Accumulation Mechanisms of CD4(+)CD25(+)FOXP3(+) Regulatory T Cells in EBV-associated Gastric Carcinoma

Long-term survival analysis after radical gastrectomy for Epstein-Barr virus-associated gastric cancer: A multicenter study

BACKGROUND

The prognosis of Epstein-Barr virus-associated gastric cancer (EBVaGC)needs to be validated by high-quality studies. This study aimed to assess the long-term survival of EBVaGC patients after radical gastrectomy using multicenter data to explore the potential value of EBV infection status as a prognostic predictor.

METHODS

We analyzed the clinical data of patients with EBVaGC and Epstein-Barr virus-negative gastric cancer (EBVnGC) who underwent radical gastrectomy from January 2013 to July 2020. The Kaplan-Meier method and Cox regression analysis were used to evaluate overall survival (OS) and disease-free survival (DFS). A Random Survival Forest (RSF) model was constructed to predict the prognosis.

RESULTS

After propensity score matching, 205 and 410 patients were included in the EBVaGC and EBVnGC groups, respectively. The 3-year OS and DFS rates in the EBVaGC group were significantly higher than those in the EBVnGC group. Multivariate analysis indicated that EBER(Epstein-Barr virus-encoded small RNA) positivity was an independent protective factor for OS and DFS. Among stage II and III EBVaGC patients, those receiving ≥4 cycles of chemotherapy had a 3-year OS significantly better than those receiving <4 cycles. The RSF model based on EBER status outperformed the Cox model and TNM staging system in predicting the 3-year OS and DFS.

CONCLUSION

The prognostic prediction model established based on the EBER status has good clinical application value and can provide a new reference for clinical follow-up management. It is recommended that patients with stage II and III EBVaGC receive at least four cycles of chemotherapy postoperatively to improve survival.

T lymphocyte‑related immune response and immunotherapy in gastric cancer (Review)

Gastric cancer (GC) remains a global healthcare challenge because of its high incidence and poor prognosis. The efficacy of current chemotherapy regimens for advanced GC is limited. T cells, which have been implicated in the progression of GC, have a significant impact in the tumor microenvironment. With a more detailed understanding of the mechanisms underlying the cancer immunoediting process, immunotherapy may become a promising treatment option for patients with GC. Several clinical trials are currently investigating different mechanisms targeting the tumor immune response. The present review summarized T cell-involved immune responses and various immunotherapy strategies for GC.

SATB1, senescence and senescence-related diseases

Aging leads to an accumulation of cellular mutations and damage, increasing the risk of senescence, apoptosis, and malignant transformation. Cellular senescence, which is pivotal in aging, acts as both a guard against cellular transformation and as a check against cancer progression. It is marked by stable cell cycle arrest, widespread macromolecular changes, a pro-inflammatory profile, and altered gene expression. However, it remains to be determined whether these differing subsets of senescent cells result from unique intrinsic programs or are influenced by their environmental contexts. Multiple transcription regulators and chromatin modifiers contribute to these alterations. Special AT-rich sequence-binding protein 1 (SATB1) stands out as a crucial regulator in this process, orchestrating gene expression by structuring chromatin into loop domains and anchoring DNA elements. This review provides an overview of cellular senescence and delves into the role of SATB1 in senescence-related diseases. It highlights SATB1's potential in developing antiaging and anticancer strategies, potentially contributing to improved quality of life and addressing aging-related diseases.

Single-cell RNA sequencing reveals the immune microenvironment landscape of osteosarcoma before and after chemotherapy

Chemotherapy, a primary treatment for osteosarcoma (OS), has limited knowledge regarding its impact on tumor immune microenvironment (TIME). Here, tissues from 6 chemotherapy-naive OS patients underwent single-cell RNA sequencing (scRNA-seq) and were analyzed alongside public dataset (GSE152048) containing 7 post-chemotherapy OS tissues. CD45+ (PTPRC+) cells were used for cell clustering and annotation. Changes in immune cell composition pre- and post-chemotherapy were characterized. Totally, 28,636 high-quality CD45+ (PTPRC+) cells were extracted. Following chemotherapy, the proportions of regulatory T cells (Tregs) and activated CD8 T cells decreased, while CD8 effector T cells increased. GO analysis indicated that differentially expressed genes (DEGs) in T cells were associated with cell activation, adaptive immune response, and immune response to tumor cells. Furthermore, the proportions of plasma cells increased, while naive B cells decreased. B cell surface receptors expression was upregulated, and GO analysis revealed DEGs of B cells were mainly enriched in B cell-mediated immunity and B cell activation. Moreover, M2 polarization of macrophages was suppressed post-chemotherapy. Overall, this study elucidates chemotherapy remodels the OS TIME landscape, triggering immune heterogeneity and enhancing anti-tumor properties.

Endoscopic Diagnosis and Therapy for Epstein-Barr Virus-Associated Gastric Cancer

Epstein-Barr-virus-associated gastric cancer (EBVaGC) represents almost 7% of all GC and is a distinct subtype of GC with extreme DNA hypermethylation. EBVaGC is a tumor-infiltrating lymphocyte-rich tumor with little lymph-node metastasis in its early stage and with a relatively favorable prognosis in its advanced stage. Using upper gastrointestinal endoscopy, we recognize EBVaGC as a mainly depressed type with SMT-like protrusion in the upper part of the stomach near the gastric mucosal atrophic border or remnant stomach. The EBVaGC recognition rate of 21.4% with the endoscopic motif is not high, and further progress in endoscopic diagnosis of EBVaGC is needed. As less invasive endoscopic therapy, the extension of the criteria of endoscopic submucosal dissection (ESD) for early EBVaGC with little lymph-node metastasis should be discussed. Endoscopic diagnosis of EBVaGC may be relevant for the selection of patients who could benefit from endoscopic treatment or chemotherapy.

Pathogenesis and therapeutic implications of EBV-associated epithelial cancers

Epstein-Barr virus (EBV), one of the most common human viruses, has been associated with both lymphoid and epithelial cancers. Undifferentiated nasopharyngeal carcinoma (NPC), EBV associated gastric cancer (EBVaGC) and lymphoepithelioma-like carcinoma (LELC) are amongst the few common epithelial cancers that EBV has been associated with. The pathogenesis of EBV-associated NPC has been well described, however, the same cannot be said for primary pulmonary LELC (PPLELC) owing to the rarity of the cancer. In this review, we outline the pathogenesis of EBV-associated NPC and EBVaGCs and their recent advances. By drawing on similarities between NPC and PPLELC, we then also postulated the pathogenesis of PPLELC. A deeper understanding about the pathogenesis of EBV enables us to postulate the pathogenesis of other EBV associated cancers such as PPLELC.

