scholarly journals Hepatic Stellate Cells Enhance Liver Cancer Progression by Inducing Myeloid-Derived Suppressor Cells through Interleukin-6 Signaling

2019 ◽  
Vol 20 (20) ◽  
pp. 5079 ◽  
Author(s):  
Ching-Chuan Hsieh ◽  
Chien-Hui Hung ◽  
Meihua Chiang ◽  
Yu-Chin Tsai ◽  
Jie-Teng He
Keyword(s):  
T Cells ◽  
T Cell ◽  
Tumor Microenvironment ◽  
Hepatic Stellate Cells ◽  
Suppressor Cells ◽  
Stellate Cells ◽  
Myeloid Derived Suppressor Cells ◽  
Term Survival ◽  
Arginase 1

The tumor microenvironment, which consists of fibroblasts, smooth muscle cells, endothelial cells, immune cells, epithelial cells, and extracellular matrices, plays a crucial role in tumor progression. Hepatic stellate cells (HSCs), a class of unique liver stromal cells, participate in immunomodulatory activities by inducing the apoptosis of effector T-cells, generation of regulatory T-cells, and development of myeloid-derived suppressor cells (MDSCs) to achieve long-term survival of islet allografts. This study provides in vitro and in vivo evidences that HSCs induce the generation of MDSCs to promote hepatocellular carcinoma (HCC) progression through interleukin (IL)-6 secretion. HSC-induced MDSCs highly expressed inducible nitric oxide synthase (iNOS) and arginase 1 mRNA and presented potent inhibitory T-cell immune responses in the tumor environment. Wild-type HSC-induced MDSCs expressed lower levels of CD40, CD86, and MHC II, and a higher level of B7-H1 surface molecules, as well as increased the production of iNOS and arginase I compared with MDSCs induced by IL-6-deficient HSCs in vitro. A murine-transplanted model of the liver tumor showed that HCCs cotransplanted with HSCs could significantly enhance the tumor area and detect more MDSCs compared with HCCs alone or HCCs cotransplanted with HSCs lacking IL-6. In conclusion, the results indicated that MDSCs are induced mainly by HSCs through IL-6 signaling and produce inhibitory enzymes to reduce T-cell immunity and then promote HCC progression within the tumor microenvironment. Therapies targeting the pathway involved in MDSC production or its immune-modulating pathways can serve as an alternative immunotherapy for HCC.

scholarly journals P04.05 Modulating tumor microenvironment with arginase-1 specific T cells

2020 ◽  
Vol 8 (Suppl 2) ◽  
pp. A38.2-A39
Author(s):  
E Martinenaite ◽  
M Aaboe Joergensen ◽  
RE Johansson Mortensen ◽  
S Munir Ahmad ◽  
SE Weis-Banke ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Tumor Microenvironment ◽  
Therapeutic Effect ◽  
Potential Role ◽  
Myeloid Cells ◽  
Tumor Site ◽  
Arginase 1 ◽  
Part Time

BackgroundCancer progression is associated with an increased immune suppression at the tumor site. Arginase-1 is an enzyme well-known for its involvement in metabolic immune regulation. At the tumor site, arginase-1 acts by reducing availability of L-arginine to the infiltrating immune cells thus reducing T cell functionality and proliferation. While arginase-1 is expressed by some tumor cells, it has also been shown to be produced by immune inhibitory myeloid cells, such as myeloid derived suppressor cells (MDSCs), tumor associated macrophages (TAMs) and is associated with poor prognosis. Previously, we demonstrated that spontaneous CD4+ and CD8+ T-cell immune responses against arginase-derived, HLA-restricted peptides can be found in both cancer patients and healthy individuals (Martinenaite et al, 2018, DOI: 10.1080/2162402X.2017.1404215). These T cells are present in the memory T cell compartment, and that they are activated in arginase-1 inducing conditions, such as presence of TH2 cytokines IL-4 or IL-13 in vitro (Martinenaite et al, 2019, DOI: 10.1038/s41423-019-0231-3 and DOI: 10.1007/s00262-019-02425-6).Methods and ResultsIn order to explore if arginase-1-specific T cells have a potential role in modulation of immune homeostasis, human arginase-1-specific memory T cells were isolated and expanded for functional characterization. We show that arginase-1-specific T cells specifically recognize arginase-1 expressing cells, such as mRNA transfected autologous dendritic cells (DCs) and B cells as well as M2 polarized macrophages in vitro. In addition, activated arginase-1-specific T cells produce pro-inflammatory cytokines IFNγ and TNFα. Secretion of TH1 cytokines by these T cells suggests potential role as potent immune modulators in the tumor microenvironment, since many arginase-1 expressing myeloid cells are not terminally differentiated and they can be re-polarized to an immunostimulatory, M1-like phenotype. We also observed that targeting of M2-polarized arginase-1 expressing monocytic leukemia cell line THP-1 with arginase-1-specific CD4+ T cells induces upregulation of PD-L1 on the THP-1 cells. Furthermore, we demonstrate that an arginase-1-derive peptide vaccine has a therapeutic effect in syngeneic mouse tumor models (B16 and MC38), both as monotherapy and in combination with anti-PD-1 treatment. The therapeutic effect was associated with increased immune infiltration in the peptide vaccinated mice compared to the control.ConclusionsOur study provides evidence that immune modulatory vaccination targeting arginase-1 is an intriguing way of targeting the immune suppressive microenvironment.Disclosure InformationE. Martinenaite: A. Employment (full or part-time); Significant; IO Biotech. M. Aaboe Joergensen: None. R.E. Johansson Mortensen: None. S. Munir Ahmad: None. S.E. Weis-Banke: None. M. Orebo Holmström: None. A. Wakatsuki Pedersen: A. Employment (full or part-time); Significant; IO Biotech. Ö. Met: None. I.M. Svane: F. Consultant/Advisory Board; Significant; IO Biotech. M. Hald Andersen: A. Employment (full or part-time); Significant; IO Biotech.

