New insights into chronic inflammation-induced immunosuppression

Fibrocytes: A Novel Stromal Cells to Regulate Resistance to Anti-Angiogenic Therapy and Cancer Progression

An adequate blood supply is essential for cancer cells to survive and grow; thus, the concept of inhibiting tumor angiogenesis has been applied to cancer therapy, and several drugs are already in clinical use. It has been shown that treatment with those anti-angiogenic drugs improved the response rate and prolonged the survival of patients with various types of cancer; however, it is also true that the effect was mostly limited. Currently, the disappointing clinical results are explained by the existence of intrinsic or acquired resistance to the therapy mediated by both tumor cells and stromal cells. This article reviews the mechanisms of resistance mediated by stromal cells such as endothelial cells, pericytes, fibroblasts and myeloid cells, with an emphasis on fibrocytes, which were recently identified as the cell type responsible for regulating acquired resistance to anti-angiogenic therapy. In addition, the other emerging role of fibrocytes as mediator-producing cells in tumor progression is discussed.

Synergistic Antioxidant and Anti-Inflammatory Effects between Modified Citrus Pectin and Honokiol

Inflammation is a normal physiological process; however, dysregulation of this process may contribute to inflammatory-based chronic disorders and diseases in animals and humans. Therefore, the antioxidant and anti-inflammatory properties of natural products, often recognized in traditional medicine systems, represent therapeutic modalities to reduce or prevent uncontrolled inflammatory processes which in turn potentially ameliorate or prevent sequelae of inflammatory-based symptoms of chronic diseases. We have investigated the antioxidant and anti-inflammatory effects of honokiol (HNK) and modified citrus pectin (MCP) in vitro and examined whether the MCP : HNK combination has synergistic effects on antioxidant and anti-inflammatory properties. Although both HNK and MCP induced a dose-dependent increase in antioxidant activity, the latter has a consistently higher antioxidant effect. The MCP : HNK (9 : 1) combination induced a synergistic effect on antioxidant activity suggesting that the combination is significantly more efficacious than individual compounds. In mouse monocytes, the lipopolysaccharide- (LPS-) induced tumor necrosis-α (TNF-α) synthesis was significantly inhibited by HNK and the MCP : HNK combination in a dose-dependent manner and synergistic effects were clearly demonstrated with the combination on TNF-α inhibition. This combination effect was also evident on inhibition of nuclear factor-kappa B activity, cyclooxygenase-II activity, and lipid peroxidation in mouse monocytes. Further research into the combination is warranted.

CCR5 in recruitment and activation of myeloid-derived suppressor cells in melanoma

Malignant melanoma is characterized by the development of chronic inflammation in the tumor microenvironment, leading to the accumulation of myeloid-derived suppressor cells (MDSCs). Using ret transgenic mouse melanoma model, we found a significant migration of MDSCs expressing C-C chemokine receptor (CCR)5 into primary tumors and metastatic lymph nodes, which was correlated with tumor progression. An increased CCR5 expression on MDSCs was associated with elevated concentrations of CCR5 ligands in melanoma microenvironment. In vitro experiments showed that the upregulation of CCR5 expression on CD11b+Gr1+ immature myeloid cells was induced by CCR5 ligands, IL-6, GM-CSF, and other inflammatory factors. Furthermore, CCR5+ MDSCs infiltrating melanoma lesions displayed a stronger immunosuppressive pattern than their CCR5- counterparts. Targeting CCR5/CCR5 ligand signaling via a fusion protein mCCR5-Ig, which selectively binds and neutralizes all three CCR5 ligands, increased the survival of tumor-bearing mice. This was associated with a reduced migration and immunosuppressive potential of tumor MDSCs. In melanoma patients, circulating CCR5+ MDSCs were increased as compared to healthy donors. Like in melanoma-bearing mice, we observed an enrichment of these cells and CCR5 ligands in tumors as compared to the peripheral blood. Our findings define a critical role for CCR5 not only in the recruitment but also in the activation of MDSCs in tumor lesions, suggesting that novel strategies of melanoma treatment could be based on blocking CCR5/CCR5 ligand interactions.

Dynamic interplay between tumour, stroma and immune system can drive or prevent tumour progression

In the tumour microenvironment, cancer cells directly interact with both the immune system and the stroma. It is firmly established that the immune system, historically believed to be a major part of the body's defence against tumour progression, can be reprogrammed by tumour cells to be ineffective, inactivated, or even acquire tumour promoting phenotypes. Likewise, stromal cells and extracellular matrix can also have pro-and anti-tumour properties. However, there is strong evidence that the stroma and immune system also directly interact, therefore creating a tripartite interaction that exists between cancer cells, immune cells and tumour stroma. This interaction contributes to the maintenance of a chronically inflamed tumour microenvironment with pro-tumorigenic immune phenotypes and facilitated metastatic dissemination. A comprehensive understanding of cancer in the context of dynamical interactions of the immune system and the tumour stroma is therefore required to truly understand the progression toward and past malignancy.

Biological embedding of childhood adversity: from physiological mechanisms to clinical implications

BACKGROUND

Adverse psychosocial exposures in early life, namely experiences such as child maltreatment, caregiver stress or depression, and domestic or community violence, have been associated in epidemiological studies with increased lifetime risk of adverse outcomes, including diabetes, heart disease, cancers, and psychiatric illnesses. Additional work has shed light on the potential molecular mechanisms by which early adversity becomes "biologically embedded" in altered physiology across body systems. This review surveys evidence on such mechanisms and calls on researchers, clinicians, policymakers, and other practitioners to act upon evidence.

OBSERVATIONS

Childhood psychosocial adversity has wide-ranging effects on neural, endocrine, immune, and metabolic physiology. Molecular mechanisms broadly implicate disruption of central neural networks, neuroendocrine stress dysregulation, and chronic inflammation, among other changes. Physiological disruption predisposes individuals to common diseases across the life course.

CONCLUSIONS

Reviewed evidence has important implications for clinical practice, biomedical research, and work across other sectors relevant to public health and child wellbeing. Warranted changes include increased clinical screening for exposures among children and adults, scale-up of effective interventions, policy advocacy, and ongoing research to develop new evidence-based response strategies.

Identification of differentially expressed inflammatory factors in Wilms tumors and their association with patient outcomes

The present study aimed to identify differentially expressed inflammatory factors observed in Wilms tumors (WT), and to investigate the association of these factors with clinical stage, pathological type, lymph node metastasis and vascular involvement of WT. Surface-enhanced laser desorption/ionization-time of flight mass spectrometry was performed to screen differentially expressed proteins among WT and normal tissue pairs. Upregulated proteins in WT were separated and purified by solid phase extraction and Tricine SDS-PAGE, respectively. Following in-gel digestion, the peptide mixture was subjected to liquid chromatography mass spectrometry to identify proteins on the basis of their amino acid sequences. Immunohistochemistry was used to confirm the expression of differentially expressed inflammatory proteins. Of the proteins that were upregulated in WT, two proteins with mass/charge (m/z) ratio of 12,138 and 13,462 were identified as macrophage migration inhibitory factor (MIF) and C-X-C motif ligand 7 (CXCL7) chemokine, respectively. The expression of these two proteins was increased in WT compared with adjacent normal tissues and normal renal tissues, and increased with increasing clinical stage. In addition, their expression was significantly increased in patients with unfavorable pathological type, lymph node metastasis and vascular involvement compared with the groups with favorable type, and without lymph node metastasis or vascular involvement (P<0.05). Increased pro-inflammatory MIF and CXCL7 expression in WT is closely associated with the clinical stage, pathological type, lymph node metastasis and vascular involvement, and may represent biomarkers for the clinical diagnosis of WT.

