Elevated expression of Foxp3 in tumor-infiltrating Treg cells suppresses T-cell proliferation and contributes to gastric cancer progression in a COX-2-dependent manner

Notch signaling pathway regulates CD4+CD25+CD127dim/- regulatory T cells and T helper 17 cells function in gastric cancer patients

Regulatory T cells (Tregs) and T helper 17 (Th17) cells contribute to cancer progression and prognosis. However, regulatory factors associated with Tregs-Th17 balance were not completely understood. We previously demonstrated an immune-modulatory capacity by Notch signaling inactivation to reverse Tregs-Th17 disequilibrium in chronic hepatitis C. Thus, the aim of current study was to assess the role of Notch signaling in modulation Tregs and Th17 cells function in gastric cancer (GC) patients. A total of 51 GC patients and 18 normal controls (NCs) were enrolled. Notch1 and Notch2 mRNA expressions were semiquantified by real-time polymerase chain reaction. Tregs/Th17 percentages, transcriptional factors, and cytokines production were investigated in response to the stimulation of Notch signaling inhibitor DAPT. Both Notch1 and Notch2 mRNA expressions were elevated in GC tissues and peripheral bloods in GC patients. CD4⁺CD25⁺CD127^dim/- Tregs and Th17 cells percentage was also elevated in GC patients compared with in NCs. DAPT treatment did not affect frequency of either circulating Tregs or Th17 cells, however, reduced FoxP3/RORγt mRNA expression and interleukin (IL)-35/IL-17 production in purified CD4⁺ T cells from GC patients. Moreover, blockade of Notch signaling also inhibited the suppressive function of purified CD4⁺CD25⁺CD127^dim/- Tregs from GC patients, which presented as elevation of cellular proliferation and IL-35 secretion. The current data further provided mechanism underlying Tregs-Th17 balance in GC patients. The link between Notch signaling and Th cells might lead to a new therapeutic target for GC patients.

Regulatory T Cells and Plasmacytoid Dendritic Cells Within the Tumor Microenvironment in Gastric Cancer Are Correlated With Gastric Microbiota Dysbiosis: A Preliminary Study

Substantial evidence indicates that gastric microbiota dysbiosis, immune system dysfunction especially immune escape are critical for gastric cancer (GC) occurrence and progression. As two important elements of tumor microenvironment (TME), the relationship between gastric microbiota and tumor-immune microenvironment is still unclear. Our present study aimed to explore the correlation between gastric mucosal microbiota in different microhabitats and its corresponding gastric immunosuppressive cells such as regulatory T cells (Tregs) and plasmacytoid dendritic cells (pDCs) in the TME. A cohort of 64 GC patients without preoperative chemotherapy was enrolled retrospectively, and 60 normal, 61 peritumoral and 59 tumoral tissues were obtained for gastric mucosal microbiota analysis and immunohistochemistry analysis. From different microhabitats, BDCA2+pDCs and Foxp3+Tregs were observed positively correlated, and increased in tumoral and peritumoral tissues compared to normal ones. The diversity, composition and function of gastric mucosal microbiota also changed more significantly in tumoral tissues than those in normal and peritumoral ones. With pearson's correlation analysis, we found that several non-abundant genera such as Stenotrophomonas and Selenomonas were positively correlated with BDCA2+pDCs and Foxp3+Tregs, respectively, while Comamonas and Gaiella were negatively correlated with BDCA2+pDCs and Foxp3+ Tregs, respectively. The increased BDCA2+pDCs and Foxp3+Tregs might be modulated by gastric mucosal microbiota, both participated in the immunosuppression microenvironment of GC, which might provide evidence to establish new strategies in antitumor therapy targeting on gastric microbiota.

STAT5 and TET2 Cooperate to Regulate FOXP3-TSDR Demethylation in CD4+ T Cells of Patients with Colorectal Cancer

The tumor-infiltrating Tregs are linked to colorectal cancer progression and outcome. FOXP3 is regarded as a critical developmental and functional factor for Tregs. FOXP3-TSDR demethylation is required for stable expression of FOXP3 and maintenance of Treg function. In our study, we found specific DNA hypomethylation of FOXP3-TSDR in CD4⁺ T cells from colon tumor tissues as compared with normal colonic tissues. Moreover, we also found that the expression of STAT5 and TET2 was increased in CD4⁺ T cells from colon tumor tissues, and the superfluous STAT5 and TET2 binding to FOXP3-TSDR resulted in DNA hypomethylation. In conclusion, we have demonstrated that excessive amounts of STAT5 may bind more TET2 to the FOXP3-TSDR and upregulate FOXP3 expression via DNA demethylation. Our study improved the mechanism of FOXP3-TSDR hypomethylation in tumor-infiltrating CD4⁺ T cells of CRC patients.

Prostaglandin-endoperoxide synthase 2 (cyclooxygenase-2), a complex target for colorectal cancer prevention and therapy

A plentiful literature has linked colorectal cancer (CRC) to inflammation and prostaglandin-endoperoxide synthase (PTGS)2 expression. Accordingly, several nonsteroidal antiinflammatory drugs (NSAIDs) have been tested often successfully in CRC chemoprevention despite their different ability to specifically target PTGS2 and the low or null expression of PTGS2 in early colon adenomas. Some observational studies showed an increased survival for patients with CRC assuming NSAIDs after diagnosis, but no clinical trial has yet demonstrated the efficacy of NSAIDs against established CRC, where PTGS2 is expressed at high levels. The major limits for the application of NSAIDs, or specific PTGS2 inhibitors, as adjuvant drugs in CRC are (1) a frequent confusion about the physiological role of PTGS1 and PTGS2, reflecting in CRC pathology and therapy; (2) the presence of unavoidable side effects linked to the intrinsic function of these enzymes; (3) the need of established criteria and markers for patient selection; and (4) the evaluation of the immunomodulatory potential of PTGS2 inhibitors as possible adjuvants for immunotherapy. This review has been written to rediscover the multifaceted potential of PTGS2 targeting, hoping it could act as a starting point for a new and more aware application of NSAIDs against CRC.

A preclinical model to investigate the role of surgically-induced inflammation in tumor responses to intraoperative photodynamic therapy

OBJECTIVE

Inflammation is a well-known consequence of surgery. Although surgical debulking of tumor is beneficial to patients, the onset of inflammation in injured tissue may impede the success of adjuvant therapies. One marker for postoperative inflammation is IL-6, which is released as a consequence of surgical injuries. IL-6 is predictive of response to many cancer therapies, and it is linked to various molecular and cellular resistance mechanisms. The purpose of this study was to establish a murine model by which therapeutic responses to photodynamic therapy (PDT) can be studied in the context of surgical inflammation.

MATERIALS AND METHODS

Murine models with AB12 mesothelioma tumors were treated with either surgical resection or sham surgery with tumor incision but no resection. The timing and extent of IL-6 release in the tumor and/or serum was measured using enzyme-linked immunosorbent assay (ELISA) and compared to that measured in the serum of 27 consecutive, prospectively enrolled patients with malignant pleural mesothelioma (MPM) who underwent macroscopic complete resection (MCR).

RESULTS

MPM patients showed a significant increase in IL-6 at the time MCR was completed. Similarly, IL-6 increased in the tumor and serum of mice treated with surgical resections. However, investigations that combine resection with another therapy make it necessary to grow tumors for resection to a larger volume than those that receive secondary therapy alone. As the larger size may alter tumor biology independent of the effects of surgical injury, we assessed the tumor incision model. In this model, tumor levels of IL-6 significantly increased after tumor incision.

CONCLUSION

The tumor incision model induces IL-6 release as is seen in the surgical setting, yet it avoids the limitations of surgical resection models. Potential mechanisms by which surgical induction of inflammation and IL-6 could alter the nature and efficacy of tumor response to PDT are reviewed. These include a wide spectrum of molecular and cellular mechanisms through which surgically-induced IL-6 could change the effectiveness of therapies that are combined with surgery. The tumor incision model can be employed for novel investigations of the effects of surgically-induced, acute inflammation on therapeutic response to PDT (or potentially other therapies). Lasers Surg. Med. 50:440-450, 2018. © 2018 Wiley Periodicals, Inc.

