Inhibition of the Differentiation of Dendritic Cells From CD34+ Progenitors by Tumor Cells: Role of Interleukin-6 and Macrophage Colony-Stimulating Factor

The role of C1QBP in CSF-1-dependent PKCζ activation and macrophage migration

Macrophages view as double agents in tumor progression. Trafficking of macrophages to the proximity of tumors is mediated by colony-stimulating factor-1 (CSF-1), a growth factor. In this study, we investigated the role of complement1q-binding protein (C1QBP)/ atypical protein kinase C ζ (PKCζ) in CSF-1-induced macrophage migration. Disruption of C1QBP expression impaired chemotaxis and adhesion of macrophage. Phosphorylation of PKCζ is an essential component in macrophage chemotaxis signaling pathway. C1QBP could interact with PKCζ in macrophage. C1QBP knockdown inhibited CSF-1 induced phosphorylation of PKCζ and integrin-β1. However, C1QBP knockdown didn't affect the phosphorylation of PKCζ induced by MCP-1. Furthermore, CSF-1 from RCC cell condition medium promoted macrophage chemotaxis and adhesion. Taken together, our results demonstrated that C1QBP plays an essential role in CSF-1 induced migration of macrophages.

Tumor-derived factors affecting immune cells

Tumor progression is accompanied by the production of a wide array of immunosuppressive factors by tumor and non-tumor cells forming the tumor microenvironment. These factors belonging to cytokines, growth factors, metabolites, glycan-binding proteins and glycoproteins are responsible for the establishment of immunosuppressive networks leading towards tumor promotion, invasion and metastasis. In pre-clinical tumor models, the inactivation of some of these suppressive networks reprograms the phenotypic and functional features of tumor-infiltrating immune cells, ultimately favoring effective anti-tumor immune responses. We will discuss factors and mechanisms identified in both mouse and human tumors, and the possibility to associate drugs inhibiting these mechanisms with new immunotherapy strategies already entered in the clinical practice.

Epigenetic mechanisms of myeloid differentiation in the tumor microenvironment

Myeloid cells are extremely plastic as they respond and terminally differentiate into a plethora of functional types, in the blood or tissues, in response to a variety of growth factors, cytokines and pathogenic molecules. This plasticity is also manifested by the subversion of normal differentiation into the aberrant generation of a variety of tolerogenic myeloid cells in the tumoral microenvironment, where a variety of factors are released. Epigenetic mechanisms are in great part responsible for the plasticity of myeloid cells both under physiological and tumoral conditions. The development of compounds that inhibit epigenetic enzymes provides novel therapeutic opportunities to intercept the crosstalk between cancer cells and host myeloid cells. Here, we summarize our current knowledge on the myeloid cell types generated in the cancer environment, the factors and epigenetic enzymes participating in these processes and propose a number of potential targets for future pharmacological use.

Weekday of Surgery Affects Postoperative Complications and Long-Term Survival of Chinese Gastric Cancer Patients after Curative Gastrectomy

Many factors have been reported to affect the long-term survival of gastric carcinoma patients after gastrectomy; the present study took the first attempt to find out the potential role of weekday carried out surgery in the postoperative prognosis of gastric cancer patients. 463 gastric cancer patients have been followed up successfully. Pearson χ² test was used for univariate analyses. Survival curves were constructed by using Kaplan-Meier method and evaluated by using the log-rank test. The Cox proportional hazard regression model was used to find out the risk factors, and subgroup analysis was conducted to rule out confounding factors. We found that the patients who underwent gastrectomy on the later weekday (Wednesday–Friday) more easily suffered from a higher postoperative morbidity. Weekday of surgery was one of the independent indicators for the prognosis of patients after gastric cancer surgery. However, the role of weekday of surgery was significantly weakened in the complications group. In conclusion, surgery performed in the later weekday was more likely to lead to increased postoperative complications and an unfavorable role in prognosis of Chinese gastric cancer patients after curative gastrectomy.

Engineering Chimeric Antigen Receptor T-Cells for Racing in Solid Tumors: Don't Forget the Fuel

T-cells play a critical role in tumor immunity. Indeed, the presence of tumor-infiltrating lymphocytes is a predictor of favorable patient prognosis for many indications and is a requirement for responsiveness to immune checkpoint blockade therapy targeting programmed cell death 1. For tumors lacking immune infiltrate, or for which antigen processing and/or presentation has been downregulated, a promising immunotherapeutic approach is chimeric antigen receptor (CAR) T-cell therapy. CARs are hybrid receptors that link the tumor antigen specificity and affinity of an antibody-derived single-chain variable fragment with signaling endodomains associated with T-cell activation. CAR therapy targeting CD19 has yielded extraordinary clinical responses against some hematological tumors. Solid tumors, however, remain an important challenge to CAR T-cells due to issues of homing, tumor vasculature and stromal barriers, and a range of obstacles in the tumor bed. Protumoral immune infiltrate including T regulatory cells and myeloid-derived suppressor cells have been well characterized for their ability to upregulate inhibitory receptors and molecules that hinder effector T-cells. A critical role for metabolic barriers in the tumor microenvironment (TME) is emerging. High glucose consumption and competition for key amino acids by tumor cells can leave T-cells with insufficient energy and biosynthetic precursors to support activities such as cytokine secretion and lead to a phenotypic state of anergy or exhaustion. CAR T-cell expansion protocols that promote a less differentiated phenotype, combined with optimal receptor design and coengineering strategies, along with immunomodulatory therapies that also promote endogenous immunity, offer great promise in surmounting immunometabolic barriers in the TME and curing solid tumors.

