Expression of cytokine and chemokine genes in Epstein-Barr virus-associated nasopharyngeal carcinoma: comparison with Hodgkin's disease

Epstein-Barr Virus-Associated Malignancies and Immune Escape: The Role of the Tumor Microenvironment and Tumor Cell Evasion Strategies

Simple Summary

The Epstein–Barr virus, also termed human herpes virus 4, is a human pathogenic double-stranded DNA virus. It is highly prevalent and has been linked to the development of 1–2% of cancers worldwide. EBV-associated malignancies encompass various structural and epigenetic alterations. In addition, EBV-encoded gene products and microRNAs interfere with innate and adaptive immunity and modulate the tumor microenvironment. This review provides an overview of the characteristic features of EBV with a focus on the intrinsic and extrinsic immune evasion strategies, which contribute to EBV-associated malignancies.

Abstract

The detailed mechanisms of Epstein–Barr virus (EBV) infection in the initiation and progression of EBV-associated malignancies are not yet completely understood. During the last years, new insights into the mechanisms of malignant transformation of EBV-infected cells including somatic mutations and epigenetic modifications, their impact on the microenvironment and resulting unique immune signatures related to immune system functional status and immune escape strategies have been reported. In this context, there exists increasing evidence that EBV-infected tumor cells can influence the tumor microenvironment to their own benefit by establishing an immune-suppressive surrounding. The identified mechanisms include EBV gene integration and latent expression of EBV-infection-triggered cytokines by tumor and/or bystander cells, e.g., cancer-associated fibroblasts with effects on the composition and spatial distribution of the immune cell subpopulations next to the infected cells, stroma constituents and extracellular vesicles. This review summarizes (i) the typical stages of the viral life cycle and EBV-associated transformation, (ii) strategies to detect EBV genome and activity and to differentiate various latency types, (iii) the role of the tumor microenvironment in EBV-associated malignancies, (iv) the different immune escape mechanisms and (v) their clinical relevance. This gained information will enhance the development of therapies against EBV-mediated diseases to improve patient outcome.

Serum and Tissue Level of TLR9 in EBV-Associated Oropharyngeal Cancer

Simple Summary

The Epstein–Barr virus (EBV) is associated with the development and progression of various epithelial malignancies including cancer in the head and neck region. Toll-like receptors (TLRs) are molecules distinguishing self and non-self antigens. They are required for congenital immune response to infections with viruses such as EBV because, during viral infection, the congenital immunity is the first line of human defense preventing the replication of the virus. Moreover, TLR response may influence the transformation to malignancy. The aim of our study was to assess TLR9 level in patients with diagnosed oropharyngeal cancer with or without EBV infection. We wanted to know whether infection with EBV influences TLR9 level and maybe changes the immune response which may lead to malignant transformation. The results obtained in our research may improve understanding of the role viral infections play in head and neck cancers and influence future diagnosis, prevention and treatment strategies in these malignancies.

Abstract

The Epstein–Barr virus (EBV) is associated with the development of various epithelial malignancies including cancer in the head and neck region. Several studies have shown that Toll-like receptors (TLRs) are required for an innate immune response to infection with human DNA viruses, e.g., EBV. During viral infections, TLR response may influence the transformation to malignancy. The aim of the study was to assess TLR9 serum and tissue level in EBV(+) and EBV(−) oropharyngeal cancer patients. The study involved 78 patients: 42 EBV(+) and 36 EBV(−). EBV DNA was detected in fresh frozen tumor tissue. TLR9 level was measured in homogenate of tumor tissue and in serum. Moreover, in serum samples IL-10, VEGF, TGFβ, TNFα and antibodies against EBV were detected using ELISA test. TLR9 level was significantly lower in EBV(+) patients, both in tissue and serum, while EBVCA, EBNA and VEGF level was statistically higher in EBV(+) patients. An increase in EBVCA and EBNA antibodies titer was correlated with a TLR9 level decrease. TLR9 level was higher in poorly-differentiated tumors (G3), in tumor of larger dimensions (T3-T4) and with lymph nodes involvement (N3-N4) but without statistical significance. High levels of anti-EA antibodies in the majority of EBV(+) patients may point to the reactivation of EBV infection.

The role of Epstein–Barr virus-encoded latent membrane proteins in host immune escape

Epstein–Barr virus (EBV) is a type IV herpesvirus that widely infects the vast majority of adults, and establishes a latent infection pattern in host cells to escape the clearance of immune system. The virus is intimately associated with the occurrence and progression of lymphomas and epithelial cell cancers. EBV latent membrane proteins (LMPs) can assist its immune escape by downregulating host immune response. Besides EBV, LMPs have important effects on the functions of exosomes and autophagy, which also help EBV to escape immune surveillance. These escape mechanisms may provide conditions for further development of EBV-associated tumors. In this article, we discussed the potential functions of EBV-encoded LMPs in promoting immune escape.

Targeting the signaling in Epstein-Barr virus-associated diseases: mechanism, regulation, and clinical study

Epstein–Barr virus-associated diseases are important global health concerns. As a group I carcinogen, EBV accounts for 1.5% of human malignances, including both epithelial- and lymphatic-originated tumors. Moreover, EBV plays an etiological and pathogenic role in a number of non-neoplastic diseases, and is even involved in multiple autoimmune diseases (SADs). In this review, we summarize and discuss some recent exciting discoveries in EBV research area, which including DNA methylation alterations, metabolic reprogramming, the changes of mitochondria and ubiquitin-proteasome system (UPS), oxidative stress and EBV lytic reactivation, variations in non-coding RNA (ncRNA), radiochemotherapy and immunotherapy. Understanding and learning from this advancement will further confirm the far-reaching and future value of therapeutic strategies in EBV-associated diseases.

An Unusual Presentation of Nasopharyngeal Carcinoma as Lemierre Syndrome

BACKGROUND Clinical presentation of nasopharyngeal carcinoma (NPC) is correlated with the extent of primary and nodal disease. Hence, depending on the anatomical structures affected, the clinical presentation varies accordingly, ranging from non-specific symptoms of epistaxis, unilateral nasal obstruction, and auditory complaints, to cranial nerve palsies. Nodal metastasis in the neck is a frequent clinical finding in nasopharyngeal carcinoma. CASE REPORT A female was admitted to the hospital because of fever and trismus with painful swelling in the right neck. Computed tomography (CT) revealed a mass in the nasopharynx with heterogeneous enhancement and multiple swollen lymph nodes in the corresponding neck. Initial biopsies of nasopharyngeal mass and lymph node of the neck revealed nonspecific lymphoid hyperplasia; we administered antibiotics with the provisional diagnosis of bacterial infection, including Lemierre syndrome that is typically defined by the constellation of septic internal jugular vein thrombophlebitis, pulmonary and other septic emboli, and sterile site bacterial infection. However, the patient was refractory to antibiotics over a month of treatments. The third biopsy of the throat lesion revealed NPC and bacterial cultures using the biopsy specimen were negative. She received intensity-modulated radiation therapy and chemotherapy for NPC stage II (TNM staging: T2N1M0). She never developed Lemierre syndrome-like symptoms after chemoradiotherapy. CONCLUSIONS We report a unique case of NPC presenting with Lemierre syndrome-like symptoms, including prior sore throat, trismus, painful swollen neck, and high fever. Since these symptoms have not been reported in NPC, we included NPC as a differential diagnosis.

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.