Follicular Helper and Regulatory T Cells Drive the Development of Spontaneous Epstein-Barr Virus Lymphoproliferative Disorder

Epstein-Barr virus (EBV) is a ubiquitous herpes virus associated with various cancers. EBV establishes latency with life-long persistence in memory B-cells and can reactivate lytic infection placing immunocompromised individuals at risk for EBV-driven lymphoproliferative disorders (EBV-LPD). Despite the ubiquity of EBV, only a small percentage of immunocompromised patients (~20%) develop EBV-LPD. Engraftment of immunodeficient mice with peripheral blood mononuclear cells (PBMCs) from healthy EBV-seropositive donors leads to spontaneous, malignant, human B-cell EBV-LPD. Only about 20% of EBV+ donors induce EBV-LPD in 100% of engrafted mice (High-Incidence, HI), while another 20% of donors never generate EBV-LPD (No-Incidence, NI). Here, we report HI donors to have significantly higher basal T follicular helper (Tfh) and regulatory T-cells (Treg), and depletion of these subsets prevents/delays EBV-LPD. Transcriptomic analysis of CD4+ T cells from ex vivo HI donor PBMC revealed amplified cytokine and inflammatory gene signatures. HI vs. NI donors showed a marked reduction in IFNγ production to EBV latent and lytic antigen stimulation. In addition, we observed abundant myeloid-derived suppressor cells in HI donor PBMC that decreased CTL proliferation in co-cultures with autologous EBV+ lymphoblasts. Our findings identify potential biomarkers that may identify individuals at risk for EBV-LPD and suggest possible strategies for prevention.

Tumor-Infiltrating T Cells in EBV-Associated Gastric Carcinomas Exhibit High Levels of Multiple Markers of Activation, Effector Gene Expression, and Exhaustion

Epstein-Barr virus (EBV) is a gamma-herpesvirus associated with 10% of all gastric cancers (GCs) and 1.5% of all human cancers. EBV-associated GCs (EBVaGCs) are pathologically and clinically distinct entities from EBV-negative GCs (EBVnGCs), with EBVaGCs exhibiting differential molecular pathology, treatment response, and patient prognosis. However, the tumor immune landscape of EBVaGC has not been well explored. In this study, a systemic and comprehensive analysis of gene expression and immune landscape features was performed for both EBVaGC and EBVnGC. EBVaGCs exhibited many aspects of a T cell-inflamed phenotype, with greater T and NK cell infiltration, increased expression of immune checkpoint markers (BTLA, CD96, CTLA4, LAG3, PD1, TIGIT, and TIM3), and multiple T cell effector molecules in comparison with EBVnGCs. EBVaGCs also displayed a higher expression of anti-tumor immunity factors (PDL1, CD155, CEACAM1, galectin-9, and IDO1). Six EBV-encoded miRNAs (miR-BARTs 8-3p, 9-5p, 10-3p, 22, 5-5p, and 14-3p) were strongly negatively correlated with the expression of immune checkpoint receptors and multiple markers of anti-tumor immunity. These profound differences in the tumor immune landscape between EBVaGCs and EBVnGCs may help explain some of the observed differences in pathological and clinical outcomes, with an EBV-positive status possibly being a potential biomarker for the application of immunotherapy in GC.

Identifying the key genes of Epstein-Barr virus-regulated tumour immune microenvironment of gastric carcinomas

The Epstein-Barr virus (EBV) is involved in the carcinogenesis of gastric cancer (GC) upon infection of normal cell and induces a highly variable composition of the tumour microenvironment (TME). However, systematic bioinformatics analysis of key genes associated with EBV regulation of immune infiltration is still lacking. In the present study, the TCGA and GEO databases were recruited to analyse the association between EBV infection and the profile of immune infiltration in GC. The weighted gene co-expression analysis (WGCNA) was applied to shed light on the key gene modules associated with EBV-associated immune infiltration in GC. 204 GC tissues were used to analysed the expression of key hub genes by using the immunohistochemical method. Real-time PCR was used to evaluate the association between the expression of EBV latent/lytic genes and key immune infiltration genes. Our results suggested that EBV infection changed the TME of GC mainly regulates the TIICs. The top three hub genes of blue (GBP1, IRF1, and LAP3) and brown (BIN2, ITGAL, and LILRB1) modules as representative genes were associated with EBV infection and GC immune infiltration. Furthermore, EBV-encoded LMP1 expression is account for the overexpression of GBP1 and IRF1. EBV infection significantly changes the TME of GC, and the activation of key immune genes was more dependent on the invasiveness of the whole EBV virion instead of single EBV latent/lytic gene expression.

Presence of regulatory T-cells in endometrial cancer predicts poorer overall survival and promotes progression of tumor cells

PURPOSE

Endometrial cancer (EC) is one of the most common gynaecologic malignancies. Tumor infiltrating regulatory T-cells (Treg) have been reported to have a prognostic impact in many malignancies. Immunotherapeutic strategies are gaining interest for advanced and recurrent EC cases, where treatment options are rare. Our study was aimed at determining the value of Treg in EC progression.

METHODS

EC specimens from 275 patients and 28 controls were screened immunohistochemically for the presence of Treg represented by FoxP3. Correlations with clinicopathological and survival parameters were performed. Functional assays were performed using EC cell lines Ishikawa + and RL95-2 after co-culturing with isolated CD4 + CD25 + CD127dim Treg. To assess the influence of EC on the composition of peripheral blood mononuclear cells (PBMC), flow cytometric analyses were performed.

RESULTS

We found that an increased infiltration of Treg was associated with high grades and a reduced overall survival. Treg were almost absent in endometrium tissues from healthy control patients. Co-culture of tumor cells with CD4 + CD25 + CD127dim Treg led to functional changes: enhanced invasion, migration and viability indicated that increased levels of Treg in the tumor microenvironment may promote tumor growth. Furthermore, we found that the presence of EC cells led to phenotypic changes in PBMC, showing significantly increased levels of CD25 and FoxP3.

CONCLUSION

Our results indicate that the presence of Treg in the EC tumor environment is associated with a poorer outcome. A remarkable impact of Treg on tumor cell behaviour and vice versa of tumor cells on PBMC subpopulations support this notion mechanistically. Our findings provide a basis for focusing on Treg as potential future therapeutic targets in EC.

Immunosuppressive Tumor Microenvironment and Immunotherapy of Epstein–Barr Virus-Associated Malignancies

The Epstein–Barr virus (EBV) can cause different types of cancer in human beings when the virus infects different cell types with various latent patterns. EBV shapes a distinct and immunosuppressive tumor microenvironment (TME) to its benefit by influencing and interacting with different components in the TME. Different EBV-associated malignancies adopt similar but slightly specific immunosuppressive mechanisms by encoding different EBV products to escape both innate and adaptive immune responses. Strategies reversing the immunosuppressive TME of EBV-associated malignancies have been under evaluation in clinical practice. As the interactions among EBV, tumor cells, and TME are intricate, in this review, we mainly discuss the epidemiology of EBV, the life cycle of EBV, the cellular and molecular composition of TME, and a landscape of different EBV-associated malignancies and immunotherapy by targeting the TME.

