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

Pathogenic roles for Epstein-Barr virus (EBV) gene products in EBV-associated proliferative disorders

Epstein-Barr virus (EBV) is associated with a still growing spectrum of clinical disorders, ranging from acute and chronic inflammatory diseases to lymphoid and epithelial malignancies. Based on a combination of in vitro and in vivo findings, EBV is thought to contribute in the pathogenesis of these diseases. The different EBV gene expression patterns in the various disorders, suggest different EBV-mediated pathogenic mechanisms. In the following pages, an overview of the biology of EBV-infection is given and functional aspects of EBV-proteins are discussed and their putative role in the various EBV-associated disorders is described. EBV gene expression patterns and possible pathogenic mechanisms are discussed. In addition, expression of the cellular genes upregulated by EBV in vitro is discussed, and a comparison with the in vivo situation is made.

Chemokines, cytokines and their receptors in Hodgkin's lymphoma cell lines and tissues

BACKGROUND

Hodgkin's lymphoma (HL) is characterized by a minority of neoplastic cells, the so-called Reed-Sternberg (RS) cells, and an admixture of reactive cells including lymphocytes, plasma cells, eosinophils and histiocytes. Cytokines produced in HL, either by RS or infiltrating cells, might explain the presence and maintenance of an impaired immune response. Chemokines (cytokines with chemoattractant properties) produced by RS cells play a major role in leukocyte trafficking. These molecules with specific receptor affinities contribute, for example by attracting TH2-like T cells, to the maintenance of a favorable environment for survival of RS cells.

RESULTS AND DISCUSSION

Cross-talk between RS cells and reactive elements involves several cytokine/chemokines that process proliferative [interleukin (IL)-13 and IL-17], immunosuppressive (IL-10 and transforming growth factor-beta) and background formation (IL-5, TARC, MDC, IP-10, RANTES, Mig and others) messages. These autocrine and paracrine interactions lead to an environment where RS cells are able to proliferate, escape from apoptosis and survive host anti-tumor defense.

CONCLUSIONS

The proper modulation of these complex pathways may allow the development of new strategies in HL therapy.

High numbers of granzyme B/CD8-positive tumour-infiltrating lymphocytes in nasopharyngeal carcinoma biopsies predict rapid fatal outcome in patients treated with curative intent

This study determined whether tumour-infiltrating lymphocytes (TILs) in nasopharyngeal carcinomas (NPCs) include activated cytotoxic T lymphocytes (CTLs) and whether the numbers of activated CTLs in these biopsies are related to clinical outcome. Moreover, the study investigated whether the numbers of activated CTLs are associated with the expression of MHC class I proteins and the granzyme B antagonist PI-9 in the tumour cells. Forty-three Indonesian NPC patients (T(1-3), N(1-3), M(0)), who were treated with curative intent by radiotherapy only, were studied. Tumour-infiltrating activated CTLs were detected using antibodies against granzyme B, CD8, and CD56. Expression of MHC class I proteins and PI-9 was also determined by immunohistochemistry. Granzyme B-positive TILs were detected in all NPC biopsies. The presence of a high percentage (>25%) of granzyme B-positive TILs appeared to be a very strong predictor of a rapid fatal clinical outcome, independent of stage. Complete absence of MHC class I heavy chain expression in tumour cells was observed in 11 of 31 evaluable cases and low levels were observed in seven additional cases. No association between MHC class I expression and the numbers of granzyme B-positive TILs was observed. Expression of the granzyme B antagonist PI-9 in tumour cells was detected in three cases. It is concluded that the presence of many granzyme B-positive TILs in a selected group of Indonesian NPC patients is a strong and stage-independent marker for a rapid fatal clinical outcome.

Nasopharyngeal carcinoma and the EBV-specific T cell response: prospects for immunotherapy

T cells specific for Epstein-Barr virus (EBV) can effectively target the virus-transformed B lymphoproliferative lesions that arise in immunosuppressed transplant patients. This review explores the possibility of developing similar T cell-based strategies to treat an EBV-positive epithelial tumour, nasopharyngeal carcinoma (NPC), which arises in relatively immunocompetent individuals and where EBV antigen expression in the tumour is more limited.