Interplay of Viral Infection, Host Cell Factors and Tumor Microenvironment in the Pathogenesis of Nasopharyngeal Carcinoma

Undifferentiated nasopharyngeal carcinoma (NPC) is strongly associated with Epstein-Barr virus (EBV) infection. In addition, heavy infiltration of leukocytes is a common characteristic of EBV-associated NPC. It has long been suggested that substantial and interactive impacts between cancer and stromal cells create a tumor microenvironment (TME) to promote tumorigenesis. The coexistence of tumor-infiltrating lymphocytes with EBV-infected NPC cells represents a distinct TME which supports immune evasion and cancer development from the early phase of EBV infection. Intracellularly, EBV-encoded viral products alter host cell signaling to facilitate tumor development and progression. Intercellularly, EBV-infected cancer cells communicate with stromal cells through secretion of cytokines and chemokines, or via release of tumor exosomes, to repress immune surveillance and enhance metastasis. Although high expression of miR-BARTs has been detected in NPC patients, contributions of these more recently discovered viral products to the establishment of TME are still vaguely defined. Further investigations are needed to delineate the mechanistic linkage of the interplay between viral and host factors, especially in relation to TME, which can be harnessed in future therapeutic strategies.

Elevated Serum Levels of sCD30 and IL6 and Detectable IL10 Precede Classical Hodgkin Lymphoma Diagnosis

Background: We investigated whether an immune system environment characterized by elevated serum levels of B-cell activation molecules was associated with the subsequent development of classical Hodgkin lymphoma (cHL).Methods: We measured serum levels of B-cell-stimulatory cytokines, IL6 and IL10, soluble CD30 (sCD30), and total IgE prior to cHL diagnosis in 103 cases and 206 matched controls with archived specimens in the DoD Serum Repository.Results: Prediagnosis serum sCD30 and IL6 levels had strong positive associations with risk of a cHL diagnosis 0 to 1 year prior to diagnosis [sCD30 OR = 5.5; 95% confidence interval (CI), 3.4-9.0; IL6 OR = 4.6; 95% CI, 2.9-7.5] and >1 year to 2 years pre-cHL diagnosis (sCD30 OR = 3.3; 95% CI, 1.6-6.7; IL6 OR = 2.9; 95% CI, 1.3-6.5). We observed similar, albeit not consistently significant positive associations, over 4 or more years preceding diagnosis. We did not observe a clear association with IgE levels. Of note, detectable IL10 levels were significantly associated with Epstein-Barr virus (EBV)-positive cHL cases compared with EBV-negative cases.Conclusion: In this prospective analysis, elevated sCD30 and IL6 levels and detectable IL10 preceded cHL diagnosis.Impact: The associations of these cytokines with cHL risk may reflect the production of these molecules by proliferating nascent cHL tumor cells, or by immune cells responding to their presence, prior to clinical detection. The stable elevation in cHL risk, 4 or more years prediagnosis, also suggests that a B-cell-stimulatory immune system milieu precedes, and may promote, lymphomagenesis. Cancer Epidemiol Biomarkers Prev; 26(7); 1114-23. ©2017 AACR.

Therapeutic vaccine targeting Epstein-Barr virus latent protein, LMP1, suppresses LMP1-expressing tumor growth and metastasis in vivo

Background

In endemic area, nasopharyngeal carcinoma (NPC) tumor cells harbor EBV latent infection and expresses viral antigens such as EBNA1, LMP1 and LMP2. In this study, we established a NPC-mimicry animal model and assessed the therapeutic potential of LMP1 vaccine.

Methods

Animal models were established by injection of LMP1-expressing TC-1 cells in C57BL6/J mice subcutaneously or through tail veins. pcDNA3.1 empty vector or LMP1/pcDNA3.1 vaccine was delivered by a helium-driven gene gun. Effectiveness of vaccine was evaluated by measuring the tumor size and numbers of metastatic lung nodules. Circulating cytokines were evaluated by ELISArray. Populations of activated cytotoxic T lymphocytes (CTLs) and LMP1-specific T lymphocytes were evaluated by flow cytometry with CD8/CD107a double staining and interferon-γ ELISPOT assay, respectively.

Results

LMP1 vaccine significantly suppressed tumor growth (n = 3) and metastasis (n = 4) in vivo. When vaccinated before tumor challenge, all mice in vaccine group were tumor-free, whereas all mice in the control group developed tumors within 2 weeks after tumor challenge (n = 10). Cytokine ELISArray revealed elevation of a panel of proinflammatory cytokines in mice receiving LMP1 vaccine. Flow cytometry and interferon-γ ELISPOT assay revealed that LMP1 vaccine induced larger populations of activated CTLs and LMP1-specific T lymphocytes.

Conclusions

This pre-clinical study provides a promising result that LMP1 vaccine suppresses LMP1-expressing tumor growth and metastasis in vivo.

Polymorphisms in host immune response associated genes and risk of nasopharyngeal carcinoma development in Portugal

BACKGROUND

Host genetic susceptibility markers in immune response associated genes may contribute to identify individuals with high risk of developing viral infection and viral-associated cancers. We aimed to characterize different polymorphisms in immune response associated genes and evaluate its association with nasopharyngeal carcinoma (NPC) development.

METHODS

We have developed a hospital-based case-control study selecting 134 patients with NPC (cases) and 732 healthy individuals (controls) from the Northern Region of Portugal. Eight single nucleotide polymorphisms (SNP) were selected: -56C>T IFNGR1 (rs2234711), +4854G>T IL1A (rs17561), +3954C>T IL1B (rs1143634), +1902A>G IL4RA (rs1801275), -1082G>A IL10 (rs1800896), +2018T>C IL1RN (rs419598), HLA-A locus A>T (rs2530388), HCGA9 locus A>T (rs6457110). All polymorphisms were analysed by real-time methodology using TaqMan(®) SNP Genotyping Assays.

RESULTS

The overall analysis revealed no statistical significant differences between genotypes distributions in all of studied polymorphisms (p>0.05). However, the results for HCGA9 rs6457110 polymorphism showed a tendency for an increased risk of NPC development among TT carriers with an almost of 2-fold increased risk (OR=1.86; 95%CI 1.00-3.65).

CONCLUSIONS

This is the first study to characterize these polymorphisms in NPC patients in Portugal. Our study indicates that HCGA9 rs6457110 polymorphism might represent a risk marker for NPC development in our population and that other SNPs should be further studied in larger populations to clarify the evidences. This data reinforces the need for more studies, especially in NPC low-prevalent populations.

Association between interleukin 8 -251 A/T and +781 C/T polymorphisms and osteosarcoma risk in Chinese population: a case-control study

Interleukin-8 (IL-8) is an angiogenic chemokine that plays a potent role in both development and progression of many human malignancies. However, there are no data about the role of IL-8 polymorphism in development of osteosarcoma. A hospital-based case-control study was conducted among 190 patients with osteosarcoma and 190 healthy controls to investigate the possible association between the IL-8 -251 A/T and +781 C/T polymorphisms, respectively, and the risk of osteosarcoma. Significant differences of genotype distribution were observed between osteosarcoma cases and controls at the IL-8 -251T/A genotypes. Compared with the IL-8 -251T/A homozygote TT, the heterozygous TA genotype was associated with significantly increased risk for osteosarcoma (odds ratio (OR) = 2.16, 95 % confidence interval (CI) = (1.38-4.52), P = 0.021); the AA genotype was associated with increased risk for osteosarcoma (OR = 1.94, 95 % CI = 1.31-3.83, P = 0.018). TA and AA combined variants were associated with increased risk for osteosarcoma compared with the TT genotype (OR = 1.72, 95 % CI = 1.45-4.41, P = 0.023). Moreover, the genotype AA of IL-8 -251T/A carried a higher risk of osteosarcoma metastasis and later Enneking stages, compared with the TT genotype. However, the genotype and allele frequencies of IL-8 +781 C/T polymorphisms in osteosarcoma patients were not significantly different from controls. Our results showed that the IL-8 -251 A/T genotype was associated with increased risk for development and metastasis of osteosarcoma in Chinese Han population.