Myeloid-Derived Suppressor Cells Increase in Chronic Myeloid Leukemia and Exert Immune Suppressive Activity.

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 2779-2779
Author(s):  
Cesarina Giallongo ◽  
Nunziatina Parrinello ◽  
Daniele Tibullo ◽  
Piera La Cava ◽  
Alessandra Cupri ◽  
...  
Keyword(s):  
T Cell ◽  
Chronic Myeloid Leukemia ◽  
T Lymphocytes ◽  
Enzymatic Activity ◽  
Myeloid Leukemia ◽  
Myeloid Cells ◽  
Suppressor Cells ◽  
Myeloid Derived Suppressor Cells ◽  
Arginase 1

Abstract Abstract 2779 Background: Tumor cells are able to develop immune evasion mechanisms which induce a state of immune tolerance and inactivate tumor-specific T cells. In this context, in some solid tumors it has been demonstrated that a subpopulation of myeloid cells, defined as “myeloid-derived suppressor cells” (MDSCs), plays an important role in inducing T cell tolerance by production of arginase that depletes microenvironment of arginine, an essential aminoacid for T cell function. Since chronic myeloid leukemia (CML) patients have high levels of immature myeloid cells it is of interest to investigate if these cells have MDSCs phenotype and activity. Aim: The aim of this study was to analyze MDSCs and investigate their involvement in T-cell anergy of CML patients. Methods: MDSCs were analyzed in peripheral blood (PB) of 13 CML patients (at diagnosis and during therapy) and healthy donors (HD; n=20) by cytofluorimetric analysis (CD14+DR- for monocytic MDSCs and CD11b+CD33+CD14-DR- for granulocytic MDSCs). Arginase 1 expression was assessed in PB of HD and CML patient using real time PCR. Purification of granulocytes, monocytes and lymphocytes from PB was performed by a positive magnetic separation kit (EasySep, STEMCELL Technologies). Arginase activity was measured in granulocyte lysates using a colorimetric test after enzymatic activation and arginine hydrolysis. To evaluate the activation of CD3+ T lymphocytes after incubation with phytoemagglutinin, we analyzed at 24, 48, 72 h the following markers: CD69+, CD71+, DR+. Microvesicles were isolated from CML serum at diagnosis (n=5) by sequential ultracentrifugation. Results: CML patients showed high levels of monocytic and granulocytic MDSCs at diagnosis in comparison to HD (63±8 and 83±12,2% respectively in CML vs 4,9±2,1 and 55,8±5,3% respectively in HD; p<0.001) while after 3–6 months of tyrosine kinase inhibitors (TKIs) therapy MDSC levels returned to normal values. Either in PB and in the purified granulocytes subpopulation, arginase1 expression showed a 30 fold increase in CML at diagnosis (CML vs HD: p<0.01) and decreased after therapy. We also evaluated arginase enzymatic activity in granulocytes and we found it increased in CML patients (n=4) compared to HD (n=5) (p<0.05). CML as well as HD T lymphocytes showed a normal activation in vitro which was significantly lost when they was incubated with CML serum (n=4). In addition, an increase of monocytic MDSCs in vitro was observed after incubation of HD monocytes with CML serum (39±6%; p<0.01) or microvescicles (9,2±1,2%; p<0.05) compared to control serum. Conclusions: Granulocytic and monocytic MDSCs are increased in CML patients at diagnosis and decrease during TKIs treatment. Their levels also correlates with Arginase 1 expression and enzymatic activity in granulocytes. CML serum as well as CML microvesicles increase the percentage of HD monocytic MDSCs. Moreover, CML serum leads to anergy of T lymphocytes, probably by Arginase 1 secretion. Disclosures: Off Label Use: Eltrombopag is a thrombopoietin receptor agonist indicated for the treatment of thrombocytopenia in patients with chronic immune (idiopathic) thrombocytopenic purpura (ITP).

