Secretion Of Soluble Mediators Research Articles

Three-Dimensional In Vitro Tumor Spheroid Models for Evaluation of Anticancer Therapy: Recent Updates.

Advanced tissue engineering processes and regenerative medicine provide modern strategies for fabricating 3D spheroids. Several different 3D cancer models are being developed to study a variety of cancers. Three-dimensional spheroids can correctly replicate some features of solid tumors (such as the secretion of soluble mediators, drug resistance mechanisms, gene expression patterns and physiological responses) better than 2D cell cultures or animal models. Tumor spheroids are also helpful for precisely reproducing the three-dimensional organization and microenvironmental factors of tumors. Because of these unique properties, the potential of 3D cell aggregates has been emphasized, and they have been utilized in in vitro models for the detection of novel anticancer drugs. This review discusses applications of 3D spheroid models in nuclear medicine for diagnosis and therapy, immunotherapy, and stem cell and photodynamic therapy and also discusses the establishment of the anticancer activity of nanocarriers.

Mesenchymal stromal cell therapy for chronic lung diseases: experimental and clinical evidence

Introduction Cell therapy has emerged as an alternative option for chronic lung diseases with the highest rates of morbidity and mortality rates worldwide. Areas covered This review addresses the definition of mesenchymal stromal cells (MSCs), their properties, mechanisms of action, as well as preclinical and clinical studies that have used cell therapy in chronic lung diseases such as asthma, chronic obstructive pulmonary disease, idiopathic pulmonary fibrosis, pulmonary arterial hypertension, and silicosis. Ongoing clinical trials are also presented. Expert opinion Experimental evidence has shown that MSCs have immunomodulatory and regenerative properties that could rescue impaired lung function and histoarchitecture. Their beneficial effects have been mainly associated with their ability to communicate with target cells through the secretion of soluble mediators and extracellular vesicles or even through transfer of organelles (e.g. mitochondria). MSC-derived conditioned medium, extracellular vesicles and mitochondria induce beneficial effects in selected scenarios. The initial results in clinical trials were modest compared with the experimental results, therefore researchers were encouraged to move from bedside back to bench to develop new strategies able to potentiate the effects of MSCs.

Low Abundance Fusobacterium Nucleatum Supports Early Pregnancy Development - An In Vitro Study.

Pregnancy success depends greatly on a balanced immune homeostasis. The detection of bacterial components in the upper reproductive tract in non-pregnant and pregnant women raised questions on its possible beneficial role in reproductive health. The local conditions that allow the presence of bacteria to harmonize with the establishment of pregnancy are still unknown. Among the described bacterial species in endometrial and placental samples, Fusobacterium nucleatum was found. It has been observed that F. nucleatum can induce tumorigenesis in colon carcinoma, a process that shares several features with embryo implantation. We propose that low concentrations of F. nucleatum may improve trophoblast function without exerting destructive responses. Inactivated F. nucleatum and E. coli were incubated with the trophoblastic cell lines HTR8/SVneo, BeWo, and JEG-3. Viability, proliferation, migratory capacity, invasiveness and the secretion of chemokines, other cytokines and matrix metalloproteinases were assessed. The presence of F. nucleatum significantly induced HTR8/SVneo invasion, accompanied by the secretion of soluble mediators (CXCL1, IL-6 and IL-8) and metalloproteinases (MMP-2 and MMP-9). However, as concentrations of F. nucleatum increased, these did not improve invasiveness, hindered migration, reduced cell viability and induced alterations in the cell cycle. Part of the F. nucleatum effects on cytokine release were reverted with the addition of a TLR4 blocking antibody. Other effects correlated with the level of expression of E-cadherin on the different cell lines tested. Low amounts of F. nucleatum promote invasion of HTR8/SVneo cells and induce the secretion of important mediators for pregnancy establishment. Some effects were independent of LPS and correlated with the expression of E-cadherin on trophoblasts.

Genetic Engineering as a Strategy to Improve the Therapeutic Efficacy of Mesenchymal Stem/Stromal Cells in Regenerative Medicine.

