Mechanisms of myeloid-derived suppressor cell-mediated immunosuppression in colorectal cancer and related therapies

Severe immunosuppression is a hallmark of colorectal cancer(CRC).Myeloid-derived suppressor cells(MDSCs),one of the most abundant components of the tumor stroma,play an important role in the invasion,metastasis,and immune escape of CRC.MDSCs create an immunosuppressive microenvironment by inhibiting the proliferation and activation of immunoreactive cells,including T and natural killer cells,as well as by inducing the proliferation of immunosuppressive cells,such as regulatory T cells and tumor-associated macrophages,which,in turn,promote the growth of cancer cells.Thus,MDSCs are key contributors to the emergence of an immunosup-pressive microenvironment in CRC and play an important role in the breakdown of antitumor immunity.In this narrative review,we explore the mechanisms through which MDSCs contribute to the immunosuppressive microenvironment,the current therapeutic approaches and technologies targeting MDSCs,and the therapeutic potential of modulating MDSCs in CRC treatment.This study provides ideas and methods to enhance survival rates in patients with CRC.

Increased frequency and clinical significance of myeloidderived suppressor cells in human colorectal carcinoma

AIM： To investigate the frequency and clinical signifi- cance of the myeloid-derived suppressor cells （MDSC） in human colorectal carcinoma （CRC）. METHODS： Samples of peripheral blood and tumor tis- sue from 49 CRC patients were analyzed. Mononuclear cells were isolated by FicolI-Hypaque density gradient centrifugation and were subjected to a flow cytometry- based immunophenotypic analysis. RESULTS： A considerable increase in the percentage of CD33＋HLA-DR MDSCs was observed in the periph- eral blood （1.89% ：1= 0.75%） and tumor tissues （2.99%±1.29%） of CRC patients as compared with that in theperipheral blood of healthy controls （0.54%±0.35%）. This expanded CD33＋HLA-DR subset exhibited imma- ture myeloid cell markers, but not lineage markers, and showed up-regulation of CD18/CD11b expression as compared with the MDSCs from healthy donors. Fur- ther studies showed that the MDSC proportion in CRC peripheral blood was correlated with nodal metastasis （P = 0.023）, whereas that in tumor tissues was cor- related with nodal/distant metastasis （P = 0.016/P = 0.047） and tumor stage （P = 0.028）, suggesting the involvement of MDSCs in CRC tumor development. CONCLUSION： Characterization of MDSCs in CRC sug- gests the clinical significance of circulating and tumor- infiltrating MDSCs and may provide new insights into the CRC immunotherapy targeting MDSCs.

Circulating myeloid-derived suppressor cells in patients with pancreatic cancer

BACKGROUND： Myeloid-derived suppressor cells （MDSCs） are heterogeneous cell types that suppress T-cell responses in cancer patients and animal models, some MDSC subpopulations are increased in patients with pancreatic cancer. The present study was to investigate a specific subset of MDSCs in patients with pancreatic cancer and the mechanism of MDSCs increase in these patients. METHODS： Myeloid cells from whole blood were collected from 37 patients with pancreatic cancer, 17 with cholangiocarcinoma, and 47 healthy controls. Four pancreatic cancer cell lines were co- cultured with normal peripheral blood mononudear cells （PBMCs） to test the effect of tumor cells on the conversion of PBMCs to MDSCs. Levels of granulocyte-macrophage colony-stimulating factor （GM-CSF） and arginase activity in the plasma of cancer patients were analyzed by enzyme-linked immunosorbent assay. RESULTS： CD14＋/CD11b＋/HLA-DR MDSCs were increased in patients with pancreatic or bile duct cancer compared with those in healthy controls, and this increase was correlated with clinical cancer stage. Pancreatic cancer cell lines induced PBMCs to MDSCs in a dose-dependent manner. GM-CSF and arginase activity levels were significantly increased in the se rum of patients with pancreatic cancer. CONCLUSIONS： MDSCs were tumor related： tumor cells induced PBMCs to MDSCs in a dose-dependent manner and circulating CD14＋/CD11b＋/HLA-DR- MDSCs in pancreatic cancer patients were positively correlated with tumor burden. MDSCs might be useful markers for pancreatic cancer detection and progression.