scholarly journals MYd88 Blockade Caused Reduction of PDL1 on Tumor Infiltrating MDSCs in a Murine Model of Melanoma

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 1012-1012
Author(s):  
Parvin Forghani ◽  
Edmund K Waller
Keyword(s):  
T Cells ◽  
T Cell ◽  
Tumor Immunity ◽  
Murine Model ◽  
Suppressor Cells ◽  
B16 Melanoma ◽  
Myeloid Derived Suppressor Cells ◽  
Antitumor Effects ◽  
Arginase 1 ◽  
Significant Difference

Abstract Introduction: Myeloid differentiation primary response gene 88 (Myd 88) is an important adaptor molecule for the activation of NADPH oxidase and regulation of arginase-1, which are responsible for the suppressive function of myeloid-derived suppressor cells (MDSCs). Blockade of Myd88 signaling induces antitumor effects in mice by skewing the immunosuppressive function of myeloid-derived suppressor cells. As the PD-L1/PD-1 axis has been characterized as a potent inhibitor of immune activation, particularly through inhibition of effector T cell function, we characterized the effect of Myd88 on checkpoint expression on tumor-infiltrating MDSC/T cells in a murine model melanoma. Methods: Pathogen-free 8-10-week-old WT(B6-background) and Myd 88−/− mice that been backcrossed to a C57BL/6 genetic background were challenged with 1 × 106 B16 (F1) tumor cells s.c. On day 14, mice were sacrificed and spleen and tumors were removed and digested into single-cell suspensions, blocked with anti-FcR mAbs and analyzed for surface and intracellular staining by flow cytometry. We analyzed CD11b+/Gr-1+hi/int myeloid cells subsets and T cells in the blood, spleen and tumors of mice by flow cytomery. Results: The growth of B16 melanoma tumor was significantly slower in Myd 88−/− mice compared with WT mice. No significant difference between two groups was found in the frequency of absolute number of MDSC subsets and expression of PDL1 check-point marker on spleen-derived MDSC subsets. In contrast CD4(+) and C8(+) T cells residing in spleens of Myd88(-/-) mice showed increased expression of TNF-α/IFN-α and GrZB compared with T cells from wild-type mice following short-term activation with PMA/iono. Of note, the frequencies and absolute numbers of infiltrating CD11b+/Gr1+ MDSC in tumor-bearing Myd 88−/− mice were lower than those in WT mice. Also we found that viable CD11b+/Gr1+ MDSC subsets from WT mice expressed higher level of PD-L1 compared with MDSCs from Myd 88−/− mice in concordance with the reduced expression of PD-1 on tumor infiltrating CD4+ T cells in Myd 88−/− mice. Collectively, the profile of PD-L1 and PD-1 expression in tumor microenvironments is favorably altered to enhance adaptive immune response in myd 88 KO vs WT mice harboring B16 melanoma. Conclusion: The results of this study provide further evidence that blocking Myd 88 signaling increases anti tumor immunity against melanoma, and that the enhanced immunity can be explained, in part, by reduction of expression PDL1/PD1 immune checkpoint molecules. Considering the importance of tumor-infiltrating MDSCs in regulating anti tumor immunity in the tumor microenvironment, our findings could provide insight into the design of new therapeutics targeting Myd 88. Further experiments are needed to show how alteration in profile of PDL1 checkpoint expression on MDSCs influences anti-tumor T cell responses. Disclosures No relevant conflicts of interest to declare.

scholarly journals Functional myeloid-derived suppressor cells expand in blood but not airways of COVID-19 patients and predict disease severity

2020 ◽  
Author(s):  
Sara Falck-Jones ◽  
Sindhu Vangeti ◽  
Meng Yu ◽  
Ryan Falck-Jones ◽  
Alberto Cagigi ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Disease Severity ◽  
Respiratory Infections ◽  
Suppressor Cells ◽  
Myeloid Derived Suppressor Cells ◽  
Inflammatory Conditions ◽  
Arginase 1 ◽  
T Cell Lymphopenia ◽  
Dependent Mechanism