Dendritic cells respond to nasopharygeal carcinoma cells through annexin A2-recognizing DC-SIGN

Dendritic cells (DCs) play an essential role in immunity and are used in cancer immunotherapy. However, these cells can be tuned by tumors with immunosuppressive responses. DC-specific intercellular adhesion molecule 3-Grabbing Nonintegrin (DC-SIGN), a C-type lectin expressed on DCs, recognizes certain carbohydrate structures which can be found on cancer cells. Nasopharyngeal carcinoma (NPC) is an epithelial cell-derived malignant tumor, in which immune response remains unclear. This research is to reveal the molecular link on NPC cells that induces the immunosuppressive responses in DCs. In this article, we report identification of annexin A2 (ANXA2) on NPC cells as a ligand for DC-SIGN on DCs. N-linked mannose-rich glycan on ANXA2 may mediate the interaction. ANXA2 was abundantly expressed in NPC, and knockdown of ANXA2 suppressed NPC xenograft in mice, suggesting a crucial role of ANXA2 in NPC growth. Interaction with NPC cells caused DC-SIGN activation in DCs. Consequently DC maturation and the proinflammatory interleukin (IL)-12 production were inhibited, and the immunosuppressive IL-10 production was promoted. Blockage of either DC-SIGN or ANXA2 eliminated the production of IL-10 from DCs. This report suggests that suppression of ANXA2 at its expression or glycosylation on NPC may improve DC-mediated immunotherapy for the tumor.

Microenvironment abnormalities and lymphomagenesis: Immunological aspects

Innate and adaptive immune cells within the microenvironment identify and eliminate cells displaying signs of malignant potential. Immunosurveillance effector Natural Killer (NK) cells and Cytotoxic T Lymphocytes (CTL) identify malignant cells through germline receptors such as NKG2D and in the case of CTLs, presentation of antigen through the T cell receptor. Manipulation of immunosurveillance through altered tumor-identifying ligand expression or secretion, resistance to cytotoxicity, or compromised cytotoxic cell activity through immune tolerance mechanisms all contribute to failure of these systems to prevent cancer development. This review examines the diverse mechanisms by which alterations in the immune microenvironment can promote lymphomagenesis.

A pooled analysis of the IL-10-1082 A/G polymorphism and the nasopharyngeal carcinoma susceptibility

It has been reported that IL-10-1082 A/G polymorphism might influence the transcription and secretion of IL10 and tumor development. While many studies have been conducted to investigate the association between IL-10-1082 A/G polymorphism and risk of nasopharyngeal carcinoma (NPC) in various populations, the results of these studies are still controversial. We aimed to explore this relationship through a cumulative meta-analysis. A search of the literature was performed using the Cochrane Library, PubMed, and EMBASE databases. The odds ratio (OR) and corresponding 95 % confidence interval (CI) were calculated to assess this possible association. Six studies were included in the study. The meta-analysis reveals a significant effect in the allelic model (G vs. A: OR 1.516, 95 % CI 1.077-2.133, P heterogeneity = 0.003), dominant model (AG + GG vs. AA: OR = 1.770, 95 % CI 1.415-2.212, P heterogeneity = 0.169), and co-dominant model (AG vs. AA: OR = 1.747, 95 % CI 1.377-2.216, P heterogeneity = 0.491). Similarly, in the stratified analyses, significant effects were reported in studies of Asian populations. Our meta-analysis results suggest that the IL-10-1082 A/G variant is associated with increased risk of NPC in Asian populations.

Control of the inflammatory response mechanisms mediated by natural and induced regulatory T-cells in HCV-, HTLV-1-, and EBV-associated cancers

Virus infections are involved in chronic inflammation and, in some cases, cancer development. Although a viral infection activates the immune system's response that eradicates the pathogen mainly through inflammatory mechanisms, it is now recognized that this inflammatory condition is also favorable to the development of tumors. Indeed, it is well described that viruses, such as hepatitis C virus (HCV), Epstein Barr virus (EBV), human papillomavirus (HPV) or human T-cell lymphotropic virus type-1 (HTLV-1), are important risk factors for tumor malignancies. The inflammatory response is a fundamental immune mechanism which involves several molecular and cellular components consisting of cytokines and chemokines that are released by various proinflammatory cells. In parallel to this process, some endogenous recruited components release anti-inflammatory mediators to restore homeostasis. The development of tools and strategies using viruses to hijack the immune response is mostly linked to the presence of regulatory T-cells (Treg) that can inhibit inflammation and antiviral responses of other effector cells. In this review, we will focus on current understanding of the role of natural and induced Treg in the control and the resolution of inflammatory response in HCV-, HTLV-1-, and EBV-associated cancers.

IL-1RN VNTR polymorphism as a susceptibility marker for nasopharyngeal carcinoma in Portugal

BACKGROUND

Nasopharyngeal carcinoma (NPC) is a rare malignancy in Western countries that is widely associated with the infection by Epstein-Barr virus (EBV). Several studies have showed that a common allele (allele 2) of the 86-bp variable number of tandem repeats (VNTR) polymorphism within intron 2 of the interleukin 1 receptor antagonist (IL-1RN) gene is associated with several disorders, including viral-associated cancers.

METHODS

We have developed a hospital-based case-control study to characterise the role of the IL-1RN 86-bp VNTR polymorphism in the development of NPC with 112 patients with the disease and 433 healthy individuals from the northern region of Portugal. IL-1RN genotypes were combined according to the number of repeats: allele 2 (A2), the short allele that corresponds to two repeats, and L, the long allele that corresponds to three or more repeats.

RESULTS

Our study revealed that 31.2% of NPC patients were IL-1RN A2*A2, compared with 9.7% observed in the control group. The statistical analysis revealed that IL-1RN*A2 homozygosity for the A2 allele was associated with a fourfold increased risk for NPC development (p<0.001). Additionally, cumulative hazard analysis revealed that estimated median age of onset of NPC is significantly (p<0.001) different for A2*A2 homozygous versus non-A2*A2 (57.0 vs. 74.0, respectively).

CONCLUSIONS

This is the first study to evaluate the role of the IL-1RN VNTR in NPC development in Portugal. Our study indicates IL-1RN*A2 homozygosity as a significant risk marker in our population and that it should be further investigated for the potential role in the definition of a susceptibility profile for NPC onset.

c-Myc and EBV-LMP1: two opposing regulators of the HLA class I antigen presentation machinery in epithelial cells

Background:

Epstein–Barr virus (EBV)-encoded latent membrane protein 1 (LMP1) up-regulates the human leukocyte antigen (HLA) class I antigen presentation machinery (APM). This appears counterintuitive with immune evasion in EBV-associated tumours like nasopharyngeal carcinoma (NPC).

Methods:

Latent membrane protein 1-transfected epithelial cell lines were used as a model system to study the impact of LMP1 and c-Myc on HLA class I components. The expression of components of the HLA class I APM, c-Myc and Ki-67 was analysed in LMP1+ and LMP1− NPC by immunohistochemistry.

Results:

In epithelial cells, LMP1 up-regulated HLA class I APM. This effect could be counteracted by c-Myc, which itself was up-regulated by LMP1 apparently through IL6 induction and Jak3/STAT3 activation. Studies of NPC biopsies revealed down-regulation of HLA class I APM expression. No difference was observed between LMP1+ and LMP1− NPC. However, expression of Ki-67 and c-Myc were up-regulated in LMP1+ tumours.