Immunohistochemical Expression of Regulatory T Cells (CD4 + CD25 + bright FOXP3 + ) in Pemphigus patients

BACKGROUND

Pemphigus is a series of autoimmune skin disorders caused by IgG. Regulatory T cells (Tregs) are a subset of CD4+ T cells that mostly block pathogenic immune responses mediated by self-reactive cells, therefore a lack of Tregs or a malfunction in their activity could lead to a loss of tolerance and the development of autoimmunity. .

AIMS

to evaluate the expression of lesional and perilesional Treg markers (CD4+ CD25+ bright FOXP3+) in pemphigus patients.

PATIENTS AND METHODS

Twenty three pemphigus patients and 20 healthy controls were included in this study. The expression of CD4, CD25 and Foxp3 were evaluated by immunohistochemistry.

RESULTS

There was statistically significant increase in CD4+ T lymphocytes in lesional skin of pemphigus compared to perilesional skin and control group (P-value: 0.001). There was statistically significant decrease in CD25+ and Foxp3+ cells in lesional skin compared to perilesional and control group (P-value: <0.001, 0.025 respectively ).

CONCLUSION

The reduction of lesional skin Tregs may play an important role in the pemphigus pathogenesis.

Regulatory T Cell Apoptosis during Preeclampsia May Be Prevented by Gal-2

There are several open questions to be answered regarding the pathophysiology of the development of preeclampsia (PE). Numerous factors are involved in its genesis, such as defective placentation, vascular impairment, and an altered immune response. The activation of the adaptive and innate immune system represents an immunologic, particularity during PE. Proinflammatory cytokines are predominantly produced, whereas immune regulatory and immune suppressive factors are diminished in PE. In the present study, we focused on the recruitment of regulatory T cells (Tregs) which are key players in processes mediating immune tolerance. To identify Tregs in the decidua, an immunohistochemical staining of FoxP3 of 32 PE and 34 control placentas was performed. A clearly reduced number of FoxP3-positive cells in the decidua of preeclamptic women could be shown in our analysis (p = 0.036). Furthermore, CCL22, a well-known Treg chemoattractant, was immunohistochemically evaluated. Interestingly, CCL22 expression was increased at the maternal-fetal interface in PE-affected pregnancies (p_{syncytiotrophoblast} = 0.035, p_decidua = 0.004). Therefore, the hypothesis that Tregs undergo apoptosis at the materno-fetal interface during PE was generated, and verified by FoxP3/TUNEL (TdT-mediated dUTP-biotin nick end labeling) staining. Galectin-2 (Gal-2), a member of the family of carbohydrate-binding proteins, which is known to be downregulated during PE, seems to play a pivotal role in T cell apoptosis. By performing a cell culture experiment with isolated Tregs, we could identify Gal-2 as a factor that seems to prevent the apoptosis of Tregs. Our findings point to a cascade of apoptosis of Tregs at the materno-fetal interface during PE. Gal-2 might be a potential therapeutic target in PE to regulate immune tolerance.

Mice transgenic for human CTLA4-CD28 fusion gene show proliferation and transformation of ATLL-like and AITL-like T cells

CTLA4-CD28 gene fusion has been reported to occur in diverse types of T cell lymphoma. The fusion event is expected to convert inhibitory signals to activating signals and promote proliferation and potentially transformation of T cells. To test the function of the CTLA4-CD28 fusion gene in vivo, we generated a murine model that expresses the gene in a T cell-specific manner. The transgenic mice have shorter life spans and display inflammatory responses including lymphadenopathy and splenomegaly. T cells in turn show higher levels of activation and infiltrate various organs including the lung and skin. T cells, in particular CD4+ helper T cells, were also readily transplantable to immunocompromised mice. Transcriptomic profiling revealed that the gene expression pattern in CD4 + T cells closely resembles that of adult T cell leukemia/lymphoma (ATLL) and that of angioimmunoblastic T cell lymphoma (AITL) tissues. Consistently, we detected supernumerary FOXP3+ cells and PD-1+ cells in transgenic and transplanted mice. This is the first report demonstrating the transforming activity of the CTLA4-CD28 fusion gene in vivo, and this murine model should be useful in dissecting the molecular events downstream to this mutation.

EBV-associated diseases: Current therapeutics and emerging technologies

EBV is a prevalent virus, infecting >90% of the world's population. This is an oncogenic virus that causes ~200,000 cancer-related deaths annually. It is, in addition, a significant contributor to the burden of autoimmune diseases. Thus, EBV represents a significant public health burden. Upon infection, EBV remains dormant in host cells for long periods of time. However, the presence or episodic reactivation of the virus increases the risk of transforming healthy cells to malignant cells that routinely escape host immune surveillance or of producing pathogenic autoantibodies. Cancers caused by EBV display distinct molecular behaviors compared to those of the same tissue type that are not caused by EBV, presenting opportunities for targeted treatments. Despite some encouraging results from exploration of vaccines, antiviral agents and immune- and cell-based treatments, the efficacy and safety of most therapeutics remain unclear. Here, we provide an up-to-date review focusing on underlying immune and environmental mechanisms, current therapeutics and vaccines, animal models and emerging technologies to study EBV-associated diseases that may help provide insights for the development of novel effective treatments.

EBV+ tumors exploit tumor cell-intrinsic and -extrinsic mechanisms to produce regulatory T cell-recruiting chemokines CCL17 and CCL22

The Epstein-Barr Virus (EBV) is involved in the etiology of multiple hematologic and epithelial human cancers. EBV+ tumors employ multiple immune escape mechanisms, including the recruitment of immunosuppressive regulatory T cells (Treg). Here, we show some EBV+ tumor cells express high levels of the chemokines CCL17 and CCL22 both in vitro and in vivo and that this expression mirrors the expression levels of expression of the EBV LMP1 gene in vitro. Patient samples from lymphoblastic (Hodgkin lymphoma) and epithelial (nasopharyngeal carcinoma; NPC) EBV+ tumors revealed CCL17 and CCL22 expression of both tumor cell-intrinsic and -extrinsic origin, depending on tumor type. NPCs grown as mouse xenografts likewise showed both mechanisms of chemokine production. Single cell RNA-sequencing revealed in vivo tumor cell-intrinsic CCL17 and CCL22 expression combined with expression from infiltrating classical resident and migratory dendritic cells in a CT26 colon cancer mouse tumor engineered to express LMP1. These data suggest that EBV-driven tumors employ dual mechanisms for CCL17 and CCL22 production. Importantly, both in vitro and in vivo Treg migration was effectively blocked by a novel, small molecule antagonist of CCR4, CCR4-351. Antagonism of the CCR4 receptor may thus be an effective means of activating the immune response against a wide spectrum of EBV+ tumors.