Mesenchymal stem/stromal cells (MSCs) have been widely studied in the field of regenerative medicine for applications in the treatment of several disease settings. The therapeutic potential of MSCs has been evaluated in studies in vitro and in vivo, especially based on their anti-inflammatory and pro-regenerative action, through the secretion of soluble mediators. In many cases, however, insufficient engraftment and limited beneficial effects of MSCs indicate the need of approaches to enhance their survival, migration and therapeutic potential. Genetic engineering emerges as a means to induce the expression of different proteins and soluble factors with a wide range of applications, such as growth factors, cytokines, chemokines, transcription factors, enzymes and microRNAs. Distinct strategies have been applied to induce genetic modifications with the goal to enhance the potential of MCSs. This review aims to contribute to the update of the different genetically engineered tools employed for MSCs modification, as well as the factors investigated in different fields in which genetically engineered MSCs have been tested.

Pre-conditioning of Equine Bone Marrow-Derived Mesenchymal Stromal Cells Increases Their Immunomodulatory Capacity.

Mesenchymal stem/stromal cells (MSCs) are increasingly explored for the treatment of degenerative and inflammatory diseases in human and veterinary medicine. One of the key characteristics of MSCs is that they modulate inflammation mainly through the secretion of soluble mediators. However, despite widespread clinical use, knowledge regarding the effector mechanisms of equine MSCs, and consequently their effectiveness in the treatment of diseases, is still unknown. The objectives of this study were to determine the mechanisms underlying inhibition of lymphocyte proliferation by equine bone marrow-derived MSCs, and to evaluate the effect of pre-conditioning of equine MSCs with different pro-inflammatory cytokines on inhibition of lymphocyte proliferation. We determined that inhibition of lymphocyte proliferation by equine MSCs depends on activity of prostaglandin-endoperoxide synthase 2 and indoleamine 2,3-dioxygenase. Additionally, pre-conditioning of MSCs with TNF-α, IFN-γ or their combination significantly increased the expression of prostaglandin-endoperoxide synthase 2, indoleamine 2,3-dioxygenase, iNOS and IL-6. This upregulation correlated with an increased inhibitory effect of MSCs on lymphocyte proliferation. In conclusion, pre-conditioning of bone marrow-derived MSC increases their inhibitory effect on lymphocyte proliferation in horses.

DYNAMICS OF SECRETION OF PROSTAGLANDINS E2 AND D2 WITH DIBOTHRIOCHEPHALLUS DENDRITICUS (CESTODA) PLEROCERCOIDS IN RESPONSE TO EXPOSURE OF BLOOD SERUM OF BAIKAL CISCO, THE HOST

Parasites regulate host immune response via secretion of soluble mediators which interact in a certain way with cells and molecules of the immune system. The aim of the study was to determine changes of prostaglandins E2 и D2 content in Dibothriochephallus dendriticus plerocercoids and also in the incubation media during incubation of tapeworms with addition of blood serum from the intermediate host – Baikal cisco. D. dendriticus plerocercoids were retrieved from the host body cavity, ashed in the physiological solution and placed in incubation media. Microcolumn high-performance liquid chromatography was used to detect prostaglandins. Concentration of prostaglandins in the plerocercoid organism increased insignificantly after incubation in the Hanks’ solution with addition of blood serum, when compared with incubation in the Hanks’ solution only. Concentration of prostaglandin E2 increased significantly in the incubation media after incubation of plerocercoids in the Hanks’ solution with addition of blood serum. Prostaglandin D2 was also identified in high concentrations after 12 h and 24 h of incubation, whereas prostaglandin D2 was not quite detected during incubation in Hanks’ solution only.