Adaptive Resistance to Cancer Immunotherapy

Immunosuppressive mechanisms within the tumor microenvironment have emerged as a major impediment to cancer immunotherapy. While a broad range of secreted factors, receptors/ligands, and cell populations have been described that contribute to the immunosuppression, the involvement of these processes in immune evasion by tumors is typically considered to be an intrinsic property of the tumor. Evidence is now emerging that the processes underlying immune suppression within the tumor are, in fact, triggered by immune attack and reflect a dynamic interplay between the tumor and the host's immune system. The term adaptive resistance has been coined to describe the induction of immune suppressive pathways in the tumor following active attack on the tumor. Adaptive resistance is a scalable process where the magnitude of immune suppression matches the magnitude of the immune attack; the net balance between suppression and attack determines the durability of the anti-tumor response and tumor outcome. In this chapter, we will examine the data supporting adaptive resistance and the opposing roles of T cells in simultaneously promoting both anti-tumor immunity and immune suppression within the tumor microenvironment. The clinical implications of adaptive resistance in the design and application of immunotherapeutic strategies is also discussed.

Myeloid-derived suppressor cells and myeloid regulatory cells in cancer and autoimmune disorders

Myeloid-derived suppressor cells (MDSCs) were originally described as a heterogeneous population of immature cells derived from myeloid progenitors with immune-suppressive functions in tumor-bearing hosts. In recent years, increasing number of studies have described various populations of myeloid cells with MDSC-like properties in murine models of cancer and autoimmune diseases. These studies have observed that the populations of MDSCs are increased during inflammation and autoimmune conditions. In addition, MDSCs can effectively suppress T cell responses and modulate the activity of natural killer cells and other myeloid cells. MDSCs have also been implicated in the induction of regulatory T cell production. Furthermore, these cells have the potential to suppress the autoimmune response, thereby limiting tissue injury. Myeloid regulatory cells (Mregs) are recently attracting increasing attention, since they function in proinflammatory and immune suppression in autoimmune diseases, as well as in various types of cancer. Currently, research focus is directed from MDSCs to Mregs in cancer and autoimmune diseases. The present study reviewed the suppressive roles of MDSCs in various autoimmune murine models, the immune modulation of MDSCs to T helper 17 lymphocytes, as well as the proinflammatory and immunosuppressive roles of Mregs in various types of cancer and autoimmune diseases.

Augmentation of Cytolytic Activity in Murine Natural Killer Cells and Inhibition of Tumor Growth by the Ethanol Fraction of Oyster Extract

A reduced number and/or reduced activity of natural killer (NK) cells, which are important for defense against a variety of cancers and viral infections, occur under various stress conditions and in patients with various diseases. In this article, we report that the 30% to 50% ethanol precipitate of oyster extract (EPOE50) dose-dependently enhanced the activity of mouse spleen NK cells in vitro and in vivo. The activity of EPOE50 was eluted with a molecular weight of about 2000 by gel filtration and was inactivated by periodate but not by proteinase K. The activity of highly purified NK cells was also augmented by EPOE50 but not by oligodeoxyribonucleotide 1585, which mimics bacterial DNA. Administration of EPOE50 to mice stimulated splenic NK cell activity without a change in splenic NK cell populations. Although the proliferation of B16 tumor cells in vitro was slightly stimulated by EPOE50, the growth of B16 melanoma in vivo was dose-dependently suppressed by administration of EPOE50. Taken together, our results indicate that EPOE50 augmented NK cell activity and that its administration to mice inhibited tumor growth presumably through the activation of NK cells and also suggest that the active substance is a sugar-containing oligomer or polymer and is not of bacterial origin.

Action mechanism and cardiovascular effect of anthocyanins: a systematic review of animal and human studies

Cardiovascular diseases (CVD) are an important cause of death worldwide. Anthocyanins are a subgroup of flavonoids found in berries, flowers, fruits and leaves. In epidemiological and clinical studies, these polyphenols have been associated with improved cardiovascular risk profiles as well as decreased comorbidities. Human intervention studies using berries, vegetables, parts of plants and cereals (either fresh or as juice) or purified anthocyanin-rich extracts have demonstrated significant improvements in low density lipoproteins oxidation, lipid peroxidation, total plasma antioxidant capacity, and dyslipidemia as well as reduced levels of CVD molecular biomarkers. This review discusses the use of anthocyanins in animal models and their applications in human medicine, as dietary supplements or as new potent drugs against cardiovascular disease.

The Role of Myeloid-Derived Suppressor Cells (MDSC) in Cancer Progression

The immunosuppressive tumor microenvironment represents not only one of the key factors stimulating tumor progression but also a strong obstacle for efficient tumor immunotherapy. Immunosuppression was found to be associated with chronic inflammatory mediators including cytokines, chemokines and growth factors produced by cancer and stroma cells. Long-term intensive production of these factors induces the formation of myeloid-derived suppressor cells (MDSCs) representing one of the most important players mediating immunosuppression. Moreover, MDSCs could not only inhibit anti-tumor immune reactions but also directly stimulate tumor growth and metastasis. Therefore, understanding the mechanisms of their generation, expansion, recruitment and activation is required for the development of novel strategies for tumor immunotherapy.

Human melanomas and ovarian cancers overexpressing mechanical barrier molecule genes lack immune signatures and have increased patient mortality risk

We have identified eight genes whose expression in human melanoma metastases and ovarian cancers is associated with a lack of Th1 immune signatures. They encode molecules with mechanical barrier function in the skin and other normal tissues and include filaggrin (FLG), tumor-associated calcium signal transducer 2 (TACSTD2), and six desmosomal proteins (DST, DSC3, DSP, PPL, PKP3, and JUP). This association has been validated in an independent series of 114 melanoma metastases. In these, DST expression alone is sufficient to identify melanomas without immune signatures, while FLG and the other six putative barrier molecules are overexpressed in a different subset of melanomas lacking immune signatures. Similar associations have been identified in a set of 186 ovarian cancers. RNA-seq data from 471 melanomas and 307 ovarian cancers in the TCGA database further support these findings and also reveal that overexpression of barrier molecules is strongly associated with early patient mortality for melanoma (p = 0.0002) and for ovarian cancer (p < 0.01). Interestingly, this association persists for FLG for melanoma (p = 0.012) and ovarian cancer (p = 0.006), whereas DST overexpression is negatively associated with CD8⁺ gene expression, but not with patient survival. Thus, overexpression of FLG or DST identifies two distinct patient populations with low immune cell infiltration in these cancers, but with different prognostic implications for each. These data raise the possibility that molecules with mechanical barrier function in skin and other tissues may be used by cancer cells to protect them from immune cell infiltration and immune-mediated destruction.

