Identification of a human epithelial cell surface protein sharing an epitope with the C3d/Epstein-Barr virus receptor molecule of B lymphocytes

Investigating the role of Epstein-Barr virus and human papillomavirus types 16 and 18 co-infections in cervical disease of Iranian women

Introduction

High-risk human papillomaviruses (HR-HPVs) are known to contribute to cervical cancer (CC), but the role of Epstein-Barr virus (EBV) in this process remains unclear, despite EBV's widespread detection in premalignant and malignant cervical tissues.

Methods

In this cross-sectional study of 258 cervical samples, including both formalin-fixed paraffin-embedded (FFPE) and fresh cervical tissues, the presence and viral load of HR-HPVs (HPV-16 and HPV-18) and EBV were evaluated in Iranian women with cervical intraepithelial neoplasia (CIN), squamous cell carcinoma (SCC), and a cervicitis control group using real-time PCR.

Results

The study revealed a significant correlation between disease severity and both increased HPV-16 positivity and HPV-16 and HPV-18 co-infection (p<0.001). Interestingly, the control group had a higher frequency of EBV-positive cases than SCC/CIN groups (p<0.001). HPV-16 DNA load increased with disease severity (P<0.001), while HPV-18 showed no significant difference (P=0.058). The control group had a higher EBV DNA load compared to SCC/CIN groups (P=0.033). HPV-16 increased the risk of CIN II, CIN III, and SCC, while HPV-18 increased the risk of CIN II and CIN III. Notably, EBV was associated with a lower risk of CIN groups and SCC.

Conclusions

No significant difference in EBV co-infection with HPV-16/18 was found, failing to support the hypothesis that EBV is a cofactor in CC. However, high EBV viral load in the control group suggests a potential "hit and run hypothesis" role in CC progression. This hypothesis suggests that EBV may contribute briefly to the initiation of CC with an initial impact but then becomes less actively involved in its ongoing progression.

Tumor-educated platelets

Beyond traditional roles in homeostasis and coagulation, growing evidence suggests that platelets also reflect malignant transformation in cancer. Platelets are present in the tumor microenvironment where they interact with cancer cells. This interaction results in direct and indirect "education" as evident by platelet alterations in adhesion molecules, glycoproteins, nucleic acids, proteins and various receptors. Subsequently, these tumor-educated platelets (TEPs) circulate throughout the body and play pivotal roles in promotion of tumor growth and dissemination. Accordingly, platelet status can be considered a unique blood-based biomarker that can potentially predict prognosis and therapeutic success. Recently, liquid biopsies including TEPs have received much attention as safe, minimally invasive and sensitive alternatives for patient management. Herein, we provide an overview of TEPs and explore their benefits and limitations in cancer.

The CD40 agonist HERA-CD40L results in enhanced activation of antigen presenting cells, promoting an anti-tumor effect alone and in combination with radiotherapy

Introduction

The ability to modulate and enhance the anti-tumor immune responses is critical in developing novel therapies in cancer. The Tumor Necrosis Factor (TNF) Receptor Super Family (TNFRSF) are potentially excellent targets for modulation which result in specific anti-tumor immune responses. CD40 is a member of the TNFRSF and several clinical therapies are under development. CD40 signaling plays a pivotal role in regulating the immune system from B cell responses to myeloid cell driven activation of T cells. The CD40 signaling axis is well characterized and here we compare next generation HERA-Ligands to conventional monoclonal antibody based immune modulation for the treatment of cancer.

