scholarly journals Myeloid-Derived Suppressor Cells Are Expanded in Patients with AML and Are Dependent on MUC1 Expression

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 226-226
Author(s):  
Athalia Rachel Pyzer ◽  
Dina Stroopinsky ◽  
Jacalyn Rosenblatt ◽  
Kristen Anna Palmer ◽  
Maxwell Douglas Coll ◽  
...  
Keyword(s):  
T Cells ◽  
Healthy Donor ◽  
Suppressor Cells ◽  
Fold Increase ◽  
Muc1 Expression ◽  
Healthy Controls ◽  
Myeloid Derived Suppressor Cells ◽  
Control Vector ◽  
Donor Pbmcs

Abstract Introduction: Myeloid-derived suppressor cells (MDSCs) are a critical component of the immunosuppressive milieu of the tumor microenvironment and play an important role in promoting immune tolerance and disease growth. They are comprised of granulocytic and monocytic compartments defined by a unique immunophenotypic signature. Importantly, the mechanism by which tumor cells evoke the expansion of MDSCs has not been well elucidated. In the present study, we examined the interaction of MDSCs with AML cells, a setting in which the presence and function of MDSC has not been well described. Methods and Results: Peripheral blood mononuclear cells (PBMCs) were isolated from patients with active AML and granulocytic (CD33+/CD11b+/HLADR-/CD15+) and monocytic (CD33+/CD11b+/HLADR-/CD15-) MDSCs were quantified by multichannel flow cytometry. AML patients had a significantly higher mean granulocytic MDSC population of 17.2% (n=3) compared to healthy controls 1.9%, (n=10) p=0.0083 and a mean monocytic MDSC population of 6.5% (n=3), which was similar to healthy controls (monocytic MDSCs 4.1%, n=10). MDSCs isolated from an AML patient exhibited immunosuppressive effects as measured by the suppression of dendritic cell mediated stimulation of T cells. The addition of AML derived MDSCs resulted in a 40% reduction in CD4+T cell production of IFNϒ and an 11 fold increase IL-10 secretion by CD4 and CD8 T cells following coculture with allogenic DC stimulation. The ability of AML blasts to directly induce the expansion of MDSC was assessed in vitro. Healthy donor PBMCs were co-cultured for 6 days with or without the AML cell lines MOLM-14 and THP-1 at a ratio of 100:1. MDSCs were quantified after 6 days. Coculture with MOLM-14 and THP-1 induced a 2.35 and 8.2 fold increase in MDSCs respectively (n=4). MUC1 is a critical oncogene expressed on leukemic blasts and leukemia initiating cells and plays an important role in the tumor microenvironment promoting tumor growth and immune escape. In the present study, we demonstrated that silencing of MUC1 via shRNA significantly diminishes AML recruitment and expansion of MDSCs in vitro. MOLM-14 cells underwent lentiviral transfection to silence MUC1-C expression which was confirmed by Western Blot. MOLM-14 wild type, MUC1 silenced, and control vector treated cells were co-cultured with healthy PBMCs for 6 days in a ratio of 100:1. Of note, MUC1-C silenced MOLM-14 and THP-1 cells exhibited decreased capacity to expand MDSCs upon co-culture with healthy donor PBMCs, as compared to the control vector (2.4 fold higher expansion of MDSCs with control vector MOLM-14 compared to MUC1-C silenced MOLM-14, n=4, 1.92 fold higher expansion of MDSCs with control vector THP-1 compared to MUC-1C silenced THP-1, n=4). In an in vivo model, NSG mice were irradiated and inoculated with THP-1 control and THP-1 MUC1 silenced cells. Following establishment of disease, mice were sacrificed and spleens were FACS analysed for MDSC quantification. Mice inoculated with THP-1 MUC1 silenced cells had mean MDSCs of 7.5%, compared to 16.25% in mice innoculated with THP-1 Wildtype cells (n=4). In conclusion, the data demonstrates that MDSCs are increased in the circulation of patients with AML, and that leukemic blasts directly induce the expansion of MDSCs. MUC1 expression on AML blasts contributes to the immunosuppressive milieu, and notably, silencing of MUC1 in AML cells blunts their capacity to induce the expansion of MDSCs. Incorporating strategies to inhibit the expansion of MDSC in AML, and reverse their immunosuppressive phenotype has the potential to improve response to therapy in AML. Disclosures No relevant conflicts of interest to declare.