WP1066 exhibits antitumor efficacy in nasal‑type natural killer/T-cell lymphoma cells through downregulation of the STAT3 signaling pathway

Nasal-type natural killer/T-cell lymphoma (nasal NKTCL) is an aggressive hematological neoplasm with poor prognosis, and its incidence is higher in Asia than in Western countries. Increasing evidence suggests that aberrant activation of signal transducers and activators of transcription 3 (STAT3) is related to numerous malignancies. However, the involvement of STAT3 in the pathogenesis of nasal NKTCL is poorly understood. In this study, immunohistochemistry (IHC) showed that 21/28 (75.0%) nasal NKTCL tissues harbored constitutively expression of phospho‑STAT3 (p‑STAT3) which was positively correlated with the Ki‑67 levels (P﹤0.05). Immunofluorescence (IF) also detected p‑STAT3 expression in SNK6 cells (NKTCL cell line). Furthermore, WP1066 (a novel selective STAT3 inhibitor) was able to inhibit proliferation and induce apoptosis of SNK6 cells. Moreover, western blot analysis and RT‑PCR demonstrated that WP1066 downregulated the protein and mRNA expressions of the pro‑survival molecules (including c‑Myc, cyclin D1, and Bcl‑2) in SNK6 cells. These results suggested that STAT3 activation represents a potential target in nasal NKTCL. WP1066 may be a promising agent in antitumor therapy against nasal NKTCL.

Inflammation has a role in urethane‑induced lung cancer in C57BL/6J mice

Lung cancer is a common and highly frequent cause of cancer‑associated mortality worldwide. Several studies have indicated that chronic inflammation is associated with an increased risk of several types of human cancer. The lung is vulnerable to various chemical and biological insults, and persistent exposure to these factors may result in the release of several inflammatory cytokines from inflammatory cells, thus leading to chronic inflammation and a risk of lung cancer. Due to the extensive application of C57BL/6J mice in lipid metabolism‑related research, it appears important to establish a lung cancer model based on C57BL/6J mice. Therefore, the present study designed an experimental model, in which C57BL/6J mice received several injections of urethane. The study aimed to explore whether inflammation has a role in this model of lung cancer. The results demonstrated that 10 weekly intraperitoneal injections of urethane induced a 100% lung tumor incidence, and urethane‑treated mice possessed higher numbers of immune cells. In addition, the expression levels of cytokines and chemokines in bronchoalveolar lavage fluid were significantly different between the two groups. Activation of the transcription factor nuclear factor‑κB was increased in the lung tissues of urethane‑treated mice, and its expression was upregulated in a time‑dependent manner. These results suggested that the accumulation of lung inflammation may be associated with the occurrence of lung cancer in C57BL/6J mice.

Myeloid-derived suppressor cells as intruders and targets: clinical implications in cancer therapy

Chronic inflammation, typical of various diseases including cancer, is a "silent bomb within the body," leading to complications that are only evident in most cases upon their appearance, when disease is already deteriorated. Chronic inflammation is associated with accumulation of myeloid-derived suppressor cells (MDSCs), which lead to immunosuppression. MDSCs have numerous harmful effects as they support tumor initiation, tumor growth and spreading, which in turn, perpetuate the inflammatory and suppressive conditions, thus preventing anticancer responses. As the concept of the immune system combating many types of tumors was revived in recent years, immunotherapy has dramatically changed the view of cancer treatment, and numerous novel therapies have been developed and approved by the FDA. However, cumulative clinical data point at very limited success rates. It is most likely that the developing chronic inflammation and MDSC-induced immunosuppression interfere with responses to such treatments and hence are major obstacles in achieving higher response rates to immune-based therapies. Moreover, chemotherapies were shown to have adverse immunoregulatory effects, enhancing or decreasing MDSC levels and activity, thus affecting treatment success. Therefore, therapeutic manipulations of chronic inflammation and MDSCs during cancer development are likely to enhance efficacy of immune- and chemo-based treatments, switching chronic pro-cancer inflammatory environments to an anticancerous milieu. Based on the functional relevance of immune networking in tumors, it is critical to merge monitoring immune system biomarkers into the traditional patient's categorization and treatment regimens. This will provide new tools for clinical practice, allowing appropriate management of cancer patients toward a better-personalized medicine.

Arsenic-induced dose-dependent modulation of the NF-κB/IL-6 axis in thymocytes triggers differential immune responses

Arsenic contamination of drinking water is a matter of global concern. Arsenic intake impairs immune responses and leads to a variety of pathological conditions including cancer. In order to understand the intricate tuning of immune responses elicited by chronic exposure to arsenic, a mouse model was established by subjecting mice to different environmentally relevant concentrations of arsenic in drinking water for 30days. Detailed study of the thymus, a primary immune organ, revealed arsenic-mediated tissue damage in both histological specimens and scanning electron micrographs. Analysis of molecular markers of apoptosis by Western blot revealed a dose-dependent activation of the apoptotic cascade. Enzymatic assays supported oxidative stress as an instigator of cell death. Interestingly, assessment of inflammatory responses revealed disparity in the NF-κB/IL-6/STAT3 axis, where it was found that in animals consuming higher amounts of arsenic NF-κB activation did not lead to the classical IL-6 upregulation response. This deviation from the canonical pathway was accompanied with a significant rise in numbers of CD4+ CD25+ FoxP3 expressing cells in the thymus. The cytokine profile of the animals exposed to higher doses of arsenic also indicated an immune-suppressed milieu, thus validating that arsenic shapes the immune environment in context to its dose of exposure and that at higher doses it leads to immune-suppression. Our study establishes a novel role of arsenic in regulating immune homeostasis in context to its dose, where, at higher doses, arsenic related upregulation of NF-κB cascade takes on an alternative role that is correlated with increased immune-suppression.

Clinical Significance of Circulating CD33+CD11b+HLA-DR- Myeloid Cells in Patients with Stage IV Melanoma Treated with Ipilimumab

PURPOSE

High levels of circulating myeloid-derived suppressor cells (MDSCs) in various cancer types, including melanoma, were shown to correlate with poor survival. We investigated whether frequencies of circulating CD33⁺CD11b⁺HLA-DR^- MDSCs could be used as immune system monitoring biomarkers to predict response and survival of patients with stage IV melanoma treated with anti-CTLA4 (ipilimumab) therapy.