A generic RNA pulsed DC based approach for developing therapeutic intervention against nasopharyngeal carcinoma

The recurrent nasopharyngeal carcinoma of head-and-neck cancers pathology showed unique symptoms and clinical characteristics. The complexity of pathology poses challenges for developing therapeutic interventional approaches against nasopharyngeal carcinoma (NPC). The conventional treatment regimens offer limited local control and survival, which, leads to adverse delayed complications. Our study present a generic monocyte derived dendritic cell (MoDC) vaccine strategy for NPC in which RNA is used as a source of tumor-associated antigens (TAAgs). The RNA extracted from well-characterized highly immunogenic NPC cells (C666-1) was transfected into MoDCs. The formulated and characterized cationic liposomes were used to achieving efficient RNA transfection of immature DCs. Further, DCs were forcibly matured with a cytokine cocktail to achieve greater expression of MHC and co-stimulatory molecules. Moreover, our results did not see any effect of RNA or lipids on MoDCs phenotype or cytokine expression. RNA loaded DCs derived from HLA-A2-positive donors were shown to activate effector memory cytotoxic T lymphocytes (CTLs) specific for TAAg ligand expressed by C666-1 cells. Our results show the comparison of cytotoxic response mounted against RNA-loaded DCs with those directly stimulated by C666-1 tumor cells. Our findings suggest that DCs expressing tumor cell RNA primed naïve T cells show T cells priming with lesser cytotoxicity and cytokine secretion when exposed with with C666-1 tumor cells. These results surface the potential of DCs to deliver RNA in NPCs, sufficient presentation of RNA to provoke perdurable immune responses against nasopharyngeal carcinoma. Our results implies that DC based vaccine approach may be useful to develop therapeutic interventional approach in the form of vaccine to address NPCs.

Genetically Modified T-Cell-Based Adoptive Immunotherapy in Hematological Malignancies

A significant proportion of hematological malignancies remain limited in treatment options. Immune system modulation serves as a promising therapeutic approach to eliminate malignant cells. Cytotoxic T lymphocytes (CTLs) play a central role in antitumor immunity; unfortunately, nonspecific approaches for targeted recognition of tumor cells by CTLs to mediate tumor immune evasion in hematological malignancies imply multiple mechanisms, which may or may not be clinically relevant. Recently, genetically modified T-cell-based adoptive immunotherapy approaches, including chimeric antigen receptor (CAR) T-cell therapy and engineered T-cell receptor (TCR) T-cell therapy, promise to overcome immune evasion by redirecting the specificity of CTLs to tumor cells. In clinic trials, CAR-T-cell- and TCR-T-cell-based adoptive immunotherapy have produced encouraging clinical outcomes, thereby demonstrating their therapeutic potential in mitigating tumor development. The purpose of the present review is to (1) provide a detailed overview of the multiple mechanisms for immune evasion related with T-cell-based therapies; (2) provide a current summary of the applications of CAR-T-cell- as well as neoantigen-specific TCR-T-cell-based adoptive immunotherapy and routes taken to overcome immune evasion; and (3) evaluate alternative approaches targeting immune evasion via optimization of CAR-T and TCR-T-cell immunotherapies.

Tertiary lymphoid structures, drivers of the anti-tumor responses in human cancers

The characterization of the microenvironment of human tumors led to the description of tertiary lymphoid structures (TLS) characterized by mature dendritic cells in a T-cell zone adjacent to B-cell follicle including a germinal center. TLS represent sites of lymphoid neogenesis that develop in most solid cancers. Analysis of the current literature shows that the TLS presence is associated with a favorable clinical outcome for cancer patients, regardless of the approach used to quantify TLS and the stage of the disease. Using several approaches that combine immunohistochemistry, gene expression assays, and flow cytometry on large series of lung tumors, our work demonstrated that TLS are important sites for the initiation and/or maintenance of the local and systemic T- and B-cell responses against tumors. Surrounded by high endothelial venules, they represent a privileged area for the recruitment of lymphocytes into tumors and generation of central-memory T and B cells that circulate and limit cancer progression. TLS can be considered as a novel biomarker to stratify the overall survival risk of untreated cancer patients and as a marker of efficient immunotherapies. The induction and manipulation of cancer-associated TLS using drug agonists and/or biotherapies should open new avenues to treat cancer patients.

Ganoderma lucidum beta 1,3/1,6 glucan as an immunomodulator in inflammation induced by a high-cholesterol diet

BACKGROUND

Binding of beta 1,3/1,6 glucan of Ganoderma lucidum (G. lucidum) with the receptor results in a series of signal transfers (signalling cascades), which activates the transcription factors for regulating inflammation. Excess cholesterol intake leads to an increase in the distance between fat cells and capillaries, which may cause hypoxia in the fat tissue of obese mice. This hypoxia induces the death of fat cells, resulting in the inflammation of adipose tissue or an increase in the inflammatory gene expression associated with obesity.

METHODS

The current study examined the immunomodulation effect of G. lucidum beta 1,3/1,6 glucan according to immunoglobulin, poly-Ig receptor expression, Nature Killer cell (NK cell) activity, lymphocytes proliferation and cytokines expression.

RESULTS

Our present study shows that feeding G. lucidum beta 1,3/1,6 glucan to mice induces IgA or IgG expression in the serum and small intestine washing fluid and enhances poly-Ig receptor expression in the small intestine moreover, the observation of the IL-2 and Nature killer cell activity were exchanged.

CONCLUSIONS

The effect of a high-cholesterol diet in the inflammatory response was observed in heart, liver, kidney, spleen, and colon tissues through histopathological evaluations. The presented evidence demonstrates that the inflammation response in the high-cholesterol diet group was much higher than in the other groups and the beta 1,3/1,6 glucan reduces inflammation in obese mice fed a high-cholesterol diet.

Incidence of Perioperative Complications Following Resection of Adrenocortical Carcinoma and Its Association with Long-Term Survival

BACKGROUND

The association of postoperative complications with long-term oncologic outcomes remains unclear. We sought to determine the incidence of complications among patients who underwent surgery for adrenocortical carcinoma (ACC) and define the relationship of morbidity with long-term survival.

METHODS

Patients who underwent surgery for ACC between 1993 and 2014 were identified from 13 academic institutions participating in the US ACC group study. The incidence and type of the postoperative complications, the factors associated with them as well their association with long-term survival were analyzed.