Expression of viral and human dUTPase in Epstein-Barr virus-associated diseases

Deoxyuridine triphosphatase (dUTPase) catalyses the hydrolysis of dUTP to dUMP and pyrophosphate thus preventing the incorporation of uracil into replicating DNA. Previous studies of several virus models have suggested that viral dUTPases may be required for virus replication in resting cells whereas in proliferating cells cellular dUTPase may substitute for a mutant viral protein. Using monoclonal antibodies and immunohistochemistry, Epstein-Barr virus-associated non-neoplastic and neoplastic diseases were studied for the expression of viral and human dUTPases. Oral hairy leukoplakia, an AIDS-associated lesion of the tongue, is known to support EBV replication in the upper epithelial cell layers. In agreement with this, strong focal expression of EBV dUTPase was detected in the upper epithelial cell layers of oral hairy leukoplakia whereas expression of human dUTPase was confined to the basal proliferative cell compartment. Furthermore, in infectious mononucleosis tonsils, rare scattered small lymphoid cells expressed EBV dUTPase, consistent with the expression pattern of other EBV lytic cycle antigens. These findings are in agreement with the notion that EBV replicates in resting cells. Three EBV-associated tumours, Hodgkin lymphoma, Burkitt lymphoma and nasopharyngeal carcinoma, lacked detectable expression of EBV dUTPase, in agreement with the notion that EBV infection is largely latent in these tumours. By contrast, expression of human dUTPase was observed regularly in these tumours. These results suggest that EBV dUTPase may be a suitable target for anti-viral therapy and that inhibitors of human dUTPase should prove useful for the treatment of human tumours, including EBV-associated cancers.

Immunological aspects of Epstein-Barr virus infection

Epstein-Barr virus (EBV) is a member of ubiquitous gamma herpes viruses, which primarily induces acute infectious mononucleosis (IM) or subclinical infection in susceptible subjects. The host reactions account for the clinical manifestation of IM. This virus also contributes to the development of lymphoid or epithelial malignancies. The outgrowth of EBV-infected B-cells is first controlled by interferon (IFN)-gamma and natural killer (NK) cells, and later by EBV-specific cytotoxic T-lymphocytes (CTL). To overcome the host responses and establish the persistent infection, EBV conducts the protean strategies of immune evasion. Several EBV genes modulate apoptotic signals and cytokine balances to persist B-cell infection without insulting the host. Uncontrolled lymphoproliferation occurs as EBV(+) B-cell lymphoproliferative disease (LPD)/lymphoma in AIDS, posttransplant, or primary immunodeficiency diseases (PID). On the other hand, EBV(+) T/NK cells are involved in EBV-associated hemophagocytic lymphohistiocytosis (EBV-HLH) or chronic active EBV infection (CAEBV) in children having no underlying immunodeficiencies, and at times lead to the clonal evolution of T/NK-cell LPD/lymphomas. Recent advance in molecular techniques has enabled us to analyze the clonality of EBV-infected lymphocytes and to quantify the gene expression of EBV and cytokines. Dominant autocrine loop of T helper (Th) 2 and Th1 may exert in EBV(+) B-LPD and T-LPD, respectively. Intensive studies on the immunological interface between effector components and EBV(+) target cells will provide more information on clarifying the pathogenesis of EBV-associated lymphoid malignancies, as well as on exploiting the therapeutic and preventive strategies for the formidable EBV-associated disease in childhood.

Frequent expression of the Epstein-Barr virus (EBV)-induced gene, EBI3, an IL-12 p40-related cytokine, in Hodgkin and Reed-Sternberg cells

Epstein-Barr virus (EBV)-associated Hodgkin lymphoma (HL) and nasopharyngeal carcinoma (NPC) usually occur in patients without clinically manifest deficiencies in anti-viral immunity. In spite of expressing viral proteins, both tumours are apparently able to escape EBV-specific immunity in vivo. EBI3 is an EBV-induced cytokine homologous to the interleukin (IL)-12 p40 subunit and can heterodimerize with IL-12 p35. It has been suggested that EBI3 may function to antagonize IL-12 and to inhibit the development of a Th1 immune response. EBI3 expression has been studied in tumour entities frequently associated with EBV infection to examine if EBI3 might contribute to local modulation of the immune response. It is shown that EBI3 is strongly expressed in Hodgkin and Reed-Sternberg cells in 32 of 33 HL cases, independently of the EBV status of the tumour cells. Furthermore, EBI3 expression was detected in the epithelial tumour cells of six of 40 NPC biopsies but not in Burkitt lymphomas. The results suggest that EBI3 may be an additional component of the repertoire employed by Hodgkin and Reed-Sternberg cells to inhibit an effective anti-tumour or anti-viral immune response.