EXPERIMENTAL DESIGN

Peripheral blood samples from 56 patients and 50 healthy donors (HDs) were analyzed for CD33⁺CD11b⁺HLA-DR^- MDSC percentage, NO^-, and hROS levels by flow cytometry. We determined whether MDSC levels and suppressive features detected before anti-CTLA4 therapy correlate with the patients' response and overall survival (OS).

RESULTS

Patients with melanoma had significantly higher levels of circulating CD33⁺CD11b⁺HLA-DR^- MDSCs with suppressive phenotype when compared with HDs. Low levels of MDSCs before CTLA-4 therapy correlated with an objective clinical response, long-term survival, increased CD247 expression in T cells, and an improved clinical status. No predictive impact was observed for lactate dehydrogenase (LDH). Kaplan-Meier and log-rank tests performed on the 56 patients showed that the presence of more than 55.5% of circulating CD33⁺CD11b⁺ out of the HLA-DR^- cells, were associated with significant short OS (P < 0.003), a median of 6.5 months, in comparison with the group showing lower MDSC frequencies, with a median survival of 15.6 months.

CONCLUSIONS

Our study suggests the use of CD33⁺CD11b⁺HLA-DR^- cells as a predictive and prognostic biomarker in patients with stage IV melanoma treated with anti-CTLA4 therapy. This monitoring system may aid in the development of combinatorial modalities, targeting the suppressive environment in conjunction with iplimumab, toward facilitating better disease outcomes. Clin Cancer Res; 22(23); 5661-72. ©2016 AACR.

Predictive immune markers in advanced melanoma patients treated with ipilimumab

Myeloid-derived suppressor cells (MDSCs) and chronic inflammatory factors induce immunosuppression and disease progression in advanced melanoma patients. They could serve as important markers allowing the identification of patients with high risk of melanoma progression as well as the detection of those patients who may benefit from the therapy with ipilimumab.

Effects of kramecyne on LPS induced chronic inflammation and gastric ulcers

Preclinical Research Krameria cytisoides is used for the treatment of inflammation, stomach pain, and gastric ulcers. The active ingredient from this plant is a peroxide, kramecyne (KACY) which has anti-inflammatory effects. The aim of the present study was to evaluate the anti-inflammatory activities of KACY in lipopolysaccharide (LPS)-induced systemic chronic inflammation in mice for 60 days, using dexamethasone (DEX) as the positive control, vehicle (the LPS group) as the negative control and the control group (mice without inflammation). KACY did not affect survival, body weight or relative organ weight in mice but it: decreased nitric oxide (NO) production by 68%; prostaglandin E2 (PGE2 ) by 67%; increased release of anti-inflammatory cytokine IL-10 (2.0-fold), and reduced production of the proinflammatory cytokines, IL-6 (2.0-fold), IL-1β (2.4-fold), and TNF-α (2.0-fold). Furthermore, the gastroprotective effects of KACY in mice were evaluated in an ethanol-induced gastric ulcer model. The results showed that KACY at 50 and 100 mg/kg exerted gastroprotective effects with similar activity to 50 mg/kg ranitidine. In gastric tissues, KACY decreased the level of malondialdehyde (MDA) but increased the catalase (CAT) activity. KACY have potential for the treatment of chronic inflammatory diseases due its similar activity to that of DEX. It also has gastroprotective effects.

Effect of interleukin-1β and tumor necrosis factor α gene silencing on mouse gastric cancer cell proliferation and migration

The aim of the present study was to investigate the effect of interleukin-1β (IL-1β) and tumor necrosis factor α (TNFα) gene co-silencing in mouse gastric cancer (GC) cells. Respectively, three pairs of liposome-encapsulated IL-1β and TNFα small interfering RNA (siRNA) were transfected into the mouse GC cell line MFC. The most effective siRNA, as identified by reverse transcription-polymerase chain reaction, was used for co-suppression of IL-1β and TNFα genes. The activities of cell proliferation, colony formation and migration were determined by the Cell Counting Kit 8 method, colony formation assay and Transwell assay, respectively. Protein array analysis was performed to identify the differentially expressed factors. The possible signaling pathways of the various factors targeting the genes were identified by pathway enrichment analysis using KOBAS 2.0. siRNA1 and siRNAc were the most effective interference sequences for IL-1β and TNFα, respectively. Following co-transfection of siRNA1 and siRNAc, the expression of IL-1β and TNFα was inhibited at the mRNA and protein levels, and the cell proliferation, colony forming and migration abilities were reduced (P<0.05). The expression of inflammatory factors, including chemokine ligand 5, cyclooxygenase-2, IL-6, transforming growth factor β, IL-17A, matrix metallopeptidase 9 and stromal cell-derived factor 1α were also inhibited (P<0.05). These factors are mainly involved in the rheumatoid arthritis pathway, the intestinal immune network for IgA production, the TNF signaling pathway and the inflammatory bowel disease pathway. IL-1β and TNFα gene silencing inhibits the proliferation and migration of MFC. The mechanisms may involve multiple inflammatory factors that participate in the signaling pathways of tumor tissue inflammation, the immune network and TNF.

Hydrogel dual delivered celecoxib and anti-PD-1 synergistically improve antitumor immunity

Two major challenges facing cancer immunotherapy are the relatively low therapeutic efficacy and the potential side effects. New drug delivery system and efficient drug combination are required to overcome these challenges. We utilize an alginate hydrogel system to locally deliver 2 FDA-approved drugs, celecoxib and programmed death 1 (PD-1) monoclonal antibody (mAb), to treat tumor-bearing mice. In two cancer models, B16-F10 melanoma and 4T1 metastatic breast cancer, the alginate hydrogel delivery system significantly improves the antitumor activities of celecoxib (CXB), PD-1 mAb, or both combined. These effects are associated with the sustained high concentrations of the drugs in peripheral circulation and within tumor regions. Strikingly, the simultaneous dual local delivery of celecoxib and PD-1 from this hydrogel system synergistically enhanced the presence of CD4+inteferon (IFN)-γ+ and CD8+IFN-γ+ T cells within the tumor as well as in the immune system. These effects are accompanied with reduced CD4+FoxP3+ regulatory T cells (Tregs) and myeloid derived suppressor cells (MDSCs) in the tumor, reflecting a weakened immuosuppressive response. Furthermore, this combinatorial therapy increases the expression of two anti-angiogenic chemokines C-X-C motif ligand (CXCL) 9 and CXCL10, and suppresses the intratumoral production of interleukin (IL)-1, IL-6, and cycloxygenase-2 (COX2), suggesting a dampened pro-tumor angiogenic and inflammatory microenvironment. This alginate-hydrogel-mediated, combinatorial therapy of celecoxib and PD-1 mAb provides a potential valuable regimen for treating human cancer.

Whom to blame for metastasis, the epithelial-mesenchymal transition or the tumor microenvironment?