Toll-like receptor signaling induces a temporal switch towards a resolving lipid profile in monocyte-derived macrophages

Inflammation is a tightly regulated process. During the past decade it has become clear that the resolution of inflammation is an active process and its dysregulation can contribute to chronic inflammation. Several cells and soluble mediators, including lipid mediators, regulate the course of inflammation and its resolution. It is, however, unclear which signals and cells are involved in initiating the resolution process. Macrophages are tissue resident cells and key players in regulating tissue inflammation through secretion of soluble mediators, including lipids. We hypothesize that persistent inflammatory stimuli can initiate resolution pathways in macrophages.In this study, we detected 21 lipids in LPS-stimulated human monocyte-derived macrophages by liquid chromatography coupled to tandem mass spectrometry. Cyclooxygenase-derived Prostaglandins were observed in the first six hours of stimulation. Interestingly, a switch towards 15-lipoxygenase products, such as the pro-resolving lipid precursors 15-HEPE and 17-HDHA was observed after 24 h. The RNA and protein expression of cyclooxygenase and 15-lipoxygenase were in line with this trend. Treatment with 17-HDHA increased IL-10 production of monocyte-derived macrophages and decreased LTB4 production by neutrophils, indicating the anti-inflammatory property of this lipid.These data reveal that monocyte-derived macrophages contribute to the resolution of inflammation in time by the production of pro-resolving lipids after an initial inflammatory stimulus.

Analysis of spatial relationships between CD8 and FoxP3 cells using digital imaging in head and neck squamous cell carcinoma

T cell-mediated anti-tumor immune responses are gated in part by the relative abundance of cytotoxic T cells (Teffs) and regulatory (Tregs) in the tumor microenvironment (TME) whereby Treg may impair the efficacy of Teffs. Tregs can affect Teff function by direct cell-to-cell contact or by secretion of soluble mediators, consistent with the hypothesis that proximity of Tregs to Teff within tumor tissues may have prognostic significance. Here we used a novel chromogenic multiplex assay to investigate the spatial relationship of these functionally diverse T cell subsets in HPV positive and HPV negative head and neck squamous cell carcinomas (HNSCCs).

Neuronal Regulation of Cutaneous Immunity.

The skin is innervated by numerous sensory afferent neurons that respond to a diverse array of stimuli ranging from gentle touch to noxious pain. Various features of the immune system-pathogen recognition, secretion of soluble mediators-are shared with the nervous system. This has led to the recognition that neurons share some functions with innate immune cells and have the capacity to recognize pathogens and participate in innate immune responses. Neuroimmune interactions are bidirectional. Soluble mediators from immune cells activate neurons and soluble mediators from neurons can activate immune cells. In this review, we will focus on the interplay between neurons and innate immunity in the skin in the context of host defense and inflammation.

Predicting Reactive Astrogliosis Propagation by Bayesian Computational Modeling: the Repeater Stations Model.

Reactive astrogliosis occurs upon focal brain injury and in neurodegenerative diseases. The mechanisms that propagate reactive astrogliosis to distal parts of the brain, in a rapid wave that activates astrocytes and other cell types along the way, are not completely understood. It is proposed that damage-associated molecular patterns (DAMP) released by necrotic cells from the injury core have a major role in the reactive astrogliosis initiation but whether they also participate in reactive astrogliosis propagation remains to be determined. We here developed a Bayesian computational model to define the most probable model for reactive astrogliosis propagation. Starting with experimental data from GFAP-immunostained reactive astrocytes, we defined five types of astrocytes based on morphometrical cues and registered the position of each reactive astrocyte cell type in the hemisphere ipsilateral to the injured site after 3 and 7days post-ischemia. We developed equations for the changes in DAMP concentration (due to diffusion, binding to receptors or degradation), soluble mediators secretion, and for the evolution reactive astrogliosis. We tested four predefined models based on abovementioned previous hypothesis and modifications to it. Our results showed that DAMP diffusion alone has not justified the reactive astrogliosis propagation as previously assumed. Only two models succeeded in accurately reproducing the experimentally measured data and they highlighted the role of microglia and the glial secretion of soluble mediators to sustain the reactive signal and activating neighboring astrocytes. Thus, our in silico analysis proposes that glial cells behave as repeater stations of the injury signal in order to propagate reactive astrogliosis.