Methods & results

HERA-CD40L is a novel molecule that targets CD40 mediated signal transduction and demonstrates a clear mode of action in generating an activated receptor complex via recruitment of TRAFs, cIAP1, and HOIP, leading to TRAF2 phosphorylation and ultimately resulting in the enhanced activation of key inflammatory/survival pathway and transcription factors such asNFkB, AKT, p38, ERK1/2, JNK, and STAT1 in dendritic cells. Furthermore, HERA-CD40L demonstrated a strong modulation of the tumor microenvironment (TME) via the increase in intratumoral CD8+ T cells and the functional switch from pro-tumor macrophages (TAMs) to anti-tumor macrophages that together results in a significant reduction of tumor growth in a CT26 mouse model. Furthermore, radiotherapy which may have an immunosuppressive modulation of the TME, was shown to have an immunostimulatory effect in combination with HERA-CD40L. Radiotherapy in combination with HERA-CD40L treatment resulted in an increase in detected intratumoral CD4+/8+ T cells compared to RT alone and, additionally, the repolarization of TAMs was also observed, resulting in an inhibition of tumor growth in a TRAMP-C1 mouse model.

Discussion

Taken together, HERA-CD40L resulted in activating signal transduction mechanisms in dendritic cells, resulting in an increase in intratumoral T cells and manipulation of the TME to be pro-inflammatory, repolarizing M2 macrophages to M1, enhancing tumor control.

Epstein-Barr Virus-Associated Carcinoma of the Larynx: A Systematic Review with Meta-Analysis

Over the past few decades, several publications have investigated the role of Epstein-Barr virus (EBV) in head and neck squamous cell carcinomas, and an increasing number of them have shown its presence in laryngeal tumors. The purpose of this meta-analysis was to evaluate the association of EBV with laryngeal carcinoma. The search was carried out in two databases, Scopus and PubMed, using the following terms: “Epstein-Barr virus” and “laryngeal carcinoma”. A total of 187 records were found, of which 31 were selected for meeting the inclusion and exclusion criteria. The meta-analysis yielded an overall pooled prevalence of 43.72% (95% confidence interval (CI): 34.35–53.08). Studies carried out in Europe and Eurasia had slightly higher pooled prevalence than other subgroups, while the prevalence of studies performed in developed countries was higher than in developing countries (46.37% vs. 34.02%). Furthermore, laryngeal carcinoma occurred almost three times as often among EBV-infected individuals compared to those without EBV infection (odds ratio = 2.86 (95% CI: 1.18–6.90); Begg’s test, p = 0.843 and Egger’s test, p = 0.866). Our findings support the idea that EBV is related to laryngeal carcinoma. However, further studies are needed before recognizing a definitive etiological role of EBV in the development and/or progression of laryngeal carcinomas.

Tackling Immune Targets for Breast Cancer: Beyond PD-1/PD-L1 Axis

The burden of breast cancer is imposing a huge global problem. Drug discovery research and novel approaches to treat breast cancer have been carried out extensively over the last decades. Although immune checkpoint inhibitors are showing promising preclinical and clinical results in treating breast cancer, they are facing multiple limitations. From an immunological perspective, a recent report highlighted breast cancer as an "inflamed tumor" with an immunosuppressive microenvironment. Consequently, researchers have been focusing on identifying novel immunological targets that can tune up the tumor immune microenvironment. In this context, several novel non-classical immune targets have been targeted to determine their ability to uncouple immunoregulatory pathways at play in the tumor microenvironment. This article will highlight strategies designed to increase the immunogenicity of the breast tumor microenvironment. It also addresses the latest studies on targets which can enhance immune responses to breast cancer and discusses examples of preclinical and clinical trial landscapes that utilize these targets.

Impacts of Cancer on Platelet Production, Activation and Education and Mechanisms of Cancer-Associated Thrombosis

Platelets are small anucleate cells that are traditionally described as the major effectors of hemostasis and thrombosis. However, increasing evidence indicates that platelets play several roles in the progression of malignancies and in cancer-associated thrombosis. A notable cross-communication exists between platelets and cancer cells. On one hand, cancer can “educate” platelets, influencing their RNA profiles, the numbers of circulating platelets and their activation states. On the other hand, tumor-educated platelets contain a plethora of active biomolecules, including platelet-specific and circulating ingested biomolecules, that are released upon platelet activation and participate in the progression of malignancy. The numerous mechanisms by which the primary tumor induces the production, activation and aggregation of platelets (also known as tumor cell induced platelet aggregation, or TCIPA) are directly related to the pro-thrombotic state of cancer patients. Moreover, the activation of platelets is critical for tumor growth and successful metastatic outbreak. The development or use of existing drugs targeting the activation of platelets, adhesive proteins responsible for cancer cell-platelet interactions and platelet agonists should be used to reduce cancer-associated thrombosis and tumor progression.