Interleukin-1beta expression in human gastric carcinoma with Epstein-Barr virus infection

The KT tumor is a transplantable strain of a human Epstein-Barr virus (EBV)-associated gastric carcinoma (EBVaGC), established in severe combined immunodeficiency (SCID) mice, with which the cytokine expression of EBVaGC can be investigated without interference from the infiltrating lymphocytes. As a part of a high-density oligonucleotide array (GeneChip) analysis of EBVaGC, the interleukin-1beta (IL-1beta) gene was the only cytokine gene that showed markedly higher expression in the KT tumor cells than in two tumor strains of EBV-negative GC. The results were confirmed by Northern blotting, Western blotting, and enzyme-linked immunosorbent assay. Furthermore, we demonstrated a positive signal for IL-1beta mRNA in the carcinoma cells of a surgically resected EBVaGC, but not in EBV-negative GC, by in situ hybridization. In vitro, IL-1beta increased the cell growth of a GC cell line, TMK1. Thus, IL-1beta may act as an autocrine growth factor in EBVaGC.

The role of cytokines in classical Hodgkin lymphoma

The clinical and pathologic features of classical Hodgkin lymphoma (cHL) reflect an abnormal immune response that is thought to be due to the elaboration of a variety of cytokines by the malignant Reed-Sternberg (RS) cells or surrounding tissues. The majority of cHL cases are characterized by expression of tumor necrosis factor receptor (TNFR) family members and their ligands, as well as an unbalanced production of Th2 cytokines and chemokines. Activation of TNFR members results in constitutive activation of nuclear factor-kappa B (NF-kappa B), a transcription factor important for the in vitro and in vivo growth of RS cell lines. The expression of Th2 cytokines and chemokines leads to the reactive infiltrate of eosinophils, Th2 cells, and fibroblasts characteristic of cHL, and can also contribute to a local suppression of Th1 cell-mediated cellular immune response. Another particularly important growth and survival factor for RS cell lines is the Th2 cytokine interleukin 13, which is also commonly expressed by primary RS cells. In approximately 40% of cHL cases, the presence of Epstein-Barr virus influences the Th1/Th2 balance toward the production of Th1 cytokines and chemokines, but this shift is apparently insufficient for the stimulation of an effective antitumor cell-mediated immune response. This review summarizes the current literature on cytokine expression by and activity on RS cell lines and primary cHL tissues, examines cytokine signaling pathways in RS cells, and discusses the role that cytokines play in the specific clinical and pathologic features of cHL.

Common and differential chemokine expression patterns in rs cells of NLP, EBV positive and negative classical Hodgkin lymphomas

Hodgkin lymphoma (HL) is characterized by a minority of neoplastic cells, the so-called Reed-Sternberg (RS) cells and a vast majority of reactive cells. RS cells produce chemokines that can attract subsets of peripheral blood cells into HL tissues. To gain insight in the chemokines involved in HL, 16 chemokines were selected based on their ability to recruit different subsets of cells. Five HL, 5 non-HL-derived cell lines, 22 HL, 5 non-HL and 3 control tissues were analyzed by reverse transcriptase-polymerase chain reaction (RT-PCR). Products for 13 of these 16 chemokines were detected in 1 or more of the cell lines tested. No or only very faint signals were obtained in HL for CXCL12, CCL7 and CCL8, but CXCL10, CCL5, CCL13, CCL17 and CCL22 were highly or differentially expressed in HL cell lines and tissues. Immunohistochemistry was performed with antibodies reactive with the latter 5 chemokines on paraffin sections of 21 cases of HL. CCL17 and CCL22 had the highest signals in RS cells at gene expression and at protein levels. CCL17 was specific for the classic HL subtypes, whereas CCL22 also had low signals in NLP samples, as well as in some non-HL. CXCL10 was expressed in a large proportion of HL cases with a predominant expression in EBV-positive cases. The results indicate that RS cells produce a complex pattern of chemokines that are involved in the recruitment of reactive cells and contribute to the paradox of an extensive but ineffective host immune response.