Role of prostanoids in gastrointestinal cancer

Chronic inflammation is a risk factor for gastrointestinal cancer and other diseases. Most studies have focused on cytokines and chemokines as mediators connecting chronic inflammation to cancer, whereas the involvement of lipid mediators, including prostanoids, has not been extensively investigated. Prostanoids are among the earliest signaling molecules released in response to inflammation. Multiple lines of evidence suggest that prostanoids are involved in gastrointestinal cancer. In this Review, we discuss how prostanoids impact gastrointestinal cancer development. In particular, we highlight recent advances in our understanding of how prostaglandin E2 induces the immunosuppressive microenvironment in gastrointestinal cancers.

Regulatory network analysis of high expressed long non-coding RNA LINC00941 in gastric cancer

Accumulating evidence suggests that the aberrant expression of long non-coding RNAs is closely related to the carcinogenesis and progression of gastric cancer (GC), which is a type of prevalent tumor with a high incidence and mortality rate. However, it is still a challenge to find reliable biomarkers and to understand their molecular mechanisms in GC. In this study, we first confirmed that LINC00941was up-regulated in GC tumor tissues compared with adjacent normal tissues by RT-PCR, and found that the expression level of LINC00941 was correlated with invasion depth, lymphatic metastasis, and the TNM stage of patients with GC. Furthermore, by performing enrichment analysis based on the co-expression network and regulatory network, we found that LINC00941 was associated with cancer related biological processes such as cell cycle, cell communication, cell migration, cell division, as well as processes associated with the immune system. Our results suggested that LINC00941 may be a potential novel biomarker for therapeutic or diagnostic of GC.

Enhanced Suppressive Activity of Regulatory T Cells in the Microenvironment of Malignant Pleural Effusions

Cancer metastatic spread to serous cavity causes malignant pleural effusions (MPEs), indicating dismal prognosis. Tumor microenvironment can implement suppressive activity on host immune responses. Thus, we investigated the prevalence of Tregs and the relationship between them and TGF-β and IL-10 concentrations and measured expression of FOXP3, CTLA-4, CD28, and GITR genes, as well as protein expression of selected genes in benign effusions and MPEs. The percentage of Tregs was determined by means of multicolor flow cytometry system. TGF-β and IL-10 concentrations were measured using human TGF-β1 and IL-10 ELISA kit. Relative mRNA expression of studied genes was analyzed by real-time PCR. The frequency of Tregs was significantly higher in MPEs compared to benign effusions; however, the level of TGF-β and IL-10 in analyzed groups was comparable, and no correlation between concentrations of TGF-β and IL-10 and percentage of Tregs was observed. Relative mRNA expression of all the genes was higher in CD4⁺CD25⁺ compared to CD4⁺CD25⁻ cells. In CD4⁺CD25⁺ cells from MPEs, relative mRNA expression of FOXP3, CTLA-4, and CD28 genes was significantly higher than in benign effusions; however, the level of CD4⁺CD25⁺CTLA-4⁺ cells in analyzed groups showed no significant differences. We found numerous genes correlations in an entire CD4⁺CD25⁺ cell subset and CD4⁺CD25⁺ cells from MPEs. Enhanced suppressive activity of Tregs is observed in the microenvironment of MPEs. Understanding of relations between cellular and cytokine immunosuppressive factors in tumor microenvironment may determine success of anticancer response.

The Progress of T Cell Immunity Related to Prognosis in Gastric Cancer

Gastric cancer is the fifth most common malignancy all over the world, and the factors that can affect progress and prognosis of the gastric cancer patients are various, such as TNM stages, invasive depth, and lymph node metastasis ratio. T cell immunity is important component of human immunity system and immunity responding to tumor and dysfunction or imbalance of T cell immunity will lead to serious outcomes for body. T cell immunity includes many different types of cells, CD4+ T cell, CD8+ T cell, memory cell, and so on, and each of them has special function on antitumor response or tumor immune escape which is revealed in lung cancer, colorectal cancer, breast cancer, ovarian cancer, and so on. But its correlation with gastric cancer is not clear. Our review was preformed to explore the relationship between the progress and prognosis of gastric cancer (GC) and T cell immunity. According to recent researches, T cell immunity may have an important role in the progress and prognosis of GCs, but its function is affected by location, category, related molecule, and interaction between the cells, and some effects still are controversial. More researches are needed to clarify this correlation.

PD-L1 expression is a prognostic factor in subgroups of gastric cancer patients stratified according to their levels of CD8 and FOXP3 immune markers

Current studies aiming at identifying single immune markers with prognostic value have limitations in the context of complex antitumor immunity and cancer immune evasion. Here, we show how the integration of several immune markers influences the predictions of prognosis of gastric cancer (GC) patients. We analyzed Tissue Microarray (TMA) by multiplex immunohistochemistry and measured the expression of immune checkpoint molecule PD-L1 together with antitumor CD8 T cells and immune suppressive FOXP3 Treg cells in a cohort of GC patients. Unsupervised hierarchical clustering analysis of these markers was used to define correlations between CD8 T, FOXP3 Treg and PD-L1 cell densities. We found that FOXP3 and PD-L1 densities were elevated while CD8 T cells were decreased in tumor tissues compared to their adjacent normal tissues. However, patient stratification based on each one of these markers individually did not show significant prognostic value on patient survival. Conversely, combination of the ratios of CD8/FOXP3 and CD8/PD-L1 enabled the identification of patient subgroups with different survival outcomes. As such, high densities of PD-L1 in patients with high CD8/FOXP3 and low CD8/PD-L1 ratios correlated with increased survival. Collectively, this work demonstrates the need for the integration of several immune markers to obtain more meaningful survival prognosis and patient stratification. In addition, our work provides insights into the complex tumor immune evasion and immune regulation by the tumor-infiltrating effector and suppressor cells, informing on the best use of immunotherapy options for treating patients.

Astragalus mongholicus (Fisch.) Bge Improves Peripheral Treg Cell Immunity Imbalance in the Children With Viral Myocarditis by Reducing the Levels of miR-146b and miR-155

Viral myocarditis (VMC) is a common cardiac disease, however, there still lacks an effective therapeutic strategy for VMC. Astragalus mongholicus (Fisch.) Bge (AB), a Chinese herb with some functional metabolites, may have some pharmacological effects on VMC. AB ingredients were measured by a full-scan LCQ mass spectrum. We aimed to explore the effects of AB on the VMC children by investigating peripheral Treg cell homeostasis. A total of 68 VMC children were random and evenly assigned into an AG group (received 10-mL AB oral liquid daily), and a CG group (received placebo daily). Peripheral blood mononuclear cells (PBMC) were obtained from peripheral blood and Treg cells were isolated. The levels of miR-146b, miR-155, Treg immunity activity and myocarditis biomarkers were measured in Treg cells. There were four main components (sucrose, calycosin, Astragaloside IV and calycosin-7-glucoside) in AB. The cases sinus tachycardia, frequent premature ventricular contractions, and supraventricular tachycardia were significantly reduced in the AG group (P < 0.05). Meanwhile, the myocardial enzymes and cardiac function indexes were improved in the AG group when compared with the CG group (P < 0.05). The time of electrocardiogram recovery, symptom duration and hospital stay was shorter in the AG group than in the CG group (P < 0.05). The levels of miR-146b and miR-155 were higher in the CG group than in the AG group (P < 0.05). The levels of ROR-γt (retinoic acid receptor-related orphan nuclear receptor gamma), FoxP3 (forkhead transcription factor), IL-10 (interleukin-11) and TGF-β (transforming growth factor beta) were lower in the CG group than in the AG group (P < 0.05). In contrast, the levels of IL-17, IL-21, CK-MB (creatine kinase-MB), cTnI (cardiac troponin I), GrB (granzyme B), sFasL (soluble fas ligand) and caspase-3 were higher in the CG group than in the AG group (P < 0.05). Furthermore, the levels of ROR-γt, FoxP3, IL-10, and TGF-β were positively, whereas the levels of IL-17, IL-21, CK-MB, cTnI, GrB, sFasL and caspase-3 were negatively, associated with the levels of miR-146b and miR-155 (P < 0.05). AB treatment improved cardiac functions, peripheral Treg cell immunity imbalance in the children with VMC by reducing the levels of miR-146b and miR-155.

Understanding immune phenotypes in human gastric disease tissues by multiplexed immunohistochemistry

Background

Understanding immune phenotypes and human gastric disease in situ requires an approach that leverages multiplexed immunohistochemistry (mIHC) with multispectral imaging to facilitate precise image analyses.