Cyclooxygenase-2 Blockade Inhibits Accumulation and Function of Myeloid-derived Suppressor Cells and Restores T Cell Response after Traumatic Stress

Myeloid-derived suppressor cells （MDSCs） play a crucial role in T cell dysfunction, which is related to poor outcome in patients with severe trauma. Cyclooxygenase-2 （Cox-2） contributes to immune disorder in trauma and infection via production of prostaglandin E2. However, the role of Cox-2 in the accumulation and function of MDSCs after traumatic stress has not been fully elucidated. In the present study, we treated murine trauma model with NS398, a selective Cox-2 inhibitor. Then the percentages of CD1 lb＋/Gr-l＋ cells, proliferation and apoptosis of CD4＋ T cells were determined. Ar- ginase activity and arginase-1 （Arg-1） protein expression of splenic CDllb＋/Gr-I＋ cells, and de- layed-type hypersensitivity （DTH） response were analyzed. The results showed that Cox-2 blockade significantly decreased the percentages of CD1 lb＋/Gr-l＋ cells in the spleen and bone marrow 48 and 72 h after traumatic stress. NS398 inhibited arginase activity and down-regulated the Arg-1 expression of splenic CD1 lb＋/Gr-l＋ ceils. Moreover, NS398 could promote proliferation and inhibit apoptosis of CD4＋ T cells. It also restored DTH response of traumatic mice. Taken together, our data revealed that Cox-2 might play a pivotal role in the accumulation and function of MDSC after traumatic stress.

NEDD9 promotes cancer stemness by recruiting myeloid-derived suppressor cells via CXCL8 in esophageal squamous cell carcinoma

Objective:Esophageal squamous cell carcinoma(ESCC)has high morbidity and mortality rates worldwide.Cancer stem cells(CSCs)may cause tumor initiation,metastasis,and recurrence and are also responsible for chemotherapy and radiotherapy failures.Myeloid-derived suppressor cells(MDSCs),in contrast,are known to be involved in mediating immunosuppression.Here,we aimed to investigate the mechanisms of interaction of CSCs and MDSCs in the tumor microenvironment.Methods:ESCC tissues and cell lines were evaluated.Neural precursor cell expressed,developmentally downregulated 9(NEDD9)was knocked down and overexpressed by lentiviral transfection.Quantitative PCR,Western blot,immunohistochemistry,cell invasion,flow cytometry,cell sorting,multiplex chemokine profiling,and tumor growth analyses were performed.Results:Microarray analysis revealed 10 upregulated genes in esophageal CSCs.Only NEDD9 was upregulated in CSCs using the sphere-forming method.NEDD9 expression was correlated with tumor invasion(P=0.0218),differentiation(P=0.0153),and poor prognosis(P=0.0373).Additionally,NEDD9 was required to maintain the stem-like phenotype.Screening of chemokine expression in ESCC cells with NEDD9 overexpression and knockdown showed that NEDD9 regulated C-X-C motif chemokine ligand 8(CXCL8)expression via the ERK pathway.CXCL8 mediated the recruitment of MDSCs induced by NEDD9 in vitro and in vivo.MDSCs promoted the stemness of ESCC cells through NEDD9 via the Notch pathway.Conclusions:As a marker of ESCC,NEDD9 maintained the stemness of ESCC cells and regulated CXCL8 through the ERK pathway to recruit MDSCs into the tumor,suggesting NEDD9 as a therapeutic target and novel prognostic marker for ESCC.

Role of myeloid-derived suppressor cells in autoimmune disease

Myeloid-derived suppressor cells(MDSCs) represent an important class of immunoregulatory cells that can be activated to suppress T cell functions. These MDSCs can inhibit T cell functions through cell surface interactions and the release of soluble mediators. MDSCs accumulate in the inflamed tissues and lymphoid organs of patients with autoimmune diseases. Much of our knowledge of MDSC function has come from studies involving cancer models, however many recent studies have helped to characterize MDSC involvement in autoimmune diseases. MDSCs are a heterogeneous group of immature myeloid cells with a number of different functions for the suppression of T cell responses. However, we have yet to fully understand their contributions to the development and regulation of autoimmune diseases. A number of studies have described beneficial functions of MDSCs during autoimmune diseases, and thus there appears to be a potential role for MDSCs in the treatment of these diseases. Nevertheless, many questions remain as to the activation, differentiation, and inhibitory functions of MDSCs. This review aims to summarize our current knowledge of MDSC subsets and suppressive functions in tissue-specific autoimmune disorders. We also describe the potential of MDSC-basedcell therapy for the treatment of autoimmune diseases and note some of hurdles facing the implementation of this therapy.