Increased immunomodulatory capacity of human amniotic cells after activation by pro-inflammatory chemokines

Human amniotic cells (hAC) possess multiple unique immunomodulatory properties. They are believed to be a very appealing and safe material for clinical applications. Primary hAC have been proposed as an efficient source of immunomodulatory factors that could be used as alternative or supporting to classical drug immunosuppression. The aim of this study was to evaluate hAC immunomodulatory properties post-activation by inflammatory cytokines as Interleukin 1β and Interferon γ.hAC were isolated and characterized by the expression of pluripotency marker SSEA4, epithelial marker CK7, HLA-G antigen, mRNA for PTGS2, NOS2 and HLA-G gene, and secretion of soluble mediators as HLA-G and PGE2 in the culture medium in presence or absence of INF-γ and IL-1β.Heterogeneity of the cultured hAC was proved, with 50 ± 8% of cells positive for epithelial marker (CK7), and 73 ± 3% expressing SSEA4 pluripotency marker. Priming effect by in vitro exposure to INF-γ and IL-1β resulted in a significant increase in expression of PTGS2, NOS2 and HLA-G gene, with a peak between 32 and 64 h. The highest PGE2 concentration was measured in the culture medium at 48 h. At 96 h, a significant difference in the percentage of SSEA4+ hAC between activated and non-activated cells, as well as the highest expression of HLA-G - especially in SSEA4+ cells, and highly elevated concentration of soluble HLA-G (sHLA-G) in the medium of activated cells, were found.The prolonged exposure of primary human amnion-derived cells to inflammatory cytokines INF-γ and IL-1β may result in enhanced expression and secretion of immunomodulatory molecules important in allogenic therapies.

Signals from the Niche: Insights into the Role of IGF-1 and IL-6 in Modulating Skeletal Muscle Fibrosis.

Muscle regeneration, characterized by the activation and proliferation of satellite cells and other precursors, is accompanied by an inflammatory response and the remodeling of the extracellular matrix (ECM), necessary to remove cellular debris and to mechanically support newly generated myofibers and activated satellite cells. Muscle repair can be considered concluded when the tissue architecture, vascularization, and innervation have been restored. Alterations in these connected mechanisms can impair muscle regeneration, leading to the replacement of functional muscle tissue with a fibrotic scar. In the present review, we will discuss the cellular mediators of fibrosis and how the altered expression and secretion of soluble mediators, such as IL-6 and IGF-1, can modulate regulatory networks involved in the altered regeneration and fibrosis during aging and diseases.

Abstract P1-07-35: Adipokine receptor CAP1 expression as predictor of survival outcome among breast cancer patients

Abstract Background: Obesity is a challenging health concern in breast cancer. Not only are obese women at higher risk of breast cancer, but if diagnosed with the disease, obesity is also impairing the prognosis of a breast cancer. Understanding the underlying biology behind these associations are key to improve survival rates in breast cancer. In obesity, the more abundant, activated adipose tissue may lead to insulin resistance and secretion of soluble mediators that may contribute to impaired breast cancer outcomes observed among obese women. The adipokine resistin is implied to be an important link between obesity and insulin resistance, and to be elevated among breast cancer patients. Yet, the expression of the newly identified resistin receptor CAP1 and its impact on breast cancer prognosis is poorly understood. Purpose: To evaluate the impact by the adipokine receptor CAP1 tumor expression on breast cancer outcomes. Experimental Design: CAP1 mRNA expression was explored among 1,881 primary breast tumors. Associations between CAP1 expression, categorized into tertiles, and survival outcomes were estimated using the Kaplan-Meier method and log-rank test, and by multivariable Cox regression models providing adjusted hazard ratios (HRadj) with 95% confidence intervals (CI). Independent biological network interaction analyzes were conducted in a subset of 1,105 invasive breast carcinomas within The Cancer Genome Atlas (TCGA) project. Results: CAP1 was linked to poor tumor characteristics with higher CAP1 expression found among estrogen receptor (ER)-negative tumors, relative to ER-positive tumors, as well as with increasing tumor grade (P=0.025). High CAP1 tumor expression was further associated with shorter overall survival (HRadj 1.54; 95% CI, 1.11-2.13) and relapse-free survival (HRadj 1.47; 95% CI, 1.10-1.96), compared with low or intermediate CAP1 expression, particularly among ER-positive tumors or lymph node positive tumors. Additionally, CAP1 was identified in complex with genes involved in growth promoting and cell motility processes. Conclusion: These results highlight the potential role of the resistin receptor CAP1 regarding breast cancer outcomes. Further investigations are needed to elucidate the biological and clinical implication of the resistin-CAP1 link in obesity-associated breast cancer. Citation Format: Rosendahl AH, Bergqvist M, Kimbung S, Borgquist S. Adipokine receptor CAP1 expression as predictor of survival outcome among breast cancer patients [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P1-07-35.