Allogeneic Vδ1 gamma delta T cells engineered with glypican-3 (GPC3)-specific CAR expressing soluble IL-15 have enhanced antitumor efficacy against hepatocellular carcinoma in preclinical models.

2021 ◽  
Vol 39 (15_suppl) ◽  
pp. e14511-e14511
Author(s):  
Amani Makkouk ◽  
Xue (Cher) Yang ◽  
Taylor Barca ◽  
Anthony Lucas ◽  
Mustafa Turkoz ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
T Cells ◽  
T Cell ◽  
Healthy Donor ◽  
Cytokine Production ◽  
Tumor Control ◽  
Gamma Delta ◽  
T Cell Therapy ◽  
Donor Pbmcs

e14511 Background: Autologous αβ chimeric antigen receptor (CAR) T cell therapy has shown promising clinical results in hematologic malignancies but limited success in solid tumors. Allogeneic αβ T cell therapy may overcome several challenges faced by autologous therapy but carries the risk of graft-versus-host disease (GvHD) and does not readily recognize multiple tumor-associated antigens. Gamma delta (γδ) T cells are highly cytolytic effectors that can recognize and kill tumor cells in an MHC-unrestricted manner without causing GvHD. The Vδ1 subset is preferentially localized in peripheral tissue and is critical for tumor immunosurveillance. Engineering Vδ1 T cells with CARs can further enhance antitumor activity and represents an attractive and safe approach to treating solid tumors. However, their clinical use has been hindered by the limited number of circulating Vδ1 T cells. Here, we describe the development of the first allogeneic Vδ1 T cells that have been expanded from healthy donor PBMCs and genetically modified to secrete IL-15 (sIL15) and express a CAR targeting glypican-3 (GPC3), a rational target for hepatocellular carcinoma (HCC). Methods: Vδ1 T cells in healthy donor PBMCs were activated by a Vδ1-specific monoclonal antibody and transduced with 41BBζ or 41BBζ-sIL15 GPC3-CARs prior to cell expansion, αβ T cell depletion and cryopreservation. In vitro characterization included: 1) co-culture assays with GPC3-expressing HCC targets HepG2 and PLC/PRF/5, 2) phenotypic analysis by flow cytometry, and 3) cytokine production by multiplexed immunoassay. For in vivo assessment of tumor control, immunodeficient NSG mice were subcutaneously injected with HepG2 cells and treated with a single dose of 41BBζ or 41BBζ-sIL15 GPC3-CAR Vδ1 T cells. Additionally, tissues were harvested 7 days post transfer and analyzed by flow cytometry for Vδ1 T cell tissue homing and proliferation, or at end of study and analyzed for GvHD by immunohistochemistry. Results: Vδ1 T cells expanded over 10,000-fold and routinely reached >80% purity. Expanded Vδ1 T cells showed a primarily naïve-like phenotype (CD45RA+CD27+) with minimal exhaustion receptor expression and displayed robust proliferation, cytokine production, and cytotoxic activity against HCC cell lines expressing low and high GPC3 levels in vitro. In a HepG2 mouse model, GPC3-CAR Vδ1 T cells primarily accumulated and proliferated in the tumor, and a single dose was able to efficiently control tumor burden without causing GvHD. Importantly, 41BBζ-sIL15 GPC3-CAR Vδ1 cells displayed enhanced tumor-specific proliferation that resulted in better tumor control without any toxicity. Conclusions: Our results show that expanded Vδ1 T cells engineered with GPC3-CAR and sIL-15 represent a promising platform for safe and effective off-the-shelf treatment of HCC.