Emerging roles of myeloid derived suppressor cells in hepatic inflammation and fibrosis

Myeloid derived suppressor cells(MDSC) are a heterogeneous population of immune cells that are potent suppressors of immune responses. MDSC emerge in various compartments in the body, such as blood, bonemarrow or spleen, especially in conditions of cancer, infections or inflammation. MDSC usually express CD11 b, CD33, and low levels of human leukocyte antigen-DR in humans or CD11 b and Gr1(Ly6C/G) in mice, and they can be further divided into granulocytic or monocytic MDSC. The liver is an important organ for MDSC induction and accumulation in hepatic as well as extrahepatic diseases. Different hepatic cells, especially hepatic stellate cells, as well as liver-derived soluble factors, including hepatocyte growth factor and acute phase proteins(SAA, KC), can promote the differentiation of MDSC from myeloid cells. Importantly, hepatic myeloid cells like neutrophils, monocytes and macrophages fulfill essential roles in acute and chronic liver diseases. Recent data from patients with liver diseases and animal models linked MDSC to the pathogenesis of hepatic inflammation, fibrosis and hepatocellular carcinoma(HCC). In settings of acute hepatitis, MDSC can limit immunogenic T cell responses and subsequent tissue injury. In patients with chronic hepatitis C, MDSC increase and may favor viral persistence. Animal models of chronic liver injury, however, have not yet conclusively clarified the involvement of MDSC for hepatic fibrosis. In human HCC and mouse models of liver cancer, MDSC are induced in the tumor environment and suppress anti-tumoral immune responses. Thus, the liver is a primary site of MDSC in vivo, and modulating MDSC functionality might represent a promising novel therapeutic target for liver diseases.

Amplification of Functional Myeloid-derived Suppressor Cells during Stem Cell Mobilization Induced by Granulocyte Colony-stimulation-factor

The effects of granulocyte colony-stimulation-factor （G-CSF） on stem cell mobilization and its impact on the amplification of myeloid-derived suppressor cells （MDSCs） of donor mice were ex- amined. A mouse model of stem cell mobilization was established by consecutive subcutaneous injec- tion of 100 μg/kg G-CSF for 5 days. The blood from the donor mice was routinely examined during mobilization. Stem cells and MDSCs were analyzed by flow cytometry. The immunosuppressive mole- cules derived from MDSCs in serum and spleen, including hydrogen dioxide （H202） and nitric oxide （NO）, and the activity of nitric oxide synthase （NOS） were determined during the mobilization. Apop- tosis of T lymphocytes was assessed by using Annexin-V/PI. During stem cell mobilization, the number of lymphocytes and white blood cells in the peripheral blood was increased, and peaked on the 4th day. The number of stem cells in G-CSF-treated mice was significantly greater than that in controls （P〈0.01）. The expansions of MSDCs were also observed after G-CSF mobilization, with a more notable rate of growth in the peripheral blood than in the spleen. The activity of NOS and the production of NO were increased in the donor mice, and the serum H202 levels were approximately 4-fold greater than the con- trois. Consequently, apoptosis of T lymphocytes was increased and showed a positive correlation with the elevated percentage of MDSCs. It was concluded that G-CSF could provide sufficient peripheral blood stem cells for transplantation. Exogenous administration of G-CSF caused the accumulation of MDSCs in the peripheral blood and the spleen, which could lead to apoptosis ofT lymphocytes and may offer a new strategy for the prevention and treatment of graft versus host disease.

Changes in the frequency of myeloid-derived suppressor cells after transarterial chemoembolization with gelatin sponge microparticles for hepatocellular carcinoma