The immunopathology of COVID-19 remains enigmatic, exhibiting immunodysregulation and T cell lymphopenia. Monocytic myeloid-derived suppressor cells (M-MDSC) are T cell suppressors that expand in inflammatory conditions, but their role in acute respiratory infections remains unclear. We studied blood and airways of COVID-19 patients across disease severity at multiple timepoints. M-MDSC frequencies were elevated in blood but not in nasopharyngeal or endotracheal aspirates of COVID-19 patients compared to controls. M-MDSCs isolated from COVID-19 patients suppressed T cell proliferation and IFNγ production partly via an arginase-1 (Arg-1) dependent mechanism. Furthermore, patients showed increased Arg-1 and IL-6 plasma levels. COVID-19 patients had fewer T cells, and displayed downregulated expression of the CD3ζ chain. Ordinal regression showed that early M-MDSC frequency predicted subsequent disease severity. In conclusion, M-MDSCs expand in blood of COVID-19 patients, suppress T cells and strongly associate with disease severity, suggesting a role for M-MDSCs in the dysregulated COVID-19 immune response.

Myeloid Derived Suppressor Cells (MDSCs) Are Increased and Exert Immunosuppressive Activity In CML Patients At Diagnosis

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 2711-2711
Author(s):  
Cesarina Giallongo ◽  
Nunziatina Parrinello ◽  
Daniele Tibullo ◽  
Piera La Cava ◽  
Alessandra Romano ◽  
...  
Keyword(s):  
T Cell ◽  
Western Blot ◽  
Cell Function ◽  
Conflicts Of Interest ◽  
Myeloid Cells ◽  
Suppressor Cells ◽  
Myeloid Derived Suppressor Cells ◽  
Immunosuppressive Activity ◽  
Arginase 1

Abstract Introduction In some solid tumors it has been demonstrated that a subpopulation of myeloid cells, defined as “myeloid-derived suppressor cells” (MDSCs), plays an important role in inducing T cell tolerance by production of arginase 1 (arg1) that depletes microenvironment of arginine, an essential aminoacid for T cell function. Since chronic myeloid leukemia (CML) patients have high levels of immature myeloid cells it is of interest to investigate if these cells have MDSCs phenotype and activity. The aim of this study was to analyze MDSCs and investigate their activity in CML patients. Methods MDSCs were analyzed in peripheral blood (PB) of 20 healthy donors (HD) and 30 CML patients at diagnosis. In 21 patients MDSCs were also measured during TKI treatment. Granulocytic MDSCs (G-MDSCs) were identified as CD11b+CD33+CD14-HLADR- cells, while the monocytic MDSCs (Mo-MDSCs) as CD14+HLADR by cytofluorimetric analysis. Arg1 expression was assessed using real time PCR and Western Blot. Arg activity was measured in granulocyte lysates using a colorimetric test after enzymatic activation and arginine hydrolysis. Microvesicles (MV) were isolated from CML serum at diagnosis (n=5) by sequential ultracentrifugation. Results CML patients showed high levels of Mo- and G-MDSCs at diagnosis in comparison to HD (41±8 and 82,5±12,2% respectively for CML vs 9±2,1 and 55±5,3% for HD; p<0.001), while after TKIs therapy both subpopulations decreased, returning to normal values. T-reg (CD4+ CD25high Foxp3+ cells) were also significantly increased in CML patients at diagnosis in respect to HD (9±2% vs 6,1±0,8%, p<0.001) with a significant correlation with the percentage of Gr-MDSCs (r=0,6254; p<0.001). Both in PB and purified granulocytic cells, Arg1 expression showed a 30 fold increase in CML at diagnosis compared to HD (p<0.001) and decreased after therapy. The same data were confirmed by Western Blot analysis. Arg enzymatic activity in granulocytes resulted also increased in CML (n=10) compared to HD (n=10) (p<0.001). The suppressive function of CML G-MDSCs was demonstrated by their ability to inhibit the proliferation of CFSE+ HD T cells (p<0.001). In addition, an increase of Mo-MDSCs in vitro was observed after incubation of HD monocytes with CML sera (29±13%; p<0.0001) or MV (8±2,8%; p<0.05). Conclusions MDSCs are increased in CML patients at diagnosis and decrease during TKIs treatment. CML granulocytes have high arg1 activity and immunosuppressive activity. Moreover, CML serum as well as CML microvesicles increase the percentage of HD Mo-MDSCs. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Myeloid-derived suppressor cells are bound and inhibited by anti-thymocyte globulin