Methods

We developed a novel 4-color mIHC assay based on tyramide signal amplification that allowed us to reliably interrogate immunologic checkpoints, including programmed death-ligand 1 (PD-L1), cytotoxic T cells (CD8⁺T) and regulatory T cells (Foxp3), in formalin-fixed, paraffin-embedded tissues of various human gastric diseases. By observing cell phenotypes within the disease tissue microenvironment, we were able to determine specific co-localized staining combinations and various measures of cell density.

Results

We found that PD-L1 was expressed in gastric ulcer and in tumor cells (TCs), as well as in tumor-infiltrating immune cells (TIICs), but not in normal gastric mucosa or other gastric intraepithelial neoplastic tissues. Furthermore, we found no significant reduction in CD8⁺T cells, whereas the ratio of CD8⁺T:Foxp3 cells and CD8⁺T:PD-L1 cells was suppressed in tumor tissues and elevated in adjacent normal tissues. An unsupervised hierarchical analysis also identified correlations between CD8⁺T and Foxp3⁺ tumor-infiltrating lymphocyte (TIL) densities and average PD-L1 levels. Three main groups were identified based on the results of CD8⁺T:PD-L1 ratios in gastric tumor tissues. Furthermore, integrating CD8⁺T:Foxp3 ratios, which increased the complexity for immune phenotype status, revealed 6–7 clusters that enabled the separation of gastric cancer patients at the same clinical stage into different risk-group subsets.

Conclusions

Characterizing immune phenotypes in human gastric disease tissues via multiplexed immunohistochemistry may help guide PD-L1 clinical therapy. Observing unique disease tissue microenvironments can improve our understanding of immune phenotypes and cell interactions within these microenvironments, providing the ability to predict safe responses to immunotherapies.

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-017-1311-8) contains supplementary material, which is available to authorized users.

Prognostic Significance of Tumor-Infiltrating Lymphocytes in Patients With Pancreatic Ductal Adenocarcinoma Treated With Neoadjuvant Chemotherapy

OBJECTIVES

The aim of this study was to examine tumor-infiltrating lymphocytes (TILs) and their prognostic value in patients with pancreatic ductal adenocarcinoma (PDAC) after neoadjuvant therapy.

METHODS

Intratumoral CD4, CD8, and FOXP3 lymphocytes were examined by immunohistochemistry using a computer-assisted quantitative analysis in 136 PDAC patients who received neoadjuvant therapy and pancreaticoduodenectomy. The results were correlated with clinicopathological parameters and survival.

RESULTS

High CD4 TILs in treated PDAC were associated with high CD8 TILs (P = 0.003), differentiation (P = 0.04), and a lower frequency of recurrence (P = 0.02). Patients with high CD4 TILs had longer disease-free survival and overall survival (OS) than did patients with low CD4 TILs (P < 0.01). The median OS of patients with a high CD8/FOXP3 lymphocyte ratio (39.5 [standard deviation, 6.1] months) was longer than that of patients with a low CD8/FOXP3 lymphocyte ratio (28.3 [standard deviation, 2.3] months; P = 0.01). In multivariate analysis, high CD4 TILs were an independent prognostic factor for disease-free survival (hazard ratio, 0.49; 95% confidence interval, 0.30-0.81; P = 0.005) and OS (hazard ratio, 0.54; 95% confidence interval, 0.33-0.89; P = 0.02).

CONCLUSIONS

High level of CD4 lymphocytes is associated with tumor differentiation and lower recurrence and is an independent prognostic factor for survival in PDAC patients treated with neoadjuvant therapy.

COX-2 regulates Snail expression in gastric cancer via the Notch1 signaling pathway

The conversion of arachidonic acid into prostaglandins by cyclooxygenase (COX)-2 contributes to the biological properties of malignant tumours. During the initiation and development of various tumours, the Notch family plays a key role. However, the association between COX‑2 and the Notch family in gastric cancer (GC) remains unclear. The present study aimed to clarify the mechanisms through which COX‑2 participates in the pathogenesis of GC. Quantitative PCR and western blot analysis were used to detect the expression of Notch family members and COX‑2 in human GC and paracancerous tissues, GES‑1 cells and GC cell lines (AGS, SGC‑7901, BGC‑823, and MGC‑803) treated with or without celecoxib, prostaglandin E2 and small interfering RNA (siRNA). A CCK‑8 assay was performed to detect the proliferation of GC cells transfected with siRNA against COX‑2 (si‑COX‑2). A high mRNA expression of Notch1 and a decreased expression of Notch-1 intracellular active domain (N1IC) in GC were found to be related to the depth of invasion and TNM staging. The mRNA levels of Notch2, Notch3, Jagged1 and N2IC were found to be high in GC. A High expression of COX‑2 was associated with poorly differentiated and deeply invasive GC. COX‑2 and Notch1 exhibited an inverse expression pattern in the GES‑1 cells and different GC cell lines; the inhibition of COX‑2 increased Notch1 expression and activated the GC cells, whereas Notch1 downregulation had the opposite effect. Notch1 exhibited varying effects on Snail in the GC cell lines. The downregulation of COX‑2 expression significantly inhibited the proliferation of GC cells. On the whole, the expression of Notch signalling molecules differed in GC. COX‑2 inversely regulated Notch1 in GC and partially depended on the Notch1 signalling pathway in altering the expression of Snail.

Role of Cyclooxygenase-2 Pathway in Creating an Immunosuppressive Microenvironment and in Initiation and Progression of Wilms' Tumor

Wilms' tumors (WT), which accountfor 6% of all childhood cancers, arise from dysregulated differentiation of nephrogenic progenitor cells from embryonic kidneys. Though there is an improvement in the prognosis of WT, still 10% of patients with WT die due to recurrence. Thus more effective treatment approaches are necessary. We previously characterized the inflammatory microenvironment in human WT and observed the robust expression of COX-2. The aim of this study was to extend our studies to analyze the role of COX-2 pathway components in WT progression using a mouse model of WT. Herein, COX-2 pathway components such as COX-2, HIF1-α, p-ERK1/2, and p-STAT3 were upregulated in mouse and human tumor tissues. In our RPPA analysis, COX-2 was up-regulated in M15 cells after Wt1 gene was knocked down. Flow cytometry analysis showed the increased infiltration of immune suppressive inflammatory cells such as pDC's and Treg cells in tumors. The chemotactic chemokines responsible for the infiltration of these cells were also induced in CCR5 and CXCR4 dependent manner respectively. The immunosuppressive cytokines IL-10, TGF-β, and TNF-α were also up-regulated. Furthermore, more pronounced Th2 and Treg induced cytokine response was observed than Th1 response in tumors. Basing on all these evidences it is speculated that COX-2 pathway may be a beneficial target for the treatment of WT. It may be most effective as an adjuvant therapy together with other inhibitors. Thus, our current study provides a good rationale for initiating animal studies to confirm the efficacy of COX-2 inhibitors in decreasing tumor cell growth in vivo.

Histidine decarboxylase (HDC)-expressing granulocytic myeloid cells induce and recruit Foxp3+ regulatory T cells in murine colon cancer

The colorectal tumor microenvironment contains a diverse population of myeloid cells that are recruited and converted to immunosuppressive cells, thus facilitating tumor escape from immunoediting. We have identified a genetically and functionally distinct subset of dynamic bone marrow myeloid cells that are characterized by histidine decarboxylase (HDC) expression. Lineage tracing in Hdc-CreERT2;R26-LSL-tdTomato mice revealed that in homeostasis, there is a strong bias by HDC⁺ myeloid cells toward the CD11b⁺Ly6G^hi granulocytic lineage, which was accelerated during azoxymethane/dextran sodium sulfate (AOM/DSS)-induced colonic carcinogenesis. More importantly, HDC⁺ myeloid cells strongly promoted colonic tumorigenesis, and colon tumor progression was profoundly suppressed by diphtheria toxin A (DTA)-mediated depletion of HDC⁺ granulocytic myeloid cells. In addition, tumor infiltration by Foxp3⁺ regulatory T cells (Tregs) was markedly impaired following HDC⁺ myeloid cell depletion. We identified an HDC⁺ myeloid-derived Cxcl13/Cxcr5 axis that mediated Foxp3 expression and Treg proliferation. Ablation of HDC⁺ myeloid cells or disruption of the Cxcl13/Cxcr5 axis by gene knockdown impaired the production and recruitment of Tregs. Cxcl13 induction of Foxp3 expression in Tregs during tumorigenesis was associated with Stat3 phosphorylation. Overall, HDC⁺ granulocytic myeloid cells affect CD8⁺ T cells directly and indirectly through the modulation of Tregs and thus appear to play key roles in suppressing tumoricidal immunity.