Purpose: A series of clinical studies have established the safety and efficacy of transcatheter arterial chemoembolization(TACE) with gelatin sponge microparticles(GSMs) in treating hepatocellular carcinoma(HCC). HCC can lead to obvious necrosis inside tumors, especially larger ones, although it is unclear whether such necrotic tumor tissue can induce favorable immune reactions against the tumor. Myeloid-derived suppressor cells(MDSCs)have immunosuppressive functions and are currently considered a very important cell type affecting tumor immunity. This study observed changes in MDSC frequency in peripheral blood before and after GSM–TACE to evaluate the effect on the immune function of HCC patients.Methods: Eight patients diagnosed with HCC underwent GSM–TACE treatment in the Hepatobiliary Interventional Department of Beijing Tsinghua Chang Gung Hospital, Beijing, China;we followed up with the patients over a period of 30 days post-surgery. We used flow cytometry(FCM) to quantify the frequency of MDSCs in peripheral blood before TACE, 10 days after surgery and 30 days after surgery.Results: MDSC frequency after GSM–TACE had a significant downward trend. Pre-TACE, it was 30.73% ? 11.93%,decreasing to 18.60% ? 11.37% at 10 days after operation. This decrease was not statistically significant(P > 0.05). MDSC frequency was even lower 30 days after TACE(7.63% ? 7.32%) than at 10 days after TACE(P < 0.05), and there was a significant difference compared with pre-TACE(P < 0.001). We evaluated tumor response at 30 days after GSM–TACE according to the Modified Response Evaluation Criteria in Solid Tumors(mRECIST), and all eight patients showed partial response(PR).Conclusion: Our results confirmed that GSM–TACE was beneficial for improving anti-tumor immunity in the treatment of HCC.

Correlation between circulating myeloid-derived suppressor cells and Th17 cells in esophageal cancer

AIM: To perform a comprehensive investigation into the potential correlation between circulating myeloidderived suppressor cells (MDSCs) and Th17 cells in esophageal cancer (ECA). METHODS: A total of 31 patients newly diagnosed with ECA and 26 healthy subjects were included in the current study. The frequencies of MDSCs and Th17 cells in peripheral blood were determined by flow cytometry. The mRNA expression of cytokines, arginase 1 (Arg1) and inducible NO synthase (iNOS) in peripheral blood mononuclear cells (PBMCs) and plasma Arg1 were assessed by real-time polymerase chain reaction and enzyme-linked immunosorbent assay, respectively. RESULTS: There was an increased prevalence of MDSCs in the peripheral blood from ECA patients (15.21% ± 2.25%) when compared with healthy control (HC) (1.10% ± 0.12%, P < 0.0001). The plasma levels of Arg1 in ECA patients were significantly higher than those in HC (28.28 ± 4.10 ng/mL vs 9.57 ± 1.51 ng/ mL, P=0.0003). iNOS mRNA levels in the peripheral blood of ECA patients also showed a threefold increase compared with HC (P=0.0162). The frequencies of Th17 cells (CD4 + IL-17A + ) were significantly elevated in ECA patients versus HC (3.50% ± 0.33% vs 1.82% ± 0.19%, P=0.0001). Increased mRNA expression of IL-17 and ROR-γt was also observed in ECA patients compared with HC (P=0.0041 and P=0.0004, respectively), while the mRNA expression of IL-6 and tumor necrosis factor-α (TNF-α) showed significant decreases (P=0.0049 and P < 0.0001, respectively). No obvious correlations were found between the frequencies of MDSCs and Th17 cells in the peripheral blood from ECA patients(r=-0.1725, P=0.3534). Arg1 mRNA levels were positively correlated with levels of IL-6 (r=0.6404, P=0.0031) and TNF-α (r=0.7646, P=0.0001). Similarly, iNOS mRNA levels were also positively correlated with levels of IL-6 (r=0.6782, P=0.0007) and TNF-α (r=0.7633, P < 0.0001). CONCLUSION: This study reveals the relationship between circulating MDSCs and Th17 cells, which may lead to new immunotherapy approaches for ECA based on the associated metabolites and cytokines.

Analysis of CD8^+CD28^-T-suppressor cells in living donor liver transplant recipients

BACKGROUND:Human CD8 + CD28 - T-suppressor(Ts) cells have been considered to indicate a reduced need for immunosuppression in pediatric liver-intestine transplant recipients and recipients of deceased heart-kidney transplants.However,in adult-to-adult living donor liver transplantation(A-A LDLT)little information is available and the clinical significance is still unknown. METHODS:Flow cytometry was used to detect the population of CD8+CD28 -Ts cells present in peripheral blood in A-A LDLT recipients(n=31),patients with end- stage liver disease(n=24)and healthy controls(n=19). Meanwhile,we tested the graft function and trough levels of immunosuppression in recipients.The clinical and follow- up data of 31 transplant recipients were analyzed. RESULTS:Compared with diseased controls(P=0.007) and healthy individuals(P=0.000),a notable expansion of CD8 + CD28 - Ts cells was found in recipients of A-A LDLT.This was associated with graft function,levels of immunosuppression and rejection episodes. CONCLUSIONS:To monitor the CD8 + CD28 - Ts cells levels is important to evaluate the immune state of recipients. Meanwhile,it is also important to promote expansion of CD8+CD28 -Ts cells in recipients of A-A LDLT,not only to sustain good graft function and decrease the dosage of immunosuppressants,but also to reduce the occurrence of rejection.