Antiviral Responses in Cancer: Boosting Antitumor Immunity Through Activation of Interferon Pathway in the Tumor Microenvironment

In recent years, it became apparent that cancers either associated with viral infections or aberrantly expressing endogenous retroviral elements (EREs) are more immunogenic, exhibiting an intense intra-tumor immune cell infiltration characterized by a robust cytolytic apparatus. On the other hand, epigenetic regulation of EREs is crucial to maintain steady-state conditions and cell homeostasis. In line with this, epigenetic disruptions within steady-state cells can lead to cancer development and trigger the release of EREs into the cytoplasmic compartment. As such, detection of viral molecules by intracellular innate immune sensors leads to the production of type I and type III interferons that act to induce an antiviral state, thus restraining viral replication. This knowledge has recently gained momentum due to the possibility of triggering intratumoral activation of interferon responses, which could be used as an adjuvant to elicit strong anti-tumor immune responses that ultimately lead to a cascade of cytokine production. Accordingly, several therapeutic approaches are currently being tested using this rationale to improve responses to cancer immunotherapies. In this review, we discuss the immune mechanisms operating in viral infections, show evidence that exogenous viruses and endogenous retroviruses in cancer may enhance tumor immunogenicity, dissect the epigenetic control of EREs, and point to interferon pathway activation in the tumor milieu as a promising molecular predictive marker and immunotherapy target. Finally, we briefly discuss current strategies to modulate these responses within tumor tissues, including the clinical use of innate immune receptor agonists and DNA demethylating agents.

Conversion therapy with tislelizumab for high microsatellite instability, unresectable stage III gastric cancer: a case report

Gastric cancer (GC) is the fifth-highest ranked cancer for incidence and second for mortality from cancer worldwide. Conversion therapy has recently emerged as an alternative therapy for advanced/metastatic GC patients who are unable to undergo surgical resection at the time of diagnosis. Herein, we present the case of a patient with unresectable stage III GC of high microsatellite instability (MSI), high tumor mutation burden (TMB), and Epstein-Barr virus (EBV) positive. The patient received conversion therapy involving a combination of chemotherapy and immunotherapy regimens. After 3 courses of chemotherapy combined with tislelizumab, the patient underwent laparoscopic radical total gastrectomy. The pathological examination demonstrated that there was no cancerous tissue at the proximal or distal end of the tumor and no lymph node metastases in the lesser or greater curvature, indicating a pathologic complete response. Thereafter, the patient continued tislelizumab treatment to prevent postoperative carcinoma recurrence and metastasis, and to improve prognosis. In conclusion, our study confirmed that chemotherapy combined with immunotherapy is a promising conversion therapy for GC patients with locally unresectable lesions or distant lymph node metastasis, and these findings warrant large-scale clinical studies. This report highlights the clinical importance of next-generation sequencing technology in investigating therapeutic strategy to provide the maximal clinical benefit for patients with GC.

Recruitment and Expansion of Tregs Cells in the Tumor Environment-How to Target Them?

Simple Summary

The immune response against cancer is generated by effector T cells, among them cytotoxic CD8⁺ T cells that destroy cancer cells and helper CD4⁺ T cells that mediate and support the immune response. This antitumor function of T cells is tightly regulated by a particular subset of CD4⁺ T cells, named regulatory T cells (Tregs), through different mechanisms. Even if the complete inhibition of Tregs would be extremely harmful due to their tolerogenic role in impeding autoimmune diseases in the periphery, the targeted blockade of their accumulation at tumor sites or their targeted depletion represent a major therapeutic challenge. This review focuses on the mechanisms favoring Treg recruitment, expansion and stabilization in the tumor microenvironment and the therapeutic strategies developed to block these mechanisms.

Abstract

Regulatory T cells (Tregs) are present in a large majority of solid tumors and are mainly associated with a poor prognosis, as their major function is to inhibit the antitumor immune response contributing to immunosuppression. In this review, we will investigate the mechanisms involved in the recruitment, amplification and stability of Tregs in the tumor microenvironment (TME). We will also review the strategies currently developed to inhibit Tregs’ deleterious impact in the TME by either inhibiting their recruitment, blocking their expansion, favoring their plastic transformation into other CD4⁺ T-cell subsets, blocking their suppressive function or depleting them specifically in the TME to avoid severe deleterious effects associated with Treg neutralization/depletion in the periphery and normal tissues.

Identification and validation of methylated differentially expressed miRNAs and immune infiltrate profile in EBV-associated gastric cancer

BACKGROUND

The recent discovery of cancer/tissue specificity of miRNA has indicated its great potential as a therapeutic target. In Epstein-Barr virus-associated gastric cancer (EBVaGC), host genes are affected by extensive DNA methylation, including miRNAs. However, the role of methylated miRNA in the development of EBVaGC and immune cell infiltration has largely remained elusive.

RESULTS

After crossmatching the DNA methylation and expression profile of miRNA and mRNA in the Gene Expression Omnibus (GEO) and the Cancer Genome Atlas Research Network (TCGA), we discovered that miR-129-2-3p was significantly suppressed due to hypermethylation on its enhancer in EBVaGC. The differentially expressed genes (DEGs) added up to 30, among which AKAP12 and LARP6 were predicted to be the target genes of miR-129-2-3p and negatively correlated with patients' survival. Accordingly, miR-129-2-3p was significantly down-regulated in tumor samples in 26 (65%) out of 40 cases in our cohort (P < 0.0001). The proliferation, migration and invasion functions of GC cells were significantly promoted when transfected with miR-129-2-3p inhibitor and suppressed when transfected with mimics or treated with 5-aza-2'-deoxycytidine. Moreover, a comprehensive regulation network was established by combining the putative transcription factors, miRNA-mRNA and protein-protein interaction (PPI) analysis. Pathway enrichment analysis showed that cytokine activity, especially CCL20, was the most prominent biological process in EBVaGC development. Immune cell infiltration analysis demonstrated CD4+ T cell, macrophage and dendritic cell infiltrates were significantly enriched for the prognostic-indicated hub genes.

CONCLUSION

This study has provided a comprehensive analysis of differentially expressed miRNAs and mRNAs associated with genome-wide DNA methylation by integrating multi-source data including transcriptome, methylome and clinical data from GEO and TCGA, QPCR of tumor samples and cell function assays. It also gives a hint on the relationships between methylated miRNA, DEGs and the immune infiltration. Further experimental and clinical investigations are warranted to explore the underlying mechanism and validate our findings.

Clinicopathological and Immunomicroenvironment Characteristics of Epstein-Barr Virus-Associated Gastric Cancer in a Chinese Population

BACKGROUND

Epstein-Barr virus-associated gastric cancer(EBVaGC)has a unique tumor immune microenvironment. We performed a comprehensive analysis of the tumor-infiltrating immune cells in a cohort of EBVaGC in a Chinese population.

METHODS

Epstein-Barr encoding region (EBER) in situ hybridization was performed in 1,328 consecutive cases of surgically resected GC. Densities of immune cells, including T cells, B cells, natural killer cells, and macrophages from the patients were calculated after immunohistochemical staining with CD3, CD20, CD57, and CD68 antibodies in tissue microarrays, respectively.