RESULTS

A total of 265 patients with median age of 52 years (IQR 44-63) were identified; at surgery, the majority of patients underwent an open abdominal procedure (n = 169, 66.8%). A postoperative complication occurred in 99 patients for a morbidity of 37.4%; five patients (1.9%) died in hospital. Factors associated with morbidity included a thoraco-abdominal operative approach (reference: open abdominal; OR 2.85, 95% CI 1.00-8.18), and a hormonally functional tumor (OR 3.56, 95% CI 1.65-7.69) (all P < 0.05). Presence of any complication was associated with a worse long-term outcome (median survival: no complication, 58.9 months vs. any complication, 25.1 months; P = 0.009). In multivariate analysis, after adjusting for patient- and disease-related factors postoperative infectious complications independently predicted shorter overall survival (hazard ratio (HR) 5.56, 95% CI 2.24-13.80; P < 0.001).

CONCLUSION

Postoperative complications were independently associated with decreased long-term survival after resection for ACC. The prevention of complications may be important from an oncologic perspective.

The predictive value of dendritic cells in early squamous cell carcinoma of the tongue

OBJECTIVES

The aim of this study was to evaluate the relationship between dendritic cell density in early squamous cell carcinoma (SCC) of the tongue and patients' clinical outcome.

METHODS

Representative samples of low-risk SCC of the tongue (T1-2,N0,M0) from a homogeneous group of 18 patients following local complete excision and elective selective neck dissection, were immunostained with antibodies against S100 and CD1a. Dendritic cell density was analyzed by outcome.

RESULTS

Mean dendritic cell densities were 17 cells/HPF for tumoral S100 and CD1a counts, and 10 cells/HPF for peritumoral S100 and CD1a counts. Better disease-free survival was associated with low peritumoral S100- and CD1a- positive cell counts (p=0.006 and p=0.004, respectively), and with low tumoral S100- and CD1a- positive cell counts (p=0.037 and p=0.04, respectively). Lymphocytic response was decreased in tumors with high dendritic cell density (p=NS). There was no association of dendritic cell density with patient age, tumor size and depth of invasion.

CONCLUSIONS

These results may suggest an association between dendritic cell accumulation and functional immunologic impairment.

Tumor-derived factors modulating dendritic cell function

Dendritic cells (DC) play unique and diverse roles in the tumor occurrence, development, progression and response to therapy. First of all, DC can actively uptake tumor-associated antigens, process them and present antigenic peptides to T cells inducing and maintaining tumor-specific T cell responses. DC interaction with different immune effector cells may also support innate antitumor immunity, as well as humoral responses also known to inhibit tumor development in certain cases. On the other hand, DC are recruited to the tumor site by specific tumor-derived and stroma-derived factors, which may also impair DC maturation, differentiation and function, thus resulting in the deficient formation of antitumor immune response or development of DC-mediated tolerance and immune suppression. Identification of DC-stimulating and DC-suppressing/polarizing factors in the tumor environment and the mechanism of DC modulation are important for designing effective DC-based vaccines and for recovery of immunodeficient resident DC responsible for maintenance of clinically relevant antitumor immunity in patients with cancer. DC-targeting tumor-derived factors and their effects on resident and administered DC in the tumor milieu are described and discussed in this review.

Sensitivity of Dendritic Cells to Microenvironment Signals

Dendritic cells are antigen-presenting cells capable of either activating the immune response or inducing and maintaining immune tolerance. They do this by integrating stimuli from the environment and changing their functional status as a result of plasticity. The modifications suffered by these cells have consequences in the way the organism may respond. In the present work two opposing situations known to affect dendritic cells are analyzed: tumor growth, leading to a microenvironment that favors the induction of a tolerogenic profile, and organ transplantation, which leads to a proinflammatory profile. Lessons learned from these situations may help to understand the mechanisms of modulation resulting not only from the above circumstances, but also from other pathologies.

Rescue management of early complications after liver transplantation-key for the long-term success

PURPOSE

Postoperative complications may have not only immediate but also long-term effects on the outcomes. Here, we analyzed the effect of postoperative complications requiring a reoperation (grade 3b) within the first 30 days on patients' and graft survival following liver transplantation.

METHODS

Graft and patient survival in relation to donor and recipient variables and the need of reoperation for complications of 277 consecutive liver transplants performed from January 2007 to December 2012 were analyzed.

RESULTS

Two hundred seventy-seven liver transplants were performed in 252 patients. Overall patient and graft survival at 1, 2, and 3 years were significantly reduced in patients requiring a reoperation. The labMELD score was significantly elevated (p = 0.04) and cold ischemia time was prolonged (p = 0.03) in recipients undergoing reoperations. Kaplan-Meier curves indicate that complications impact the outcome primarily within the first 3 months after transplantation. In multivariate analyses, the actual need of reoperation (p < 0.001), the labMELD score (p = 0.05), cold ischemia time (p = 0.02), and the need for hemodialysis pre-transplant (p = 0.05) were the only variables which correlated with the overall survival.

CONCLUSION

Postoperative complications resulting in reoperations have a significant impact on the outcome primarily in the early phase after liver transplantation. Successful management of postoperative complications is key to every successful liver transplant program.

Human monocytes undergo functional re-programming during differentiation to dendritic cell mediated by human extravillous trophoblasts

Maternal immune adaptation is required for a successful pregnancy to avoid rejection of the fetal–placental unit. Dendritic cells within the decidual microenvironment lock in a tolerogenic profile. However, how these tolerogenic DCs are induced and the underlying mechanisms are largely unknown. In this study, we show that human extravillous trophoblasts redirect the monocyte-to-DC transition and induce regulatory dendritic cells. DCs differentiated from blood monocytes in the presence of human extravillous trophoblast cell line HTR-8/SVneo displayed a DC-SIGN⁺CD14⁺CD1a⁻ phenotype, similar with decidual DCs. HTR8-conditioned DCs were unable to develop a fully mature phenotype in response to LPS, and altered the cytokine secretory profile significantly. Functionally, conditioned DCs poorly induced the proliferation and activation of allogeneic T cells, whereas promoted CD4⁺CD25⁺Foxp3⁺ Treg cells generation. Furthermore, the supernatant from DC and HTR-8/SVneo coculture system contained significant high amount of M-CSF and MCP-1. Using neutralizing antibodies, we discussed the role of M-CSF and MCP-1 during monocyte-to-DCs differentiation mediated by extravillous trophoblasts. Our data indicate that human extravillous trophoblasts play an important role in modulating the monocyte-to-DC differentiation through M-CSF and MCP-1, which facilitate the establishment of a tolerogenic microenvironment at the maternal–fetal interface.