scholarly journals Myeloid-Derived Suppressor Cells Therapy Enhance Immunoregulatory Properties in Acute Graft Versus Host Diseas with Combination of Regulatory T Cells

2020 ◽  
Author(s):  
Min-Jung Park ◽  
Jin-Ah Baek ◽  
Se-Young Kim ◽  
Kyung-Ah Jung ◽  
Jeong Won Choi ◽  
...  
Keyword(s):  
T Cells ◽  
Cell Therapy ◽  
B Cell ◽  
Immune Tolerance ◽  
Cell Subset ◽  
Suppressor Cells ◽  
Myeloid Derived Suppressor Cells ◽  
Graft Versus Host ◽  
Acute Graft

Abstract Background: Myeloid-derived suppressor cells (MDSCs) play a critical role in modulating the immune response and suppressing autoimmunity and transplantation. Regulatory T cells (Tregs) exert therapeutic potential due to their immunomodulatory properties, which have been demonstrated both in vitro and in clinical trials. Cell-based therapy for acute Graft-versus-host disease (aGVHD) may enable induction of donor-specific tolerance in the preclinical setting. Methods: We investigated whether the immunoregulatory activity of the combination of MDSCs and Tregs on T cell and B cell subset and alloreactive T cell response. We evaluated the therapeutic effects of combined cell therapy for aGVHD following MHC-mismatched bone marrow transplantation. We compared histologic analysis from the target tissues of each groups were and immune cell population by flow cytometric analysisResults: We report a novel approach to inducing immune tolerance using a combination of donor-derived MDSCs and Tregs. The combined cell-therapy modulated in vitro the proliferation of alloreactive T cells and the Treg/Th17 balance in mice system. Systemic infusion of MDSCs and Tregs ameliorated serverity and inflammation of aGVHD by reducing the populations of proinflammatory Th1/Th17 cells and the expression of proinflammatory cytokines in target tissue. The combined therapy promoted the differentiation of allogeneic T cells toward Foxp3+Tregs and IL-10-producing regulatory B cells. The combination treatment control also activated human T and B cell subset.Conclusions: Therefore, the combination of MDSCs and Tregs has immunomodulatory activity and induces immune tolerance to prevent of aGVHD severity. This could lead to the development of new clinical approaches to the prevent aGVHD.

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 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 MGTA-145 in Combination with Plerixafor Rapidly Mobilizes High Numbers of Hematopoietic Stem Cells and Graft-Versus-Host Disease Inhibiting Myeloid-Derived Suppressor Cells in Non-Human Primates

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 116-116
Author(s):  
Kevin A. Goncalves ◽  
Patrick C. Falahee ◽  
Sharon L. Hyzy ◽  
Shuping Li ◽  
Anthony E. Boitano ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Acute Gvhd ◽  
Suppressor Cells ◽  
Fold Increase ◽  
Employment Equity ◽  
Hematopoietic Stem ◽  
Nsg Mice ◽  
Equity Ownership