2019 ◽  
Vol 25 (1) ◽  
pp. 46-59 ◽  
Author(s):  
Young Suk Lee ◽  
Eduardo Davila ◽  
Tianshu Zhang ◽  
Hugh P Milmoe ◽  
Stefanie N Vogel ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
T Cells ◽  
T Cell ◽  
Suppressor Cells ◽  
Arginase Activity ◽  
T Cell Proliferation ◽  
Myeloid Derived Suppressor Cells ◽  
Tumor Bearing ◽  
And Function

Myeloid-derived suppressor cells (MDSCs) inhibit T cell responses and are relevant to cancer, autoimmunity and transplant biology. Anti-thymocyte globulin (ATG) is a commonly used T cell depletion agent, yet the effect of ATG on MDSCs has not been investigated. MDSCs were generated in Lewis Lung Carcinoma 1 tumor-bearing mice. MDSC development and function were assessed in vivo and in vitro with and without ATG administration. T cell suppression assays, RT-PCR, flow cytometry and arginase activity assays were used to assess MDSC phenotype and function. MDSCs increased dramatically in tumor-bearing mice and the majority of splenic MDSCs were of the polymorphonuclear subset. MDSCs potently suppressed T cell proliferation. ATG-treated mice developed 50% fewer MDSCs and these MDSCs were significantly less suppressive of T cell proliferation. In vitro, ATG directly bound 99.6% of MDSCs. CCR7, L-selectin and LFA-1 were expressed by both T cells and MDSCs, and binding of LFA-1 was inhibited by ATG pre-treatment. Arg-1 and PD-L1 transcript expression were reduced 30–40% and arginase activity decreased in ATG-pretreated MDSCs. MDSCs were bound and functionally inhibited by ATG. T cells and MDSCs expressed common Ags which were also targets of ATG. ATG may be helpful in tumor models seeking to suppress MDSCs. Alternatively, ATG may inadvertently inhibit important T cell regulatory events in autoimmunity and transplantation.

scholarly journals 778 Modulating tumor microenvironment with arginase-1 specific T cells

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A813-A813
Author(s):  
Evelina Martinenaite ◽  
Mia Aaboe Jørgensen ◽  
Rasmus Erik Johansson Mortensen ◽  
Shamaila Munir Ahmad ◽  
Stine Emilie Weis-Banke ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Tumor Microenvironment ◽  
Memory T Cells ◽  
Ethics Committee ◽  
Mouse Tumor ◽  
Immune Modulators ◽  
Arginase 1 ◽  
Mouse Tumor Models

BackgroundIO112 is an immune modulatory cancer therapy under preclinical development to target arginase-1-expressing tumor cells and immune inhibitory myeloid cells, such as myeloid derived suppressor cells (MDSCs), and tumor associated macrophages (TAMs). Arginase-1 acts as a metabolic immune regulator at the tumor site by reducing availability of L-arginine to the infiltrating immune cells thus reducing T cell functionality and proliferation. Previously, we demonstrated that IO112 triggers activation of spontaneous CD4+ and CD8+ T-cell responses against arginase-1, found in both cancer patients and healthy individuals.1 These T cells are present in the memory T cell compartment, and are activated in arginase-1 inducing conditions, such as presence of TH2 cytokines IL-4 or IL-13 in vitro.2 3 In this study we aimed to explore the role of arginase-1-specific T cells as immune modulators in immune homeostasis and tumor microenvironment for the development of IO112 immunomodulatory therapy.MethodsHuman arginase-1-specific T cells were isolated and expanded for functional characterization of reactivity against arginase-1 expressing target cells as well as subsequent phenotyping of the targeted arginase-1 positive cells. Syngeneic C57BL/6 mouse tumor models were used to assess the therapeutic efficacy of IO112.ResultsWe show that arginase-1-specific memory T cells specifically recognize arginase-1 expressing cells, such as mRNA transfected autologous dendritic cells (DCs) and B cells as well as M2 polarized macrophages in vitro. In addition, activated arginase-1-specific T cells produce pro-inflammatory cytokines IFNγ and TNFα. Secretion of TH1 cytokines by these T cells suggests that they may act as potent immune modulators in the tumor microenvironment, since many arginase-1 expressing myeloid cells are not terminally differentiated and they can be re-polarized to an immunostimulatory, M1-like phenotype. We also observed that targeting of M2-polarized arginase-1 expressing monocytic leukemia cell line THP-1 with arginase-1-specific CD4+ T cells induces upregulation of PD-L1 on the THP-1 cells. Furthermore, we demonstrate anti-tumor activity of IO112 in syngeneic mouse tumor models (B16 and MC38), both as monotherapy and in combination with anti-PD-1 treatment. The therapeutic effect was associated with increased immune infiltration in the IO112-treated mice compared to the control.ConclusionsWe demonstrate that arginase-1 specific T cells can influence the polarization of arginase-1-expressing immune cells. Our study provides evidence that IO112 immune therapy against arginase-1 is an attractive way of modulating the immune suppressive tumor microenvironment for therapeutic benefit. With this rationale, we are currently undertaking Investigational New Drug (IND) application enabling studies to explore this approach in a clinical setting.ReferencesMartinenaite E, Mortensen REJ, Hansen M, Holmström MO, Ahmad SM, Jørgensen NGD, Met Ö, Donia M, Svane IM, Andersen MH. Frequent adaptive immune responses against arginase-1. Oncoimmunology 2018;7(3):e1404215.Martinenaite E, Ahmad SM, Svane IM, Andersen MH. Peripheral memory T cells specific for Arginase-1. Cell Mol Immunol 2019;16(8):718–719.Martinenaite E, Ahmad SM, Bendtsen SK, Jørgensen MA, Weis-Banke SE, Svane IM, Andersen MH. Arginase-1-based vaccination against the tumor microenvironment: the identification of an optimal T-cell epitope. Cancer Immunol Immunother 2019;68(11):1901–1907.Ethics ApprovalThis study was approved by the Scientific Ethics Committee for The Capital Region of Denmark and Danish Ethics Committee on experimental animal welfare.