Prostaglandin E2 Inhibition of IL-27 Production in Murine Dendritic Cells: A Novel Mechanism That Involves IRF1

IL-27, a multifunctional cytokine produced by APCs, antagonizes inflammation by affecting conventional dendritic cells (cDC), inducing IL-10, and promoting development of regulatory Tr1 cells. Although the mechanisms involved in IL-27 induction are well studied, much less is known about the factors that negatively impact IL-27 expression. PGE₂, a major immunomodulatory prostanoid, acts as a proinflammatory agent in several models of inflammatory/autoimmune disease, promoting primarily Th17 development and function. In this study, we report on a novel mechanism that promotes the proinflammatory function of PGE₂ We showed previously that PGE₂ inhibits IL-27 production in murine bone marrow-derived DCs. In this study, we show that, in addition to bone marrow-derived DCs, PGE₂ inhibits IL-27 production in macrophages and in splenic cDC, and we identify a novel pathway consisting of signaling through EP2/EP4→induction of cAMP→downregulation of IFN regulatory factor 1 expression and binding to the p28 IFN-stimulated response element site. The inhibitory effect of PGE₂ on p28 and irf1 expression does not involve endogenous IFN-β, STAT1, or STAT2, and inhibition of IL-27 does not appear to be mediated through PKA, exchange protein activated by cAMP, PI3K, or MAPKs. We observed similar inhibition of il27p28 expression in vivo in splenic DC following administration of dimethyl PGE₂ in conjunction with LPS. Based on the anti-inflammatory role of IL-27 in cDC and through the generation of Tr1 cells, we propose that the PGE₂-induced inhibition of IL-27 in activated cDC represents an important additional mechanism for its in vivo proinflammatory functions.

Decreased frequencies and impaired functions of the CD31+ subpopulation in Treg cells associated with decreased FoxP3 expression and enhanced Treg cell defects in patients with coronary heart disease

Coronary heart disease (CHD) is one of the most common types of organ lesions caused by atherosclerosis, in which CD4⁺ CD25⁺ forkhead box protein 3 (FoxP3⁺ ) regulatory T cells (T_reg ) play an atheroprotective role. However, T_reg cell numbers are decreased and their functions are impaired in atherosclerosis; the underlying mechanisms remain unclear. CD31 plays an important part in T cell response and contributes to maintaining T cell tolerance. The immunomodulatory effects of CD31 are also implicated in atherosclerosis. In this study, we found that decreased frequencies of the CD31⁺ subpopulation in T_reg cells (CD31⁺ Tr cells) correlated positively with decreased FoxP3 expression in CHD patients. Cell culture in vitro demonstrated CD31⁺ Tr cells maintaining stable FoxP3 expression after activation and exhibited enhanced proliferation and immunosuppression compared with the CD31^- subpopulation in T_reg cells (CD31^- Tr cells). We also confirmed impaired secretion of transforming growth factor (TGF)-β1 and interleukin (IL)-10 in CD31⁺ Tr cells of CHD patients. Further analysis revealed reduced phospho-SHP2 (associated with CD31 activation) and phospho-signal transducer and activator of transcription-5 (STAT-5) (associated with FoxP3 transcription) levels in CD31⁺ Tr cells of CHD patients, suggesting that decreased FoxP3 expression in CD31⁺ Tr cells might be because of attenuated SHP2 and STAT-5 activation. These data indicate that decreased frequencies and impaired functions of the CD31⁺ Tr subpopulation associated with decreased FoxP3 expression give rise, at least in part, to T_reg cell defects in CHD patients. Our findings emphasize the important role of the CD31⁺ Tr subpopulation in maintaining T_reg cell normal function and may provide a novel explanation for impaired immunoregulation of T_reg cells in CHD.

A Comparative Approach of Tumor-Associated Inflammation in Mammary Cancer between Humans and Dogs

Infiltrating cells of the immune system are widely accepted to be generic constituents of tumor microenvironment. It has been well established that the development of mammary cancer, both in humans and in dogs, is associated with alterations in numbers and functions of immune cells at the sites of tumor progression. These tumor infiltrating immune cells seem to exhibit exclusive phenotypic and functional characteristics and mammary cancer cells can take advantage of signaling molecules released by them. Cancer related inflammation has an important role in mammary carcinogenesis, contributing to the acquisition of core hallmark capabilities that allow cancer cells to survive, proliferate, and disseminate. Indeed, recent studies in human breast cancer and in canine mammary tumors have identified a growing list of signaling molecules released by inflammatory cells that serve as effectors of their tumor-promoting actions. These include the COX-2, the tumor EGF, the angiogenic VEGF, other proangiogenic factors, and a large variety of chemokines and cytokines that amplify the inflammatory state. This review describes the intertwined signaling pathways shared by T-lymphocytic/macrophage infiltrates and important tissue biomarkers in both human and dog mammary carcinogenesis.

Regulatory T cells function at the early stage of tumor progression in a mouse model of tongue squamous cell carcinoma

The objective of this study was to observe the distribution of regulatory T cells (Tregs) in the development of tongue squamous cell carcinoma (SCC) and to determine the role of Tregs in the progression of tongue SCC. A mouse model of 4-nitroquinoline-1-oxide (4NQO)-induced-tongue SCC was established. The expression of Forkhead box P3 (Foxp3), interleukin 10, transforming growth factor-β, chemokine CC motif ligands 17, 20, and CC chemokine receptor 4 was determined using real-time quantitative polymerase chain reaction. Foxp3 expression was also analyzed using immunohistochemistry. The results were compared with those of control mice and of 4NQO-treated mice treated with a cyclooxygenase-2 (COX-2) inhibitor. Well to moderately differentiated tongue SCC was induced in all of the experimental mice. The amount of Tregs of the experimental mice was over 10 times as much as control mice at the early stage of tumor progression. COX-2 inhibitor did not prevent the progression of tongue SCC and did not reduce the total amount of Tregs. Tregs function at the early stage of the development of tongue SCC, and it may be effective to suppress Tregs at the early stage of tumor progression for the treatment and/or prevention of tongue SCC.

CD19+CD24hiCD38hiBregs involved in downregulate helper T cells and upregulate regulatory T cells in gastric cancer

Regulatory B cells (Bregs) play a critical role in inflammation and autoimmune disease. We characterized the role of Bregs in the progression of gastric cancer. We detected an increase in Bregs producing IL-10 both in peripheral blood mononuclear cells (PBMCs) and in gastric tumors. Multicolor flow cytometry analysis revealed that a subset of CD19⁺CD24^hiCD38^hi B cells produces IL-10. Functional studies indicated that increased Bregs do not inhibit the proliferation of CD3⁺T cells or CD4⁺ helper T cells (Th cells). However, Bregs do suppress the secretion of IFN-γ and TNF-α by CD4⁺Th cells. CD19⁺CD24^hiCD38^hiBregs were also found to correlate positively with CD4⁺FoxP3⁺ regulatory T cells (Tregs). Neutralization experiments showed that Bregs convert CD4⁺CD25⁻ effector T cells to CD4⁺FoxP3⁺Tregs via TGF-β1. Collectively, these findings demonstrate that increased Bregs play a immunosuppressive role in gastric cancer by inhibiting T cells cytokines as well as conversion to Tregs. These results may provide new clues about the underlying mechanisms of immune escape in gastric cancer.

Regulatory T Cells in the Tumor Microenvironment and Cancer Progression: Role and Therapeutic Targeting

Recent years have seen significant efforts in understanding and modulating the immune response in cancer. In this context, immunosuppressive cells, including regulatory T cells (Tregs) and myeloid-derived suppressor cells (MDSCs), have come under intense investigation for their proposed roles in suppressing tumor-specific immune responses and establishing an immunosuppressive tumor microenvironment, thus enabling tumor immune evasion. Additionally, recent evidence indicates that Tregs comprise diverse and heterogeneous subsets; phenotypically and functionally distinct subsets of tumor-infiltrating Tregs could contribute differently to cancer prognosis and clinical outcomes. Understanding Treg biology in the setting of cancer, and specifically the tumor microenvironment, is important for designing effective cancer therapies. In this review, we critically examine the role of Tregs in the tumor microenvironment and in cancer progression focusing on human studies. We also discuss the impact of current therapeutic modalities on Treg biology and the therapeutic opportunities for targeting Tregs to enhance anti-tumor immune responses and clinical benefits.