RESULTS

EBVaGC patients accounted for 4.1% (55 of 1,328) cases in the overall population. The average age of patients with EBVaGC was lower than that of non-EBVaGC patients. Histologically, EBVaGC patients exhibited poorly differentiated adenocarcinoma (P = 0.004) and lower frequency of vascular invasion (P = 0.034). The density of CD3+ T lymphocytes (CD3, 23.84 ± 14.49 vs. 12.76 ± 8.93, P < 0.001) and CD68+ macrophages (CD68, 9.73 ± 5.25 vs. 5.44 ± 4.18, P < 0.001) was significantly higher in EBVaGC patients. CD3+ T cell density predicted better 5-year overall survival of EBVaGC patients (P = 0.022).

CONCLUSIONS

EBVaGC patients were younger with low-differentiated adenocarcinoma and less vascular invasion. Increased infiltration of multiple immune cells affected the prognosis of patients, especially EBVaGC patients with more CD3+ T lymphocytes, who survived longer.

Mechanisms of Epstein-Barr virus nuclear antigen 1 favor Tregs accumulation in nasopharyngeal carcinoma

Background

Documented reports proved that Epstein‐Barr virus (EBV) infection increased infiltration of Tregs in malignancy. However, the mechanism of EBV recruitment Tregs into nasopharyngeal carcinoma (NPC) tissues has not been detailed discussion.

Methods

Expression of EBV nuclear antigen 1 (EBNA1) and Foxp3 in NPC tissue samples was detected by immunohistochemistry. EBNA1+ NPC cell lines were used to coculture with PBMC, naïve T cells, Tregs, and monocytes. Percent of Treg was detected by flow cytometry.

Results

EBNA1 protein was overexpressed in NPC tissues, and was associated with a number of infiltrated Tregs. EBNA1+ NPC cells converted naïve T cells into Tregs by up‐regulated TGF‐β1. Enhanced CCL20 production in EBNA1‐expressed tumor cells increased Tregs migration. Polarized‐M2 macrophages by EBNA1 expression cells converted naïve T cells into Tregs.

Conclusions

EBNA1 favors accumulation of Tregs in NPC through: (a) upregulated TGF‐β1 converted naïve T cell into Treg; (b) upregulated CCL20 increased Treg migration; and (c) polarized‐M2 macrophage converted naïve T cell into Treg.

Immune subtyping of extranodal NK/T-cell lymphoma: a new biomarker and an immune shift during disease progression

Extranodal NK/T-cell lymphoma is an aggressive lymphoma that is strongly associated with Epstein-Barr virus infection. Although some extranodal NK/T-cell lymphoma patients have shown responses to immune checkpoint blockade, biomarkers for predicting extranodal NK/T-cell lymphoma patient response to immunotherapy have not yet been defined. To understand the tumor immune microenvironment, we analyzed the expression of 579 immune-related genes and characterized the immune cells using immunohistochemistries and in situ hybridization for EBER. Based on comprehensive analyses, we developed an immune subtyping model that classifies extranodal NK/T-cell lymphoma patients into four tumor immune microenvironment subgroups using three immunohistochemical markers (FoxP3, PD-L1, and CD68). The four tumor immune microenvironment subgroups were named immune tolerance, immune evasion-A, immune evasion-B, and immune silenced. The immune tolerance group was characterized by high-Treg counts and was frequently observed in early stage, and nasal extranodal NK/T-cell lymphoma. The immune evasion group showed high cytotoxic T-cell counts and high PD-L1 expression but low Treg counts. In the immune-silenced group, almost all immune responses were exhausted, most patients were at an advanced stage, and had the poorest disease prognosis among the tumor immune microenvironment subgroups. In some patients (n = 3), a shift in the tumor immune microenvironment subgroup classification was observed in sequential biopsies. The response rate to pembrolizumab, an anti-PD-1 antibody, was 100% (1/1) in the immune tolerance group, 60% (3/5) in the immune evasion group, and 0% (0/5) in the immune-silenced group. We classified extranodal NK/T-cell lymphoma into four tumor immune microenvironment subgroups using a new classification system. In conclusion, we propose that the tumor immune microenvironment of extranodal NK/T-cell lymphoma may change during disease progression and may serve as a useful biomarker for immunotherapy.

MicroRNA (miR) dysregulation during Helicobacter pylori-induced gastric inflammation and cancer development: critical importance of miR-155

Dysregulation of noncoding microRNA molecules has been associated with immune cell activation in the context of Helicobacter pylori induced gastric inflammation as well as carcinogenesis, but also with downregulation of mismatch repair genes, and may interfere with immune checkpoint proteins that lead to the overexpression of antigens on gastric tumor cells. Numerous miR-molecules have been described as important tools and markers in gastric inflammation and cancer development -including miR-21, miR-143, miR-145, miR-201, and miR-335- all of which are downregulated in gastric tumors, and involved in cell cycle growth or tumor invasion. Among the many microRNAs involved in gastric inflammation, adenocarcinoma development and immune checkpoint regulation, miR-155 is notable in that its upregulation is considered a key marker of chronic gastric inflammation that predisposes a patient to gastric carcinogenesis. Among various other miRs, miR-155 is highly expressed in activated B and T cells and in monocytes/macrophages present in chronic gastric inflammation. Notably, miR-155 was shown to downregulate the expression of certain MMR genes, such as MLH1, MSH2, and MSH6. In tumor-infiltrating miR-155-deficient CD8⁺ T cells, antibodies against immune checkpoint proteins restored the expression of several derepressed miR-155 targets, suggesting that miR-155 may regulate overlapping pathways to promote antitumor immunity. It may thus be of high clinical impact that gastric pathologies mediated by miR-155 result from its overexpression. This suggests that it may be possible to therapeutically attenuate miR-155 levels for gastric cancer treatment and/or to prevent the progression of chronic gastric inflammation into cancer.

Gastric cancer: genome damaged by bugs

Gastric cancer (GC) is one of the leading causes of cancer-related death worldwide. The role of the microorganisms in gastric tumorigenesis attracts much attention in recent years. These microorganisms include bacteria, virus, and fungi. Among them, Helicobacter pylori (H. pylori) infection is by far the most important risk factor for GC development, with special reference to the early-onset cases. H. pylori targets multiple cellular components by utilizing various virulence factors to modulate the host proliferation, apoptosis, migration, and inflammatory response. Epstein–Barr virus (EBV) serves as another major risk factor in gastric carcinogenesis. The virus protein, EBER noncoding RNA, and EBV miRNAs contribute to the tumorigenesis by modulating host genome methylation and gene expression. In this review, we summarized the related reports about the colonized microorganism in the stomach and discussed their specific roles in gastric tumorigenesis. Meanwhile, we highlighted the therapeutic significance of eradicating the microorganisms in GC treatment.