Immune Therapy

Lung cancer has long been considered an unsuitable target for immunotherapy due to its proposed immunoresistant properties. However, recent evidence has shown that anti-tumor immune responses can occur in lung cancer patients, paving the way for lung cancer as a novel target for immunotherapy. In order to take full advantage of the potential of immunotherapy, research is focusing on the presence and function of various immunological cell types in the tumor microenvironment. Immune cells which facilitate or inhibit antitumor responses have been identified and their prognostic value in lung cancer has been established. Knowledge regarding these pro- and anti-tumor immune cells and their mechanisms of action has facilitated the identification of numerous potential immunotherapeutic strategies and opportunities for intervention. A plethora of immunotherapeutic approaches is currently being developed and studied in lung cancer patients and phase 3 clinical trials are ongoing. Many different immunotherapies have shown promising clinical effects in patients with limited and advanced stage lung cancer, however, future years will have to tell whether immunotherapy will earn its place in the standard treatment of lung cancer.

Dendritic Cells in Oncolytic Virus-Based Anti-Cancer Therapy

Dendritic cells (DCs) are specialized antigen-presenting cells that have a notable role in the initiation and regulation of innate and adaptive immune responses. In the context of cancer, appropriately activated DCs can induce anti-tumor immunity by activating innate immune cells and tumor-specific lymphocytes that target cancer cells. However, the tumor microenvironment (TME) imposes different mechanisms that facilitate the impairment of DC functions, such as inefficient antigen presentation or polarization into immunosuppressive DCs. These tumor-associated DCs thus fail to initiate tumor-specific immunity, and indirectly support tumor progression. Hence, there is increasing interest in identifying interventions that can overturn DC impairment within the TME. Many reports thus far have studied oncolytic viruses (OVs), viruses that preferentially target and kill cancer cells, for their capacity to enhance DC-mediated anti-tumor effects. Herein, we describe the general characteristics of DCs, focusing on their role in innate and adaptive immunity in the context of the TME. We also examine how DC-OV interaction affects DC recruitment, OV delivery, and anti-tumor immunity activation. Understanding these roles of DCs in the TME and OV infection is critical in devising strategies to further harness the anti-tumor effects of both DCs and OVs, ultimately enhancing the efficacy of OV-based oncotherapy.

Primary Human Blood Dendritic Cells for Cancer Immunotherapy-Tailoring the Immune Response by Dendritic Cell Maturation

Dendritic cell (DC)-based cancer vaccines hold the great promise of tipping the balance from tolerance of the tumor to rejection. In the last two decades, we have gained tremendous knowledge about DC-based cancer vaccines. The maturation of DCs has proven indispensable to induce immunogenic T cell responses. We review the insights gained from the development of maturation cocktails in monocyte derived DC-based trials. More recently, we have also gained insights into the functional specialization of primary human blood DC subsets. In peripheral human blood, we can distinguish at least three primary DC subsets, namely CD1c⁺ and CD141⁺ myeloid DCs and plasmacytoid DCs. We reflect the current knowledge on maturation and T helper polarization by these blood DC subsets in the context of DC-based cancer vaccines. The maturation stimulus in combination with the DC subset will determine the type of T cell response that is induced. First trials with these natural DCs underline their excellent in vivo functioning and mark them as promising tools for future vaccination strategies.

Dendritic cell defects in the colorectal cancer

Colorectal cancer (CRC) results from the accumulation of both genetic and epigenetic alterations of the genome. However, also the formation of an inflammatory milieu plays a pivotal role in tumor development and progression. Dendritic cells (DCs) play a relevant role in tumor by exerting differential pro-tumorigenic and anti-tumorigenic functions, depending on the local milieu. Quantitative and functional impairments of DCs have been widely observed in several types of cancer, including CRC, representing a tumor-escape mechanism employed by cancer cells to elude host immunosurveillance.

Understanding the interactions between DCs and tumors is important for comprehending the mechanisms of tumor immune surveillance and escape, and provides novel approaches to therapy of cancer. This review summarizes updated information on the role of the DCs in colon cancer development and/or progression.

Which is a more reliable indicator of survival after gastric cancer surgery: Postoperative complication occurrence or C-reactive protein elevation?

BACKGROUND AND OBJECTIVES

The impact of postoperative complications on long-term outcome has been reported in several types of malignancies. However, it is unclear why postoperative complications affect long-term outcome. The aim of this study is evaluating whether postoperative complication occurrence or C-reactive protein (CRP) elevation better reflects long-term outcome in gastric cancer patients.

METHODS

This study included 305 patients who underwent curative surgery for pT2-T4b gastric cancer. Patients were divided into two groups based on the peak CRP value (CRPmax): low (<12 mg/dl) and high CRPmax (≥ 12 mg/dl). A multivariate analysis was conducted to identify independent prognostic factors for recurrence-free survival (RFS).

RESULTS

Postoperative complications (≥ Grade II) occurred in 86 of 305 patients (28.2%). Although CRP elevation (P = 0.001) and postoperative complication occurrence (P = 0.045) was each significantly associated with RFS in the univariate analysis, multivariate analysis identified CRP elevation (P = 0.017) but not complication occurrence (P = 0.682) as an independent prognostic factor. Among patients without complications, those in the high CRPmax group had significantly worse RFS than those in the low CRPmax group (P = 0.004).