Conclusion:

These findings raise the possibility that c-Myc activation in NPC might antagonise the effect of LMP1 on HLA class I expression thus contributing to immune escape of tumour cells.

Exploiting the interplay between innate and adaptive immunity to improve immunotherapeutic strategies for Epstein-Barr-virus-driven disorders

The recent demonstration that immunotherapeutic approaches may be clinically effective for cancer patients has renewed the interest for this strategy of intervention. In particular, clinical trials using adoptive T-cell therapies disclosed encouraging results, particularly in the context of Epstein-Barr-virus- (EBV-) related tumors. Nevertheless, the rate of complete clinical responses is still limited, thus stimulating the development of more effective therapeutic protocols. Considering the relevance of innate immunity in controlling both infections and cancers, innovative immunotherapeutic approaches should take into account also this compartment to improve clinical efficacy. Evidence accumulated so far indicates that innate immunity effectors, particularly NK cells, can be exploited with therapeutic purposes and new targets have been recently identified. We herein review the complex interactions between EBV and innate immunity and summarize the therapeutic strategies involving both adaptive and innate immune system, in the light of a fruitful integration between these immunotherapeutic modalities for a better control of EBV-driven tumors.

The role of the EBV-encoded latent membrane proteins LMP1 and LMP2 in the pathogenesis of nasopharyngeal carcinoma (NPC)

Although frequently expressed in EBV-positive malignancies, the contribution of the oncogenic latent membrane proteins, LMP1 and LMP2, to the pathogenesis of nasopharyngeal carcinoma (NPC) is not fully defined. As a key effector in EBV-driven B cell transformation and an established "transforming" gene, LMP1 displays oncogenic properties in rodent fibroblasts and induces profound morphological and phenotypic effects in epithelial cells. LMP1 functions as a viral mimic of the TNFR family member, CD40, engaging a number of signalling pathways that induce morphological and phenotypic alterations in epithelial cells. Although LMP2A plays an essential role in maintaining viral latency in EBV infected B cells, its role in epithelial cells is less clear. Unlike LMP1, LMP2A does not display "classical" transforming functions in rodent fibroblasts but its ability to engage a number of potentially oncogenic cell signalling pathways suggests that LMP2A can also participate in EBV-induced epithelial cell growth transformation. Here we review the effects of LMP1 and LMP2 on various aspects of epithelial cell behaviour highlighting key aspects that may contribute to the pathogenesis of NPC.

Host-tumor interactions in nasopharyngeal carcinomas

Like other human solid tumors, nasopharyngeal carcinoma (NPC) is a tissue and a systemic disease as much as a cell disease. Tumor cell population in NPC is highly heterogeneous. Heavy infiltration by non-malignant leucocytes results at least in part from the production of abundant inflammatory cytokines by the malignant epithelial cells. There is indirect evidence that interactions between stromal and malignant cells contribute to tumor development. Peripheral blood samples collected from NPC patients contain multiple products derived from the tumor, including cytokines, non-cytokine tumor proteins, tumor exosomes and viral nucleic acids. These products represent a potential source of biomarkers for assessment of tumor aggressiveness, indirect exploration of cellular interactions and monitoring of tumor response to therapeutic agents. Most NPC patients are immunocompetent with evidence of active humoral and cellular immune responses against EBV-antigens at the systemic level. Tumor development is facilitated by local immunosuppressive factors which are not fully understood. Local accumulation of regulatory T-cells is probably one important factor. At least two NPC tumor products are suspected to contribute to their expansion, the cytokine CCL20 and the tumor exosomes carrying galectin 9. In the future, new therapeutic modalities will probably aim at breaking immune tolerance or at blocking cellular interactions critical for tumor growth.

Lymphocyte deficiency limits Epstein-Barr virus latent membrane protein 1 induced chronic inflammation and carcinogenic pathology in vivo

BACKGROUND

The importance of the malignant cell environment to its growth and survival is becoming increasingly apparent, with dynamic cross talk between the neoplastic cell, the leukocyte infiltrate and the stroma. Most cancers are accompanied by leukocyte infiltration which, contrary to an anticipated immuno-protective role, could be contributing to tumour development and cancer progression. Epstein-Barr virus (EBV) associated cancers, including nasopharyngeal carcinoma and Hodgkin's Disease, show a considerable leukocyte infiltration which surrounds the neoplastic cells, raising the questions as to what role these cells play in either restricting or supporting the tumour and what draws the cells into the tumour. In order to begin to address this we have studied a transgenic model of multistage carcinogenesis with epithelial expression of the EBV primary oncoprotein, latent membrane protein 1 (LMP1). LMP1 is expressed particularly in the skin, which develops a hyperplastic pathology soon after birth.

RESULTS

The pathology advances with time leading to erosive dermatitis which is inflamed with a mixed infiltrate involving activated CD8+ T-cells, CD4+ T-cells including CD4+/CD25+/FoxP3+ Treg cells, mast cells and neutrophils. Also significant dermal deposition of immunoglobulin-G (IgG) is observed as the pathology advances. Along with NF-kappaB activation, STAT3, a central factor in inflammation regulation, is activated in the transgenic tissue. Several inflammatory factors are subsequently upregulated, notably CD30 and its ligand CD153, also leukocyte trafficking factors including CXCL10, CXCL13, L-selectin and TGFβ1, and inflammatory cytokines including IL-1β, IL-3 and the murine IL-8 analogues CXCL1, CXCL2 and CXCL5-6, amongst others. The crucial role of mature T- and/or B-lymphocytes in the advancing pathology is demonstrated by their elimination, which precludes mast cell infiltration and limits the pathology to an early, benign stage.

CONCLUSIONS

LMP1 can lead to the activation of several key factors mediating proliferation, angiogenesis and inflammation in vivo. With the initiation of an inflammatory programme, leukocyte recruitment follows which then itself contributes to the progressing pathology in these transgenic mice, with a pivotal role for B-and/or T-cells in the process. The model suggests a basis for the leukocyte infiltrate observed in EBV-associated cancer and its supporting role, as well as potential points for therapeutic intervention.

Prognostic biomarkers in malignant lymphomas

There has recently been a rapid expansion in research aimed at identifying biomarkers that could improve the prognosis for patients with various subtypes of malignant lymphoma. Genomic and genetic studies have led to the identification of biological and clinical subgroups of diffuse large B-cell lymphomas with distinct underlying molecular features, divergent activation of oncogenetic pathways, and clinical course. Molecular studies of follicular lymphoma have suggested complex interactions between malignant cells and the surrounding immunological network that could affect disease progression. Moreover, the inflammatory cells of Hodgkin lymphoma have been shown to produce a complex network of cytokines and chemokines that provide a permissive microenvironment for tumor growth. Research into specific biomarkers and signaling pathways of malignant lymphomas might therefore result in the identification of novel targets for future therapeutic strategies. As gene expression profiling techniques are not yet feasible in the clinical laboratory, studies have aimed to translate the findings into more widely applicable techniques that might allow this research to be applied to routine clinical practice. This review focuses on recent advances in translational and clinical research on biomarkers in malignant lymphomas.

