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In recent years, studying the role of myeloid-derived suppressor cells (MDSCs) in many pathological inflammatory conditions has become a very active research area. Although the role of MDSCs in cancer is relatively well established, their role in non-cancerous pathological conditions remains in its infancy resulting in much confusion. Our objectives in this review are to address some recent advances in MDSC research in order to minimize such confusion and to provide an insight into their function in the context of other diseases. The following topics will be specifically focused upon: (1) definition and characterization of MDSCs; (2) whether all MDSC populations consist of immature cells; (3) technical issues in MDSC isolation, estimation and characterization; (4) the origin of MDSCs and their anatomical distribution in health and disease; (5) mediators of MDSC expansion and accumulation; (6) factors that determine the expansion of one MDSC population over the other; (7) the Yin and Yang roles of MDSCs. Moreover, the functions of MDSCs will be addressed throughout the text.
Subject(s)
Humans , Biology , Myeloid-Derived Suppressor Cells , NeoplasmsABSTRACT
@#Myeloid-derived suppressor cells (MDSCs) are a group of highly heterogeneous immunosuppressive cells produced in the bone marrow, which accumulate in large amounts under pathological conditions such as malignant tumors. MDSCs are the significant cell subsets that reduce patients' response to traditional treatment and promote tumor progression. In recent years, immune checkpoint blockade and adoptive transfusion of engineered T cells have significantly prolonged the survival of many patients with advanced malignant tumors, but the effective rate from 15% to 40% in some solid tumors including lung cancer, colorectal cancer etc., which is closely related to the immunosuppressive microenvironment in solid cancers. With the accumulation in tumor microenvironment, MDSCs reduce the anti-tumor immune response of patients by inhibiting T cell or NK cell proliferation and function, which is the key mechanism for patients tolerating to immunotherapy. Therefore, clarifying the accumulation and functional characteristics of MDSCs is an important research direction to explore the improvement of restoring immunotherapy. This article will systematically elaborate the regulatory mechanism of MDSC production, aggregation and immunosuppressive function, and outline the latest research progress of targeted MDSC therapy
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Objective: To investigate the effect of cisplatin on heart failure in bladder cancer mice by impairing granulocytic myeloid-derived suppressor cells (G-MDSCs). Methods: Fifty 8-week-old specific pathogen free (SPF) C3H/He healthy female mice were used to establish the bladder cancer model after subcutaneous injection of MBT-2 mice bladder cancer cells. The mice were divided into group A-E,10 mice in each group,and the group A was set as the blank control group. The group B-E mice were continuously intraperitoneally injected with 5 mg/ (kg•d) isoproterenol for 14 d to successfully establish the heart failure model. The group B was set as the control group. The mice were intraperitoneally injected with 7.5 mg/kg cisplatin every 48 h for chemotherapy,and killed at 14 d in the group C. G-MDSCs were identified,isolated and purified by flow cytometry. 1×107 purified G-MDSCs were intravenously injected into the group D mice via the tail vein every 7 d. The group E mice was treated by combining the procedure of the group C and the group D. The myocardial tissue of the mice was stained by hematoxylin-eosin staining. And the heart failure degree of the mice was analyzed by the heart weight/body weight ratio and the observation under the inverted phase contrast microscope. Results: Flow cytometry results showed that compared with the group B,the level of G-MDSCs in the circulation system of the group C mice was significantly decreased (P=0.000). Hematoxylin-eosin staining and Image J software analysis showed that compared with the group B,the heart weight/body weight ratio and the area of myocardial cells of the group C mice were significantly increased (P=0.001,P=0.002). However,after G-MDSCs injection,the above two indexes in the group D mice were decreased compared with those in the group B (P=0.000,P=0.011). After cisplatin/G-MDSCs combined treatment,the above two indexes in the group E were also decreased compared with those in the group C (P=0.000,P=0.001). Conclusion: G-MDSCs have cardioprotective effects,while cisplatin can facilitate heart failure by impairing G-MDSCs.