Changes in the tumor microenvironment (TME) can trigger the activation of otherwise non-malignant cells to become highly aggressive and motile. This is evident during initial tumor growth when the poor vascularization in tumors generates hypoxic regions that trigger the latent embryonic program, epithelial-to-mesenchymal transition (EMT), in epithelial carcinoma cells (e-cars) leading to highly motile mesenchymal-like carcinoma cells (m-cars), which also acquire cancer stem cell properties. After that, specific bidirectional interactions take place between m-cars and the cellular components of TME at different stages of metastasis. These interactions include several vicious positive feedback loops in which m-cars trigger a phenotypic switch, causing normal stromal cells to become pro-tumorigenic, which then further promote the survival, motility, and proliferation of m-cars. Accordingly, there is not a single culprit accounting for metastasis. Instead both m-cars and the TME dynamically interact, evolve and promote metastasis. In this review, we discuss the current status of the known interactions between m-cars and the TME during different stages of metastasis and how these interactions promote the metastatic activity of highly malignant m-cars by promoting their invasive mesenchymal phenotype and CSC properties.

Impaired SNX9 Expression in Immune Cells during Chronic Inflammation: Prognostic and Diagnostic Implications

Chronic inflammation is associated with immunosuppression and downregulated expression of the TCR CD247. In searching for new biomarkers that could validate the impaired host immune status under chronic inflammatory conditions, we discovered that sorting nexin 9 (SNX9), a protein that participates in early stages of clathrin-mediated endocytosis, is downregulated as well under such conditions. SNX9 expression was affected earlier than CD247 by the generated harmful environment, suggesting that it is a potential marker sensing the generated immunosuppressive condition. We found that myeloid-derived suppressor cells, which are elevated in the course of chronic inflammation, are responsible for the observed SNX9 reduced expression. Moreover, SNX9 downregulation is reversible, as its expression levels return to normal and immune functions are restored when the inflammatory response and/or myeloid-derived suppressor cells are neutralized. SNX9 downregulation was detected in numerous mouse models for pathologies characterized by chronic inflammation such as chronic infection (Leishmania donovani), cancer (melanoma and colorectal carcinoma), and an autoimmune disease (rheumatoid arthritis). Interestingly, reduced levels of SNX9 were also observed in blood samples from colorectal cancer patients, emphasizing the feasibility of its use as a diagnostic and prognostic biomarker sensing the host's immune status and inflammatory stage. Our new discovery of SNX9 as being regulated by chronic inflammation and its association with immunosuppression, in addition to the CD247 regulation under such conditions, show the global impact of chronic inflammation and the generated immune environment on different cellular pathways in a diverse spectrum of diseases.

Pi (Spleen)-deficiency syndrome in tumor microenvironment is the pivotal pathogenesis of colorectal cancer immune escape

Cancer immunoediting consists of three sequential phases: elimination, equilibrium, and escape. For colorectal adenoma-carcinoma sequence, the adenoma dysplastic progression may represent an equilibrium phase and the cancer stage as escape phase. Immune system eliminates transformed enterocytes by destroying them at first, sculpts them at the same time and selects the variants subsequently that are no longer recognized and insensitive to immune effectors, and finally induces immunosuppressive state within the tumor microenvironment that facilitates immune escape and tumor outgrowth. Immunosuppression and inflammation are the two crucial features of Pi (Spleen)-deficiency. Classic quotations, immune evidence and clinical observations suggest that Spleen (but not other organs) deficiency is the key pathogenesis of colorectal cancer (CRC) microenvironment. Weakness of old age, immunosuppressive cytokines from chronic inflammation, tumor-derived immunosuppressive factors and surrendered immune cells-regulatory T cells, myeloid-derived suppressor cells and tumor associated macrophages (TAMs) constitutes CRC microenvironment of Pi-deficiency. Furthermore, excess in superficiality, such as phlegm stagnation, blood stasis and toxin accumulation are induced by chronic inflammation on the basis of asthenia in origin, an immunosuppressive state. Great masters of Chinese medicine emphasize that strengthen Pi is the chief therapeutic principle for CRC which receives good therapeutic effects. So, Pi-deficiency based syndrome is the pivotal pathogenesis of tumor microenvironment. The immunosuppressive microenvironment facilitates immune escape which play an important role in the transition from adenoma to adenocarcinoma. There are some signs that strengthen Pi based treatment has potential capacity to ameliorate tumor environment. It might be a novel starting point to explore the mechanism of strengthen Pi based therapy in the prevention and treatment of CRC through regulation of tumor environment and immunoediting.

The Role of the Transcriptional Regulation of Stromal Cells in Chronic Inflammation

Chronic inflammation is a common process connecting pathologies that vary in their etiology and pathogenesis such as cancer, autoimmune diseases, and infections. The response of the immune system to tissue damage involves a carefully choreographed series of cellular interactions between immune and non-immune cells. In recent years, it has become clear that stromal resident cells have an essential role perpetuating the inflammatory environment and dictating in many cases the outcome of inflammatory based pathologies. Signal transduction pathways remain the main focus of study to understand how stimuli contribute to perpetuating the inflammatory response, mainly due to their potential role as therapeutic targets. However, molecular events orchestrated in the nucleus by transcription factors add additional levels of complexity and may be equally important for understanding the phenotypic differences of activated stromal components during the chronic inflammatory process. In this review, we focus on the contribution of transcription factors to the selective regulation of inducible proinflammatory genes, with special attention given to the regulation of the stromal fibroblastic cell function and response.

Paving the Road to Tumor Development and Spreading: Myeloid-Derived Suppressor Cells are Ruling the Fate

Cancer development is dependent on intrinsic cellular changes as well as inflammatory factors in the tumor macro and microenvironment. The inflammatory milieu nourishes the tumor and contributes to cancer progression. Numerous studies, including ours, have demonstrated that the tumor microenvironment is immunosuppressive, impairing the anticancer immune responses. Chronic inflammation was identified as the key process responsible for this immunosuppression via induction of immature myeloid-derived suppressor cells (MDSCs). Upon a prolonged immune response, MDSCs are polarized toward immunosuppressive cells meant to control the exacerbated immune response. In cancer, the chronic inflammatory response renders the MDSCs harmful. Polarized MDSCs suppress T-cells and natural killer cells, as well as antigen-presenting cells, abrogating the beneficial immune response. These changes in the immunological milieu could also lead to high frequency of mutations, enhanced cancer cell stemness, and angiogenesis, directly supporting tumor initiation, growth, and spreading. The presence of MDSCs in cancer poses a serious obstacle in a variety of immune-based therapies, which rely on the stimulation of antitumor immune responses. Cumulative data, including our own, suggest that the selection of an appropriate and effective anticancer therapy must take into consideration the host’s immune status as well as tumor-related parameters. Merging biomarkers for immune monitoring into the traditional patient’s categorization and follow-up can provide new predictive and diagnostic tools to the clinical practice. Chronic inflammation and MDSCs could serve as novel targets for therapeutic interventions, which can be combined with conventional cancer treatments such as chemotherapy, radiotherapy, and cancer cell-targeted and immune-based therapies. Intervention in environmental and tumor-specific inflammatory mechanisms will allow better clinical management of cancer toward more efficient treatment.