Association of IL-1 polymorphisms and IL-1 serum levels with susceptibility to nasopharyngeal carcinoma

Previous studies demonstrated that the polymorphism of interleukin-1 (IL-1) produce alterations of the protein expression and may contribute to oncogenetic processes. The aim of this study was to investigate the relationship between IL-1A gene polymorphisms and NPC susceptibility and the influence of on IL-1α serum levels in cases versus controls. To test whether the genetic variants of IL-1A gene modify the risk of nasopharyngeal carcinoma (NPC), we compared the -889C/T and rs3783553 polymorphisms between 248 patients with NPC and 296 healthy controls using polymerase chain reaction-restriction fragment length polymorphism. Serum IL-1α levels were measured by enzyme-linked immunosorbent assay. The rs3783553 (TTCA insertion or deletion) polymorphism of the IL-1A gene was significantly associated with the susceptibility to NPC. The variant homozygote genotype +/+ was associated with a significantly reduced risk of NPC as compared with the wild homozygote -/- genotype, and the serum IL-1α levels were significantly lower in individuals with homozygous +/+ genotypes. No association was found between the -889C/T polymorphisms and risk of NPC, and no statistically significant differences were found between rs3783553 polymorphism and clinical pathology indices. The IL-1A rs3783553 polymorphism might contribute to a risk of developing NPC by affecting the serum IL-1α secretion in the Chinese population.

Photodynamic therapy-mediated modulation of inflammatory cytokine production by Epstein-Barr virus-infected nasopharyngeal carcinoma cells

Nasopharyngeal carcinoma (NPC) is a malignant disease associated with Epstein-Barr virus (EBV) infection. This study aims to examine the effects of EBV infection on the production of proinflammatory cytokines in NPC cells after the Zn-BC-AM photodynamic therapy (PDT) treatment. Cells were treated with the photosensitiser Zn-BC-AM for 24 h before light irradiation. Quantitative ELISA was used to evaluate the production of cytokines. Under the same experimental condition, HK-1-EBV cells produced a higher basal level of IL-1alpha (1561 pg/ml), IL-1beta (16.6 pg/ml) and IL-8 (422.9 pg/ml) than the HK-1 cells. At the light dose of 0.25-0.5 J/cm(2), Zn-BC-AM PDT-treated HK-1-EBV cells were found to produce a higher level of IL-1alpha and IL-1beta than the HK-1 cells. The production of IL-1beta appeared to be mediated via the IL-1beta-converting enzyme (ICE)-independent pathway. In contrast, the production of angiogenic IL-8 was downregulated in both HK-1 and HK-1-EBV cells after Zn-BC-AM PDT. Our results suggest that Zn-BC-AM PDT might indirectly reduce tumour growth through the modulation of cytokine production.

Significance of Epstein-Barr virus (EBV) load and Interleukin-10 in post-transplant lymphoproliferative disorders

The complex relationship between EBV, IL-10 and lymphomagenesis has been widely investigated and several studies have highlighted the diagnostic value of EBV DNA copies and serum IL-10, that may be considered as tumor markers. Notwithstanding the great number of data published in the last few years on the behavior of EBV DNA copies in the peripheral blood of transplanted patients, a threshold value significant for impending or overt post-transplant lymphoproliferative disorder (PTLD) has not yet been defined. Too many factors, both technical and clinicopathological, may affect the results of clinical studies, making their comparison difficult. On the contrary, although the role of IL-10 in PTLDs has been well documented, a sufficient number of studies exploring sensitivity and specificity of serum IL-10 measurement is lacking. The aim of this review is to summarise data on EBV load quantification and serum IL-10 detection in transplanted patients, providing clinicians with wide and useful information in order to improve bedside management of transplanted patients with regard to PTLDs occurrence and treatment.

Latent Epstein-Barr virus infection of tumor cells in classical Hodgkin's lymphoma predicts adverse outcome in older adult patients

PURPOSE

In classical Hodgkin's lymphoma (cHL), the impact of tumor cell Epstein-Barr virus (EBV) status on clinical outcome is controversial.

PATIENTS AND METHODS

We assessed failure-free survival (FFS) and relative survival (RS) in 412 patients with cHL and age-defined subgroups in a population-based study in the northern Netherlands. Tumor cell EBV status was positive in 34%, and the median follow-up time was 7.1 years. Patients' median age at diagnosis was 35 years (range, 7 to 91 years), and 63% had Ann Arbor stage I or II, 24% had stage III, and 12% had stage IV disease.

RESULTS

EBV status influenced 5-year FFS and RS only in patients from the age group 50 to 74 years. Five-year FFS was 60% in patients with EBV-positive versus 85% in EBV-negative tumors (P = .01). Five-year RS was 69% in patients with EBV-positive versus 82% in EBV-negative tumors (P = .03). After adjusting for histology, HLA class II expression by tumor cells, stage, presence of extranodal localizations and treatment, and the effect of positive EBV tumor status remained significant in FFS multivariate analysis (hazard ratio, 3.11; 95% CI, 1.28 to 7.53; P = .01).

CONCLUSION

This study indicates that treatment failure in older adult patients with cHL is associated with positive tumor cell EBV status.

Pre-treatment serum levels of interleukin-10, interleukin-12 and their ratio predict response to therapy and probability of event-free and overall survival in childhood soft tissue sarcomas, Hodgkin's lymphomas and acute lymphoblastic leukemias

OBJECTIVES

Deregulated serum IL-10, IL-12 and their reciprocal balance have been stated in malignancies of adults. In children with cancer the issue has not been investigated so far.

DESIGN AND METHODS

To determine the diagnostic and prognostic roles of pre-treatment serum levels of IL-10 (Th2 cytokine), IL-12 (Th1) and their ratios (measured by the IL-10 and IL-12p70 ELISA kits; Endogen) in 91 children with soft tissue sarcomas (STS), Hodgkin's lymphomas (HL) and acute lymphoblastic leukemias (ALL).

RESULTS

Median IL-10 and IL-12 levels were significantly higher in cancer patients than in healthy controls. Increased IL-10 indicated presence of general symptoms in HL and high risk group in ALL. Elevated IL-10 and IL-10/IL-12 ratios and decreased IL-12 correlated with poor-risk histology in STS, poor response to therapy, relapse and death from cancer. Multivariate analysis identified IL-10/IL-12 ratio>0.14 and IL-12<40 pg/mL as significant predictors for shorter EFS and OS, respectively.

CONCLUSION

Pre-treatment serum levels of IL-10, IL-12 and IL-10/IL-12 balance in children with STS, HL and ALL may be of value as additional prognostic tools to predict the response to therapy and probability of EFS and OS.

Serum chemokine levels in Hodgkin lymphoma patients: highly increased levels of CCL17 and CCL22

Hodgkin lymphoma (HL) is characterized by a minority of neoplastic Hodgkin-Reed Sternberg (HRS) cells surrounded by a non-neoplastic reactive infiltrate. As immunological mechanisms appear to be crucial in classical HL pathogenesis, altered serum chemokine levels might be related to disease activity. Serum levels of nine chemokines were examined in 163 untreated HL patients and 334 controls. We investigated single nucleotide polymorphisms (SNPs) for association with serum CCL17 (thymus and activation-regulated chemokine, TARC) levels and HL susceptibility. Serum CCL17 and CCL22 (macrophage-derived chemokine, MDC) levels were significantly increased in 82% and 57% of the HL patients. Nodular sclerosis cases showed increased serum CCL17 and CCL22 levels (P < 0.001) and serum levels were correlated with Ann Arbor stage. Of nine patients with pre- and post-treatment serum samples, the majority showed decreased CCL17 and CCL22 levels after treatment. HRS cells expressed CCL17 and CCL22 in 77% and 75% of 74 cases. Three SNPs showed a trend of increased serum CCL17 levels with minor alleles in controls, but were not associated with HL susceptibility. CCL17 and CCL22 were the only chemokines with increased serum levels in the vast majority of HL patients, which provides further insight into the molecular mechanism(s) leading to infiltrations of reactive lymphocytes in HL.