Abstract Background. The majority of bone marrow transplants (BMTs) are performed with granulocyte-colony stimulating factor (G-CSF) mobilized peripheral blood (mPB) as the source of hematopoietic stem cells (HSCs) for patients. Up to 80% of mPB allogeneic recipients, however, will experience graft-versus-host disease (GvHD). Despite higher levels of CD3+ T cells in mPB grafts compared to BM, the level of acute GvHD observed following transplant of HLA-matched mPB is comparable to HLA-matched BM. One explanation is that G-CSF mobilized grafts contain myeloid-derived suppressor cells (MDSCs) possessing potent immunosuppressive properties capable of inhibiting T cell proliferation in vitro. The percentage of MDSCs is variable in grafts mobilized with G-CSF and clinical data suggest that patients transplanted with mPB grafts that contain higher numbers of MDSCs may have better outcomes including lower rates of acute GvHD (Vendramin et al., BBMT 2014). Identification of a mobilizing regimen that consistently produces high numbers of HSCs and MDSCs may be preferred. We recently reported that MGTA-145 (GroβT), a CXCR2 agonist, when combined with the CXCR4 inhibitor, plerixafor, robustly mobilizes HSCs (Blood 2017 130:1920). In this study, non-human primates (NHPs) were mobilized with a single dose of MGTA-145, plerixafor, or MGTA-145/plerixafor versus a multi-dose regimen of G-CSF, and mPB was harvested to allow detailed immune profiling at 0 through 24 hours. We observed a significant and rapid increase in number of HSCs and CD34dim monocytes with potent in vitro and in vivo immunosuppressive properties. Results. MGTA-145/plerixafor consistently produced a 16-fold increase in number of CD34+CD90+CD45RA- HSCs within four hours of dosing (p=0.0003, n=11). Profiling of graft subsets from these primates also showed a 10-fold increase over baseline in the number of CD34dim monocytes at 4 hours post treatment (p<0.0001, n=11, Figure 1A) that corresponded to 2-3-fold higher frequency and number compared to G-CSF or plerixafor alone (p<0.01, n=2-5) and correlated with degree of HSC mobilization (p<0.0001). To determine if this monocytic cell population had immunosuppressive properties, CD34dim cells were sorted from peripheral blood of NHPs treated with MGTA-145/plerixafor and co-cultured with anti-CD2, anti-CD3 and anti-CD28-stimulated autologous T cells. MGTA-145/plerixafor CD34dim monocytes suppressed T cell proliferation, as measured by CFSE staining after four days. To assess whether these immunosuppressive monocytes may prevent GvHD, we developed a xenograft GvHD model in NSG mice. MGTA-145/plerixafor mPB (6 x 106 PBMCs) containing a high percentage of CD34dim monocytes were injected into sublethally irradiated NSG mice. This was compared to unmobilized primate PBMCs (6 x 106 PBMCs) containing relatively low numbers of CD34dim cells. At day 20, all mice (8/8) transplanted with unmobilized PBMCs had died of acute GvHD compared to none of the mice transplanted with MGTA-145/plerixafor mPB. Mice transplanted with unmobilized PBMCs also demonstrated 3-fold higher numbers of T-cells and increased T-cell activation compared to mice transplanted with MGTA-145/plerixafor mobilized PBMCs (p<0.01, n=6-8). At day 60 post-transplant, 7/8 mice remained alive (Figure 1B, p<0.0001). To assess whether this immunosuppressive effect is due to CD34dim monocytes, we sorted these cells and transplanted PBMCs depleted of CD34dim monocytes into NSG mice. In addition, experiments comparing the number and function of primate HSCs mobilized by MGTA-145/plerixafor or G-CSF alone using the NSG engraftment model and using autologous NHP transplant coupled with ex vivo HSC gene therapy are ongoing. Conclusions. Co-administration of MGTA-145/plerixafor in NHPs results in both rapid and efficacious mobilization of highly enriched HSCs and a CD34dim monocyte population with potent immunosuppressive activity compared to cells mobilized with plerixafor alone or with the current standard of care, G-CSF. The increased number of these immunosuppressive monocytes compared to G-CSF has the potential to reduce GvHD in the allogenic transplant setting. Thus, MGTA-145/plerixafor may offer an advantageous graft in the allogeneic setting where the risk of GvHD remains a significant clinical problem. IND-enabling studies of MGTA-145 are in progress to assess this regimen for mPB collection and transplant. Disclosures Goncalves: Magenta Therapeutics: Employment, Equity Ownership, Patents & Royalties. Falahee:Magenta Therapeutics: Employment, Equity Ownership, Patents & Royalties. Hyzy:Magenta Therapeutics: Employment, Equity Ownership. Li:Magenta Therapeutics: Employment, Equity Ownership. Boitano:Magenta Therapeutics: Employment, Equity Ownership, Patents & Royalties. Morrow:Magenta Therapeutics: Employment, Equity Ownership, Patents & Royalties. Cooke:Magenta Therapeutics: Employment, Equity Ownership, Patents & Royalties.