Immunosuppression associated with chronic inflammation in the tumor microenvironment

Chronic inflammation contributes to cancer development via multiple mechanisms. One potential mechanism is that chronic inflammation can generate an immunosuppressive microenvironment that allows advantages for tumor formation and progression. The immunosuppressive environment in certain chronic inflammatory diseases and solid cancers is characterized by accumulation of proinflammatory mediators, infiltration of immune suppressor cells and activation of immune checkpoint pathways in effector T cells. In this review, we highlight recent advances in our understanding of how immunosuppression contributes to cancer and how proinflammatory mediators induce the immunosuppressive microenvironment via induction of immunosuppressive cells and activation of immune checkpoint pathways.

Systemic inflammation in xenograft recipients (SIXR): A new paradigm in pig-to-primate xenotransplantation?

Inflammation is a complex response that involves interactions between multiple proteins in the human body. The interaction between inflammation and coagulation is well-recognized, but its role in the dysregulation of coagulation in xenograft recipients is not well-understood. Additionally, inflammation is known to prevent the development of T cell tolerance after transplantation. Recent evidence indicates that systemic inflammation precedes and may be promoting activation of coagulation after pig-to-primate xenotransplantation. Activated recipient innate immune cells expressing tissue factor are increased after xenotransplantation, irrespective of immunosuppressive therapy. With immunosuppression, C-reactive protein (C-RP), fibrinogen, and interleukin-6 levels are significantly increased in pig artery patch recipients. In pig organ recipients, increased C-RP levels are observed prior to the development of features of consumptive coagulopathy. Systemic inflammation in xenograft recipients (Sixr) may be a key factor in the development of dysregulation of coagulation, as well as in resistance to immunosuppressive therapy. While genetic modification of the donor pigs provides protection against humoral responses and the development of thrombotic microangiopathy, therapeutic prevention of Sixr may be essential in order to prevent systemic dysregulation of coagulation in xenograft recipients without the use of intensive immunosuppression.

Modulation of Acid Sphingomyelinase in Melanoma Reprogrammes the Tumour Immune Microenvironment

The inflammatory microenvironment induces tumours to acquire an aggressive and immunosuppressive behaviour. Since acid sphingomyelinase (A-SMase) downregulation in melanoma was shown to determine a malignant phenotype, we aimed here to elucidate the role of A-SMase in the regulation of tumour immunogenic microenvironment using in vivo melanoma models in which A-SMase was either downregulated or maintained at constitutively high levels. We found high levels of inflammatory factors in low A-SMase expressing tumours, which also displayed an immunosuppressive/protumoural microenvironment: high levels of myeloid-derived suppressor cells (MDSCs) and regulatory T lymphocytes (Tregs), as well as low levels of dendritic cells (DCs). In contrast, the restoration of A-SMase in melanoma cells not only reduced tumour growth and immunosuppression, but also induced a high recruitment at tumour site of effector immune cells with an antitumoural function. Indeed, we observed a poor homing of MDSCs and Tregs and the increased recruitment of CD8⁺ and CD4⁺ T lymphocytes as well as the infiltration of DCs and CD8⁺/CD44^high T lymphocytes. This study demonstrates that change of A-SMase expression in cancer cells is sufficient per se to tune in vivo melanoma growth and that A-SMase levels modulate immune cells at tumour site. This may be taken into consideration in the setting of therapeutic strategies.

Shenling Baizhu San supresses colitis associated colorectal cancer through inhibition of epithelial-mesenchymal transition and myeloid-derived suppressor infiltration

Background

Shenling Baizhu San (SBS) is a well-known and classical Chinese medicine formula. It has been used for treatment of gastrointestinal disorders for about nine hundred years. Recent reports showed that it was effective in curing colitis and ameliorating the major manifestations of postoperational colorectal cancer (CRC). This study was to evaluate the effects of SBS on azoxymethane (AOM) and dextran sodium sulfate (DSS) induced colitis associated CRC (caCRC) and to analyze the underlying mechanism of SBS in preventing CRC.

Methods

The colon tissue of mice in different group was determined by immunohistochemistry and western blot. TGF-β1 in serum was measured by ELISA. Myeloid-derived suppressor cells (MDSCs) were identified by flow cytometry and immunohistochemistry.

Results

The formed neoplasms phenotypically resembled human caCRC with upregulated β-catenin, p53 and proliferating cell nuclear antigen (PCNA). SBS treatment reduced the death rate of mice and decreased the incidence and multiplicity of colonic neoplasms. SBS decreased the number of MDSCs and the level of transforming growth factor β1 (TGF-β1). SBS alleviated epithelial mesenchymal transition (EMT) through downregulating N-cadherin (N-cad), Vimentin, Fibronectin, Snail, and upregulating E-cadherin (E-cad). It reduced the activation of Wnt5a and EMT induced by TGF-β1.

Conclusions

SBS reduced the death rate through decreasing the incidence and multiplicity of colonic tumors. SBS lowered MDSCs infiltration and inhibited TGF-β1 induced EMT to exert its anti-caCRC effects.

Electronic supplementary material

The online version of this article (doi:10.1186/s12906-015-0649-9) contains supplementary material, which is available to authorized users.

Contrasting inflammatory responses in severe and non-severe community-acquired pneumonia

The objective of this study was to compare systemic and local cytokine profiles and neutrophil responses in patients with severe versus non-severe community-acquired pneumonia (CAP). Hospitalized patients with CAP were grouped according to the pneumonia severity index (PSI), as non-severe (PSI < 91 points) or severe (PSI ≥ 91 points). Blood and sputum samples were collected upon admission. Compared to non-severe CAP patients, the severe CAP group showed higher plasma levels of pro- and anti-inflammatory cytokines but in contrast, lower sputum concentrations of pro-inflammatory cytokines. Blood neutrophil functional responses were elevated in CAP patients compared to healthy controls. However, neutrophils from severe CAP patients showed reduced respiratory burst activity compared to the non-severe group. Results indicate that patients with severe CAP fail to mount a robust local pro-inflammatory response but exhibit instead a more substantial systemic inflammatory response, suggesting that a key driver of CAP severity may be the ability of the patient to generate an optimal local inflammatory response.

Early Growth Response 3 regulates genes of inflammation and directly activates IL6 and IL8 expression in prostate cancer

Background:

Transcription factor EGR3 (Early Growth Response 3) is a little-studied member of the EGR family that is highly expressed in human prostate tumours compared with normal tissue. Its function in prostate cancer, however, is unknown.

Methods:

Stable shRNA silencing was achieved in naturally overexpressing prostate cancer cells, followed by Affymetrix expression analysis. Fold changes of ⩾2 and ⩽−2 were considered valid and t-tests P-values of ⩽0.01 were considered statistically significant. Potential EGR3 target genes were validated by real-time qPCR, chromatin immunoprecipitation, and gain-of-function experiments. Promoter analysis confirmed the presence of consensus binding sites in the promoters of target genes.