CONCLUSIONS

CRP elevation is a more reliable indicator of survival after gastric cancer surgery than postoperative complication occurrence. Surgeons should minimize the postoperative inflammatory response to improve prognosis.

Transcriptional regulation of myeloid-derived suppressor cells

Myeloid-derived suppressor cells are a heterogeneous group of pathologically activated immature cells that play a major role in the negative regulation of the immune response in cancer, autoimmunity, many chronic infections, and inflammatory conditions, as well as in the regulation of tumor angiogenesis, tumor cell invasion, and metastases. Accumulation of myeloid-derived suppressor cells is governed by a network of transcriptional regulators that could be combined into 2 partially overlapping groups: factors promoting myelopoiesis and preventing differentiation of mature myeloid cells and factors promoting pathologic activation of myeloid-derived suppressor cells. In this review, we discuss the specific nature of these factors and their impact on myeloid-derived suppressor cell development.

Rapamycin Prolongs Cardiac Allograft Survival in a Mouse Model by Inducing Myeloid-Derived Suppressor Cells

Mammalian target of rapamycin (mTOR) inhibitors are the main immunosuppressive drugs for organ transplant recipients. Nevertheless, the mechanisms by which mTOR inhibitors induce immunosuppression is not fully understood. Myeloid-derived suppressor cells (MDSCs) maintain host immunity; however, the relationship between mTOR inhibitors and MDSCs is unclear. Here, the results from a murine cardiac transplantation model revealed that rapamycin treatment (3 mg/kg, intraperitoneally on postoperative days 0, 2, 4, and 6) led to the recruitment of MDSCs and increased their expression of inducible nitric oxide synthase (iNOS). Immunohistochemical analysis revealed that rapamycin induced the migration of iNOS-expressing MDSCs into the subintimal space within the allograft vessels, resulting in a significant prolongation of graft survival compared with that in the untreated group (67 days vs. 7 days, respectively). These effects were counterbalanced by the administration of an anti-Gr-1, which reduced allograft survival to 21 days. Moreover, adoptive transcoronary arterial transfer of MDSCs from rapamycin-treated recipients prolonged allograft survival; this increase was reversed by the anti-Gr-1 antibody. Finally, co-administration of rapamycin and a mitogen-activated protein kinase kinase (MEK) inhibitor trametinib reversed rapamycin-mediated MDSC recruitment. Thus, the mTOR and Raf/MEK/extracellular signal regulated kinase (ERK) signaling pathways appear to play an important role in MDSC expansion.

The extent to which melanoma alters tissue-resident dendritic cell function correlates with tumorigenicity

We have shown that melanoma-derived factors alter the function of differentiated tissue-resident dendritic cells (DC) in a tumorigenicity-dependent manner. Soluble factors, including TGFβ1 and VEGF-A, contributed to dendritic cell dysfunction associated with a highly-aggressive melanoma and conferred a phenotype upon DC likely to favor immune escape and tumor outgrowth.

Mushroom β-Glucan May Immunomodulate the Tumor-Associated Macrophages in the Lewis Lung Carcinoma

The present study showed that oral mushroom beta-glucan treatment significantly increased IFN-γ mRNA expression but significantly reduced COX-2 mRNA expression within the lung. For LLC tumor model, oral Ganoderma lucidum or Antrodia camphorata polysaccharides treatments significantly reduced TGF-β production in serum. In addition, IL-12 and IFN-γ mRNA expression were significantly increased, but IL-6, IL-10, COX-2, and TGF-β mRNA expression were substantially following oral mushroom polysaccharides treatments. The study highlights the efficacious effect of mushroom polysaccharides for ameliorating the immune suppression in the tumor microenvironment. Increased M1 phenotype of tumor-associated macrophages and attenuated M2 phenotype of tumor-associated macrophages could be achieved by ingesting mushroom polysaccharides.

A top-down view of the tumor microenvironment: structure, cells and signaling

It is well established that the tumor microenvironment (TME) contributes to cancer progression. Stromal cells can be divided into mesenchymal, vascular, and immune. Signaling molecules secreted by the tumor corrupts these cells to create "activated" stroma. Equally, the extracellular matrix (ECM) contributes to tumor development and invasion by forming a biologically active scaffold. In this review we describe the key structural, cellular and signaling components of the TME with a perspective on stromal soluble factors and microRNAs (miRNAs).

Melanoma-derived factors alter the maturation and activation of differentiated tissue-resident dendritic cells

Dendritic cells (DCs) are key regulators of host immunity that are capable of inducing either immune tolerance or activation. In addition to their well-characterized role in shaping immune responses to foreign pathogens, DCs are also known to be critical for the induction and maintenance of anti-tumor immune responses. Therefore, it is important to understand how tumors influence the function of DCs and the quality of immune responses they elicit. Although the majority of studies in this field to date have utilized either immortalized DC lines or DC populations that have been generated under artificial conditions from hematopoietic precursors in vitro, we wished to investigate how tumors impact the function of already differentiated, tissue-resident DCs. Therefore, we used both an ex vivo and in vivo model system to assess the influence of melanoma-derived factors on DC maturation and activation. In ex vivo studies with freshly isolated splenic DCs, we demonstrate that the extent to which DC maturation and activation are altered by these factors correlates with melanoma tumorigenicity, and we identify partial roles for tumor-derived transforming growth factor (TGF)β1 and vascular endothelial growth factor (VEGF)-A in the altered functionality of DCs. In vivo studies using a lung metastasis model of melanoma also demonstrate tumorigenicity-dependent alterations to the function of lung-resident DCs, and skewed production of proinflammatory cytokines and chemokines by these tumor-altered cells is associated with recruitment of an immune infiltrate that may ultimately favor tumor immune escape and outgrowth.