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BACKGROUND AND OBJECTIVES: Patients suffer from long-term diabetes can result in severe complications in multiple organs through induction of vascular dysfunctions. However, the effects of chronic hyperglycemic conditions on hematopoiesis and the microenvironment in the bone marrow (BM) are not yet well understood. METHODS: BM cells were harvested from femurs of mice and analyzed using flow cytometry. Human PVCs were cultured in serum-free α-MEM. After 24hrs, PVC-CM was collected and filtered through a 0.22 μm filter. RESULTS: In this study, we showed that hyperglycemia alters hematopoietic composition in the BM, which can partially be restored via paracrine mechanisms, including perivascular cells (PVCs) and NADPH oxidase (NOX) inhibition in mice with streptozotocin-induced diabetes. Prolonged hyperglycemic conditions resulted in an increase in the frequency and number of long-term hematopoietic stem cells as well as the number of total BM cells. The altered hematopoiesis in the BM was partially recovered by treatment with PVC-derived conditioned medium (CM). Long-term diabetes also increased the number of myeloid-derived suppressor cells in the BM, which was partially restored by the administration of PVC-CM and diphenyleneiodonium (DPI), a NOX inhibitor. We further showed the downregulation of ERK and p38 phosphorylation in BM cells of diabetic mice treated with PVC-CM and DPI. This may be associated with dysfunction of hematopoietic cells and promotion of subsequent diabetic complications. CONCLUSIONS: Our data suggested that alterations in BM hematopoietic composition due to prolonged hyperglycemic conditions might be restored by improvement of the hematopoietic microenvironment and modulation of NOX activity.
Subject(s)
Animals , Humans , Mice , Bone Marrow , Culture Media, Conditioned , Diabetes Complications , Down-Regulation , Femur , Flow Cytometry , Hematopoiesis , Hematopoietic Stem Cells , Hyperglycemia , NADP , NADPH Oxidases , PhosphorylationABSTRACT
The diagnosis and treatment methods for cancer are being improved continually, but the mortality of cancer still remains high. At present, the academic circle has realized deficiency of existing treatment ideas, and the concept of cancer cells has been gradually changed from "extremely extinct" to "peaceful coexistence". The concept of "survival with tumors" is universally accepted in the cancer academia. The tumor microenvironment is the place where tumor cells survive and develop. Therefore, regulation of the tumor microenvironment has become an important new strategy for tumor treatment. Myeloid-derived suppressor cells (MDSCs) are a group of heterogeneous cells that have immunosuppressive properties on T cells in the tumor microenvironment and play an important role in tumor immune escape. Now, therapy with MDSCs in the tumor microenvironment as the treatment targets also provides new ideas for the tumor treatment. As MDSCs subpopulations are similar with neutrophils and monocytes, they can be divided into two major subtypes:granulocyte-like myeloid-derived suppressor cells (G-MDSCs) and monocyte-myeloid-derived suppressor cells(M-MDSCs). But how to differ these two subtypes from neutrophils and monocytes. What are the differences in the functional characteristics of different subtypes of MDSCs. How do they accumulate, differentiate, and exert immunosuppressive effects through different pathways. Traditional Chinese medicine(TCM) has always been good at modulating the body's microenvironment. More and more researches have shown that, the recruitment, amplification and activation of MDSCs can be effectively inhibited by TCM compound and its active ingredients, providing scientific basis for Chinese medicine targeting MDSCs in the tumor microenvironment. However, which specific pathways could regulate G-MDSCs or M-MDSCs is still in need of further studies. Most previous literature focus on the overall level of MDSCs, while the this paper would be based on the specific subpopulations of MDSCs to clarify the biological characteristics of these two subtypes of MDSCs, so as to achieve more precise targeted therapy in the tumor microenvironment.