Results:

Early Growth Response 3 regulates the expression of ∼330 genes, 35% of which are involved in immune responses and inflammatory processes, and 15% crosstalk with the NF-κB signalling pathway. In particular, EGR3 induces the expression of over 50 secreted cytokines, growth factors, and matrix remodelling factors. Two interleukins of great relevance to prostate cancer, IL6 and IL8, were further validated as EGR3 target genes: both promoters contain EGR consensus binding sites and are pulled down in intact cells by EGR3 chromatin immunoprecipitation. Silencing of EGR3 decreased IL6 and IL8 expression, whereas overexpression of EGR3 in nontransformed cells induced IL6 and IL8 expression.

Conclusions:

Chronic inflammation plays a critical role in prostate cancer and elevated production of pro-inflammatory cytokines IL8 and IL6, in particular, contributes to disease progression and to the onset of castration resistance. It is shown for the first time that EGR3 is involved in the upregulation of both IL6 and IL8. Together with our previous observation that EGR3 is highly expressed in prostate tumours compared with normal tissue and strongly correlates with IL6 and IL8 expression in clinical samples, the present study suggests that EGR3 promotes excessive production of IL6 and IL8 observed during the progression of prostate cancer.

A chromatin activity-based chemoproteomic approach reveals a transcriptional repressome for gene-specific silencing

Immune cells develop endotoxin tolerance (ET) after prolonged stimulation. ET increases the level of a repression mark H3K9me2 in the transcriptional-silent chromatin specifically associated with pro-inflammatory genes. However, it is not clear what proteins are functionally involved in this process. Here we show that a novel chromatin activity based chemoproteomic (ChaC) approach can dissect the functional chromatin protein complexes that regulate ET-associated inflammation. Using UNC0638 that binds the enzymatically active H3K9-specific methyltransferase G9a/GLP, ChaC reveals that G9a is constitutively active at a G9a-dependent mega-dalton repressome in primary endotoxin-tolerant macrophages. G9a/GLP broadly impacts the ET-specific reprogramming of the histone code landscape, chromatin remodeling, and the activities of select transcription factors. We discover that the G9a-dependent epigenetic environment promotes the transcriptional repression activity of c-Myc for gene-specific co-regulation of chronic inflammation. ChaC may be also applicable to dissect other functional protein complexes in the context of phenotypic chromatin architectures.

Elevated chronic inflammatory factors and myeloid-derived suppressor cells indicate poor prognosis in advanced melanoma patients

Chronic inflammation is considered to be one of the hallmarks for tumor initiation and progression. Moreover, a long-term production and accumulation of inflammatory factors lead to a local and systemic immunosuppression associated with cancer progression. However, the correlation between inflammatory mediators, immunosuppressive cells and the clinical outcome of malignant melanoma patients was poorly investigated. In this study, we performed a complex analysis of various inflammatory factors, myeloid-derived suppressor cells (MDSCs) and regulatory T cells (Tregs) in the peripheral blood of patients suffering from malignant melanoma of different stages. We demonstrated that levels of serum IL-1β, IFN-γ and CXCL10 were significantly increased in advanced melanoma patients. In addition, these factors were found to be associated with an increased frequency of MDSCs and Tregs as compared to age- and gender-matched healthy donors. Importantly, advanced melanoma patients with signs of progression displayed markedly elevated concentrations of IL-1β and CXCL10 as compared to patients with stable disease. Moreover, an enrichment of circulating monocytic (Mo)-MDSCs significantly correlated with a decreased progression free survival of these patients. Our data highlight a complex association between circulating inflammatory mediators, Mo-MDSCs and the clinical outcome as well as suggest that their levels in patients with advanced melanoma are of important prognostic value allowing the identification of those with high risk of disease progression.

Adverse immunoregulatory effects of 5FU and CPT11 chemotherapy on myeloid-derived suppressor cells and colorectal cancer outcomes

Colorectal cancer is associated with chronic inflammation and immunosuppression mediated by myeloid-derived suppressor cells (MDSC). Although chemotherapy reduces tumor burden at early stages, it tends to have limited effect on a progressive disease, possibly due to adverse effects on the immune system in dictating disease outcome. Here, we show that patients with advanced colorectal cancer display enhanced MDSC levels and reduced CD247 expression and that some conventional colorectal cancer chemotherapy supports the immunosuppressive tumor microenvironment. A FOLFOX combined therapy reduced immunosuppression, whereas a FOLFIRI combined therapy enhanced immunosuppression. Mechanistic studies in a colorectal cancer mouse model revealed that FOLFIRI-like therapy including the drugs CPT11 and 5-fluorouracil (5FU) damaged host immunocompetence in a manner that limits treatment outcomes. CPT11 blocked MDSC apoptosis and myeloid cell differentiation, increasing MDSC immunosuppressive features and mouse mortality. In contrast, 5FU promoted immune recovery and tumor regression. Thus, CPT11 exhibited detrimental immunoregulatory effects that offset 5FU benefits when administered in combination. Our results highlight the importance of developing therapeutic regimens that can target both the immune system and tumor towards improved personalized treatments for colorectal cancer.

Multi-constituent synergism is responsible for anti-inflammatory effect of Azadirachta indica leaf extract

CONTEXT

Azadirachta indica A. Juss. (Meliaceaes) leaves have been used traditionally to treat swelling and rheumatism in Indian cultures.

OBJECTIVE

To fractionate A. indica leaf extracts using bioactivity guided manner for identification of the active anti-inflammatory principles.

MATERIALS AND METHODS

Polarity-gradient sequential extracts (petroleum ether, chloroform, methanol, and water) of A. indica leaves were screened for their anti-inflammatory potential using the carrageenan-induced rat paw edema model (1 g/kg). The chloroform extract was sequentially fractionated to obtain n-hexane (F-1), n-hexane-chloroform (F-2), and chloroform (F-3) fractions and their inhibitory effect on rat paw edema was evaluated (500 mg/kg). Inhibitory effect of F-2 on granuloma formation, plasma interleukin (IL-1), and tumor necrosis factor (TNF-α) was assessed at the doses of 100, 200, and 400 mg/kg using the cotton pellet assay in rats. Three sub-fractions (SF-1, SF-2, and SF-3) were obtained upon chromatography of F-2, and their inhibitory effect on cyclooxygenase was assessed at 200 µg/mL concentration. The sub-fractions were subjected to gas chromatography-mass spectrometry (GC-MS).

RESULTS

All the extracts showed significant anti-inflammatory effect; however, chloroform extract was the most effective against paw edema (53.25% inhibition). The three fractions of chloroform extract showed significant effect, while F-2 being the most potent (51.02%). F-2 demonstrated dose-dependent inhibition of granuloma and cytokines. Interestingly, all the sub-fractions of F-2 inhibited COX-1 and COX-2 with almost equal potential. GC-MS revealed that chemically the sub-fractions were totally different from each other.