Cyclooxygenase-2 promotes tumor growth and suppresses tumor immunity

Cyclooxygenase-2 (COX-2), an inducible form of the enzyme that catalyzes the first step in the synthesis of prostanoids, is associated with inflammatory diseases and carcinogenesis, which is suspected to promote angiogenesis and tissue invasion of tumors and resistance to apoptosis. Meanwhile, COX-2 contributes to immune evasion and resistance to cancer immunotherapy, which plays a crucial role in the innate and adaptive immune response. The activity of COX-2-PGE2-EP signal pathway can suppress Dendritic cells (DCs), natural killer (NK), T cells, type-1 immunity excluding type-2 immunity which promote tumor immune evasion. COX-2 and the prostaglandin cascade play important roles in the "inflammogenesis of cancer". In addition, COX-inhibitors can inhibit tumor immune evasion. Therefore, we can exert the COX-inhibitors to facilitate the patients to benefit from addition of COX-inhibitors to standard cytotoxic therapy.

[Molecular and pathomorphological prognostic markers for melanoma: Current approaches and prospects]

The incidence of melanoma demonstrates a persistent increasing tendency, which justifies the need to study and identify new prognostic markers for the development and course of this disease. The given paper shows current approaches to melanoma staging, including those to applying pathomorphological prognostic criteria, and discusses prospects for using the results of genomic and epigenomic studies of the carcinoma in clinical practice.

Synergistic effect of HMGB1 knockdown and cordycepin in the K562 human chronic myeloid leukemia cell line

The high-mobility group box 1 (HMGB1) protein is a DNA-binding nuclear protein, which is overexpressed in leukemia cells. Cordycepin is characterized by strong antileukemic properties and is regarded as an effective natural compound for leukemia therapy. The aim of the present study was to investigate the impact of HMGB1 knockdown and cordycepin treatment on proliferation, apoptosis, reactive oxygen species (ROS) levels and adhesion of K562 human chronic myeloid leukemia cells. The Cell Counting kit‑8 assay was used to determine the proliferation of K562 cells. The cell cycle and apoptosis of K562 cells was determined using flow cytometric analysis. In addition, a cell adhesion assay was performed. Western blotting was used to determine the protein expression of cyclooxygenase 2, Bax, receptor for advanced glycation end-products and Bcl‑2. The data collected demonstrated that HMGB1 knockdown combined with cordycepin treatment had significant anti‑proliferative and pro‑apoptotic effects. In addition, it increased the ROS levels and reduced the adhesion of K562 cells. It was also identified that HMGB1 knockdown had synergistic effects with cordycepin, which aided in accelerating apoptosis, and inhibiting proliferation and adhesion in chronic myeloid leukemia cells. These results indicated that HMGB1 may be used as a potential therapeutic target, with cordycepin having potential as an auxiliary drug. Therefore, it is suggested that HMGB1 knockdown and corycepin treatement may present a promising therapeutic strategy for leukemia.

Frequency, suppressive capacity, recruitment and induction mechanisms of regulatory T cells in sinonasal squamous cell carcinoma and nasal inverted papilloma

Background

Sinonasal squamous cell carcinoma (SSCC) and nasal inverted papilloma (NIP) represent the predominant type of malignant and benign tumors in sinonasal tract, respectively. CD4⁺CD25⁺Foxp3⁺ natural regulatory T (Treg) cells might play critical role(s) in the suppression of anti-tumor immune response and thus shed light on tumor progression from benign to malignant.

Objective

This study aimed to evaluate the frequency and suppressive capacity of Treg cells in SSCC compared to NIP and further to explore the underlying mechanisms.

Patients and Methods

Frequencies of Treg, Th1 and Th2 cells were evaluated by flow cytometry in tissue homogenate and peripheral blood from 31 SSCC patients, 32 NIP patients and 35 normal controls. Treg cells were tested for regulatory function by co-culture with effector T cells. CCR4 and its ligands, CCL22 and CCL17, were analyzed by flow cytometry and Luminex, respectively. The chemoattractant properties of CCR4/CCL22 and CCR4/CCL17 for Treg cells were assessed using the Boyden chamber technique, to elucidate the potential mechanisms of Treg recruitment in tumor microenvironment. Treg cells induction via TGF-β was assessed with transwells after local CD4⁺Foxp3⁺ T cells were assessed by immunohistochemistry and TGF-β concentration was measured by Luminex.

Results

Tumor-infiltrating Treg cells increased significantly from normal to NIP to SSCC (P ≤ 0.001 for normal vs. NIP and P = 0.004 for NIP vs. SSCC). Significantly elevated frequency and enhanced suppression capacity of circulating Treg cells in SSCC were detected compared to NIP and healthy controls, concomitant with Th1 decrease and Th2 increase. Apparently increased CCL22 attracted CCR4-expressing Treg cells to tumor microenvironment in SSCC, compared to NIP. SSCC produced significantly more TGF-β than NIP and thus possessed greater potential for Treg cell induction.

Conclusion

Frequency and suppressive capacity of Treg cells enhanced with progression of malignancy from NIP to SSCC. Circulating Treg cells were recruited to tumor tissue via CCR4/CCL22 signalling, whereas tumor-synthesised TGF-β contributed to induction of peripheral Treg cells.

Exosome platform for diagnosis and monitoring of traumatic brain injury

We have previously demonstrated the release of membranous structures by cells into their extracellular environment, which are termed exosomes, microvesicles or extracellular vesicles depending on specific characteristics, including size, composition and biogenesis pathway. With activation, injury, stress, transformation or infection, cells express proteins and RNAs associated with the cellular responses to these events. The exosomes released by these cells can exhibit an array of proteins, lipids and nucleic acids linked to these physiologic events. This review focuses on exosomes associated with traumatic brain injury, which may be both diagnostic and a causative factor in the progression of the injury. Based on current data, exosomes play essential roles as conveyers of intercellular communication and mediators of many of the pathological conditions associated with development, progression and therapeutic failures and cellular stress in a variety of pathologic conditions. These extracellular vesicles express components responsible for angiogenesis promotion, stromal remodelling, signal pathway activation through growth factor/receptor transfer, chemoresistance, immunologic activation and genetic exchange. These circulating exosomes not only represent a central mediator of the pro-inflammatory microenvironment linked with secondary brain injury, but their presence in the peripheral circulation may serve as a surrogate for biopsies, enabling real-time diagnosis and monitoring of neurodegenerative progression.

Epigenetic regulations of inflammatory cyclooxygenase-derived prostanoids: molecular basis and pathophysiological consequences

The potential relevance of prostanoid signaling in immunity and immunological disorders, or disease susceptibility and individual variations in drug responses, is an important area for investigation. The deregulation of Cyclooxygenase- (COX-) derived prostanoids has been reported in several immunoinflammatory disorders such as asthma, rheumatoid arthritis, cancer, and autoimmune diseases. In addition to the environmental factors and the genetic background to diseases, epigenetic mechanisms involved in the fine regulation of prostanoid biosynthesis and/or receptor signaling appeared to be an additional level of complexity in the understanding of prostanoid biology and crucial in controlling the different components of the COX pathways. Epigenetic alterations targeting inflammatory components of prostanoid biosynthesis and signaling pathways may be important in the process of neoplasia, depending on the tissue microenvironment and target genes. Here, we focused on the epigenetic modifications of inflammatory prostanoids in physiological immune response and immunological disorders. We described how major prostanoids and their receptors can be functionally regulated epigenetically and consequently the impact of these processes in the pathogenesis inflammatory diseases and the development of therapeutic approaches that may have important clinical applications.

COX2 regulation of breast cancer bone metastasis

High expression levels of cyclooxygenase 2 expression and infiltration by regulatory T cells (Tregs) are often associated with tumor progression. We have recently reported a prostaglandin E₂ (PGE₂)-dependent recruitment of Tregs to the tumor, suggesting that targeting specific PGE₂ receptors may constitute a valuable approach to ablate the immuno-editing that occurs along with disease progression.

FOXP3+ lymphocyte density in pancreatic cancer correlates with lymph node metastasis

OBJECTIVE

To determine if the density of FOXP3+ lymphocytes in primary tumors and lymph nodes in pancreatic cancer correlates with the presence of lymph node metastases.