A. R. ENS, Mat Lazim N, Mohamud R, Yean CY, Shueb RH. Technical Considerations in Ex Vivo Human Regulatory T Cell Migration and Suppression Assays

Regulatory T cells (Tregs) are renowned for maintaining homeostasis and self-tolerance through their ability to suppress immune responses. For over two decades, Tregs have been the subject of intensive research. The immunosuppressive and migratory potentials of Tregs have been exploited, especially in the areas of cancer, autoimmunity and vaccine development, and many assay protocols have since been developed. However, variations in assay conditions in different studies, as well as covert experimental factors, pose a great challenge to the reproducibility of results. Here, we focus on human Tregs derived from clinical samples and highlighted caveats that should be heeded when conducting Tregs suppression and migration assays. We particularly delineated how factors such as sample processing, choice of reagents and equipment, optimization and other experimental conditions could introduce bias into the assay, and we subsequently proffer recommendations to enhance reliability and reproducibility of results. It is hoped that prioritizing these factors will reduce the tendencies of generating false and misleading results, and thus, help improve our understanding and interpretation of Tregs functional studies.

Viral IL-10 promotes cell proliferation and cell cycle progression via JAK2/STAT3 signaling pathway in nasopharyngeal carcinoma cells

Epstein-Barr virus (EBV) is positively related to the morbidity of nasopharyngeal carcinoma (NPC) in Asia. After infection, EBV can produce several proteins, including viral interleukin-10 (vIL-10). But the mechanism by which vIL-10 contributes to NPC cell proliferation and cell cycle progression is not well understood. In this study, EBV negative and positive cell lines, and the JAK2/STAT3 signal pathway inhibitor AG490 were used to illustrate the role of vIL-10 in NPC. Cell proliferation and cell cycle were measured by CCK-8 and flow cytometry. The expression levels of related protein were measured by Western blotting. High concentrations of vIL-10 and IL-6 were found in the EBV positive patients. The expression level of IL-6 was positively related to the presence of concentration of vIL-10. vIL-10 can promote cancer cell proliferation and G1 to S phase transmission via upregulating the IL-6 protein level by activating the JAK2/STAT3 signal pathway. Furthermore, EBV can induce the formation of cytotoxic T cells, whereas vIL-10 can block the function of cytotoxic T cells. Taken together, these results suggest that vIL-10 promotes cell proliferation and cell cycle progression via JAK2/STAT3 signaling pathway in NPC.

T-lymphocyte subsets and Th1/Th2 cytokines in convalescent patients with Epstein-Barr virus-associated aplastic anemia

Objective: The aim of this study was to analyze T-lymphocyte subsets and Th1/Th2 cytokines in convalescent patients with Epstein-Barr virus (EBV)-associated aplastic anemia (AA).Methods: Sixty AA patients were enrolled, who were in remission following immunosuppressive therapy, including 34 EBV-negative cases and 26 EBV-positive cases. Their complete blood count (CBC), T-lymphocyte subsets, Th1/Th2 cytokines were analyzed. The correlation between EBV-DNA and T-lymphocyte subsets was evaluated, as well as the relationship between EBV-DNA and Th1/Th2 cytokines. The presence of EBV-DNA in peripheral blood mononuclear cells (PBMCs) was also assessed in 60 normal controls.Results: EBV-DNA was detected in 26/60 (43.33%) patients and 21/60 (35.00%) controls. EBV-DNA copy number in AA patients was higher than in controls (Z = -2.138, P = 0.033). The percentage of CD3⁺CD4⁺ T-lymphocytes and the ratio of CD4⁺/CD8⁺ T-lymphocytes in the EBV-negative group were higher than in the EBV-positive group (P = 0.001 and 0.001, respectively). EBV was positively correlated with CD3⁺CD8⁺ T-lymphocyte percentages (Pearson R: 0.496, P = 0.009). Moreover, EBV was positively correlated with IL-10 and IFN-γ levels (Pearson R: 0.559, P = 0.002 and Pearson R: 0.621, P = 0.001, respectively).Conclusions: EBV-DNA copy number in AA patients was higher than in normal controls. Both AA and EBV infection may cause changes in the levels of T-lymphocyte subsets. We recommend monitoring the changes in the immune function and EBV infection simultaneously in AA patients, especially following immunosuppressive therapy.

The Binary Classification Of Chronic Diseases

Acute diseases start with an insult and end when insult disappears. If the trauma induces an immune reaction (which happens in most cases), this reaction must be terminated with some type of resolution mechanism, when the cause of the trauma ceases. Chronicity develops if insult is permanent or if the resolution mechanism is defective. Another way to reach disease chronicity is a positive feedback loop, whereby the immune reaction activates an internal, insult-like reaction. A distinction between chronic states characterized by a persistent, low suppressive effect and those characterized by a persistent, high suppressive effect of regulatory T cells (Treg), is proposed. This two-class division represents two ways to reach chronicity: (a) by maintaining inflammatory reaction long after insult disappears ("low Treg"), or (b) by suppressing inflammatory reaction prior to the disappearance of insult ("high Treg"). This two-class division may explain the strong association between certain pathogens and cancer, on one hand, and between several other pathogens and autoimmunity, on the other hand. The weak association between autoimmune diseases and HIV infection and the relatively weak association between autoimmune diseases and cancer may be elucidated as well. In addition, the model rationalizes why immune-modulating drugs, which are effective in cancer, are also effective in "high Treg" viral infections, while corticosteroids, which are generally effective in autoimmune diseases, are also effective in other "low Treg" diseases (such as asthma, atopic dermatitis, and "low Treg" infections) but are not effective in solid malignancies and "high Treg" infections. Moreover, the model expounds why certain bacteria inhibit tumor growth and why these very bacteria induce autoimmune diseases.

Thirty years of Epstein-Barr virus-associated gastric carcinoma

Thirty years have passed since a possible association of Epstein-Barr virus (EBV) with gastric carcinoma was reported. We now know EBV-associated gastric carcinoma to be a specific subtype of gastric carcinoma. Global epigenetic methylation and counteraction of the antitumour microenvironment are two major characteristics of this subtype of gastric carcinoma. Recent development of therapeutic modalities for gastric carcinoma, such as endoscopic mucosal dissection and immune checkpoint inhibitor therapy, has made the presence of EBV infection a biomarker for the treatment of gastric carcinoma. This review presents a portrait of EBV-associated gastric carcinoma from initiation to maturity that we define as the 'gastritis-infection-cancer sequence', followed by its molecular abnormalities and interactions with immune checkpoint molecules and the microenvironment. EBV non-coding RNAs (microRNA and circular RNA) and exosomes derived from EBV-infected cells that were previously behind the scenes are now recognized for their roles in EBV-associated gastric carcinoma. The virus utilizes cellular machinery skilfully to control infected cells and their microenvironment. We should thus strive to understand virus-host interactions more fully in the following years to overcome this virus-driven subtype of gastric carcinoma.