scholarly journals Mass Cytometry Identifies a Novel Signature for Myeloid-Derived Suppressor-Cells in Waldenstrom's Macroglobulinemia

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 3976-3976
Author(s):  
Shahrzad Jalali ◽  
Jose Villasboas ◽  
Jie Shi ◽  
Cole Bothun ◽  
Hyojin Kim ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Clinical Trials ◽  
T Cells ◽  
Research Funding ◽  
Cell Function ◽  
Suppressor Cells ◽  
High Dimensional ◽  
Healthy Controls ◽  
Myeloid Derived Suppressor Cells ◽  
Activated T Cells

Myeloid derived suppressor cells (MDSC) are a heterogeneous population of undifferentiated myeloid cells that are expanded and activated in pathological conditions and have the ability to potently suppress T-cell function and thereby contribute to immunosuppression and tumor progression. While there have been studies showing a role for MDSC in a variety of hematological malignancies, no data is available indicating that MDSCs contribute to the tumor progression in Waldenstrom's Macroglobulinemia (WM), an indolent lymphoma characterized by bone marrow (BM) infiltration of lymphoplasmacytic (LPL) cells and increased secretion of monoclonal IgM. In previous work, we have found increased GM-CSF and reduced arginine and cysteine in the BM microenvironment in WM. We hypothesized that this was due to the presence and activity of MDSCs in WM. BM aspirates from WM patients (n=17) were therefore processed to isolate LPL (CD19+/CD138+) cells from the rest of the BM cells (CD19-/CD138-). Sorted (CD19-/CD138-) cells from BM of patients with WM were studied with flow cytometry. Using a sequential gating strategy (lack of lineage markers, low levels of HLADR, CD33+, CD11b+) we identified a population of MDSCs that were then subdivided using CD14 and CD15 expression into total-, monocytic-, or granulocytic- MDSCs (m-MDSC, g-MDSC). We also analyzed unsorted BM cells using cytometry by time-of-flight (CyTOF) in order to further identify and phenotypically characterize the BM MDSC population in a group of WM patients with smoldering (asymptomatic) disease, symptomatic disease, or in remission post-treatment. BM samples from normal subjects were used as a control. Flow cytometry data showed significant higher numbers of MDSC subsets expressing PD-L1 and Arginase1 in WM patients when compared to the normal samples. BM cells from WM patients (n=18) then were compared to controls (n=11), and the absolute number of the total MDSC (p=0.05), m-MDSC (p=0.002), g-MDSC (p=0.02) was increased in WM specimens. When MDSCs from WM or normal monocytes from healthy controls were co-cultured with activated T-cells, the proliferation of activated T-cells in the presence of MDSCs from WM patients was impaired compared to controls, confirming the suppressive role of MDSCs. We then performed high dimensional analysis of the total BM MDSC cells using t-SNEand identified phenotypically distinct MDSC cell populations in the BM that were differentially present when healthy controls were compared to patients with smoldering WM or those with WM needing treatment. Specifically, WM patients needing treatment had increased numbers of a distinct MDSC population that was highly positive for CD163, and CD138. Moreover, conventional markers denoting m-MDSC and g-MDSC, such as CD14 and CD15, were highly expressed in all populations and their pattern of expression did not specifically define the MDSC subtypes, indicating that high dimensional phenotyping further details the MDSC sub-compartments beyond the conventional categorization of MDSC using conventional cytometry. In summary, we find that MDSCs are increased in the BM of WM patients compared to controls. MDSCs expressing CD163 and CD138 increase when WM patients become symptomatic and require therapy. Furthermore, MDSCs in the BM of WM patients suppress T-cell function and likely contribute to progression of the disease. MDSCs in the BM therefore present a therapeutic target that should be explored in WM patients. Disclosures Ansell: Bristol Myers Squibb: Other: research funding for clinical trials; Merck: Other: research funding for clinical trials; AI Therapeutics: Other: research funding for clinical trials; Affimed: Other: research funding for clinical trials; Takeda: Other: research funding for clinical trials; Pfizer: Other: research funding for clinical trials; Regeneron: Other: research funding for clinical trials; Seattle Genetics: Other: research funding for clinical trials.