EBNA1-targeted inhibitors: Novel approaches for the treatment of Epstein-Barr virus-associated cancers

Epstein-Barr virus (EBV) infects more than 90% of humans worldwide and establishes lifelong latent infection in the hosts. It is closely associated with endemic forms of a wide range of human cancers and directly contributes to the formation of some. Despite its critical role in cancer development, no EBV- or EBV latent protein-targeted therapy is available. The EBV-encoded latent protein, Epstein-Barr nuclear antigen 1 (EBNA1), is expressed in all EBV-associated tumors and acts as the only latent protein in some of these tumors. This versatile protein functions in the maintenance, replication, and segregation of the EBV genome and can therefore serve as an attractive therapeutic target to treat EBV-associated cancers. In the last decades, efforts have been made for designing specific EBNA1 inhibitors to decrease EBNA1 expression or interfere with EBNA1-dependent functions. In this review, we will briefly introduce the salient features of EBNA1, summarize its functional domains, and focus on the recent developments in the identification and design of EBNA1 inhibitors related to various EBNA1 domains as well as discuss their comparative merits.

Epstein-Barr virus infection and nasopharyngeal carcinoma

Epstein-Barr virus (EBV) is associated with multiple types of human cancer, including lymphoid and epithelial cancers. The closest association with EBV infection is seen in undifferentiated nasopharyngeal carcinoma (NPC), which is endemic in the southern Chinese population. A strong association between NPC risk and the HLA locus at chromosome 6p has been identified, indicating a link between the presentation of EBV antigens to host immune cells and NPC risk. EBV infection in NPC is clonal in origin, strongly suggesting that NPC develops from the clonal expansion of a single EBV-infected cell. In epithelial cells, the default program of EBV infection is lytic replication. However, latent infection is the predominant mode of EBV infection in NPC. The establishment of latent EBV infection in pre-invasive nasopharyngeal epithelium is believed to be an early stage of NPC pathogenesis. Recent genomic study of NPC has identified multiple somatic mutations in the upstream negative regulators of NF-κB signalling. Dysregulated NF-κB signalling may contribute to the establishment of latent EBV infection in NPC. Stable EBV infection and the expression of latent EBV genes are postulated to drive the transformation of pre-invasive nasopharyngeal epithelial cells to cancer cells through multiple pathways.This article is part of the themed issue 'Human oncogenic viruses'.

Association between Epstein-Barr virus (EBV) and cervical carcinoma: A meta-analysis

OBJECTIVES

Human papillomavirus (HPV) has been implicated as a major factor in cervical carcinogenesis. However, many pieces of evidence gathered over the last two decades suggest Epstein-Barr virus (EBV) plays a secondary role in this process. The purpose of the present meta-analysis was to determine whether the presence of EBV infection increases the risk of cervical carcinoma.

METHODS

Based on 25 articles, the analysis yielded a 33.44% overall pooled prevalence of EBV.

RESULTS

The pooled prevalence was higher in patients with carcinoma (43.63%) than in healthy patients (19.0%) or patients with cervical intraepithelial neoplasia 1 (CIN1) (27.34%) or CIN2/3 (34.67%). Co-infection with EBV and HPV displayed a similar pattern. EBV infection was significantly and positively associated with lesion grade in cervical epithelia and was more prevalent in malignant lesions. Moreover, cervical carcinoma occurred four times as often among EBV positive women as in women without EBV infection (OR=4.01 [1.87-8.58]; p<0.001).