CD8(+) T activation attenuates CD4(+) T proliferation through dendritic cells modification

Emerging evidence has suggested that CD8(+) T had modulatory function on CD4(+) T mediated autoimmune and inflammatory diseases. However, the underlying mechanisms remain unclear. In this study, we found that CD8(+) T activation inhibited OVA(323-339) antigen specific CD4(+) T cells proliferation in vitro and in vivo. Further investigation demonstrated that this immunosuppression largely depended on the soluble factor from activated CD8(+) T to modify the phenotype and functions of DCs. Moreover, not only the inhibitors for IDO or iNOS, but also IFN-γ neutralization markedly reversed this immunosuppression on OVA(323-339) antigen specific CD4(+) T cells proliferation. Interestingly, CD8(+) T cells absence aggravated the pathological damage in lung in OVA-induced asthma model, but alleviated by CD8(+) T transfer and activation. Thus, these findings suggested that activated CD8(+) T population exerted feedback regulation in DCs modification, and then attenuated CD4(+) T mediated immune response.

Polarization of tumor-associated macrophages and Gas6/Axl signaling in oral squamous cell carcinoma

BACKGROUND

This study investigated the potential involvement of Axl signaling in polarization of tumor-associated macrophages (TAMs) in oral squamous cell carcinoma (OSCC).

METHODS

Condition medium (CM) from OSCC cells (OEC-M1 and YD38) were collected and their effects on macrophage (THP-1) polarization were examined. Modulation of Axl, PI3/Akt, and NF-κB were performed to investigate their potential involvement in TAM polarization. Expression of pAxl and CD206 were analyzed by immunohistochemistry in OSCC tissues.

RESULTS

THP-1 polarized to M2 phenotype with increasing expression of interleukins, vascular endothelial growth factor, matrix metalloproteinase and CD206 upon treatment with CM of OSCC. Activated Axl signaling in OSCC enhanced M2 induction ability. Suppression of Axl signaling and inhibition of PI3/Akt and NF-κB diminished M2 induction. pAxl expression was significantly associated with distribution of CD206 positive cells in OSCC tissues.

CONCLUSION

Axl signaling of OSCC involved in polarizing TAMs toward M2 phenotype. Induction of M2 phenotype macrophage polarization by OSCC cells might involve the Axl/PI3/Akt/NF-κB pathway.

Accumulation of tolerogenic human 6-sulfo LacNAc dendritic cells in renal cell carcinoma is associated with poor prognosis

Dendritic cells (DCs) essentially contribute to the induction and regulation of innate and adaptive immunity. Based on these important properties, DCs may profoundly influence tumor progression in patients. However, little is known about the role of distinct human DC subsets in primary tumors and their impact on clinical outcome. In the present study, we investigated the characteristics of human 6-sulfo LacNAc (slan) DCs in clear cell renal cell carcinoma (ccRCC). slanDCs have been shown to display various tumor-directed properties and to accumulate in tumor-draining lymph nodes from patients. When evaluating 263 ccRCC and 227 tumor-free tissue samples, we found increased frequencies of slanDCs in ccRCC tissues compared to tumor-free tissues. slanDCs were also detectable in the majority of 24 metastatic lymph nodes and 67 distant metastases from ccRCC patients. Remarkably, a higher density of slanDCs was significantly associated with a reduced progression-free, tumor-specific or overall survival of ccRCC patients. Tumor-infiltrating slanDCs displayed an immature phenotype expressing interleukin-10. ccRCC cells efficiently impaired slanDC-induced T-cell proliferation and programming as well as natural killer (NK) cell activation. In conclusion, these findings indicate that higher slanDC numbers in ccRCC tissues are associated with poor prognosis. The induction of a tolerogenic phenotype in slanDCs leading to an insufficient activation of innate and adaptive antitumor immunity may represent a novel immune escape mechanism of ccRCC. These observations may have implications for the design of therapeutic strategies that harness tumor-directed functional properties of DCs against ccRCC.

STAT3-dependent VEGF production from keratinocytes abrogates dendritic cell activation and migration by arsenic: a plausible regional mechanism of immunosuppression in arsenical cancers

Arsenic remains an important environmental hazard that causes several human cancers. Arsenic-induced Bowen's disease (As-BD), a skin carcinoma in situ, is the most common arsenical cancer. While great strides have been made in our understanding of arsenic carcinogenesis, how host immunity contributes to this process remains unknown. Patients with As-BD have an impaired contact hypersensitivity response. Although impaired T cell activation has been well-documented in arsenical cancers, how dendritic cell (DC), the key cell regulating innate immunity, regulates the immune response in arsenical cancers remains unclear. Using myeloid derived DC (MDDC) from patients with As-BD and normal controls as well as bone marrow derived DC (BMDC) from mice fed with or without arsenic, we measured the migration of DC. As-BD patients showed an impaired CCL21-mediated MDDC migration in vitro. Arsenic-fed mice had defective DC migration toward popliteal lymph nodes when injected with allogenic BMDCs via foot pad. Using skin from As-BD and normal controls, we found an increased expression of STAT3, a transcriptional factor contributing to impaired DC activation. Arsenic induced STAT3 activation and the production of VEGF in keratinocytes. The increase in VEGF was blocked by inhibiting STAT3 with RNA interference or pharmaceutically with JSI-124. While VEGF by itself minimally induced the expression of CD86 and MHC-II in MDDC, arsenic induced-MDDC activation was abolished by VEGF pretreatment. We concluded that the STAT3-VEGF axis in keratinocytes inhibits DC migration in the microenvironment of As-BD, indicating that cellular interactions play an important role in regulating the disease course of arsenical cancers.