DISCUSSION AND CONCLUSION

Anti-inflammatory effect of A. indica is a result of cumulative and synergistic effects of diversified constituents with varying polarities that collectively exert the effect via suppression of cyclo-oxygenases and cytokines (IL-1 and TNF-α).

The immunomodulation and anti-inflammatory effects of garlic organosulfur compounds in cancer chemoprevention

Garlic (Allium sativum) has been used for centuries as a prophylactic and therapeutic medicinal agent. Importantly, garlic has been suggested to have both cancer-preventive potential as well as significant enhancing effects on the immune system. While these observations are supported experimentally both in vitro and in vivo, the impact of garlic in assisting the immune system in the prevention of cancer still lacks experimental confirmation. Studies addressing the immunomodulatory effects of garlic reveal conflicting data as to pro- or anti-inflammatory responses depending on the particular experimental set-ups and the garlic preparation used (i.e. garlic extract versus chemically pure garlic compounds). Here we provide an overview of the chemistry of the major garlic organosulfur compounds, summarize the current understanding and propose a link between the immunomodulating activity of garlic and the prevention of cancer. We hypothesize that garlic rather elicits anti-inflammatory and anti-oxidative responses that aid in priming the organism towards eradication of an emerging tumor.

Extracellular adenosine metabolism in immune cells in melanoma

Malignant melanoma is characterized by the development of chronic inflammation in the tumor microenvironment, which leads to a strong immunosuppression associated with a rapid tumor progression. Adenosine is considered as one of the main immunosuppressive factors in the tumor environment. It is produced via enzymatic hydrolysis of extracellular ATP by ectonucleotidases CD39 and CD73 localized on cell surface. Using the ret transgenic mouse melanoma model that closely mimics human melanoma, we demonstrated an increased frequency of ectonucleotidase-positive myeloid-derived suppressor cells (MDSCs) in melanoma lesions and lymphoid organs. Furthermore, we observed that conventional CD4(+)FoxP3(-) and CD8(+) T cells infiltrating melanoma lesions of ret transgenic mice were distinctly enriched in the CD39(+)CD73(+) subpopulation that co-expressed also PD-1. Ectonucleotidase expression was also up-regulated in CD4(+) and CD8(+) T cells upon activation. In addition, these ectoenzymes were largely found to be expressed on memory T cell compartment (in particular, on effector memory cells). Our data suggest that extracellular adenosine produced by regulatory T cells (Tregs) and MDSCs can suppress T cell effector functions through paracrine signaling. Another mechanism involves its production also by effector T cells and an inhibition of their anti-tumor reactivity via autocrine signaling as a part of the negative feedback loop. This mode of adenosine signaling could be also used by Tregs and MDSCs to enhance their immunosuppressive activity.

Myeloid-derived suppressor cells in malignant melanoma

Melanoma is known for its rapid progression, metastasis to distant organs and therapeutic resistance. Despite high melanoma immunogenicity, the results of immunotherapeutic clinical studies are mostly unsatisfactory. One explanation is the development of strong immunosuppression mediated by highly immunosuppressive regulatory leukocytes, in particular, myeloid-derived suppressor cells (MDSCs). These cells were found to be enriched and activated in the melanoma microenvironment, inducing a profound impairment of anti-tumor immune responses and leading to the tumor progression. Therefore, understanding the mechanisms of MDSC generation, migration to the tumor site and activation as well as their targeting is important for the development of novel strategies for effective melanoma immunotherapy. We suggest that such therapeutic approaches should involve the inhibition of MDSC-mediated immunosuppressive melanoma microenvironment combined with other immunologic treatments.

Enhanced antitumor immunity contributes to the radio-sensitization of ehrlich ascites tumor by the glycolytic inhibitor 2-deoxy-D-glucose in mice

Two-deoxy-D-glucose (2-DG), an inhibitor of glycolysis differentially enhances the radiation and chemotherapeutic drug induced cell death in cancer cells in vitro, while the local tumor control (tumor regression) following systemic administration of 2-DG and focal irradiation of the tumor results in both complete (cure) and partial response in a fraction of the tumor bearing mice. In the present studies, we investigated the effects of systemically administered 2-DG and focal irradiation of the tumor on the immune system in Ehrlich ascites tumor (EAT) bearing Strain "A" mice. Markers of different immune cells were analyzed by immune-flow cytometry and secretary cytokines by ELISA, besides monitoring tumor growth. Increase in the expression of innate (NK and monocytes) and adaptive CD4+cells, and a decrease in B cells (CD19) have been observed after the combined treatment, suggestive of activation of anti-tumor immune response. Interestingly, immature dendritic cells were found to be down regulated, while their functional markers CD86 and MHC II were up regulated in the remaining dendritic cells following the combination treatment. Similarly, decrease in the CD4(+) naïve cells with concomitant increase in activated CD4+ cells corroborated the immune activation. Further, a shift from Th2 and Th17 to Th1 besides a decrease in inflammatory cytokines was also observed in the animals showing complete response (cure; tumor free survival). This shift was also complimented by respective antibody class switching followed by the combined treatment. The immune activation or alteration in the homeostasis favoring antitumor immune response may be due to depletion in T regulatory cells (CD4(+)CD25(+)FoxP3(+)). Altogether, these results suggest that early differential immune activation is responsible for the heterogenous response to the combined treatment. Taken together, these studies for the first time provided insight into the additional mechanisms underlying radio-sensitization by 2-DG in vivo by unraveling its potential as an immune-modulator besides direct effects on the tumor.

Anti-inflammatory effect of the blueberry anthocyanins malvidin-3-glucoside and malvidin-3-galactoside in endothelial cells

Blueberry fruits have a wide range of health benefits because of their abundant anthocyanins, which are natural antioxidants. The purpose of this study was to investigate the inhibitory effect of blueberry's two main anthocyanins (malvidin-3-glucoside and malvidin-3-galactoside) on inflammatory response in endothelial cells. These two malvidin glycosides could inhibit tumor necrosis factor-alpha (TNF-α) induced increases of monocyte chemotactic protein-1 (MCP-1), intercellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1) production both in the protein and mRNA levels in a concentration-dependent manner. Mv-3-glc at the concentration of 1 μM could inhibit 35.9% increased MCP-1, 54.4% ICAM-1, and 44.7% VCAM-1 protein in supernatant, as well as 9.88% MCP-1 and 48.6% ICAM-1 mRNA expression (p<0.05). In addition, they could decrease IκBα degradation (Mv-3-glc, Mv-3-gal, and their mixture at the concentration of 50 μM had the inhibition rate of 84.8%, 75.3%, and 43.2%, respectively, p<0.01) and block the nuclear translocation of p65, which suggested their anti-inflammation mechanism was mediated by the nuclear factor-kappa B (NF-κB) pathway. In general malvidin-3-glucoside had better anti-inflammatory effect than malvidin-3-galactoside. These results indicated that blueberry is good resource of anti-inflammatory anthocyanins, which can be promising molecules for the development of nutraceuticals to prevent chronic inflammation in many diseases.