Intermittent fasting boosts antitumor immunity by restricting CD11b^(+)Ly6C^(low)Ly6G^(low) cell viability through glucose metabolism in murine breast tumor model

Intermittent fasting can benefit breast cancer patients undergoing chemotherapy or immunotherapy.However,it is still uncertain how to select immunotherapy drugs to combine with intermittent fasting.Herein we observed that two cycles of fasting treatment significantly inhibited breast tumor growth and lung tissue metastasis,as well as prolonged overall survival in mice bearing 4T1 and 4T07 breast cancer.During this process,both the immunosuppressive monocytic-(M-)and granulocytic-(G-)myeloid-derived suppressor cell(MDSC)decreased,accompanied by an increase in interleukin(IL)7R^(+)and granzyme B^(+)T cells in the tumor microenvironment.Interestingly,we observed that Ly6G^(low)G-MDSC sharply decreased after fasting treatment,and the cell surface markers and protein mass spectrometry data showed potential therapeutic targets.Mechanistic investigation revealed that glucose metabolism restriction suppressed the splenic granulocytemonocyte progenitor and the generation of colony-stimulating factors and IL-6,which both contributed to the accumulation of G-MDSC.On the other hand,glucose metabolism restriction can directly induce the apoptosis of Ly6G^(low)G-MDSC,but not Ly6G^(high)subsets.In summary,these results suggest that glucose metabolism restriction induced by fasting treatment attenuates the immune-suppressive milieu and enhances the activation of CD3^(+)T cells,providing potential solutions for enhancing immune-based cancer interventions.

Effects of methionine enkephalin on immune enhancement by reducing myeloid derived suppressor cells and reprogramming liver metabolism in colon cancer mice

OBJECTIVE To investigate enhanced immune function of methionine encephalin(MENK)and its anti-tumor mechanism in CT26 colon cancer mouse model.METHODS 3×10~6CT26 cells were implanted subcutaneously in BALB/c mice.Four days after,MENK was peritoneally administrated at the concentration of 20 mg·kg^(-1) for 14 d.The percentage of MDSCs in bone marrow,spleen,blood,tumor and liver were detected by flow cytometry.Non-esterified fatty acid(NEFA),triglycerides(TG)and total cholesterol(T-CHO)in liver homogenate were tested by a NEFA test kit,a TG test kit and a T-CHO test kit respectively.qRT-PCR and Western blot were used to measure m RNA and protein levels of inflammation-,glycometabolsim-and lipometabolsim-associated indexes in liver.RESULTS MENK decreased percentages of MDSCs in bone marrow,spleen,blood and tumor in colon cancer mice.MENK-treated mice displayed elevated ratio of CD4^+T and CD8^+T cells in spleen as well as increased T and B lymphocytes proliferation.Meanwhile,MENK also ameliorated liver damage reflected by lower levels of GPT and GOT in serum and reduced risks of cancer-associated index including inflammation,high lipid and high glucose.Furthermore,MENK lowered down the levels of NEFA,TG and T-CHO in liver homogenate.MENK treatment decreased expression of p-STAT3,increased expression of p-AKT,IRS1 and Glut4 at protein level as well as reduced lipogenesis-associated genes and elevated glycolysis-associated genes in liver of tumor bearing mice.Also,abated expression of genes associated with MDSCs generation(M-CSF,GM-CSF,IL-6,IL^(-1)β)and migration(S100A9,KC)was observed within shrunken subcutaneous tumor by MENK intervention.CONCLUSION MENK has the ability to strength immune function against colon cancer by reducing MDSCs and improving liver metabolism.