Tumor induced hepatic myeloid derived suppressor cells can cause moderate liver damage

Subcutaneous tumors induce the accumulation of myeloid derived suppressor cells (MDSC) not only in blood and spleens, but also in livers of these animals. Unexpectedly, we observed a moderate increase in serum transaminases in mice with EL4 subcutaneous tumors, which prompted us to study the relationship of hepatic MDSC accumulation and liver injury. MDSC were the predominant immune cell population expanding in livers of all subcutaneous tumor models investigated (RIL175, B16, EL4, CT26 and BNL), while liver injury was only observed in EL4 and B16 tumor-bearing mice. Elimination of hepatic MDSC in EL4 tumor-bearing mice using low dose 5-fluorouracil (5-FU) treatment reversed transaminase elevation and adoptive transfer of hepatic MDSC from B16 tumor-bearing mice caused transaminase elevation indicating a direct MDSC mediated effect. Surprisingly, hepatic MDSC from B16 tumor-bearing mice partially lost their damage-inducing potency when transferred into mice bearing non damage-inducing RIL175 tumors. Furthermore, MDSC expansion and MDSC-mediated liver injury further increased with growing tumor burden and was associated with different cytokines including GM-CSF, VEGF, interleukin-6, CCL2 and KC, depending on the tumor model used. In contrast to previous findings, which have implicated MDSC only in protection from T cell-mediated hepatitis, we show that tumor-induced hepatic MDSC themselves can cause moderate liver damage.

Induction of suppressive phenotype in monocyte-derived dendritic cells by leukemic cell products and IL-1β

Professional antigen-presenting cells, dendritic cells (DCs) play an important role in controlling tumors. It is known that solid tumor cell products inhibit DC differentiation. Recently a similar effect produced by leukemic cell products has been demonstrated. In this case, leukemic cell products induced the secretion of IL-1β by monocytes undergoing differentiation. The aim of the present work was to characterize and to compare the development of monocyte-derived DCs under the influence of leukemic cell products (K562 supernatant) or exogenous IL-1β. It became clear that leukemic cell products and IL-1β differentially modulate some of the parameters studied on monocytes stimulated to differentiate into DCs. In the presence of K562 supernatant, the expression of the macrophage markers CD16 and CD68 were higher than in immature DCs control. Contrasting with IL-1β, leukemic cell products possibly favor the development of cells with macrophage markers. In addition, CD80 and CD83 expressions were also higher in the presence of tumor supernatant whereas HLA-DR was lower. In the presence of IL-1β, only CD80 was increased. Furthermore, it was observed that when monocytes were induced to differentiate into DCs in the presence of tumor supernatant and then activated, they expressed less CD80 and CD83 than activated DCs control. A reduced expression of CD83 following activation was also seen in cells differentiated with IL-1β. TGF-β and VEGF were found in the tumor supernatants. Moreover, the exposure to tumor supernatant or IL-1β stimulated IL-10 production while decreased IL-12 production by activated DCs. Finally, these results suggest that the addition of products released by leukemic cells or, more discreetly, the addition of IL-1β affects DC differentiation, inducing a suppressive phenotype.

Postoperative complications influence prognosis and recurrence patterns in periampullary cancer

BACKGROUND

The present study was performed to elucidate the influence of postoperative complications on the prognosis and recurrence patterns of periampullary cancer after pancreaticoduodenectomy (PD).

METHODS

Clinical data were reviewed from 200 consecutive patients who had periampullary cancer and underwent PD between October 2003 and July 2010, and survival outcomes and recurrence patterns were analyzed. Postoperative complications were classified according to a modification of Clavien's classification.

RESULTS

Overall, 86 major complications of grade II or higher occurred in 71 patients. The patients were classified into two groups according to the presence of postoperative complications of grade II or higher: group Cx-, absence of complications (n = 129); and group Cx+, presence of complications (n = 71). There were no differences in gender, mean age, tumor node metastasis stage, biliary drainage, type of resection, and radicality between the two groups (P > 0.05). The 3-year overall and disease-free survival rates of the group Cx+ patients (31.0 and 22.3 %, respectively) were significantly lower than those of the group Cx- patients (49.0 and 40.0 %; P = 0.003 and 0.002, respectively). The multivariate analysis showed that postoperative complications (P = 0.001; RR = 1.887; 95 % confidence interval [CI] 1.278-2.785), a T stage of T3 or T4 (P = 0.001; RR = 2.503; 95 % CI 1.441-4.346), positive node metastasis (P = 0.001; RR = 2.093; 95 % CI, 1.378-3.179), R1 or R2 resection (P = 0.023; RR = 1.863; 95 % CI 1.090-3.187), and angiolymphatic invasion (P = 0.013; RR = 1.676; 95 % CI 1.117-2.513) were independent prognostic factors for disease-free survival. Regarding recurrence patterns, group Cx+ patients exhibited more distant recurrences than did group Cx- patients (P = 0.025).

CONCLUSIONS

Postoperative complications affect prognosis and recurrence patterns in patients with periampullary cancer after PD.

[Tumor microenvironment: regulatory cells and immunosuppressive cytokines]

Immunosuppression is a mechanism developed by cancer cells to help them escape the immune system. Immunosuppression involves expansion of various cell types and production of a variety of cytokines. In this review, we explore the duality of three cancer induced cell populations, regulatory T lymphocytes, Th17 lymphocytes and MDSC, and also the pleiotropic effects of several cytokines induced during cancer development.

The IL-6 feed-forward loop: a driver of tumorigenesis

IL-6 signaling plays a prominent role in tumorigenesis and metastasis. In this review we discuss the recent evidence describing the tumor intrinsic and extrinsic functions of this signaling pathway. Although blockade of this pathway in pre-clinical models leads to a reduction in tumor growth and metastasis, its clinical success is less evident. Thus, identifying the features of tumors/patients that predict response to anti-IL6 therapy are needed.

Collagen as a double-edged sword in tumor progression

It has been recognized that cancer is not merely a disease of tumor cells, but a disease of imbalance, in which stromal cells and tumor microenvironment play crucial roles. Extracellular matrix (ECM) as the most abundant component in tumor microenvironment can regulate tumor cell behaviors and tissue tension homeostasis. Collagen constitutes the scaffold of tumor microenvironment and affects tumor microenvironment such that it regulates ECM remodeling by collagen degradation and re-deposition, and promotes tumor infiltration, angiogenesis, invasion and migration. While collagen was traditionally regarded as a passive barrier to resist tumor cells, it is now evident that collagen is also actively involved in promoting tumor progression. Collagen changes in tumor microenvironment release biomechanical signals, which are sensed by both tumor cells and stromal cells, trigger a cascade of biological events. In this work, we discuss how collagen can be a double-edged sword in tumor progression, both inhibiting and promoting tumor progression at different stages of cancer development.