Targeting myeloid-derived suppressor cells and the PD-1/PD-L1 axis to enhance immunotherapy with anti-CEA designer T cells for the treatment of colorectal liver metastases.

2013 ◽  
Vol 31 (15_suppl) ◽  
pp. 3079-3079
Author(s):  
Rachel A. Burga ◽  
Mitchell Thorn ◽  
Cang T. Nguyen ◽  
Lauren Licata ◽  
N. Joseph Espat ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Liver Metastases ◽  
Suppressor Cells ◽  
Myeloid Derived Suppressor Cells ◽  
Murine Splenocytes ◽  
T Cell Suppression ◽  
Programmed Death ◽  
Cell Suppression

3079 Background: Immunotherapy for colorectal cancer liver metastases (CRCLM) is limited by the intrahepatic immunosuppressive environment mediated in part by myeloid derived suppressor cells (MDSC), which expand in response to tumor. T cell suppression can be mediated by programmed death ligand-1 (PD-L1, CD274) on MDSC binding to programmed death-1 (PD-1, CD279) on T cells. We hypothesize blocking PD-L1 will improve adoptive cellular therapy efficacy for CRCLM through inhibition of MDSC-mediated T cell suppression. Methods: “Designer” T cells (dTc) were produced from activated murine splenocytes transduced with chimeric antigen receptor (CAR) specific for CEA. C57BL/6 mice were injected with CEA+ MC38 tumor cells via spleen, and liver MDSC (CD11b+Gr1+) were purified with immunomagnetic beads after two weeks. MDSC were co-cultured with stimulated dTc with or without in vitro PD-L1 blockade. Results: MDSC expanded 2.4-fold in response to CRCLM, and expressed high levels of PD-L1 (63.8% PD-L1+). PD-L1 was equally expressed on both monocytic (CD11b+Ly6G-Ly6C+) and granulocytic (CD11b+Ly6G+) MDSC subsets (43.6% PD-L1+ and 27.9% PD-L1+, respectively). Expression of related ligand, PD-L2 was found to be negligible in both subsets. The cognate inhibitory receptor, PD-1, was expressed on dTc (23.8% PD-1+) and native T cells (37.3% PD-1+). Increasing endogenous T cell expression of PD-1 significantly correlated with MDSC expansion (r=0.9774, p<0.0001) in response to CRCLM. Co-culture of dTc with MDSC demonstrated the suppressive effect of MDSC on dTc proliferation which was abrogated with in vitro targeting of PD-L1. The percentage of dTc proliferating in the presence of CEA+ tumor decreased from 72.2% to 29.3% (p<0.001) with the addition of MDSC, and immunosuppression was reversed with blockade of PD-L1, which resulted in a 1.6-fold increase in dTc proliferation (p=0.01 ). Conclusions: Liver MDSC expand in the presence of CRCLM and mediate suppression of anti-CEA dTc via PD-L1. Our results indicate that blockade of PD-L1:PD-1 engagement is a viable strategy for enhancing the efficacy of adoptive cell therapy for liver metastases.

scholarly journals Pparα Ablation Suppresses T Cell Responses and Anti-Tumor Immunity By Compromising the Antigen-Presenting Properties of Tumor-Associated Macrophages