Immunotherapies for Hodgkin's lymphoma

Multiple immune evasion strategies characterize the pathobiology of Hodgkin's lymphoma. These must be considered when developing and testing immunotherapeutic approaches for this disease. The clinical experience with adoptive immunotherapy of Epstein-Barr virus positive tumors, and with monoclonal antibodies directed against CD30, CD20, and other antigens, is herein reviewed.

Interleukin-10 and interferon-gamma gene polymorphisms in patients with nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is a multifactorial disease. Cytokines driving the immune response seem to be disturbed in NPC patients. Since interleukin-10 (IL-10) is known to reduce the production of interferon-gamma (IFN-gamma), we supposed that genetic differences in IL-10 and IFN-gamma expression could be a mechanism by which NPC cells escape antitumour immune response. As the production of each cytokine is affected by the genetic background, we investigated the possible association between single nucleotide polymorphisms in genes of IL-10 and IFN-gamma with NPC. Different IL-10 -1082 G/A and IFN-gamma+874 Tau/Alpha genotypes were determined in 160 patients with nasopharyngeal carcinoma and 197 healthy controls. No association was found either for each SNP studied alone or for the combined analysis for both IL-10 and IFN-gamma polymorphisms among NPC patients in comparison with controls. Compared with individuals from high incidence countries, we noted huge significant differences in genotype distribution between individuals from low and intermediate NPC incidence countries. Polymorphisms of the IL-10 and IFN-gamma do not appear to be associated with NPC risk in the Tunisian population. Nevertheless, we strongly believe that the relationship between cytokines polymorphisms and NPC susceptibility deeply depends on the ethnicity.

Epstein-Barr virus infection and single nucleotide polymorphisms in the promoter region of interleukin 10 gene in patients with Hodgkin lymphoma

CONTEXT

Hodgkin lymphoma is a neoplastic disease in which the immune system plays a major role in its pathogenesis. Interleukin 10 (IL-10), an immunosuppressive cytokine actively produced in patients with Hodgkin lymphomas, favors the survival of the Hodgkin/Reed-Sternberg cells. Individual variations in IL-10 levels may be due, in part, to the presence of single nucleotide polymorphisms in the IL10 gene promoter.

OBJECTIVE

To evaluate whether particular single nucleotide polymorphisms in the IL10 gene are found more frequently in Hodgkin lymphoma cases associated with Epstein-Barr virus infection.

DESIGN

The identification of single nucleotide polymorphisms at positions -1082 and -819/-592 in the IL10 gene was performed by polymerase chain reaction and restriction length fragment polymorphisms analysis in 65 cases of Hodgkin lymphoma and 50 cases of reactive benign follicular lymphoid hyperplasia (non-Hodgkin lymphoma control group).

RESULTS

The frequency of the genotype GG at position -1082 was found to be significantly higher in patients with Epstein-Barr virus-positive Hodgkin lymphoma compared with Epstein-Barr virus-negative cases.

CONCLUSIONS

The results suggest that the presence of specific single nucleotide polymorphisms in the IL10 gene, notably those associated with high IL-10 production, may play a role in the susceptibility to Epstein-Barr virus-positive Hodgkin lymphoma development.

Association of IL-8 (−251)T/A polymorphism with susceptibility to and aggressiveness of nasopharyngeal carcinoma

Interleukin-8 (IL-8) is an angiogenic chemokine that plays a potent role in both development and progression of many human malignancies including nasopharyngeal carcinoma (NPC). In the present study, we evaluated the susceptibility and prognostic implications of the (-251) T/A genetic variation in IL-8 in NPC. We used the allele-specific polymerase chain reaction to characterize the variation of the IL-8 promoter region for 160 unrelated Tunisian patients with NPC and 169 healthy control subjects. There was a significant association between the homozygotes IL-8 (-251) AA genotype and nasopharyngeal carcinoma (OR = 2.46; P = 0.004). The presence of the IL-8 (-251) AA genotype was highly associated with elevated NPC risk for male patients. A significant association was demonstrated between the IL-8 (-251) AA genotype and the aggressive forms of NPC as defined by large tumor size, lymph node metastasis, and advanced stages. Moreover, the presence of the IL-8 (-251) AA genotype indicated a significant association with decreased overall survival. Our findings suggest that the IL-8 promoter polymorphism is associated with increased nasopharyngeal carcinoma risk, particularly in males, as well as disease progress, supporting our hypothesis for IL-8 involvement in NPC pathogenesis.

Exosomes released by EBV-infected nasopharyngeal carcinoma cells convey the viral latent membrane protein 1 and the immunomodulatory protein galectin 9

BACKGROUND

Nasopharyngeal carcinomas (NPC) are consistently associated with the Epstein-Barr virus (EBV). Their malignant epithelial cells contain the viral genome and express several antigenic viral proteins. However, the mechanisms of immune escape in NPCs are still poorly understood. EBV-transformed B-cells have been reported to release exosomes carrying the EBV-encoded latent membrane protein 1 (LMP1) which has T-cell inhibitory activity. Although this report suggested that NPC cells could also produce exosomes carrying immunosuppressive proteins, this hypothesis has remained so far untested.

METHODS

Malignant epithelial cells derived from NPC xenografts--LMP1-positive (C15) or negative (C17)--were used to prepare conditioned culture medium. Various microparticles and vesicles released in the culture medium were collected and fractionated by differential centrifugation. Exosomes collected in the last centrifugation step were further purified by immunomagnetic capture on beads carrying antibody directed to HLA class II molecules. Purified exosomes were visualized by electron microscopy and analysed by western blotting. The T-cell inhibitory activities of recombinant LMP1 and galectin 9 were assessed on peripheral blood mononuclear cells activated by CD3/CD28 cross-linking.

RESULTS

HLA-class II-positive exosomes purified from C15 and C17 cell supernatants were containing either LMP1 and galectin 9 (C15) or galectin 9 only (C17). Recombinant LMP1 induced a strong inhibition of T-cell proliferation (IC50 = 0.17 nM). In contrast recombinant galectin 9 had a weaker inhibitory effect (IC50 = 46 nM) with no synergy with LMP1.

CONCLUSION

This study provides the proof of concept that NPC cells can release HLA class-II positive exosomes containing galectin 9 and/or LMP1. It confirms that the LMP1 molecule has intrinsic T-cell inhibitory activity. These findings will encourage investigations of tumor exosomes in the blood of NPC patients and assessment of their effects on various types of target cells.

Expression of Epstein-Barr virus (EBV)-encoded latent membrane proteins and STAT3 activation in nasopharyngeal carcinoma

The Epstein-Barr virus (EBV) is associated with virtually all cases of undifferentiated nasopharyngeal carcinoma (NPC), and it was proposed that the EBV-encoded transforming protein, latent membrane protein (LMP) 1, may play a role in the neoplastic process. It was proposed recently that LMP1 expression in epithelial cells may be regulated through a loop involving activated signal transducer and activator of transcription 3 (STAT3), LMP1, LMP1-mediated induction of interleukin (IL)-6 expression and STAT3 activation through the IL-6 receptor. This autoregulatory loop may be suppressed by another viral protein, LMP2A, an effect which in turn can be overcome by exogenous IL-6. Here we show that, as expected, expression of LMP1 and LMP2A tend to be exclusive in NPC tumours. Rare cases showing a co-expression of both proteins can be explained by STAT3 activation via the receptors for IL-6 or epidermal growth factor. STAT3 activation was a consistent feature of NPC tumour cells. However, in most cases, this was not accompanied by detectable expression of LMP1, suggesting either that LMP2A expression may suffice to suppress LMP1 expression or that additional factors may be operational. This study emphasises the need to correlate in vitro results with observational studies of ex vivo tumour tissues.