T-cell tolerance in cancer

T cells are the master regulators of adaptive immune responses and maintenance of their tolerance is critical to prevent autoimmunity. However, in the case of carcinogenesis, the tumor microenvironment aids T-cell tolerance, which contributes to uncontrolled tumor growth. Recently, there has been significant progress in understanding the intrinsic extracellular (positive and negative costimulatory molecules on APCs) and intracellular mechanisms (E3 ubiquitin ligases, transcriptional and epigenetic repressors), as well as extrinsic mechanisms (Tregs and tolerogenic dendritic cells) that are required for the implementation and maintenance of T-cell tolerance. Ultimately, understanding and manipulating T-cell tolerance will help to break the tolerance state in cancer.

Inflammation-induced cancer: crosstalk between tumours, immune cells and microorganisms

Inflammation is a fundamental innate immune response to perturbed tissue homeostasis. Chronic inflammatory processes affect all stages of tumour development as well as therapy. In this Review, we outline the principal cellular and molecular pathways that coordinate the tumour-promoting and tumour-antagonizing effects of inflammation and we discuss the crosstalk between cancer development and inflammatory processes. In addition, we discuss the recently suggested role of commensal microorganisms in inflammation-induced cancer and we propose that understanding this microbial influence will be crucial for targeted therapy in modern cancer treatment.

Deciphering and reversing tumor immune suppression

Generating an anti-tumor immune response is a multi-step process that is executed by effector T cells that can recognize and kill tumor targets. However, tumors employ multiple strategies to attenuate the effectiveness of T-cell-mediated attack. They achieve this by interfering with nearly every step required for effective immunity, from deregulation of antigen-presenting cells to establishment of a physical barrier at the vasculature that prevents homing of effector tumor-rejecting cells and the suppression of effector lymphocytes through the recruitment and activation of immunosuppressive cells such as myeloid-derived suppressor cells, tolerogenic monocytes, and T regulatory cells. Here, we review the ways in which tumors exert immune suppression and highlight the new therapies that seek to reverse this phenomenon and promote anti-tumor immunity. Understanding anti-tumor immunity, and how it becomes disabled by tumors, will ultimately lead to improved immune therapies and prolonged survival of patients.

Vascular endothelial growth factor-A enhances indoleamine 2,3-dioxygenase expression by dendritic cells and subsequently impacts lymphocyte proliferation

Dendritic cells (DCs) are antigen (Ag)-presenting cells that activate and stimulate effective immune responses by T cells, but can also act as negative regulators of these responses and thus play important roles in immune regulation. Pro-angiogenic vascular endothelial growth factor (VEGF) has been shown to cause defective DC differentiation and maturation. Previous studies have demonstrated that the addition of VEGF to DC cultures renders these cells weak stimulators of Ag-specific T cells due to the inhibitory effects mediated by VEGF receptor 1 (VEGFR1) and/or VEGFR2 signalling. As the enzyme indoleamine 2,3-dioxygenase (IDO) is recognised as an important negative regulator of immune responses, this study aimed to investigate whether VEGF affects the expression of IDO by DCs and whether VEGF-matured DCs acquire a suppressor phenotype. Our results are the first to demonstrate that VEGF increases the expression and activity of IDO in DCs, which has a suppressive effect on Ag-specific and mitogen-stimulated lymphocyte proliferation. These mechanisms have broad implications for the study of immunological responses and tolerance under conditions as diverse as cancer, graft rejection and autoimmunity.

Wnt5a inhibits human monocyte-derived myeloid dendritic cell generation

Wnt5a is a non-canonical Wnt protein that is expressed at elevated levels in inflammatory conditions. Its role in inflammation remains unclear, although it is known that Wnt5a is expressed at a higher level in monocyte-derived myeloid dendritic cells (Mo-mDCs) than in monocytes and macrophages. The function of Wnt5a in dendritic cells (DCs) remains relatively unexplored. Here, we found that under Mo-mDC culture conditions, Wnt5a inhibited the generation of CD14(⁺/low) Mo-mDCs while promoting the generation of CD14⁺/⁺⁺ CD16⁺ monocytes. We could further show that stimulation of monocytes with rWnt5a induced a rapid IL-6 production and that the rWnt5a treated Mo-mDC differentiation was restored upon blocking of IL-6. Also, conditioned media from Wnt5a stimulated human breast cancer cells producing IL-6, specifically inhibited Mo-mDC differentiation. These observations are strengthened by our finding that patients with sepsis, a disease involving elevated Wnt5a and IL-6 levels, also showed a significant increase in the CD14⁺ CD16⁺⁺/CD14⁺/⁺⁺ CD16⁺ monocyte populations, which was accompanied by a significant decrease in circulating mDCs. We finally show that under typical Mo-mDC culture conditions, monocytes isolated from patients with sepsis as compared to healthy controls, preferentially differentiated into CD14CD14⁺/⁺⁺ HLA-DR⁺⁺ cells. We suggest that Wnt5a is a possible candidate mediator for the CD14⁺/⁺⁺ CD16⁺ monocyte accumulation seen in patients with infectious disease and cancer.

Phenotypical analysis, relation to malignancy and prognostic relevance of ICOS+T regulatory and dendritic cells in patients with gliomas

We determined circulating T helper, T regulatory and ICOS+T regulatory as well as DC cell counts in 29 patients with cerebral gliomas. Samples from patients with gliomas vs. healthy controls and from patients with glioblastomas vs. patients with glioma WHO grades I-III contained significantly (p<0.05) decreased numbers of total as well as mature, i.e. myeloid and plasmacytoid DCs. Patients with glioblastomas demonstrated significantly lower values of CD4+ as well as an increased fraction of ICOS+T regulatory/CD4+ cells. Higher CD4+ cell counts (≥225 cells/μl, median) were associated with improved survival in glioblastomas.