Effect of Radical Surgery for Advanced Adenocarcinoma of Esophagogastric Junction on Perioperative Cellular Cell Immunity

Background: To investigate the perioperative peripheral blood levels of CD4⁺CD25⁺ regulatory T cells, programed cell death 1 (PD-1), and lymphocyte activation gene 3 (LAG-3) in patients with advanced Siewert type II adenocarcinoma of esophagogastric junction (AEG). Methods: Patients (n = 102) with advanced Siewert type II AEG underwent open total gastrectomy/proximal gastrectomy with a transhiatal resection of the distal esophagus and lymphadenectomy of the lower mediastinum and the abdominal D2 compartment. Flow cytometry was used to detect CD4⁺CD25⁺ T cells, PD-1 and LAG-3 expression on both CD4⁺ and CD8⁺ T cells in the peripheral blood of the Siewert type II AEG patients prior to surgery and on postoperative day (POD) 1, 3, 7, and 9. Results: The proportion of CD4⁺CD25⁺ T cells rapidly decreased on POD 1, then gradually increased and peaked at POD 7. The proportion of CD4⁺PD-1⁺ T cells significantly increased after surgery, reaching a maximum on POD 1, and remained significantly elevated on POD 3 compared to the preoperative day. The proportion of CD8⁺ PD-1⁺ and CD4⁺LAG-3⁺ T cells gradually increased after surgery and reached a peak at POD 7. The change in proportion of CD8⁺LAG-3⁺ T cells in the peripheral venous blood lymphocytes after surgery was not statistically significant. Conclusion: The change in the CD4⁺PD-1⁺ T lymphocyte ratio may likely reflect the cellular immunity status of the perioperative period.

Recent advances in the study of regulatory T cells in gastric cancer

Gastric cancer (GC), which features a complex pathogenesis and mechanism, remains refractory. FOXP3⁺ regulatory T cells (Tregs), which have been implicated in the progression of gastric cancer, play an immunosuppressive role in the tumor microenvironment. However, the prognostic value of Treg infiltration is still controversial in GC patients. Recently, the association of Tregs with the clinicopathological characteristics of GC patients, the prognostic value of Tregs alone or its combination with other factors to GC patients, the role of Tregs in GC tumor microenvironment, clinical applications and Tregs-targeted therapies for GC patients have become hot issues. In this review, we are going to discuss these scientific researches which focused on these topics.

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.

Gastritis-Infection-Cancer Sequence of Epstein-Barr Virus-Associated Gastric Cancer

Epstein-Barr virus-associated gastric cancer (EBVaGC) is a representative EBV-infected epithelial neoplasm, which is now included as one of the four subtypes of The Cancer Genome Atlas molecular classification of gastric cancer. In this review, we portray a gastritis-infection-cancer sequence of EBVaGC. This virus-associated type of gastric cancer demonstrates clonal growth of EBV-infected epithelial cells within the mucosa of atrophic gastritis. Its core molecular abnormality is the EBV-specific hyper-epigenotype of CpG island promoter methylation, which induces silencing of tumor suppressor genes. This is due to the infection-induced disruption of the balance between DNA methylation and DNA demethylation activities. Abnormalities in the host cell genome, including phosphatidylinositol-4,5-biphosphate 3-kinase catalytic subunit α (PIK3CA), AT-rich interaction domain 1A (ARID1A), and programmed death-ligand 1 (PD-L1), are associated with the development and progression of EBVaGC. Furthermore, posttranscriptional modulation affects the transformation processes of EBV-infected cells, such as epithelial mesenchymal transition and anti-apoptosis, via cellular and viral microRNAs (miRNAs). Once established, cancer cells of EBVaGC remodel their microenvironment, at least partly, via the delivery of exosomes containing cellular and viral miRNAs. After exosomes are incorporated, these molecules change the functions of stromal cells, tuning the microenvironment for EBVaGC. During this series of events, EBV hijacks and uses cellular machineries, such as DNA methylation and the miRNA delivery system. This portrait of gastritis-infection-cancer sequences highlights the survival strategies of EBV in the stomach epithelial cells and may be useful for the integration of therapeutic modalities against EBV-driven gastric cancer.

T cell senescence and CAR-T cell exhaustion in hematological malignancies

T cell senescence has been recognized to play an immunosuppressive role in the aging population and cancer patients. Strategies dedicated to preventing or reversing replicative and premature T cell senescence are required to increase the lifespan of human beings and to reduce the morbidity from cancer. In addition, overcoming the T cell terminal differentiation or senescence from lymphoma and leukemia patients is a promising approach to enhance the effectiveness of adoptive cellular immunotherapy (ACT). Chimeric antigen receptor T (CAR-T) cell and T cell receptor-engineered T (TCR-T) cell therapy highly rely on functionally active T cells. However, the mechanisms which drive T cell senescence remain unclear and controversial. In this review, we describe recent progress for restoration of T cell homeostasis from age-related senescence as well as recovery of T cell activation in hematological malignancies.

Characterization of CSF2A fusion gene and its effect on Epstein-Barr virus-positive tumor cells

We build the latent membrane protein gene latent membrane protein 2A (LMP2A) and the granulocyte-macrophase colony-stimulating factor (GM-CSF) gene fusion gene (CSF2A) and discuss how the CSF2A fusion protein influenced the proliferation and apoptosis of Epstein-Barr virus-positive (EBV⁺ ) tumor cells. Reverse-transcription polymerase chain reaction (RT-PCR) method was used to amplify the LMP2A gene and GM-CSF gene fragments, respectively, according to the principle of overlap extension in the coding (Gly4Ser)₃ polypeptide gene fragments of DNA restructured under the connection. The CSF2A gene could be connected with the pIRES2-enhanced green fluorescent protein vector by recombinant DNA technology and identified by enzyme electrophoresis analysis and DNA sequencing. Then, the recombinant vector was transfected into dendritic cells (DCs); RT-PCR and Western blot analysis were used for testing the CSF2A gene messenger RNA and protein expression. The impacts of CSF2A on the proliferation and apoptosis of EBV⁺ tumor cells were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and Hochest 33342 staining. We successfully obtained the recombinant vector named pIRES2-CSF2A. The expression of CSF2A could be detected by transfecting pIRES2-CSF2A into DCs. The DCs were cocultured with T lymphocytes and then acted on the EBV⁺ CNE2 nasopharyngeal carcinoma cells. MTT assay showed that the inhibiting effect of CSF2A obviously increased and the time dependency (**P < 0.01, *P < 0.05) also existed. Hochest 33342 staining showed apoptosis morphological changes of cells in nucleus staining and generated the apoptotic body. Apoptosis cells of the pIRES2-CSF2A group increased significantly at 48 hours. The results showed that the pIRES2-CSF2A recombinant vector was effectively transfected into DCs and the fusion gene CSF2A could promote EBV⁺ CNE2 cell apoptosis, laying the foundation for the specificity of EBV⁺ tumor targeting immune gene therapy in the future.