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@# Objective: To investigate the immunosuppressive effect and underlying molecular mechanisms of Myeloid-derived suppressor cells (MDSCs) on T cells activity through IL-6activatingSTAT3/IDO signaling pathway. Methods: Twenty pairs of cancer tissues and the corresponding adjacent normal tissues from breast cancer patients treated at Tianjin Medical University Cancer Institute and Hospital from November 2015 to February 2016 were collected for this study; in the meanwhile, peripheral blood samples from 40 healthy donorswere also collected. CD33+ cells in tumor tissues and CD33+ CD14 + cells in peripheral blood of helthy donors were sorted out with MicroBeads technology. CD33+ cells were in vitro co-cultured with breast cancer cell line MDA-MB-231 to induce MDSCs. Flow cytometry was used to detect the proportion of CD45+ CD13+CD33+CD14-CD15- MDSCs.Western Blotting was used to detect the expression ofSOCS1，SOCS3, JAK1, JAK2, TYK2, STAT1, STAT3 and their phosphorylation levels. qRT-PCR was used to detect the expression of IL-6 and SOCS1-3. CCK8 was used to detect the T cell proliferation. Annexin V staining was used to detect T cell apoptosis. ELISA was used to detect IL-10 and IFN-γ secreted by T cells. Results: There were MDSCs infiltration in all 20 cases of breast cancer tissues for different levels (15.3%~58.1%), with a mean level of (29.82± 11.46%); the infiltration of IL-6high group was significantly higher than that of the IL-6low group [（13.75±3.44） % vs（4.31±1.50） %， P< 0.05], indicating that IL-6 expression was positively correlated with MDSCs infiltration (R2=0.4399, P<0.01). In vitro experiments showed that tumor-derived IL-6 significantly promoted the generation and immunosuppressive activity of MDSCs (P<0.05), which could be reversed by the blocking of IL-6. In the meanwhile, the expression of SOCS3 in MDSCs that induced in vitro was absent, which can be inhibited by blocking IL-6 (P<0.05). Conclusion: The study has demonstrated that tumor-derived IL-6 stimulates the continuous activation of the JAK/STAT signaling pathway and the absence of SOCS3 expression in MDSCs, thereby promoting the infiltration, generation and immunological activity of MDSCs. Therefore, IL-6 signaling pathway can be used as therapeutic target to weaken MDSCs generation and reverse MDSCs activity.
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Graft-versus-host disease (GHVD) is a severe complication after allogeneic hematopoietic stem cell transplantation. The degree of inflammation in the gastrointestinal tract, a major GVHD target organ, correlates with the disease severity. Intestinal inflammation is initiated by epithelial damage caused by pre-conditioning irradiation. In combination with damages caused by donor-derived T cells, such damage disrupts the epithelial barrier and exposes innate immune cells to pathogenic and commensal intestinal bacteria, which release ligands for Toll-like receptors (TLRs). Dysbiosis of intestinal microbiota and signaling through the TLR/myeloid differentiation primary response gene 88 (MyD88) pathways contribute to the development of intestinal GVHD. Understanding the changes in the microbial flora and the roles of TLR signaling in intestinal GVHD will facilitate the development of preventative and therapeutic strategies.
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Bacteria , Dysbiosis , Gastrointestinal Microbiome , Gastrointestinal Tract , Graft vs Host Disease , Hematopoietic Stem Cell Transplantation , Immunity, Innate , Inflammation , Ligands , T-Lymphocytes , Toll-Like ReceptorsABSTRACT
PD-1 antibody immunotherapy has been used as a first-line treatment against various malignancies,but resistance to this treatment limits its efficacy.For instance,myeloid derived suppressor cells,myeloid derived suppressor cells induce resistance to PD-1 antibody in a tumor microenvironment.A few combination regimens of an IDO inhibitor plus PD-1 antibody are currently subjected to ongoing clinical trials in the US,and preliminary results have shown that this inhibitor can reverse the resistance of malignancies to PD-1 antibody.This study reviewed the research progress on the resistance mechanism of malignancies to PD-1 antibody and revealed that IDO inhibitor regulates MDSCs to reverse the resistance to PD-1 antibody.This study also described the clinical efficacy of this in-hibitor plus PD-1 antibody.
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PD-1 antibody immunotherapy has been used as a first-line treatment against various malignancies,but resistance to this treatment limits its efficacy.For instance,myeloid derived suppressor cells,myeloid derived suppressor cells induce resistance to PD-1 antibody in a tumor microenvironment.A few combination regimens of an IDO inhibitor plus PD-1 antibody are currently subjected to ongoing clinical trials in the US,and preliminary results have shown that this inhibitor can reverse the resistance of malignancies to PD-1 antibody.This study reviewed the research progress on the resistance mechanism of malignancies to PD-1 antibody and revealed that IDO inhibitor regulates MDSCs to reverse the resistance to PD-1 antibody.This study also described the clinical efficacy of this in-hibitor plus PD-1 antibody.
