclinical and clinical studies. It is known that FAK acts pleiotropically, as a kinase and as a scaffolding protein, and our goal is to explore targeting the scaffolding function of FAK to inhibit protein-protein interactions important for tumor progression. Previously, we have shown that FAK physically interacts with VEGFR3 and we identified small molecule inhibitor CFAK-C4 that targets this site of interaction. Both of these kinases are overexpressed in gastric cancers and were found to be independent poor prognostic factors. The prognosis of patients with gastric cancer remains unfavorable and molecular based treatments are necessary for a potential breakthrough in the therapy of this disease. We hypothesize that FAK-VEGFR3 interaction provides essential survival signals for gastric tumor growth and that simultaneous inhibition of these signals will inhibit tumor progression. Methods: Effects of CFAK-C4 on gastric cancer cell lines AGS and NCI-N87 were examined by MTT assay (viability), colony formation assay and Western blotting (phosphorylation, apoptosis). Subcutaneous mouse model was used to demonstrate effect of CFAK-C4 in vivo. Results: CFAK-C4 specifically blocked phosphorylation of VEGFR3 and FAK, directly inhibited cell viability (p<0.05), increased cell detachment and inhibited colony formation in a dose-dependent manner (range 1-100µM). CFAK-C4 (50mg/kg, IP) effectively caused tumor regression in vivo, when administered alone and its effects were synergistic (p<0.05) with chemotherapy. In vivo effects of C4 were confirmed by a decrease in tumor FAK and VEGFR3 phosphorylation, and disruption of their complexes. Conclusions: In this study we have shown that CFAK-C4 inhibits FAK-VEGFR3 signaling in gastric cancer cells and affects tumor growth. This result demonstrates that targeting the scaffolding function of FAK is a unique approach of highly-specific molecular-targeted therapy and can be used to develop oral-based cancer therapeutics.

scholarly journals Granulocytic Myeloid-Derived Suppressor Cell Exosomal Prostaglandin E2 Ameliorates Collagen-Induced Arthritis by Enhancing IL-10+ B Cells

2020 ◽  
Vol 11 ◽  
Author(s):  
Xinyu Wu ◽  
Dongwei Zhu ◽  
Jie Tian ◽  
Xinyi Tang ◽  
Hongye Guo ◽  
...  
Keyword(s):  
B Cells ◽  
Prostaglandin E2 ◽  
Plasma Cells ◽  
Suppressor Cells ◽  
Suppressor Cell ◽  
Serum Levels ◽  
Biologically Active ◽  
Collagen Induced Arthritis

The results of recent studies have shown that granulocytic-myeloid derived suppressor cells (G-MDSCs) can secrete exosomes that transport various biologically active molecules with regulatory effects on immune cells. However, their roles in autoimmune diseases such as rheumatoid arthritis remain to be further elucidated. In the present study, we investigated the influence of exosomes from G-MDSCs on the humoral immune response in murine collagen-induced arthritis (CIA). G-MDSCs exosomes-treated mice showed lower arthritis index values and decreased inflammatory cell infiltration. Treatment with G-MDSCs exosomes promoted splenic B cells to secrete IL-10 both in vivo and in vitro. In addition, a decrease in the proportion of plasma cells and follicular helper T cells was observed in drainage lymph nodes from G-MDSCs exosomes-treated mice. Moreover, lower serum levels of IgG were detected in G-MDSCs exosomes-treated mice, indicating an alteration of the humoral environment. Mechanistic studies showed that exosomal prostaglandin E2 (PGE2) produced by G-MDSCs upregulated the phosphorylation levels of GSK-3β and CREB, which play a key role in the production of IL-10+ B cells. Taken together, our findings demonstrated that G-MDSC exosomal PGE2 attenuates CIA in mice by promoting the generation of IL-10+ Breg cells.

scholarly journals IMMU-28. TARGETING IMMUNOSUPPRESSIVE MYELOID DERIVED SUPPRESSOR CELLS VIA MIF/CD74 SIGNALING AXIS TO ATTENUATE GBM GROWTH

2019 ◽  
Vol 21 (Supplement_6) ◽  
pp. vi125-vi125
Author(s):  
Tyler Alban ◽  
Defne Bayik ◽  
Balint Otvos ◽  
Matthew Grabowski ◽  
Manmeet Ahluwalia ◽  
...  
Keyword(s):  
Tumor Microenvironment ◽  
Tumor Growth ◽  
Immune Cell ◽  
Suppressor Cells ◽  
Myeloid Derived Suppressor Cells ◽  
Signaling Axis ◽  
Immunosuppressive Microenvironment ◽  
And Function