Quantification of Epstein-Barr virus DNA load, interleukin-6, interleukin-10, transforming growth factor-beta1 and stem cell factor in plasma of patients with nasopharyngeal carcinoma

Background

Nasopharyngeal carcinoma (NPC) is a common epithelial neoplasm among the Chinese populations in Southern China and South East Asia. Epstein-Barr virus (EBV) is known to be an important etiologic agent of NPC and the viral gene products are frequently detected in NPC tissues along with elevated antibody titres to the viral proteins (VCA and EA) in a majority of patients. Elevated plasma EBV DNA load is regarded as an important marker for the presence of the disease and for the monitoring of disease progression. However, other serum/plasma parameters such as the levels of certain interleukins and growth factors have also been implicated in NPC. The objectives of the present study are, 1) to investigate the correlations between plasma EBV DNA load and the levels of interleukin (IL)-6, IL-10, TGF-β1 and SCF (steel factor) and 2) to relate these parameters to the stages of NPC and the effect of treatment.

Methods

A total of 78 untreated NPC patients were enrolled in this study. Of these, 51 were followed-up after treatment. The remaining patients had irregular or were lost to follow-up. Plasma EBV DNA was quantified using real-time quantitative PCR. The levels of plasma interleukins and growth factors were quantified using ELISA.

Results

A significant decrease in EBV DNA load was detected in plasma of untreated NPC patients (1669 ± 637 copies/mL; n = 51) following treatment (57 ± 37 copies/mL, p < 0.05); n = 51). Plasma EBV DNA load was shown to be a good prognosticator for disease progression and clinical outcome in five of the follow-up patients. A significant difference in IL-6 levels was noted between the untreated patients (164 ± 37 pg/mL; n = 51) and following treatment (58 ± 16 pg/mL, p < 0.05; n = 51). Positive correlations between EBV DNA load and IL-10 (r(49) = 0.535, p < 0.01), between IL6 and IL-10 (r(49) = 0.474, p < 0.01) and between TGF and SCF (r(49) = 0.464, p < 0.01) were observed in patients following treatment. None of the parameters tested including IgA-VCA were associated with tumour stages.

Conclusion

We conclude that among the parameters investigated, EBV DNA load and IL-6 levels were promising markers for the presence of NPC and for the assessment of treatment outcome.

In nasopharyngeal carcinoma cells, Epstein-Barr virus LMP1 interacts with galectin 9 in membrane raft elements resistant to simvastatin

Nasopharyngeal carcinomas (NPC) are etiologically related to the Epstein-Barr virus (EBV), and malignant NPC cells have consistent although heterogeneous expression of the EBV latent membrane protein 1 (LMP1). LMP1 trafficking and signaling require its incorporation into membrane rafts. Conversely, raft environment is likely to modulate LMP1 activity. In order to investigate NPC-specific raft partners of LMP1, rafts derived from the C15 NPC xenograft were submitted to preparative immunoprecipitation of LMP1 combined with mass spectrometry analysis of coimmunoprecipitated proteins. Through this procedure, galectin 9, a beta-galactoside binding lectin and Hodgkin tumor antigen, was identified as a novel LMP1 partner. LMP1 interaction with galectin 9 was confirmed by coimmunoprecipitation and Western blotting in whole-cell extracts of NPC and EBV-transformed B cells (lymphoblastoid cell lines [LCLs]). Using mutant proteins expressed in HeLa cells, LMP1 was shown to bind galectin 9 in a TRAF3-independent manner. Galectin 9 is abundant in NPC biopsies as well as in LCLs, whereas it is absent in Burkitt lymphoma cells. In subsequent experiments, NPC cells were treated with Simvastatin, a drug reported to dissociate LMP1 from membrane rafts in EBV-transformed B cells. We found no significant effects of Simvastatin on the distribution of LMP1 and galectin 9 in NPC cell rafts. However, Simvastatin was highly cytotoxic for NPC cells, regardless of the presence or absence of LMP1. This suggests that Simvastatin is a potentially useful agent for the treatment of NPCs although it has distinct mechanisms of action in NPC and LCL cells.

Expression of the interferon-inducible chemokine IP-10 (CXCL10), a chemokine with proposed anti-neoplastic functions, in Hodgkin lymphoma and nasopharyngeal carcinoma

Hodgkin lymphoma (HL) and nasopharyngeal carcinoma (NPC) are characterized by their association with Epstein-Barr virus (EBV) and an abundant infiltrate of reactive lymphoid cells. The presence of this lymphoid stroma may influence the effect of anti-viral immunotherapy. The interferon-inducible chemokine IP-10 has anti-neoplastic effects in several model systems mediated by T-cells expressing the CXCR3 chemokine receptor. Using in situ hybridization, it is shown that IP-10 is expressed in neoplastic cells of HL and correlates both with the mixed cellularity histotype and with EBV infection. IP-10 expression was also detected in tumour cells of most NPCs as well as in EBV-negative squamous cell carcinomas of the tongue. Thus, in carcinomas, IP-10 expression showed no correlation with EBV infection. Numerous CXCR3-positive lymphocytes were detected in the lymphoid stroma of HL and NPC, raising the possibility of a Th1-predominant immune response in these cases. In view of the proposed anti-neoplastic functions of IP-10 and CXCR3-positive lymphocytes, these findings are unexpected and raise the possibility that endogenous IP-10 expression in the context of human tumours may not exert the anti-tumour effects ascribed to it by in vitro experiments.

Les carcinomes du nasopharynx : de la biologie à la clinique

Nasopharyngeal carcinomas (NPC) are very different from other head and neck cancers because of their specific multifactorial etiology and their geographic distribution. Epstein-Barr Virus (EBV) is implicated in oncogenesis of NPC in association with genetic alterations such as inactivation of the p16/Ink4, p19/ARF, RASSF1 or Blu genes. Tumoral tissues include a very abundant characteristic lymphoid infiltrate. Inflammatory cytokines are produced by both malignant and infiltrating cells. There is no efficient immune response against the tumor. On the opposite, infiltrating lymphocytes might play a role in tumor development. Serological methods and detection of circulating viral DNA are expected to become useful for early detection of relapse and on a longer term for primary screening. NPC are often diagnosed at a late stage because patients may remain asymptomatic for a long time. Computed tomography (CT scan) and magnetic resonance imaging (MRI) are complementary for the initial evaluation. Positron emission tomography (PET) is efficient for the evaluation of treatment efficiency and detection of relapses. Treatment is based on radiotherapy and chemotherapy. Their optimal use needs to be evaluated by phase III trials but positive results have been obtained by concomitant association of radiotherapy and chemotherapy. Targeted therapies are being studied with strategies based on disruption of viral latency, use of replicative adenoviruses or anti-tumor vaccination.

Epstein-Barr virus-encoded LMP2A regulates viral and cellular gene expression by modulation of the NF-kappaB transcription factor pathway

Epstein-Barr virus (EBV)-associated malignancies display distinct patterns of virus latent gene expression that reflect the complex interplay between the virus and its host cell. In the EBV-associated epithelial tumor nasopharyngeal carcinoma (NPC), the virus-encoded latent membrane protein LMP2A is consistently expressed whereas the oncogenic LMP1 protein appears to be restricted to only a proportion of tumors. In an attempt to understand the contribution of LMP2A to the pathogenesis of NPC, we established carcinoma cell lines stably infected in vitro with either a wild-type recombinant EBV (rEBV) or a mutant rEBV in which LMP2A is deleted (rEBV-2A). An NPC-like pattern of EBV gene expression including LMP2A but not LMP1 was consistently observed in carcinoma cells infected with rEBV. However, carcinoma cells infected with rEBV-2A expressed high levels of LMP1 from the signal transducer and activator of transcription (STAT)-regulated L1-TR promoter. Consistent with this effect, basal STAT activity was reduced in rEBV-infected carcinoma cells, and this repression was relieved in the absence of LMP2A. This modulation of STAT activity correlated with the ability of LMP2A to inhibit the autocrine secretion of IL-6 from carcinoma cell lines. Exogenous IL-6 was able to induce expression of LMP1 by means of STAT3 activation both in rEBV-infected carcinoma cell lines and in the EBV-positive C666-1 NPC cell line. The LMP2A-mediated suppression of IL-6 was a consequence of NF-kappaB inhibition. These data reveal that LMP2A modulates two key transcription factor pathways in carcinoma cells and suggest that this finding may be important in the pathogenesis of EBV-associated tumors.