Identification of a transitional fibroblast function in very early rheumatoid arthritis

ObjectivesSynovial fibroblasts actively regulate the inflammatory infiltrate by communicating with neighbouring endothelial cells (EC). Surprisingly, little is known about how the development of rheumatoid arthritis (RA) alters these immunomodulatory properties....

Kupffer cells in immune activation and tolerance toward HBV/HCV infection.

Kupffer cells (KCs) are macrophages that are found in the sinusoids of the liver. KCs are a crucial part of the innate immune system, acting as scavengers and phagocytes. KCs and sinusoidal endothelial cells together form the first immune barrier of the portal system. Studies show that KCs can not only maintain homeostasis in the immune response, but also facilitate the pathogenesis of type B and type C hepatitis (HBV/HCV) through their antigen-presenting function and secretion of soluble mediators. KCs can express toll-like receptors (TLRs), Fas ligand (FasL) and programmed cell death ligand 1 (PD-L1), and secrete large amounts of inflammatory factors leading to immune tolerance toward HBV/HCV. On the one hand, KCs contribute to the clearance of HBV/HCV due to their nature as innate immune cells. At the same time, KCs induce immune tolerance toward HBV/HCV, which leads to chronicity of the infection. The dual role of KCs in the immune response toward HBV/HCV means it is a gigantic challenge for scientists to illuminate the detailed mechanisms involved, but it also offers important potential therapeutic targets.

Epithelial Cell Regulation of Allergic Diseases

Allergic diseases, which have escalated in prevalence in recent years, arise as a result of maladaptive immune responses to ubiquitous environmental stimuli. Why only certain individuals mount inappropriate type 2 immune responses to these otherwise harmless allergens has remained an unanswered question. Mounting evidence suggests that the epithelium, by sensing its environment, is the central regulator of allergic diseases. Once considered to be a passive barrier to allergens, epithelial cells at mucosal surfaces are now considered to be the cornerstone of the allergic diathesis. Beyond their function as maintaining barrier at mucosal surfaces, mucosal epithelial cells through the secretion of mediators like IL-25, IL-33, and TSLP control the fate of downstream allergic immune responses. In this review, we will discuss the advances in recent years regarding the process of allergen recognition and secretion of soluble mediators by epithelial cells that shape the development of the allergic response.

Abstract 12008: Increased Circulating Endothelial Microparticles in the Acute Phase of Kawasaki Disease

Introduction: Kawasaki disease(KD) is a typically acute inflammatory syndrome that takes the form of systemic vasculitis. The acute inflammation and subsequent reparative process may lead to lasting changes in arterial structure even in the convalescence of KD including increased endothelial dysfunction. Endothelial microparticles(EMPs) are vesicles formed by the cell membrane after endothelial activation. EMPs typically contain microRNAs(miRs). MiRs can affect mRNA degradation and translation. EMPs may transfer information from the parent cell to various target cells by direct cell-to-cell contact or alternatively through secretion of soluble mediators and effectors. Methods: We enrolled 35 patients (aged 3 months to 14 years, 21 male, 14 female), 35 controls. KD patients were divided into two subgroups; coronary artery lesion (CAL, Zsocre>2.5, n=5) and no coronary lesion (NCAL, Zscore≦2.5, n=30). Blood samples were collected at the time of diagnosis before the initiation of IVIG treatment, then immediately after the first IVIG infusion and at 2-4 weeks after disease onset. EMPs were measured by using flow cytometry, and we performed miR expression profiling by using microarrays(Affymetrix® GeneChip® miRNA 4.0). Results: The percentage counts of EMPs were 2.90±1.26% in KD children before initial treatment, which were significantly higher (P<0.005) than those of controls (0.09±0.08%). The highest percentage count of EMPs (5.47%) was observed in the patient with CAL before initial treatment. In the patients with acute phase of KD with CAL, miR-320a (Fold change 22.66), miR-320b (Fold change 17.52) and miR-320c (Fold change 11.78) which were extracted from EMPs were up-regulated, while miR-550a (Fold change -4.81) and miR-3613-3p (Fold change -5.51) were down-regulated in comparison with those in convalescent phase. These 5 miRs were normalized after treatment. Conclusions: These results suggested that EMPs could serve as a sensitive marker of the severity of endothelial dysfunction and vasculitis in patients with KD. Moreover, miR-320 may have a pivotal role of vasculitis and the development of CAL during acute phase of KD.