Myeloid-derived Suppressor Cells Activate Liver Natural Killer Cells in a Murine Model in Uveal Melanoma

Objective Elevated myeloid-derived suppressor cells(MDSCs)in many malignancies are associated with the increased risk for metastases and poor prognosis.Therefore,a mouse model of intraocular melanoma was established to explore how MDSCs influence liver metastases.Methods In this study,murine B16LS melanoma cells were transplanted into the posterior compartment(PC)of the eye of C57BL/6 mice.Leucocytes from the liver of naive mice and mice bearing melanoma liver metastasis were isolated using isotonic Percoll centrifugation,examined by flow cytometry for their expression of Gr1,CD11b,F4/80,RAE-1,and Mult-1,and further isolated for MDSCs and natural killer(NK)cells.The effects of MDSCs on NK cells were tested by coculturing and assessing the ability of NK cells to produce interferon-gamma(IFN-γ)by ELISA and NK cell cytotoxicity by 3H-thymidine incorporation assay.The impact of IFN-γon liver metastases was examined via selectively depleting IFN-γin vivo.Results The results showed that mice with liver metastases had increased levels of CD11b+Gr1+F4/80+as well as CD11b+Gr1+F4/80−MDSCs.MDSCs significantly enhanced the generation of IFN-γtogether with the cytotoxicity of the NK cells.Furthermore,these effects were cell-cell contact-dependent.Although IFN-γwas not of a toxic nature to the melanoma cells,it profoundly inhibited B16LS cell proliferation.Depleting IFN-γin vivo led to increased liver metastases.Conclusion All these findings first revealed that MDSCs accumulated in liver metastasis of intraocular melanoma could activate the NK cells to produce an effective anti-tumor immune response.Thus,the MDSCs’performance in different tumor models would need more investigation to boost current immunotherapy modalities.

GM3-containing nanoparticles in immunosuppressed hosts:Effect on myeloid-derived suppressor cells

Cancer vaccines to date have not broadly achieved a significant impact on the overall survival of patients. The negative effect on the immune system of the tu-mor itself and conventional anti-tumor treatments such as chemotherapy is, undoubtedly, a key reason for these disappointing results. Myeloid-derived suppres-sor cells （MDSCs） are considered a central node of the immunosuppressive network associated with tumors. These cells inhibit the effector function of natural killer and CD8＋ T cells, expand regulatory T cells and can differentiate into tumor-associated macrophages within the tumor microenvironment. Thus, overcoming the suppressive effects of MDSCs is likely to be criti-cal for cancer immunotherapy to generate effective anti-tumor immune responses. However, the capacity of cancer vaccines and particularly their adjuvants to overcome this inhibitory population has not been well characterized. Very small size proteoliposomes （VSSP） is a nanoparticulated adjuvant specifcally designed to be formulated with vaccines used in the treatment of immunocompromised patients. This adjuvant contains immunostimulatory bacterial signals together with GM3 ganglioside. VSSP promotes dendritic cell maturation, antigen cross-presentation to CD8＋ T cells, Th1 polar-ization, and enhances CD8＋ T cell response in tumor-free mice. Currently, four cancer vaccines using VSSP as the adjuvant are in Phase？Ⅰ？and Ⅱ clinical trials. In this review, we summarize our work characterizing the unique ability of VSSP to stimulate antigen-specifc CD8＋ T cell responses in two immunocompromised sce-narios; in tumor-bearing mice and during chemother-apy-induced leukopenia. Particular emphasis has been placed on the interaction of these nanoparticles with MDSCs, as well as comparison with other cancer vac-cine adjuvants currently in preclinical or clinical studies.

Myeloid-derived suppressor cells in gastrointestinal cancers:A systemic review

Gastrointestinal(GI)cancers are one of the most common malignancies worldwide,with high rates of morbidity and mortality.Myeloid-derived suppressor cells(MDSCs)are major components of the tumor microenvironment(TME).MDSCs facilitate the transformation of premalignant cells and play roles in tumor growth and metastasis.Moreover,in patients with GI malignancies,MDSCs can lead to the suppression of T cells and natural killer cells.Accordingly,a better understanding of the role and mechanism of action of MDSCs in the TME will aid in the development of novel immune-targeted therapies.

Hepatic immune tolerance induced by hepatic stellate cells

The liver, which is a metabolic organ, plays a pivotal role in tolerance induction. Hepatic stellate cells(Hp SCs), which are unique non-parenchymal cells, exert potent immunoregulatory activity during cotransplantation with allogeneic islets effectively protecting the islet allografts from rejection. Multiple mechanisms participate in the immune tolerance induced by Hp SCs, including the marked expansion of myeloid-derived suppressor cells(MDSCs), attenuation of effector T cell functions and augmentation of regulatory T cells. Hp SC conditioned MDSC-based immunotherapy has been conducted in mice with autoimmune disease and the results show that this technique may be promising. This article demonstrates how Hp SCs orchestrate both innate immunity and adaptive immunity to build a negative network that leads to immune tolerance.