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 438-438
Author(s):  
Anthos Christofides ◽  
Carol Cao ◽  
Qi Wang ◽  
Natalia M Tijaro-Ovalle ◽  
Eirini Konstantinidou ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Suppressor Cells ◽  
T Cell Responses ◽  
Innate Immune ◽  
Myeloid Derived Suppressor Cells ◽  
Cell Responses

Abstract Peroxisome proliferator activated receptors (PPARs) are transcription factors that belong to nuclear hormone superfamily, with three distinct types identified: PPARapha (PPARα), PPARgamma (PPARγ), and PPARbeta/delta (PPARβ/δ). PPARs possess a critical role in the regulation of lipid metabolism, and thus play critical roles in the differentiation and fate of immune cells. PPARα is involved in lipid and carbohydrate metabolism and PPARα agonists, such as fibrates, have been used for the treatment of hypertriglyceridemia and cardiovascular diseases. PPARα has an anti-inflammatory role during infection, and similar to PPARγ, affects the polarization of macrophages. In acute myelogenous leukemia (AML), PPARα mutations correlate with chemoresistance, poor treatment outcomes and unfavorable prognosis. In experimental tumor models, it has been proposed that PPARα agonists might enhance anti-tumor T cell responses during PD-1 blocking immunotherapy. To dissect the mechanistic role of PPARα in tumor immunity, we used mice with global deletion of PPARα and examined tumor growth and profile of the immunological landscape, using various syngeneic tumor models. Significantly larger B16-F10 melanoma and MC-17 fibrosarcoma tumors were observed in PPARα KO mice compared with wild-type control, suggesting that PPARα deletion attenuated the immunological response against cancer. To dissect the role of PPARα in key populations of the innate and adaptive immune system involved in anti-tumor responses, we analyzed the immunological landscape of tumor, tumor draining lymph nodes (TDLN) and spleen, 14-16 days after tumor implantation. Assessment of CD4 + and CD8 + T cells, CD11b +F4/80 + tumor-associated macrophages (TAMs), CD11b +Ly6C hiLy6G - monocytic myeloid derived suppressor cells (M-MDSC), and CD11b +Ly6C loLy6G + polymorphonuclear myeloid derived suppressor cells (PMN-MDSC), by using flow cytometry, showed no quantitative differences between the two experimental groups. Functionally, MDSC from PPARα KO and WT mice showed comparable immunosuppressive properties as determined by suppression assay using splenocytes from OTI transgenic mice. However, PPARα KO TAMs demonstrated a less activated state, as determined by the lower expression levels of MHC-II that is critical for antigen presentation, and CD86 that is critical for T cell costimulation and prevention of T cell anergy and exhaustion. In agreement with these properties of TAMs, CD4 + T cells from TDLN of PPARα KO mice had diminished expression of activation markers, including PD-1, PD-L1 and ICOS, and numerically decreased central memory-like CD4 + T cells (T CM), compared to control tumor bearing mice. Furthermore, CD69, an emerging marker of T cell exhaustion, was significantly upregulated in CD4 + and CD8 + T cells from the TDLN of PPARα KO mice. To determine whether PPARα ablation altered the cell intrinsic properties of myeloid cells and/or T cells resulting in impaired anti-tumor function, we examined in vitro responses of isolated populations. In response to activation via TCR/CD3 and CD28, PPARα deficient T cells had no significant differences in expansion and cytokine production compared to control. In contrast, PPARα deficient Ly6C + monocytes isolated from the bone marrow displayed diminished responses to TLR-mediated signaling as determined by production of IL-6 and TNFα. Our in vitro and in vivo findings reveal a dominant role of PPARα in regulating the fate of innate immune cells thereby altering T cell responses and anti-tumor function. Our findings have implications for the development of new therapeutic approaches to enhance innate immune cell function for the improvement of cancer immunotherapy. Disclosures No relevant conflicts of interest to declare.

scholarly journals In CLL, Myeloid-Derived Suppressor Cells and Their Monocytic and Granulocytic Varieties Differ in T-Cell Subset Association and Polarization Induction

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 4350-4350
Author(s):  
Gerardo Ferrer ◽  
Brendan Franca ◽  
Pui Yan Chiu ◽  
Stefano Vergani ◽  
Andrea Nicola Mazzarello ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Cd4 T Cells ◽  
Th17 Cells ◽  
Research Funding ◽  
Suppressor Cells ◽  
Myeloid Derived Suppressor Cells ◽  
Cd8 Cells