METHODS

FOXP3+ lymphocyte density in primary pancreatic cancer tissue and draining lymph nodes was measured using immunohistochemistry. We analyzed the clinical and pathological aspects associated with the accumulation of FOXP3+ lymphocytes in pancreatic cancer. We also analyzed the correlation of density of FOXP3+ lymphocytes in lymph nodes with the nodal status and distance from the primary tumor.

RESULTS

FOXP3+ lymphocyte density in pancreatic cancer was significantly higher than in paratumoral pancreatic tissue. The density of FOXP3+ lymphocytes in local tumor tissue correlated significantly with the histological grade and overall lymph node status. Furthermore, FOXP3+ lymphocyte density was significantly higher in positive lymph nodes than in negative ones, while it had no correlation with the distance of the lymph node from the primary tumor.

CONCLUSION

FOXP3+ lymphocyte density in primary tumor tissue in patients with pancreatic cancer correlates with lymph node metastasis. Lymph nodes containing metastases having higher FOXP3+ lymphocyte densities than do negative lymph nodes.

B7-H1 and B7-H4 expression in colorectal carcinoma: correlation with tumor FOXP3(+) regulatory T-cell infiltration

B7-H1 and B7-H4 are newly discovered members of the B7-CD28 family. They can inhibit T cell activation and proliferation and regulate T cell immune response negatively. Both B7-H1 and B7-H4 are expressed in many tumors and are classified as co-inhibitors of cell-mediated immunity. FOXP3(+) regulatory T cells (Tregs) play an important role in the maintenance of tumor immunity tolerance. However, the implication of B7-H1 and B7-H4 expression and their interaction with Tregs infiltration in colorectal cancer are unknown. The present study aimed to determine the expression of B7-H1 and B7-H4 as well as Tregs infiltration in colorectal cancer and to explore the clinical and pathological implication of suppressor immune cells and molecules. Frozen sections and immunohistochemical assay were undertaken to assess B7-H1, B7-H4 expression and Tregs infiltration in fresh specimens collected from 56 patients with colorectal carcinoma. The results showed that expression of B7-H1 and B7-H4 in colorectal carcinoma tissues was significantly higher than in adjacent normal mucosa (P<0.001). B7-H1 expression was positively correlated to the infiltration depth, lymph node metastasis and advanced Duke's stage (P<0.05, P<0.05 and P<0.05, respectively), whereas B7-H4 expression was positively related to the infiltration depth and lymph node metastasis (P<0.01 and P<0.05, respectively). Furthermore, Tregs infiltration was more frequent in tumor tissue than in adjacent normal mucosa and was associated with poor differentiation and positive lymph node metastasis (P<0.01, and P<0.01, respectively). The statistical analysis indicated a significant correlation between Tregs infiltration and B7-H1 or B7-H4 expression respectively. These results suggest that over-expression of B7-H1 and B7-H4 has stronger prognostic significance and promote tumor tolerance, and they might contribute to Tregs development in the colorectal carcinoma tolerogenic milieu.

Level of circulating PD-L1 expression in patients with advanced gastric cancer and its clinical implications

OBJECTIVE

The programmed cell death-1 receptor/programmed cell death-1 ligand (PD-1/PD-L1) pathway plays a crucial role in tumor evasion from host immunity. This study was designed to evaluate the association between circulating PD-L1 expression and prognosis in patients with advanced gastric cancer.

METHODS

Totally 80 advanced gastric cancer patients and 40 health controls from Beijing Cancer Hospital were enrolled in the present study. Circulating PD-L1 expression was tested by enzyme-linked immunosorbent assay (ELISA). The associations between the expression level of PD-L1 and clinicopathological features and prognosis were analyzed statistically.

RESULTS

Expression of PD-L1 in advanced gastric cancer patients was significantly up-regulated compared with health people (P=0.006). The expression of PD-L1 was significantly correlated with differentiation and lymph node metastasis (P=0.026 and P=0.041, respectively). Although we didn't find significant difference in all advanced gastric cancer patients with different PD-L1 expression, the adenocarcinoma patients with higher up-regulated PD-L1 expression had much better prognosis than low expression patients (65.6% vs. 44.7%, P=0.028).

CONCLUSIONS

PD-L1 was elevated in advance gastric cancer patients and may play an important role in tumor immune evasion and patients prognosis.

High FoxP3 expression in tumour cells predicts better survival in gastric cancer and its role in tumour microenvironment

BACKGROUND

Forkhead Box P3 (FoxP3) is thought to be a key transcription factor in regulatory T cells (Tregs), and recent data indicate that it is expressed in several tumour cells. However, its precise roles in gastric cancer (GC) and the underlying mechanisms regulating the interaction between GC cells and lymphocytes remain unclear.

METHODS

FoxP3 expression was examined in tumour cells and Tregs in 150 cases of gastric precancer and cancer, and their prognostic significances were evaluated, respectively, using a tissue microarray containing 135 GC patient samples with a mean 102-month follow-up. FoxP3 involvement in the tumour cells-lymphocytes interaction and its gene function were further investigated.

RESULTS

strong cytoplasmic staining of FoxP3 was observed in GC cells. FoxP3 protein expression in tumour cells predicts a good prognosis, whereas high-density Treg predicts a poor prognosis. Moreover, FoxP3 expression in GC cells increased after coculture with peripheral blood mononuclear cells through coculture systems. Upregulation of FoxP3 inhibited tumour growth in tumour-bearing nude mice.

CONCLUSIONS

High FoxP3 expression in tumour cells predicts better survival in GC, possibility in relation to interaction between tumour cells and lymphocytes in microenvironment. Interfering with FoxP3 expression may open a new therapeutic strategy against tumour progression.

Critical role of spatial interaction between CD8⁺ and Foxp3⁺ cells in human gastric cancer: the distance matters

PURPOSE

In various cancer types, an abundance of FoxP3(+) regulatory T cells (Treg) has been associated with an unfavorable outcome. Yet, the role of Treg on cancer immunity has been shown to be complex. In single cell marker technique, other tumor-infiltrating lymphocytes (TILs) such as cytotoxic CD8(+) T cells (CTL) also influenced prognosis. This study for the first time investigates the concurrent spatial distribution pattern of CD8(+) and FoxP3(+) TILs and their prognostic impact in human gastric cancer.

MATERIALS AND METHODS

Tumor tissue microarrays of 50 patients with surgically treated adenocarcinoma of the cardia were studied. An immunohistochemical double staining of CD8(+) and FoxP3(+) TILs was performed. Cell counts and cell-to-cell distances in tumor epithelium and stroma were evaluated with image-processing software. Metastasis-free survival, no-evidence-of-disease survival, and overall survival were investigated (mean follow-up time 6.9 years).

RESULTS

High intraepithelial infiltration of CD8(+) and FoxP3(+) TIL was associated with the improved 10-year metastasis-free survival (83 vs. 54%, p = 0.04 and 85 vs. 59%, p = 0.09, respectively). Considering cell-to-cell distance and comparing patients with functional (30-110 μm) versus nonfunctional distances of CD8(+) and FoxP3(+) TILs, 10-year survival rates differed between 89 and 55% (p = 0.009), respectively.

CONCLUSION

Prognostic influence of tumor-infiltrating immune cells in gastric cancer critically depends on their cell-to-cell distance. FoxP3(+) TILs must be located within a distance between 30 and 110 μm of CD8(+) T cells to positively impact on prognosis.

The molecular basis for the pharmacokinetics and pharmacodynamics of curcumin and its metabolites in relation to cancer

This review addresses the oncopharmacological properties of curcumin at the molecular level. First, the interactions between curcumin and its molecular targets are addressed on the basis of curcumin's distinct chemical properties, which include H-bond donating and accepting capacity of the β-dicarbonyl moiety and the phenylic hydroxyl groups, H-bond accepting capacity of the methoxy ethers, multivalent metal and nonmetal cation binding properties, high partition coefficient, rotamerization around multiple C-C bonds, and the ability to act as a Michael acceptor. Next, the in vitro chemical stability of curcumin is elaborated in the context of its susceptibility to photochemical and chemical modification and degradation (e.g., alkaline hydrolysis). Specific modification and degradatory pathways are provided, which mainly entail radical-based intermediates, and the in vitro catabolites are identified. The implications of curcumin's (photo)chemical instability are addressed in light of pharmaceutical curcumin preparations, the use of curcumin analogues, and implementation of nanoparticulate drug delivery systems. Furthermore, the pharmacokinetics of curcumin and its most important degradation products are detailed in light of curcumin's poor bioavailability. Particular emphasis is placed on xenobiotic phase I and II metabolism as well as excretion of curcumin in the intestines (first pass), the liver (second pass), and other organs in addition to the pharmacokinetics of curcumin metabolites and their systemic clearance. Lastly, a summary is provided of the clinical pharmacodynamics of curcumin followed by a detailed account of curcumin's direct molecular targets, whereby the phenotypical/biological changes induced in cancer cells upon completion of the curcumin-triggered signaling cascade(s) are addressed in the framework of the hallmarks of cancer. The direct molecular targets include the ErbB family of receptors, protein kinase C, enzymes involved in prostaglandin synthesis, vitamin D receptor, and DNA.