Abstract The immunosuppressive microenvironment in glioblastoma (GBM) enables persistent tumor growth and evasion from tumoricidal immune cell recognition. Despite a large accumulation of immune cells in the GBM microenvironment, tumor growth continues, and evidence for potent immunosuppression via myeloid derived suppressor cells (MDSCs) is now emerging. In agreement with these observations, we have recently established that increased MDSCs over time correlates with poor prognosis in GBM, making these cells of interest for therapeutic targeting. In seeking to reduce MDSCs in GBM, we previously identified the cytokine macrophage migration inhibitory factor (MIF) as a possible activator of MDSC function in GBM. Here, using a novel in vitro co-culture system to reproducibly and rapidly create GBM-educated MDSCs, we observed that MIF was essential in the generation of MDSCs and that MDSCs generated via this approach express a repertoire of MIF receptors. CD74 was the primary MIF receptor in monocytic MDSCs (M-MDSC), which penetrate the tumor microenvironment in preclinical models and patient samples. A screen of MIF/CD74 interaction inhibitors revealed that MN-166, a clinically relevant blood brain barrier penetrant drug, which is currently fast tracked for FDA approval, reduced MDSC generation and function in vitro. This effect was specific to M-MDSC subsets expressing CD74, and appeared as reduced downstream pERK signaling and MCP-1 secretion. In vivo, MN-166 was able reduce tumor-infiltrating MDSCs, while conferring a significant increase in survival in the syngeneic glioma model GL261. These data provide proof of concept that M-MDSCs can be targeted in the tumor microenvironment via MN-166 to reduce tumor growth and provide a rationale for future clinical assessment of MN-166 to reduce M-MDSCs in the tumor microenvironment. Ongoing studies are assessing the effects of MDSC inhibition in combination with immune activating approaches, in order to inhibit immune suppression while simultaneously activating the immune system.

Myeloid-derived suppressor cells as a potential treatment target for pancreas adenocarcinoma.

2011 ◽  
Vol 29 (4_suppl) ◽  
pp. 194-194
Author(s):  
M. R. Porembka ◽  
J. B. Mitchem ◽  
P. S. Goedegebuure ◽  
D. Linehan
Keyword(s):  
T Cells ◽  
Tumor Growth ◽  
Animal Studies ◽  
Suppressor Cells ◽  
Disease Stage ◽  
Tumor Growth Rate ◽  
Myeloid Derived Suppressor Cells ◽  
Pancreas Adenocarcinoma

194 Background: Myeloid-derived suppressor cells (MDSC) are a heterogeneous population of immunosuppressive cells that are upregulated in cancer. Little is known about the prevalence and importance of MDSC in pancreas adenocarcinoma (PA). Here, we quantify MDSC prevalence in patients with PA and assess the efficacy of MDSC depletion in a murine model of PA. Methods: Peripheral blood and tumor samples were collected from patients with PA, analyzed for MDSC (CD15+11b+) by flow cytometry (FC) and compared to cancer-free controls (CFC). The suppressive capacity of MDSC and the effectiveness of MDSC depletion were assessed in C57BL/6 mice inoculated with Pan02, a murine PA, and treated with placebo or zoledronic acid (ZA), a potent aminobisphosphonate previously shown to target MDSC. Endpoints included tumor size, survival, and MDSC prevalence. Tumor cell infiltrate was analyzed by FC for MDSC (Gr1+CD11b+) and effector T cells; tumor cytokine levels were measured by Luminex assay. Results: Patients with PA demonstrated increased circulating MDSC compared to CFC, which correlated with disease stage (metastatic PA: 68%±3.6% of CD45+ cells, resectable PA: 57%±3.5%, CFC: 37%±3.6%; p<0.0001). Normal pancreas tissue showed no MDSC infiltrate while PA avidly recruited CD11b+15+ cells to the primary tumor. Murine tumors similarly recruited MDSC that actively suppressed CD8+ T cells in vitro measured by CFSE dilution and accelerated tumor growth in vivo by adoptive transfer with Pan02 cells (p<0.001). Treatment with ZA impaired MDSC accumulation in the tumor (Placebo: 78%, ZA: 51%, p<0.05) resulting in delayed tumor growth rate (p<0.0001) and prolonged median survival (Placebo: 59 days, ZA: 73 days, p<0.05). MDSC blockade increased recruitment of T cells to the tumor (CD4: 4.4%±1.1% vs 12.2%±2.0%, p<0.05; CD8: 3.9%±1.3% vs 10.6%±2.2%, p<0.05) and a more robust type 1 response with increased levels of IFN-g (p<0.05) and decreased levels of IL-10 (p<0.05). Conclusions: MDSC are an important mediator of tumor-induced immunosuppression in PA. Treatment with ZA effectively blocks MDSC accumulation improving anti-tumor response in animal studies. Efforts to block MDSC may represent a novel treatment strategy for PA. [Table: see text]

scholarly journals Suppressor T cells activated in a primary in vitro response to non-major histocompatibility alloantigens.

1982 ◽  
Vol 156 (5) ◽  
pp. 1398-1414 ◽  
Author(s):  
S Macphail ◽  
O Stutman
Keyword(s):  
Mixed Lymphocyte Reaction ◽  
Cytotoxic T Lymphocyte ◽  
Suppressor Cells ◽  
Suppressor Cell ◽  
Spleen Cells ◽  
Suppressor T Cells ◽  
Normal Spleen ◽  
In Vitro Response

Normal mouse spleen cells are not capable of mounting a primary cytotoxic T lymphocyte (Tc) response to non-H-2 alloantigens in vitro, although a good secondary H-2-restricted response is observable after in vivo immunization of the responder animals. Suppressor cells are generated in such a primary responses provided a Mls incompatibility exists between the responder and stimulator. These suppressors are not antigen specific, are Thy-1+, Lyt-1+, 2-, I-J-, and are highly radiosensitive. The suppressor cell precursors in normal spleen express the same phenotype. These suppressor cells are probably implicated in the lack of a primary Tc response in a primary mixed lymphocyte reaction across non-H-2 incompatibilities that include an Mls difference.

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