Abstract 1325: Evaluation of immuno-oncology related treatment in syngenic and human reconstituted immune systems

Abstract Immunotherapy based on monoclonal antibodies targeting cancer cells is now developed as a valid approach to treat cancer. Modulation of novel immune checkpoints and other targets are highly promising approaches against cancer and many other diseases. They have the potential to activate the immune system and to establish an active defense against pathological conditions. In addition, antibodies, antibody fragments, and other biologics can also have a strong impact on the immune system which needs to be evaluated early on. In order to develop and accurately evaluate these immunology linked approaches, appropriate preclinical models with relevant immunological readouts are needed at different stages of therapy development. Ideally, methods should be available that allow predictive readouts in vivo and ex vivo. A comprehensive panel of tools was constructed and validated aiming at evaluating the modulation of the immune system by new therapies. In immunocompetent mice, immune cells were studied for the detection of their cell surface markers, induction of proliferative phenotype, antigen-specific T lymphocyte detection, secretion of soluble mediators using FACS phenotyping, cytometric bead assay (CBA) or Luminex multiplex technologies and ELISPOT. We report on a panel of syngenic tumor models (4T1, B16-F10, CT26, EMT6, AY27, LLC1, MBT-2 and Renca) our capacity to correlate subpopulation of immune infiltrating cells (as T cells, macrophages, NK cells, granulocytic and monocytic cells) and the therapeutic effects of critical antibodies directed against Cytotoxic T lymphocyte antigen-4 (CTLA-4) and programmed death 1 membrane protein (PD-1). In immunodeficient mice, the reconstitution of the mature human immune system with PBMC or naïve human immune system using hematopoietic stem cells was used to evaluate the modulation of those immune cells by therapies through human cytokine release and onset of graft versus host disease. All of these tools were used in the context either of rodent syngenic models or humanized mouse models. In addition to their use in immune system modulating anti-cancer therapies, these humanized or syngenic models also have a potential application in many other therapeutic areas such as autoimmune diseases, inflammation, anti-infectives. Citation Format: Marc Hillairet de Boisferon, Francis Bichat, Caroline Mignard, Xavier Tizon, Damien France, Jean-François Mirjolet. Evaluation of immuno-oncology related treatment in syngenic and human reconstituted immune systems. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1325. doi:10.1158/1538-7445.AM2015-1325

Expression of PD-1 by CD4(+)CD25(+)CD127(low) Treg cells in the peripheral blood of lung cancer patients.