Role of cyclooxygenase-2 in gastric cancer development and progression

Although the incidence of gastric cancer has been declining in recent decades, it remains a major public health issue as the second leading cause of cancer death worldwide. In China, gastric cancer is still the main cause of death in patients with malignant tumors. Most patients are diagnosed at an advanced stage and mortality is high. Cyclooxygenase-2 (COX-2) is a rate-limiting enzyme in prostanoid synthesis and plays an important role in the development and progression of gastric cancer. The expression of COX-2 in gastric cancer is upregulated and its molecular mechanisms have been investigated. Helicobacter pylori infection, tumor suppressor gene mutation and the activation of nuclear factor-kappa B may be responsible for the elevated expression of COX-2 in gastric cancer. The mechanisms of COX-2 in the development and progression of gastric cancer are probably through promoting the proliferation of gastric cancer cells, while inhibiting apoptosis, assisting angiogenesis and lymphatic metastasis, and participating in cancer invasion and immunosuppression. This review is intended to discuss, comment and summarize recent research progress on the role of COX-2 in gastric cancer development and progression, and elucidate the molecular mechanisms which might be involved in the carcinogenesis.

Expression of CTLA-4 and Foxp3 in peripheral blood T cells of patients with squamous cell laryngeal carcinoma

Cytotoxic T lymphocyte-associated antigen 4 (CTLA-4, CD152) and Foxp3 (forkhead box P3) are receptors present on T cells which play a critical role in the down-regulation of antigen-activated immune responses. To evaluate the potential influences of CTLA-4 and Foxp3 on cancer invasiveness, a case-control study was conducted in 86 patients treated for squamous cell laryngeal carcinoma. The abundance of CTLA-4 and Foxp3 gene transcripts in the purified peripheral blood mononuclear cells (PBMCs) by quantitative real-time PCR (qRT-PCR) was determined. The analysis of proteins by Western blot was performed. The relationships between CTLA-4 and Foxp3 gene and protein expression as well as the aggressiveness of tumor determined on pT, type and depth of invasion were investigated. Our work revealed a significant dependence of mRNA CTLA-4 on tumor front grading (TFG) total score (p = 0.04) as well as CTLA-4 protein expression on pT (p = = 0.03) and type of invasion (p = 0.03). Advanced pT3-pT4 tumors with diffuse infiltration and > 14 TFG points were characterized by higher average values of CTLA-4 protein in PBMCs. Our data also demonstrated significant differences between Foxp3 protein levels in relation to pT (p = 0.04), depth of invasion (p = = 0.02) and type of invasion (p = 0.03). In tumors with the highest invasiveness identified by the pT3-pT4 status, deep invasion with involvement of cartilage and diffuse infiltration, the highest Foxp3 protein level was observed. In conclusion, these results suggest an impact of CTLA-4 and Foxp3 in determining proliferative and aggressive potential of laryngeal carcinoma, highlighting the significance of CTLA-4 and Foxp3 as potential predictive indicators.

Activation of TLR4 signaling promotes gastric cancer progression by inducing mitochondrial ROS production

Chronic infection, such as Helicobacter pylori infection, has been associated with the development of gastric cancer (GC). Pathogen-associated molecular patterns can trigger inflammatory responses via Toll-like receptors (TLRs) in GC. Here we showed that Toll-like receptor 4 (TLR4) was highly expressed in GC cells and was associated with the aggressiveness of GC. The binding of lipopolysaccharide (LPS) to TLR4 on GC cells enhanced proliferation without affecting apoptosis. Higher level of reactive oxygen species (ROS) was induced after activation of TLR4 signaling in GC. Using oxidase inhibitors and antioxidants, we found that mitochondrial ROS (mROS) was major source of TLR4-stimulated ROS generation. This elevated mROS production can be inhibited by diphenylene iodonium (DPI), and the blocking of the mROS production rather than ROS neutralization resulted in cell cycle arrest and the loss of mitochondrial potential, which were plausible reason for decreased cell viability. Furthermore, the increased mROS owing to TLR4 signaling resulted in the activation of Akt phosphorylation and NF-κB p65 nuclear translocation. Altogether, these results reveal a novel pathway linking innate immune signaling to GC cell proliferation, implicate mROS as an important component of cell survival signals and further establish mitochondria as hubs for GC therapies.

Imbalanced frequencies of Th17 and Treg cells in acute coronary syndromes are mediated by IL-6-STAT3 signaling

Aims

Extensive evidence suggests inflammatory components participate in the pathogenic processes of acute coronary syndromes (ACS). In this study, we aimed to elucidate the role and mechanism underlying the imbalance of Th17 and Treg cell peripheral populations in the pathogenesis of ACS.

Methods and Results

Using a flow cytometric analysis, we observed a significantly increased frequency of Th17 cells and a concurrently decreased CD4⁺CD25⁺Foxp3⁺ Treg cells in patients with ACS. To elucidate the mechanism of Th17/Treg imbalance in ACS, 22 inflammatory cytokines were measured using multiplexed immunobead-based assays. Of six elevated cytokines in ACS patients, only IL-6 was positively correlated with a higher Th17 cell level (r = 0.39, P<0.01). Relying on IL-6 stimulating and neutralizing studies, we demonstrated a direct role for IL-6 in sera from ACS patients with an increased frequency of Th17 cells. IL-6 induces the differentiation of Th17 cells from naïve CD4⁺ T cells through STAT3 activation and RORγt induction. However, we observed that high levels of TGF-β1 inhibited IL-6-dependent Th17 cell differentiation, indicating a complex interplay between the two cytokines in the control of Th17 and Treg cell populations.

Conclusions

Our results demonstrate the role of IL-6-STAT3 signaling in ACS through increased Th17 cell differentiation. These findings indicate that IL-6 neutralizing strategies could present novel therapeutic avenues in the treatment of ACS.

Regulatory T cells and plasmacytoid dendritic cells contribute to the immune escape of papillary thyroid cancer coexisting with multinodular non-toxic goiter

Immunosuppressive lymphocytes, such as regulatory T cells (Tregs) and plasmacytoid dendritic cells (pDCs), play crucial roles in tumor escape. To investigate the roles of Tregs and pDCs in papillary thyroid cancer (PTC) plus multinodular non-toxic goiter (MNG), thyroid tissue and blood samples from 30 patients with PTC plus MNG and 30 MNG alone were analyzed for CD4(+) T cell, CD8(+) T cell, FoxP3(+) Treg, ICOS(+)FoxP3(+) Treg, and pDC numbers by immunohistochemistry (IHC), immunofluorescence, and flow cytometry. Plasma concentration of the cytokines interleukin 10 (IL-10) and transforming growth factor β (TGF-β) were measured by enzyme-linked immunosorbent assay as well. Both in thyroid tissue and peripheral blood, the numbers of Foxp3(+) Treg were significantly higher in patients with PTC plus MNG compared to patients with MNG alone; and as a prognostic marker, ICOS(+)Foxp3(+) Tregs represent a stronger predictor of disease progression than the total numbers of Foxp3(+) Tregs. Furthermore, a positive correlation between pDC and ICOS(+)Foxp3(+) Treg numbers in tissue of patients with PTC plus MNG was observed, suggesting that PTC-derived pDCs may induce the differentiation of naive CD4(+) T cells into ICOS(+)Foxp3(+)Tregs. This may be one of the mechanisms underlying tumor escape in PTC plus MNG patients. Our results suggest that Tregs and pDCs together contribute to the tumor escape in patients with PTC plus MNG.