CONCLUSIONS

The existence of EBV(+)HPV(-) carcinomas, the confirmed expression of latent oncoproteins (EBNA1, EBNA2, LMP1) and EBERs in tumor cells, and the association of EBV with the integration of high-risk-HPV DNA in malignant specimens point to EBV as a co-factor (so far underestimated) in the genesis and/or progression of cervical carcinoma. However, further studies are necessary before the link between EBV and cervical carcinoma can be established.

The Role of Gammaherpesviruses in Cancer Pathogenesis

Worldwide, one fifth of cancers in the population are associated with viral infections. Among them, gammaherpesvirus, specifically HHV4 (EBV) and HHV8 (KSHV), are two oncogenic viral agents associated with a large number of human malignancies. In this review, we summarize the current understanding of the molecular mechanisms related to EBV and KSHV infection and their ability to induce cellular transformation. We describe their strategies for manipulating major cellular systems through the utilization of cell cycle, apoptosis, immune modulation, epigenetic modification, and altered signal transduction pathways, including NF-kB, Notch, Wnt, MAPK, TLR, etc. We also discuss the important EBV latent antigens, namely EBNA1, EBNA2, EBNA3’s and LMP’s, which are important for targeting these major cellular pathways. KSHV infection progresses through the engagement of the activities of the major latent proteins LANA, v-FLIP and v-Cyclin, and the lytic replication and transcription activator (RTA). This review is a current, comprehensive approach that describes an in-depth understanding of gammaherpes viral encoded gene manipulation of the host system through targeting important biological processes in viral-associated cancers.

Co-infection of Epstein-Barr virus and human papillomavirus in human tumorigenesis

Viral infections contribute to approximately 12% of cancers worldwide, with the vast majority occurring in developing countries and areas. Two DNA viruses, Epstein-Barr virus (EBV) and human papillomavirus (HPV), are associated with 38% of all virus-associated cancers. The probability of one patient infected with these two distinct types of viruses is increasing. Here, we summarize the co-infection of EBV and HPV in human malignancies and address the possible mechanisms for the co-infection of EBV and HPV during tumorigenesis.

Viral Entry

Epstein-Barr virus primarily, though not exclusively, infects B cells and epithelial cells. Many of the virus and cell proteins that are involved in entry into these two cell types in vitro have been identified, and their roles in attachment and fusion are being explored. This chapter discusses what is known about entry at the cellular level in vitro and describes what little is known about the process in vivo. It highlights some of the questions that still need to be addressed and considers some models that need further testing.

Human papillomavirus and Epstein-Barr virus co-infection in cervical carcinoma in Algerian women

Background

Despite the fact that the implication of human papillomavirus (HPV) in the carcinogenesis and prognosis of cervical cancer is well established, the impact of a co-infection with high risk HPV (HR-HPV) and Epstein-Barr virus (EBV) is still not fully understood.

Methods

Fifty eight randomly selected cases of squamous cell carcinomas (SCC) of the uterine cervix, 14 normal cervices specimens, 21 CIN-2/3 and 16 CIN-1 cases were examined for EBV and HPV infections. Detection of HR-HPV specific sequences was carried out by PCR amplification using consensus primers of Manos and by Digene Hybrid Capture. The presence of EBV was revealed by amplifying a 660 bp specific EBV sequence of BALF1. mRNA expression of LMP-1 in one hand and protein levels of BARF-1, LMP-1 and EBNA-1 in the other hand were assessed by RT-PCR and immunoblotting and/or immunohischemistry respectively.

Results

HR-HPV infection was found in patients with SCC (88%), low-grade (75%) and high grade (95%) lesions compared to only 14% of normal cervix cases. However, 69%, 12.5%, 38.1%, and 14% of SCC, CIN-1, CIN-2/3 and normal cervix tissues, respectively, were EBV infected. The highest co-infection (HR-HPV and EBV) was found in squamous cell carcinoma cases (67%). The latter cases showed 27% and 29% expression of EBV BARF-1 and LMP-1 oncogenes respectively.

Conclusion

The high rate of HR-HPV and EBV co-infection in SCC suggests that EBV infection is incriminated in cervical cancer progression. This could be taken into account as bad prognosis in this type of cancer. However, the mode of action in dual infection in cervical oncogenesis needs further investigation.