Acute Myeloid Leukemia Cells Export c-Myc in Extracellular Vesicles Driving a Proliferation of Immune-Suppressive Myeloid-Derived Suppressor Cells

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 703-703
Author(s):  
Athalia Rachel Pyzer ◽  
Dina Stroopinsky ◽  
Hasan Rajabi ◽  
Abigail J. Washington ◽  
Leandra Cole ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Extracellular Vesicles ◽  
Research Funding ◽  
Healthy Donor ◽  
Myeloid Cells ◽  
Suppressor Cells ◽  
Negative Regulator ◽  
Myeloid Derived Suppressor Cells ◽  
Antigen Presenting ◽  
Donor Pbmcs

Abstract Myeloid-derived suppressor cells (MDSCs) play a critical role in promoting immune tolerance and disease growth. We have previously shown that MDSCs are expanded in patients with AML and can be induced from healthy donor PBMCs by co-culture with leukemic cells; a mechanism dependent on expression of the MUC1-C oncoprotein. We sought to elucidate the precise mechanism by which MUC1-C signaling mediates the expansion of this immune suppressive population of immature myeloid cells. We have previously demonstrated that AML cells release membrane bound extracellular vesicles, which traffic to co-cultured cells. We hypothesized that AML EVs may mediate the expansion of MDSCs. MOLM-14 and THP-1 AML EVs were isolated using the ExoQuick precipitation technique, and analyzed by flow cytometry, and compared to size standardized beads, demonstrating particles between 200-300nM in diameter. Furthermoreisolated AML EVs were visualised using Transmission Electron Microscopy demonstrating multiple rounded structures measuring 100-200nM in diameter and bound by darkly staining membrane. Subsequently, healthy donor PBMCs were cultured for three days with GFP tagged AML EVs and then quantified for CD33+/HLADR-/CD11b+ MDSCs and HLADR+/CD11c+ antigen presenting myeloid cells by flow cytometry. In the PBMCs co-cultured with EVs, the proportion of MDSCs increased 8-fold, whilst the proportion of HLADR+/CD11c+ antigen presenting myeloid cells decreased by 10 fold (n=3, p<0.05). We subsequently investigated how MUC1-C signaling, necessary for the expansion of MDSCs, might alter AML extracellular vesicles composition. We evaluated AML EVs for the presence of the pro-proliferative oncoprotein c-Myc by immune-blotting, demonstrating that AML cells secrete EVs containing c-Myc, which is abrogated by downregulation of MUC1-C. Furthermore, EVs containing MUC1 and c-myc led to an up-regulation of the c-Myc downstream targets cyclin D2 and cyclin E1 in co-cultured MDSCs, indicating that c-Myc containing EVs may drive MDSC proliferation. Critically, EVs from MUC1-C silenced AML cells failed to elicit this increase in c-Myc and cyclin D2 and E1 expression in EV exposed MDSCs. Interestingly, exposure of MDSCs to AML EVs lead to an increased expression of PD-L1, which was abrogated in EVs from MUC1-C silenced AML cells. We then sought to determine how MUC1 signaling promotes c-Myc signaling in AML. MUC1-C silencing did not alter c-Myc mRNA levels suggesting a post-transcriptional level of regulation. Micro RNAs are small non-encoding RNA molecules involved in post-translational regulation of gene expression. MiR34a, a known p53 inhibitor, has been implicated in regulating the expansion of MDSCs and it is known that tumor cells suppress MiR34a expression as part of their self-protective armoury. Furthermore, MiR34a is a predicted negative regulator of c-Myc, due to a complementary sequence for MiR34a in the c-Myc promoter region. Using qPCR, we have demonstrated that MUC1-C silencing results in increased expression of MiRNA34a. Furthermore, over-expression of MiR34a in AML cells led to a dramatic down-regulation of c-Myc protein expression, and conversely silencing of MiR34a led to a significant upregulation of c-Myc expression, confirming that MiR34a regulates c-Myc expression in AML. To confirm MiR34a as a critical negative regulator of MDSC expansion, MiR34a altered cells were interrogated for their ability to elicit an expansion of MDSCs in co-cultured PBMCs. Overexpression of MiR34a in AML cells partially abrogated their ability to induce MDSCs from co-cultured donor PBMCs. In concert, silencing of MiR34a in MUC1-C silenced AML cells, recapitulated their ability to induce MDSCs in this model. Taken together, this study illustrates a novel role of the MUC1-C and c-Myc oncoproteins in driving MDSC proliferation and MDSC PD-L1 expression. We have demonstrated that AML EVs alter the tumor microenvironment away from antigen presentation capable myeloid cells and towards immature immune suppressive MDSCs. Disclosures Arnason: Gilead: Consultancy. Küfe:Genus Oncology: Equity Ownership. Rosenblatt:Astex: Research Funding; BMS: Research Funding; DCPrime: Research Funding. Avigan:Astex: Research Funding; DCPrime: Research Funding.