Abstract In chronic lymphocytic leukemia (CLL) monoclonal B cells expand and progressively accumulate in the bone marrow, eventually migrating to secondary lymphoid organs for even greater proliferation. At both sites, CLL cells engage in complex, incompletely defined cellular and molecular interactions involving multiple cell types such as T cells, myeloid cells, mesenchymal stromal cells, and matrix, collectively referred to as the "tumor microenvironment". This microenvironment is critical for the survival and proliferation of CLL cells, and data indicate that T cells and myeloid cells have an important role in these processes. In this study, we focus on two cells types: CD4+ T lymphocytes and myeloid-derived suppressor cells (MDSCs). In CLL patients, these populations are altered and impact on clinical outcome. CD4+ T cells comprise several subtypes, and CLL patients often have expanded Th2 and Tregs populations, consistent with the immunosuppressive status of these patients. Moreover, patients with higher numbers of another CD4+ subset, Th17 cells that produce IL-17 and other pro-inflammatory cytokines, can have longer survival times. Although studied minimally in CLL, MDSCs are known suppressors of T cell proliferation in vitro, and expand along with malignant cells in several cancers. However, no information is available about their effects on CD4+ T cell differentiation or on B-cell biology in CLL. In a cohort of 56 untreated CLL patients, we first explored correlation of the numbers of MDSCs and autologous T cells, using flow cytometry. CD3+ cell numbers significantly paralleled total MDSCs and monocyte-like MDSCs (mMDSCs) (P = 0.002, Spearman r = 0.44; P = 0.004, Spearman r = 0.41, respectively). Interestingly, MDSCs correlated with CD4+ and CD8+ T-cells (P < 0.001, Spearman r = 0.646; P < 0.001, Spearman r = 0.61, respectively). However, the correlation of MDSC subpopulations with CD4+ and CD8+ cells differed: mMDSCs associated significantly with CD4+ cells (P < 0.001, Spearman r = 0.73) and granulocyte-like MDSCs (gMDSCs) with CD8+ cells (P= 0.008; Spearman r = 0.45). Furthermore, although gMDSCs did not correlate with the numbers of CD4+ T-cells, we observed that they positively paralleled Tregs defined as CD3+/CD4+/CD25+/CD127-/FoxP3+ cells (P = 0.020, Spearman r = 0.44). Other subpopulations are currently under study. To address the effect of MDSCs on CD4+ cell differentiation, we FACS sorted CD3+/CD45RO- naïve CD4+ lymphocytes and stimulated them in vitro with anti-CD3/CD28 beads and IL2 in the presence or absence of mMDSCs (HLA-DRlo/CD11b+/CD33+/CD14+), gMDSCs (HLA-DRlo/CD11b+/CD33+/CD15+) or monocytes (HLA-DRhi/CD11b+/CD14+); these studies involved samples from 3 CLLs and 3 healthy controls (HCs). On day 7, cells were harvested and cytokine production was quantified by intracellular flow cytometry as the percentages of the following populations: Th1 (INFγ), Th2 (IL-4), Tregs (FoxP3), Th17 (IL-17A and IL-17F), Th9 (IL-9) and Th22 (IL-22). Culturing CLL or HC T cells in the absence of MDSCs revealed a lower percentage of cytokine-producing cells (24% vs. 55%; P = 0.017) in CLL, which was mainly due to a reduction in IL-4+ cells (P = 0.066). However, when analyzing the effects of MDSC subsets on the polarization of CLL or HC T cell, gMDSCs promoted significantly more FoxP3+ and less IL-22+ cells in CLL than in HC (P = 0.025 and P = 0.048, respectively). When analyzing only CLL T cells, supplementation with mMDSCs induced a reduction in IL-22+ cells (P = 0.027) and an insignificant increase of IL-4+ and IL-17+ cells. Conversely monocytes supported an expansion of INFγ+ T-cells (P=0.066), and gMDSCS promoted an increase of IL-9+ cells (P = 0.046) and a reduction of FoxP3+ cells (P = 0.019). In summary, in CLL the absolute numbers of total MDSCs and T cells are tightly linked. There is a significant correlation between CD4+ T cells and mMDSCs, and between CD8+ T cells and gMDSCs. Additionally, in CLL naïve CD4+ differentiation appears reduced compared to HC, in concordance with lower T-cell responses previously reported. Moreover, the preliminary aspects of the study suggest that CLL mMDSCs promote an expansion of Th2, Th17 cells and a reduction of Th22 cells, and monocytes enhance Th1s. Unexpectedly, since we observed a significant positive correlation in the PBMCs, gMDSCs may reduce Tregs and augment Th9. These findings depict differential consequences of CLL T cell - MDSC / mMDSC / gMDSC interactions. Disclosures Stamatopoulos: Abbvie: Honoraria, Other: Travel expenses; Gilead: Consultancy, Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Janssen: Honoraria, Other: Travel expenses, Research Funding.

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