Chemokines in cancer

Chemokines participate, by regulating cell trafficking and controlling angiogenesis, in the host response during infection and inflammation. Most of these mechanisms are also operating in cancer. The stimulation of angiogenesis and tumor growth--directly or indirectly through the recruitment of tumor-associated macrophages--are typical situations where chemokines promote tumor development. On the other hand, chemokines could be used to the benefit of cancer patients as they act in the recruitment of dendritic cells (DC) or/and effector cells or for their angiostatic properties. However, chemokine-mediated recruitment of immature DC within tumors, due to factors produced by the tumor milieu, could lead to the induction of immune tolerance and, therefore, novel strategies to eradicate tumors based on chemokines should attempt to avoid this risk.

Epstein-Barr virus infection and human malignancies

The Epstein-Barr virus (EBV) is a herpes virus which establishes a life-long persistent infection in over 90% of the human adult population world-wide. Based on its association with a variety of lymphoid and epithelial malignancies, EBV has been classified as a group 1 carcinogen by the International Agency for Research on Cancer. In this article we discuss the evidence supporting an aetiological role for EBV in the pathogenesis of human tumours. The biology of EBV infection will be described with special emphasis on viral transforming gene products. A brief survey of EBV-associated tumours is followed by a discussion of specific problems. Evidence is presented which suggests that failures of the EBV-specific immunity may play a role in the pathogenesis of EBV-associated tumours also in patients without clinically manifest immunodeficiencies. Finally, the timing of EBV infection in the pathogenesis of virus-associated malignancies is discussed. There is good evidence that EBV infection precedes expansion of the malignant cell populations in some virus-associated tumours. However, this is clearly not always the case and for some of these tumours there are indications that clonal genetic alterations may occur prior to EBV infection. Thus, whilst there is good evidence to suggest that EBV is a human carcinogen, its precise role(s) in the development of virus-associated human tumours requires clarification.

Epstein-Barr virus infection and human malignancies

The Epstein-Barr virus (EBV) is a herpes virus which establishes a life-long persistent infection in over 90% of the human adult population world-wide. Based on its association with a variety of lymphoid and epithelial malignancies, EBV has been classified as a group 1 carcinogen by the International Agency for Research on Cancer. In this article we discuss the evidence supporting an aetiological role for EBV in the pathogenesis of human tumours. The biology of EBV infection will be described with special emphasis on viral transforming gene products. A brief survey of EBV-associated tumours is followed by a discussion of specific problems. Evidence is presented which suggests that failures of the EBV-specific immunity may play a role in the pathogenesis of EBV-associated tumours also in patients without clinically manifest immunodeficiencies. Finally, the timing of EBV infection in the pathogenesis of virus-associated malignancies is discussed. There is good evidence that EBV infection precedes expansion of the malignant cell populations in some virus-associated tumours. However, this is clearly not always the case and for some of these tumours there are indications that clonal genetic alterations may occur prior to EBV infection. Thus, whilst there is good evidence to suggest that EBV is a human carcinogen, its precise role(s) in the development of virus-associated human tumours requires clarification.

Epstein-Barr virus infection and human malignancies

The Epstein-Barr virus (EBV) is a herpes virus which establishes a life-long persistent infection in over 90% of the human adult population world-wide. Based on its association with a variety of lymphoid and epithelial malignancies, EBV has been classified as a group 1 carcinogen by the International Agency for Research on Cancer. In this article we discuss the evidence supporting an aetiological role for EBV in the pathogenesis of human tumours. The biology of EBV infection will be described with special emphasis on viral transforming gene products. A brief survey of EBV-associated tumours is followed by a discussion of specific problems. Evidence is presented which suggests that failures of the EBV-specific immunity may play a role in the pathogenesis of EBV-associated tumours also in patients without clinically manifest immunodeficiencies. Finally, the timing of EBV infection in the pathogenesis of virus-associated malignancies is discussed. There is good evidence that EBV infection precedes expansion of the malignant cell populations in some virus-associated tumours. However, this is clearly not always the case and for some of these tumours there are indications that clonal genetic alterations may occur prior to EBV infection. Thus, whilst there is good evidence to suggest that EBV is a human carcinogen, its precise role(s) in the development of virus-associated human tumours requires clarification.