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 Myeloid-derived suppressor cells therapy enhance immunoregulatory properties in acute graft versus host disease with combination of regulatory T cells

2020 ◽  
Vol 18 (1) ◽  
Author(s):  
Min-Jung Park ◽  
Jin-Ah Baek ◽  
Se-Young Kim ◽  
Kyung-Ah Jung ◽  
Jeong Won Choi ◽  
...  
Keyword(s):  
T Cells ◽  
Cell Therapy ◽  
Immune Tolerance ◽  
Graft Versus Host Disease ◽  
Cell Subset ◽  
Suppressor Cells ◽  
Myeloid Derived Suppressor Cells ◽  
Graft Versus Host ◽  
Acute Graft

Abstract Background Myeloid-derived suppressor cells (MDSCs) play a critical role in modulating the immune response and promoting immune tolerance in models of autoimmunity and transplantation. Regulatory T cells (Tregs) exert therapeutic potential due to their immunomodulatory properties, which have been demonstrated both in vitro and in clinical trials. Cell-based therapy for acute graft-versus-host disease (aGVHD) may enable induction of donor-specific tolerance in the preclinical setting. Methods We investigated whether the immunoregulatory activity of the combination of MDSCs and Tregs on T cell and B cell subset and alloreactive T cell response. We evaluated the therapeutic effects of combined cell therapy for a murine aGVHD model following MHC-mismatched bone marrow transplantation. We compared histologic analysis from the target tissues of each groups were and immune cell population by flow cytometric analysis. Results We report a novel approach to inducing immune tolerance using a combination of donor-derived MDSCs and Tregs. The combined cell-therapy modulated in vitro the proliferation of alloreactive T cells and the Treg/Th17 balance in mice and human system. Systemic infusion of MDSCs and Tregs ameliorated serverity and inflammation of aGVHD mouse model by reducing the populations of proinflammatory Th1/Th17 cells and the expression of proinflammatory cytokines in target tissue. The combined therapy promoted the differentiation of allogeneic T cells toward Foxp3 + Tregs and IL-10-producing regulatory B cells. The combination treatment control also activated human T and B cell subset. Conclusions Therefore, the combination of MDSCs and Tregs has immunomodulatory activity and induces immune tolerance to prevent of aGVHD severity. This could lead to the development of new clinical approaches to the prevent aGVHD.

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.

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