MicroRNAs,stem cells and cancer stem cells

This review discusses the various regulatory charac-teristics of microRNAs that are capable of generating widespread changes in gene expression via post translational repression of many mRNA targets and control self-renewal, differentiation and division of cells. It controls the stem cell functions by controlling a wide range of pathological and physiological processes, including development, differentiation, cellular proliferation, programmed cell death, oncogenesis and metastasis. Through either mRNA cleavage or translational repression, miRNAs alter the expression of their cognate target genes; thereby modulating cellular pathways that affect the normal functions of stem cells, turning them into cancer stem cells, a likely cause of relapse in cancer patients. This present review further emphasizes the recent discoveries on the functional analysis of miRNAs in cancer metastasis and implications on miRNA based therapy using miRNA replacement or anti-miRNA technologies in specific cancer stem cells that are required to establish their efficacy in controlling tumorigenic potential and safe therapeutics.

mi R-382 functions as a tumor suppressor against esophageal squamous cell carcinoma

AIM To explore the effect of miR-382 on esophageal squamous cell carcinoma (ESCC) in vitro and its possible molecular mechanism. METHODS Eca 109 cells derived from human ESCC and Het-1A cells derived from human normal esophageal epithelium were used. Lentivirus-mediated miR-382 was overexpressed in Eca109 cells. The effect of miR-382 on cell proliferation was evaluated by MTT and colony formation assay. For cell cycle analysis, cells were fixed and stained for 30 min with propidium iodide (PI) staining buffer containing 10 mg/mL PI and 100 mg/mL RNase A, and analyzed by BD FACSCalibur (TM) flow cytometer. For cell apoptosis assay, cells were stained with an Annexin V-FITC/PI Apoptosis Detection Kit according to the manufacturer's instructions and analyzed by a dual-laser flow cytometer. Cell invasion and migration abilities were determined through use of transwell chambers, non-coated or pre-coated with matrigel. Levels of proteins related to cell growth and migration were examined by western blotting. RESULTS Endogenous miR-382 was down-regulated in Eca109 cells compared with Het-1A. Introduction of miR-382 not only significantly inhibited proliferation and colony formation, but also arrested cell cycle at the G2/M phase, as well as promoted apoptosis and autophagy in Eca109 cells. Migration, invasion and epithelial-mesenchymal transition of Eca109 cells were suppressed by overexpressing miR-382. Western blotting results showed that miR-382 inhibited the phosphorylation of mTOR and 4E-BP1. CONCLUSION miR-382 functions as a tumor suppressor against ESCC development and metastasis, and could be considered as a potential drug source for the treatment of ESCC patients.

Changes of NF-kB,p53,Bcl-2 and caspase in apoptosis induced by JTE-522 in human gastric adenocarcinoma cell line AGS cells:role of reactive oxygen species

AIM: To identify whether JTE-522 can induce apoptosis in AGS cells and ROS also involved in the process, and to investigate the changes in NF-kB, p53, bcl-2 and caspase in the apoptosis process. METHODS: Cell culture, MTT, Electromicroscopy, agarose gel electrophoresis, lucigenin, Western blot and electrophoretic mobility shift assay (EMSA) analysis were employed to investigate the effect of JTE-522 on cell proliferation and apoptosis in AGS cells and related molecular mechanisms. RESULTS: JTE-522 inhibited the growth of AGS cells and induced the apoptosis. Lucigenin assay showed the generation of ROS in cells under incubation with JTE-522. The increased ROS generation might contribute to the induction of AGS cells to apoptosis. EMSA and Western blot revealed that NF-kB activity was almost completely inhibited by preventing the degradation of IkBalpha. Additionally, by using Western blot we confirmed that the level of bcl-2 was decreased, whereas p53 showed a great increase following JTE-522 treatment. Their changes were in a dose-dependent manner. CONCLUSION: These findings suggest that reactive oxygen species, NF-kB, p53, bcl-2 and caspase-3 may play an important role in the induction of apoptosis in AGS cells after treatment with JTE-522.