The Microenvironment in Epstein-Barr Virus-Associated Malignancies

The Epstein–Barr virus (EBV) can cause a wide variety of cancers upon infection of different cell types and induces a highly variable composition of the tumor microenvironment (TME). This TME consists of both innate and adaptive immune cells and is not merely an aspecific reaction to the tumor cells. In fact, latent EBV-infected tumor cells utilize several specific mechanisms to form and shape the TME to their own benefit. These mechanisms have been studied largely in the context of EBV+ Hodgkin lymphoma, undifferentiated nasopharyngeal carcinoma, and EBV+ gastric cancer. This review describes the composition, immune escape mechanisms, and tumor cell promoting properties of the TME in these three malignancies. Mechanisms of susceptibility which regularly involve genes related to immune system function are also discussed, as only a small proportion of EBV-infected individuals develops an EBV-associated malignancy.

The effect of foxp3-overexpressing Treg cells on non-small cell lung cancer cells

The aim of the present study was to investigate the novel mechanisms of forkhead box protein P3 (foxp3) in T regulatory (Treg) cells in lung cancer behavior. Treg cells were isolated from the peripheral blood of healthy volunteers and then co-cultured with 95D cells. A plasmid overexpressing foxp3 was constructed and transfected into Treg cells and an MTS assay was performed to assess cell viability. Flow cytometry was performed to evaluate cell apoptosis and reverse transcription-quantitative polymerase chain reaction was used to measure mRNA expression. A Transwell assay was used to assess cell invasion. Treg cells were successfully isolated from peripheral blood with purity of 94.26%. Foxp3 expression in Treg cells was significantly increased following co-culture with 95D cells, while matrix metalloproteinase-9 expression was upregulated in 95D cells co-cultured with Treg cells. The apoptosis, invasion and migration abilities of 95D cells were suppressed by co-culture with Treg cells, whereas the adhesive ability was enhanced. Foxp3 overexpression in Treg cells enhanced the viability and invasiveness of 95D cells, whereas cell adhesion and migration were decreased. The results of the present study demonstrate that the viability and invasiveness of 95D cells are enhanced by foxp3 overexpression in Treg cells, indicating that increased levels of foxp3 in the tumor microenvironment may promote tumor cell growth.

The alternation of autophagy/apoptosis in CD4+CD25+Foxp3+ Tregs on the developmental stages of atherosclerosis

Naturally regulatory T cells (Tregs) play a critical role in the regulation of T cell-mediated immune responses in atherosclerosis. However, the regulatory mechanism underlying Tregs upon long-term development of atherosclerosis remains unknown. Therefore, in this study, atherosclerotic model was induced in ApoE-/- mice by feeding fat-diet for 10 weeks. Quantification of atherosclerotic lesions was done by calculating the lesion size in the aortic sinus every 2 weeks. The lipid levels and inflammatory mediators were detected in serum sample. The populations of CD4+CD25+Foxp3+ Tregs were compared between ApoE-/- mice (ApoE-/-) and wild type C57BL/6 littermates (WT). The expression levels of autophagy and apoptosis signaling related regulators were determined by flow cytomery, RT-qPCR, and western blot assays in the CD4+CD25+Foxp3+ Tregs isolated from ApoE-/- and WT. We found that the sizes of plaque lesions in atherosclerotic ApoE-/- mice were larger than those in WT group during 10 weeks' detection (all P<0.05); Whereas, flow cytometry assay showed that the populations of CD4+CD25+Foxp3+ Tregs were significantly reduced in atherosclerotic ApoE-/- mice compared with those in corresponding WT group from the 4th weeks' detection (all P<0.05). The lipid accumulation and increased pro-inflammatory mediators were correlated with the developmental progression of atherosclerosis. Furthermore, compared to WT group, the functional properties of CD4+CD25+Foxp3+ Tregs from ApoE-/- mice showed a gradually decreased autophagic activity with aberrant expressions of LC3, Beclin1, ATG5, ATG7, p62 (all P<0.05), and a gradually increased apoptotic activity with abnormal expressions of cleaved caspase 3, Bim, Bcl-2 (all P<0.05) during the 10 weeks' detection period. Taken together, our data demonstrated that the population of CD4+CD25+Foxp3+ Tregs was reversely correlated with plaque forming in atherosclerotic ApoE-/- mice during atherosclerosis development. And the autophagy/apoptosis-dependent Tregs might play a crucial role for the maintenance of CD4 9+CD25+Foxp3+ Tregs survival during atherosclerosis progression.

Regulatory T Cell Effect on CD8+ T Cell Responses to Human Herpesvirus 8 Infection and Development of Kaposi's Sarcoma

We assessed CD8⁺ T cell reactivity to human herpesvirus 8 (HHV-8; Kaposi's sarcoma [KS]-associated herpesvirus) and the role of CD4⁺CD25^hiFoxP3⁺ regulatory T cells (Treg) in HHV-8- and HIV-coinfected participants of the Multicenter AIDS Cohort Study who did or did not develop KS. There were similarly low CD8⁺ T cell interferon-γ responses to MHC class I-restricted epitopes of HHV-8 lytic and latent proteins over 5.7 years before KS in participants who developed KS compared to those who did not. T cell reactivity to HHV-8 antigens was low relative to responses to a combination of cytomegalovirus, Epstein-Barr virus and influenza A virus (CEF) peptide epitopes, and dominant HIV peptide epitopes. There was no change in %Treg in the HHV-8- and HIV-coinfected participants who did not develop KS, whereas there was a significant increase in %Treg in HHV-8- and HIV-coinfected participants who developed KS beginning 1.8 years before development of KS. Removal of Treg enhanced HHV-8-specific T cell responses in HHV-8- and HIV-coinfected participants who did or did not develop KS, with a similar pattern observed in response to CEF and HIV peptides. Thus, long-term, low levels of anti-HHV-8 CD8⁺ T cell reactivity were present in both HHV-8- and HIV-coinfected men who did and did not develop KS. This was related to moderately enhanced Treg function.

Janus-faced Acrolein prevents allergy but accelerates tumor growth by promoting immunoregulatory Foxp3+ cells: Mouse model for passive respiratory exposure

Acrolein, a highly reactive unsaturated aldehyde, is generated in large amounts during smoking and is best known for its genotoxic capacity. Here, we aimed to assess whether acrolein at concentrations relevant for smokers may also exert immunomodulatory effects that could be relevant in allergy or cancer. In a BALB/c allergy model repeated nasal exposure to acrolein abrogated allergen-specific antibody and cytokine formation, and led to a relative accumulation of regulatory T cells in the lungs. Only the acrolein-treated mice were protected from bronchial hyperreactivity as well as from anaphylactic reactions upon challenge with the specific allergen. Moreover, grafted D2F2 tumor cells grew faster and intratumoral Foxp3+ cell accumulation was observed in these mice compared to sham-treated controls. Results from reporter cell lines suggested that acrolein acts via the aryl-hydrocarbon receptor which could be inhibited by resveratrol and 3′-methoxy-4′-nitroflavone Acrolein- stimulation of human PBMCs increased Foxp3+ expression by T cells which could be antagonized by resveratrol. Our mouse and human data thus revealed that acrolein exerts systemic immunosuppression by promoting Foxp3+ regulatory cells. This provides a novel explanation why smokers have a lower allergy, but higher cancer risk.