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Objective PSGL-1 is specifically expressed in leucocytes.The aim of this study was to explore the changes of myeloid-derived suppressor cells (MDSCs) in the spleen and bone marrow in PSGL-1-deficient mice.Methods PSGL-1 -/-mice were used in the experiment.After identification of the offsprings, flow cytometry was used to test the expression of CD11b and Gr-1 in C57 and PSGL-1 -/-mice.Results Compared with the C57 mice, the expression of MDSCs was up-regulated in the PSGL-1-deficient mice ( P <0.001).Conclusion The expression of MDSCs is upregulated in PSGl-1-deficient mice.
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Anticancer drugs kill tumor cells and increase host anti-tumor immunity. Interestingly, gemcitabin (Gem) and 5-fluorouracil (5-FU), widely used anticancer drugs, lead to IL-1beta secretion releasing cathepsin B which activates Nlrp3 inflammasome in myeloid derived suppressor cells (MDSCs). MDSC derived IL-1beta enhance secretion of IL-17 by CD4+ T cells. This mechanism limits the antitumor efficacy of the drugs and promotes tumor growth.
Subject(s)
Cathepsin B , Cathepsins , Fluorouracil , Interleukin-17 , T-LymphocytesABSTRACT
Objective:To explore the status of STAT3 phosphorylation in myeloid-derived suppressor cells (MDSCs) of breast cancer and its function in the immunosuppressive effect of MDSCs on proliferation and cytokine secretion of T cells. Methods:CCD33+cells were isolated from healthy umbilical cord, blood-derived, peripheral blood mononuclear cells and were co-cultured with breast cancer cell line MDA-MB-231 in vitro using Transwell plates to induce MDSCs. The untreated CD33+cells were used as con-trols. Idoxuridine (IDO) suppressor expression and STAT3 phosphorylation were examined using Western blot assay. The proliferation and cytokine secretion of T cells, which were co-cultured with MDSCs, were determined by methyl thiazol tetrazolium assay and en-zyme-linked immunosorbent assay. 1-MT and JSI-124 were used to investigate the function of IDO and pSTAT3 in MDSC-mediated T cell immunosuppression. Results:The protein levels of IDO and pSTAT3 in MDSCs were significantly upregulated. MDSCs obviously suppressed T-cell proliferation, which was reversed by 1-MT or JSI-124 (P<0.05). MDSCs could promote TGF-βand IL-10 secretions, but could also remarkably inhibit IFN-γsecretion (P<0.05). After incubation with 1-MT or JSI-124, the increase in TGF-βand IL-10, as well as the decrease in IFN-γ, was significantly reversed. Conclusion:The upregulated pSTAT3 induced the IDO increase in MDSCs. JSI-124 can block MDSC-mediated immunosuppressive effect on T cells in breast cancer.
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Myeloid-derived suppressor cells(MDSCs) are heterogeneous cells derived from myeloid progenitor cells and immature myeloid cells(IMCs) in bone marrow;they are the progenitors of dendritic cells(DCs),macrophages and granulocytes.MDSCs proliferate in the blood,spleen,and tumor tissues in tumor-bearing mice and in the peripheral blood and tumor tissues in patients with cancer.MDSCs prevent tumors from attacks by body immunosurveillance and promote tumors progression through inhibiting both innate and adaptive antitumor immunity by a variety of pathways;they are recruited to the peripheral tissues from bone marrow and exert their inhibitory effects on antitumor immunity after activation in peripheral tissues.Chronic inflammation-related cytokines produced by tumors play crucial roles in the recruitment and activation of MDSCs.Progress has been made in antitumor therapies targeting MDSCs.But it has only been 10 years since the discovery of MDSCs,and many questions remain to be answered through experimental and clinical investigations.This review focuses on progress in MDSCs and its subsets,the recruitment and activation of MDSCs,the mechanisms of MDSCs-mediated immunosurveillance and antitumor treatment targeting MDSCs.