Dear editor Lung cancer is the most commonly diagnosed cancer and the leading cause of cancer death worldwide,1 with the majority of patients presenting with advanced disease.2 Treg cells diminish the activation and function of lymphocytes via cell-cell contact and secretion of soluble mediators.3 PD-1 is expressed on the surface of activated T and B cells and regulates their activation and proliferation.4 PD-L1 binds to the PD-1 receptor, leading to, among other responses, negative regulation of immune activity. Both Tregs and the PD-1/PD-L1 pathway play important roles in lung cancer pathogenesis;5,6 however, the association between these two factors remains poorly understood. Here, we examined PD-1 expression on Tregs, and compared these results with established clinical indicators of lung cancer. These analyses revealed significant expression of PD-1 on Tregs in lung cancer, which may be used to inform clinical diagnoses. PD-1 expression was studied on CD4+CD25+CD127low Tregs isolated from peripheral blood mononuclear cells by flow cytometry. Twenty-two primary lung cancer patients and 25 healthy volunteers were recruited from the Second Affiliated Hospital of Soochow University (Suzhou, People’s Republic of China). Lung cancer patients had a nearly 2-fold increase in the number of circulating Tregs relative to healthy controls (7.66%±2.25% versus [vs] 3.76%±1.06%, respectively; P<0.05). The levels of PD-1 expression by CD4+CD25+CD127low Tregs were also higher in lung cancer samples compared to controls (46.01%±11.33% vs 33.34%±13.54%, respectively). Significant differences in both CD4+CD25+CD127low Treg abundance (6.29%±1.18% vs 10.06%±1.58%; P<0.01) and Treg PD-1 expression (41.85%±6.1% vs 56.57%±12.52%; P<0.05) were observed between clinical stages III and IV, respectively (Figure 1); no differences were seen among other pathologic subtypes, or in terms of lymphatic metastasis. Figure 1 Expression of Tregs PD-1 on Tregs in peripheral blood. Tregs play a critical role in a variety of immunologic processes, including self-tolerance, anti-tumor immune responses, and transplantation.7,8 Our study revealed a significant increase in the number of CD4+CD25+CD127low Tregs in patients with lung cancer, relative to healthy controls. While the mechanisms underlying the increase in lung cancer-associated Tregs are not known, the overall increase in the number of immunosuppressive immune cells present in these patients may play an important role in both the development and progression of lung cancer.9,10 Costimulatory molecule receptors interacting with their corresponding ligand mediate both positive and negative costimulatory signals, which regulate immune cell activation, including the activation and proliferation of T cells, cytokine production, apoptosis, cell survival, and cytotoxicity.11–13 PD-1 belongs to the CD28 family of receptors, and is expressed on activated T, B, and myeloid cells.4 PD-1 and its ligand PD-L1 deliver inhibitory signals that regulate the balance between effector T cell activation and immune-mediated tissue damage.11,12 In addition, the proliferation and immune inhibitory activity of Tregs is directly related to the expression of costimulatory molecules on the cell surface.14 Conflicting reports on the role of PD-1 on Treg function have suggested that PD-1–PD-L1 ligation on Tregs promotes Treg stability and expansion,15–18 while others have suggested that this pathway inhibits Treg expansion and function.19,20 Our study revealed a distinct increase in Treg number and Treg PD-1 expression in patients with lung cancer, suggesting that the PD-1/PD-L1 pathway may play a role in Treg induction and is associated with impaired adaptive immunity. From these results, we hypothesize that the over-expression of PD-1 on Tregs and/or the increase in Treg number may participate in the immune inhibitory state of lung cancer patients. The cross-talk between Treg cells and PD-1/PD-L1-induced inhibition in lung cancer warrants further exploration for lung cancer associated immune pathogenesis.

Enhancement of phagocytosis and cytotoxicity in macrophages by tumor-derived IL-18 stimulation

Inoculation of mice with the murine NFSA cell line caused the formation of large tumors with necrotic tumor cores. FACS analysis revealed accumulations of CD11b+ cells in the tumors. Microarray analysis indicated that the NFSA cells expressed a high level of the pro-inflammatory factor interleukin-18 (il-18), which is known to play a critical role in macrophages. However, little is known about the physiological function of IL-18-stimulated macrophages. Here, we provide direct evidence that IL-18 enhances the phagocytosis of RAW264 cells and peritoneal macrophages, accompanied by the increased expression of tumor necrosis factor (tnf-α), interleukin-6 (il-6) and inducible nitric oxide synthase (Nos2). IL-18-stimulated RAW264 cells showed an enhanced cytotoxicity to endothelial F-2 cells via direct cell-to-cell interaction and the secretion of soluble mediators. Taken together, our results demonstrate that tumor-derived IL-18 plays an important role in the phagocytosis of macrophages and that IL-18-stimulated macrophages may damage tumor endothelial cells. [BMB Reports 2014; 47(5): 286-291]