The origin, function, and diagnostic potential of RNA within extracellular vesicles present in human biological fluids

We have previously demonstrated that tumor cells release membranous structures into their extracellular environment, which are termed exosomes, microvesicles or extracellular vesicles depending on specific characteristics, including size, composition and biogenesis pathway. These cell-derived vesicles can exhibit an array of proteins, lipids and nucleic acids derived from the originating tumor. This review focuses of the transcriptome (RNA) of these extracellular vesicles. Based on current data, these vesicular components play essential roles as conveyers of intercellular communication and mediators of many of the pathological conditions associated with cancer development, progression and therapeutic failures. These extracellular vesicles express components responsible for angiogenesis promotion, stromal remodeling, signal pathway activation through growth factor/receptor transfer, chemoresistance, and genetic exchange. These tumor-derived extracellular vesicles not only to represent a central mediator of the tumor microenvironment, but their presence in the peripheral circulation may serve as a surrogate for tumor biopsies, enabling real-time diagnosis and disease monitoring.

Regulatory T cells in cancer: an overview and perspectives on cyclooxygenase-2 and Foxp3 DNA methylation

Epigenetics has been gaining great attention as a therapeutic target in cancer. The cancer genome usually contains both hyper- and hypo-methylated genes to increase invasion, proliferation and metastasis. These cells not only operate their own growth, but also develop various strategies to escape from immune surveillance, and for this aim, regulatory T (Treg) cells support the cancer-mediated immune suppression. The fate of Treg cells is mainly controlled by DNA methylation within the promoter and intronic regions of Foxp3 gene. Foxp3 transcription factor is involved in the development, differentiation and function of Treg cells. COX-2 is also an epigenetically controlled gene in these processes. This enzyme and its product PGE2 plays essential roles in Treg functionality in cancer. Here, we discuss the effects of DNA methylation on cancer and nTreg cells. We also summarize the mechanisms related with COX-2/PGE2 and Foxp3 on inhibitory function of Treg cells in cancer.

Intratumor hypoxia promotes immune tolerance by inducing regulatory T cells via TGF-β1 in gastric cancer

Regulatory T cell (Treg)-mediated immunosuppression represents one of the crucial tumor immune evasion mechanisms and is a main obstacle for successful tumor immunotherapy. Hypoxia, a common feature of solid tumors, has been associated with potentiated immunosuppression, decreased therapeutic response, malignant progression and local invasion. Unfortunately, the link between hypoxia and Treg-mediated immune tolerance in gastric cancer remains poorly understood. In our study, Tregs and hypoxia inducible factor-1α were found to be positively correlated with each other and were increased with the tumor progression. A subsequent in vitro study indicated that supernatants derived from gastric cancer cells under hypoxic condition, could induce the expression of Foxp3 via TGF-β1. These findings confirmed the crucial role of Tregs as a therapeutic target in gastric cancer therapy and provided helpful thoughts for the design of immunotherapy for gastric cancer in the future.

Role of nuclear receptor NR4A2 in gastrointestinal inflammation and cancers

NR4A2 is a transcription factor belonging to the steroid orphan nuclear receptor superfamily. It was originally considered to be essential in the generation and maintenance of dopaminergic neurons, and associated with neurological disorders such as Parkinson’s disease. Recently, NR4A2 has been found to play a critical role in some inflammatory diseases and cancer. NR4A2 can be efficiently trans-activated by some proinflammatory cytokines, such as tumor necrosis factor-α, interleukin-1β, and vascular endothelial growth factor (VEGF). The nuclear factor-κB signaling pathway serves as a principal regulator of inducible NR4A expression in immune cells. NR4A2 can trans-activate Foxp3, a hallmark specifically expressed in regulatory T (Treg) cells, and plays a critical role in the differentiation, maintenance, and function of Treg cells. NR4A2 in T lymphocytes is pivotal for Treg cell induction and suppression of aberrant induction of Th1 under physiological and pathological conditions. High density of Foxp3⁺ Treg cells is significantly associated with gastrointestinal inflammation, tumor immune escape, and disease progression. NR4A2 is produced at high levels in CD133⁺ colorectal carcinoma (CRC) cells and significantly upregulated by cyclooxygenase-2-derived prostaglandin E₂ in a cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA)-dependent manner in CRC cells. The cAMP/PKA signaling pathway is the common pathway of NR4A2-related inflammation and cancer. NR4A2 trans-activates osteopontin, a direct target of the Wnt/β-catenin pathway associated with CRC invasion, metastasis, and poor prognosis. Knockdown of endogenous NR4A2 expression attenuates VEGF-induced endothelial cell proliferation, migration and in vivo angiogenesis. Taken together, NR4A2 emerges as an important nuclear factor linking gastrointestinal inflammation and cancer, especially CRC, and should serve as a candidate therapeutic target for inflammation-related gastrointestinal cancer.

FoxP3 inhibits proliferation and induces apoptosis of gastric cancer cells by activating the apoptotic signaling pathway

Forkhead Box Protein 3 (FoxP3) was identified as a key transcription factor to the occurring and function of the regulatory T cells (Tregs). However, limited evidence indicated its function in tumor cells. To elucidate the precise roles and underlying molecular mechanism of FoxP3 in gastric cancer (GC), we examined the expression of FoxP3 and the consequences of interfering with FoxP3 gene in human GC cell lines, AGS and MKN45, by multiple cellular and molecular approaches, such as immunofluorescence, gene transfection, CCK-8 assay, clone formation assay, TUNEL assay, Flow cytometry, immunoassay and quantities polymerase chain reaction (PCR). As a result, FoxP3 was expressed both in nucleus and cytoplasm of GC cells. Up-regulation of FoxP3 inhibited cell proliferation and promoted cell apoptosis. Overexpression of FoxP3 increased the protein and mRNA levels of proapoptotic molecules, such as poly ADP-ribose polymerase1 (PARP), caspase-3 and caspase-9, and repressed the expression of antiapoptotic molecules, such as cellular inhibitor of apoptosis-1 (c-IAP1) and the long isoform of B cell leukemia/lymphoma-2 (Bcl-2). Furthermore, silencing of FoxP3 by siRNA in GC cells reduced the expression of proapoptotic genes, such as PARP, caspase-3 and caspase-9. Collectively, our findings identify the novel roles of FoxP3 in inhibiting proliferation and inducing apoptosis in GC cells by regulating apoptotic signaling, which could be a promising therapeutic approach for gastric cancer.

Increased tumor-infiltrating CD8(+)Foxp3(+) T lymphocytes are associated with tumor progression in human gastric cancer

BACKGROUND

CD8(+)Foxp3(+) T lymphocytes have been detected in tumors. However, the distribution, phenotypic features, and regulation of these cells in gastric cancer remain unknown.

METHODS

The levels of CD8(+)Foxp3(+) T lymphocytes in the peripheral blood, tumor-draining lymph nodes, non-tumor tissues, and tumor tissues of patients with gastric cancer were detected by flow cytometry. Foxp3 induction in CD8(+)Foxp3(-) T cells was investigated in vitro. The suppressive function of CD8(+)Foxp3(+) T lymphocytes was analyzed by their effect on CD4(+) T-cell proliferation and IFN-γ production. The percentages of CD8(+)Foxp3(+) T lymphocytes were evaluated for the association with tumor stage.

RESULTS

The frequency of CD8(+)Foxp3(+) T lymphocytes in tumor tissues was significantly higher than that in non-tumor tissues, and similar results were also observed in tumor-draining lymph nodes compared with peripheral blood. Most intratumoral CD8(+)Foxp3(+) T lymphocytes were activated effector cells (CD45RA(-)CD27(-)). TGF-β1 levels were positively correlated with the frequency of CD8(+)Foxp3(+) T lymphocytes in tumor tissues, and in vitro TGF-β1 could induce the generation of CD8(+)Foxp3(+) T lymphocytes in a dose-dependent manner. Furthermore, intratumoral CD8(+)Foxp3(+) T lymphocytes suppressed the proliferation and IFN-γ production of CD4(+) T cells. Finally, intratumoral CD8(+)Foxp3(+) T lymphocytes were significantly increased with tumor progression in terms of tumor-node-metastasis (TNM) stage.

CONCLUSIONS

Our data have shown that increased intratumoral CD8(+)Foxp3(+) T lymphocytes are associated with tumor stage and potentially influence CD4(+) T-cell functions, which may provide insights for developing novel immunotherapy protocols against gastric cancer.