Oral dysplasia and squamous cell carcinoma: correlation between increased expression of CD21, Epstein-Barr virus and CK19

OBJECTIVES

Epstein-Barr virus is an orally transmitted human gammaherpesvirus that infects B lymphocytes and epithelial cells. Although most primary infections are asymptomatic, long term carriage of the virus can be associated with either lymphoid or epithelial malignancies. The association of EBV with oral squamous cell carcinomas is sporadic and it is uncertain if the virus is involved in initiation of the tumor or, possibly, in its progression. Complement receptor type 2, CR2 or CD21, is a receptor for the major attachment protein of EBV, which significantly enhances epithelial cell infection, but its expression on normal tissues is restricted to tonsil and adenoid epithelium. As cells become dysplastic they are reported to express higher levels of CK19. We sought to evaluate whether CD21 and CK19 expression change as oral epithelial cells outside Waldeyer's ring become dysplastic.

MATERIALS AND METHODS

Epithelial cells were isolated by laser capture microdissection and levels of CD21, CK19 and EBV RNA were measured by quantitative reverse transcriptase PCR.

RESULTS

We report that expression of CD21 increases in frequency and intensity as oral epithelial cells become more dysplastic and that expression correlates with an increase in infection by EBV. Tumors or dysplastic lesions that carry EBV also generally express higher levels of CK19 than those that do not.

CONCLUSION

The findings suggest that dysplasia may make cells more susceptible to infection by EBV and that infection by the virus may alter the phenotype of the infected cell in a manner which could affect prognosis.

Anti-CD40 monoclonal antibody

Normal, bi-directional interactions between CD 40 and its natural ligand CD 154 (CD 40 ligand) are central to the generation of both T cell-dependent, humoral immune responses and cytotoxic T-cell responses. CD 40 is expressed on a broad range of hematological and epithelial malignancies. The development of monoclonal antibodies directed against CD 40 allows effective targeting of malignant cells through multiple mechanisms that include the recruitment of immune effector mechanisms such as complement-dependent cytotoxicity and antibody-dependent cellular cytotoxicity, direct anti-proliferative effects on neoplastic cells and, importantly, by the activation of tumor-targeted cellular cytotoxicity. This review provides the background to the early clinical trial data that are now beginning to emerge for this potentially exciting new treatment approach.

Molecular mechanism and function of CD40/CD40L engagement in the immune system

SUMMARY

During the generation of a successful adaptive immune response, multiple molecular signals are required. A primary signal is the binding of cognate antigen to an antigen receptor expressed by T and B lymphocytes. Multiple secondary signals involve the engagement of costimulatory molecules expressed by T and B lymphocytes with their respective ligands. Because of its essential role in immunity, one of the best characterized of the costimulatory molecules is the receptor CD40. This receptor, a member of the tumor necrosis factor receptor family, is expressed by B cells, professional antigen-presenting cells, as well as non-immune cells and tumors. CD40 binds its ligand CD40L, which is transiently expressed on T cells and other non-immune cells under inflammatory conditions. A wide spectrum of molecular and cellular processes is regulated by CD40 engagement including the initiation and progression of cellular and humoral adaptive immunity. In this review, we describe the downstream signaling pathways initiated by CD40 and overview how CD40 engagement or antagonism modulates humoral and cellular immunity. Lastly, we discuss the role of CD40 as a target in harnessing anti-tumor immunity. This review underscores the essential role CD40 plays in adaptive immunity.

Laser-capture microdissection of oropharyngeal epithelium indicates restriction of Epstein-Barr virus receptor/CD21 mRNA to tonsil epithelial cells

BACKGROUND

Epstein-Barr virus colonizes the oropharynx of a majority of individuals. It infects B lymphocytes and epithelial cells and can contribute to the development of both lymphoid and epithelial tumors. The virus uses CD21 for attachment to B cells which constitutively express the protein. Infection of epithelial cells in vitro is also more efficient if CD21 is available. However, its potential contribution to infection in vivo has been difficult to evaluate as discrepant results with antibodies have made it difficult to determine which, if any, epithelial cells in the oropharynx express CD21.