Expression of tumor necrosis factor receptor-associated factor 1 in nasopharyngeal carcinoma: possible upregulation by Epstein-Barr virus latent membrane protein 1

EBV infection is associated with virtually all cases of undifferentiated NPC, and the EBV-encoded LMP1 is expressed in a proportion of cases. LMP1 has transforming functions similar to members of the TNF receptor family and activates intracellular signaling cascades through interaction with TRAFs. In B cells, expression of TRAF1 is in turn upregulated by LMP1. LMP1 signaling in epithelial cells may be affected by the presence or absence of TRAF1. By immunohistochemistry, we detected TRAF1 expression in 17 of 42 (40%) EBV+ undifferentiated NPCs. All 7 LMP1+ NPC biopsies were also TRAF1+. Using an RNAse protection assay, high-level TRAF1 expression was detected in an LMP1-expressing NPC-derived cell line (C15) and expression was weaker in 2 LMP1- cell lines (C17, C19). Finally, LMP1 upregulated TRAF1 expression in an EBV- keratinocyte cell line. Our results demonstrate that TRAF1 is expressed in NPC tumor cells in vivo and suggest that TRAF1 expression may be upregulated by LMP1 in NPC. An antiapoptotic function has been proposed for TRAF1, and this may be relevant for the pathogenesis of NPC.

Cytokine and immunoglobulin production by PWM-stimulated peripheral and tumor-infiltrating lymphocytes of undifferentiated nasopharyngeal carcinoma (NPC) patients

BACKGROUND

Undifferentiated Nasopharyngeal Carcinoma (NPC) patients show a characteristic pattern of antibody responses to the Epstein-Barr virus (EBV) which is regularly associated with this tumor. However, no EBV-specific cytotoxic activity is detectable by the standard chromium-release assay at both peripheral and intratumoral levels. The mechanisms underlying this discrepancy between the humoral and cellular immune responses in NPC are still unknown, but might be related to an imbalance in immunoregulatory interleukin production. In this report, we investigated the ability of peripheral (PBL) and tumor- infiltrating (TIL) lymphocytes of undifferentiated NPC patients to produce in vitro three interleukins (IL-2, IL-6, IL-10) and three immunoglobulin isotypes (IgM, IgG, IgA).

METHODS

Lymphocytes from 17 patients and 17 controls were cultured in the presence of Pokeweed mitogen (PWM) for 12 days and their culture supernatants were tested for interleukins and immunoglobulins by specific enzyme-linked immunosorbent assays (ELISA). Data were analysed using Student's t-test and probability values below 5% were considered significant.

RESULTS

The data obtained indicated that TIL of NPC patients produced significantly more IL-2 (p = 0,0002), IL-10 (p = 0,020), IgM (p= 0,0003) and IgG (p < 0,0001) than their PBL. On the other hand, patients PBL produced significantly higher levels of IL-2 (p = 0,022), IL-10 (p = 0,016) and IgM (p = 0,004) than those of controls. No significant differences for IL-6 and IgA were observed.

CONCLUSION

Taken together, our data reinforce the possibility of an imbalance in immunoregulatory interleukin production in NPC patients. An increased ability to produce cytokines such as IL-10 may underlie the discrepancy between humoral and cellular immune responses characteristic of NPC.

Expression of interleukin-18 by nasopharyngeal carcinoma cells: a factor that possibly initiates the massive leukocyte infiltration

Interleukin-18 (IL-18) is a single-chain cytokine that is produced by various cells. With interleukin-12 (IL-12), it synergistically stimulates activated T cells and natural killer (NK) cells to produce interferon-gamma (IFN-gamma). Nasopharyngeal carcinoma (NPC) is the most common form of nasal and nasopharyngeal malignancy, and in NPC tumor tissues there is an intense leukocyte infiltration comprising predominantly T cells and macrophages. We previously showed an increased expression of IFN-gamma in the infiltrating T cells. To identify the cells that provide IL-12 and IL-18 for stimulating the expression of IFN-gamma in activated T cells, NPC cell lines CNE-2 and HK-1, as well as biopsies obtained from NPC and control individuals, were examined. CNE-2 and HK-1 cells were found to express messenger RNA encoding IL-18, but not IL-12. Secreted IL-18 was detected in the culture supernatant. Addition of a caspase-1 inhibitor decreased the secretion level, indicating that this IL-18 secretion was caspase-1 dependent. Moreover, the in vitro IL-18 production in NPC cell lines correlated with the NPC tumor cells in situ. NPC tumor cells in the biopsies produced IL-18, as detected by immunohistochemistry and immunofluorescent double staining. In contrast, IL-18 expression was not observed in the control biopsies. We suggest that IL-18 secreted by NPC tumor cells plays a role in initiating the leukocyte infiltration process. IL-18 stimulates T cells and NK cells to produce IFN-gamma, which consequently activates macrophages and other immune cells to secrete chemokines to start a leukocyte recruitment cascade.

Epstein-Barr virus encoded latent membrane protein 1 (LMP1) and TNF receptor associated factors (TRAF): colocalisation of LMP1 and TRAF1 in primary EBV infection and in EBV associated Hodgkin lymphoma

AIMS

Epstein-Barr virus (EBV) immortalises B cells in vitro and is associated with several malignancies. Most phenotypic effects of EBV are mediated by latent membrane protein 1 (LMP1), which interacts with tumour necrosis factor receptor associated factors (TRAFs) to activate NF-kappaB. This study examines TRAF1 and LMP1 expression in EBV associated lymphoproliferations.

METHODS

TRAF1 expression was investigated in 26 Hodgkin lymphomas (HL; 18 EBV+, eight EBV-), seven EBV+ Burkitt lymphomas (BL), two infectious mononucleosis (IM) tonsils, and lymphoreticular tissue from eight chronic virus carriers. Seven anaplastic large cell lymphomas and 10 follicular B cell lymphomas were also studied. Colocalisation of TRAF1 and LMP1 was studied by immunofluorescent double labelling and confocal laser microscopy.

RESULTS

TRAF1 colocalises with LMP1 in EBV infected cells in IM. EBV positive lymphocytes from chronic virus carriers were negative for TRAF1 and LMP1. In HL biopsies, TRAF1 was strongly expressed independently of EBV status, whereas all BL cases were TRAF1-. In EBV+ HL cases, TRAF1 colocalised with LMP1. Eight of 10 follicular lymphomas expressed TRAF1 in centroblast-like cells. Four of seven anaplastic large cell lymphomas weakly expressed TRAF1.

CONCLUSIONS

These results suggest that in non-neoplastic lymphocytes, TRAF1 expression is dependent on the presence of LMP1, and that in IM B cells in vivo, LMP1 associated signalling pathways are active. In HL, TRAF1 is expressed independently of EBV status, probably because of constitutive NF-kappaB activation. The function of TRAF1 in HL remains to be determined.