METHODS

To reevaluate CD21 expression by an alternative method, epithelial cells were isolated by laser-capture microdissection from formalin-fixed sections of tissues from various parts of the oropharynx and mRNA was amplified with primers specific for the exons of CD21 which code for the Epstein-Barr virus binding site.

RESULTS

CD21 mRNA was expressed in tonsil epithelium, but not in epithelium from buccal mucosa, uvula, soft palate or tongue.

CONCLUSIONS

CD21 does not contribute to infection of most normal epithelial tissues in the oropharynx, but may contribute to infection of epithelial cells in the tonsil, where virus has been demonstrated in healthy carriers.

Epstein-Barr virus-targeted immunotherapy for nasopharyngeal carcinoma

Epstein-Barr virus (EBV) is constantly present in undifferentiated and poorly-differentiated nasopharyngeal cancer. Thus, tumour-associated viral antigens are potential targets for immunotherapy. Recently, both preclinical and early clinical studies have shown that various strategies can enhance EBV-specific immunity. Moreover, significant anti-tumour effect has been observed, and was generally correlated with biological response. The present review discusses the rational for EBV-targeted immunotherapy and summarises the latest developments in this area.

Nuclear CD40 interacts with c-Rel and enhances proliferation in aggressive B-cell lymphoma

CD40 is an integral plasma membrane-associated member of the TNF receptor family that has recently been shown to also reside in the nucleus of both normal B cells and large B-cell lymphoma (LBCL) cells. However, the physiological function of CD40 in the B-cell nucleus has not been examined. In this study, we demonstrate that nuclear CD40 interacts with the NF-kappaB protein c-Rel, but not p65, in LBCL cells. Nuclear CD40 forms complexes with c-Rel on the promoters of NF-kappaB target genes, CD154, BLyS/BAFF, and Bfl-1/A1, in various LBCL cell lines. Wild-type CD40, but not NLS-mutated CD40, further enhances c-Rel-mediated Blys promoter activation as well as proliferation in LBCL cells. Studies in normal B cells and LBCL patient cells further support a nuclear transcriptional function for CD40 and c-Rel. Cooperation between nuclear CD40 and c-Rel appears to be important in regulating cell growth and survival genes involved in lymphoma cell proliferation and survival mechanisms. Modulating the nuclear function of CD40 and c-Rel could reveal new mechanisms in LBCL pathophysiology and provide potential new targets for lymphoma therapy.

The CD40, CTLA-4, thyroglobulin, TSH receptor, and PTPN22 gene quintet and its contribution to thyroid autoimmunity: back to the future

Autoimmune thyroid diseases (AITD) are common autoimmune diseases, affecting up to 5% of the general population. Thyroid-directed autoimmunity is manifested in two classical autoimmune conditions, Hashimoto's thyroiditis, resulting in hypothyroidism and Graves' disease resulting in hyperthyroidism. Autoimmune thyroid diseases arise due to an interplay between environmental and genetic factors. In the past decade significant progress has been made in our understanding of the genetic contribution to the etiology of AITD. Indeed, several AITD susceptibility genes have been identified. Some of these susceptibility genes are specific to either Graves' disease or Hashimoto's thyroiditis, while others confer susceptibility to both conditions. Both immunoregulatory genes and thyroid specific genes contribute to the pathogenesis of AITD. The time is now ripe to examine the mechanistic basis for the contribution of genetic factors to the etiology of AITD. In this review, we will focus on the contribution of non-MHC II genes.

No evidence of Epstein-Barr virus association with Merkel cell carcinoma

BACKGROUND

Merkel cell carcinoma (MCC) is an aggressive tumor of cutaneous neuroendocrine cells with a reported 13-fold increased incidence in immunocompromised patients, raising the possibility that it is driven by an oncogenic virus. Additionally, Merkel cell hyperplasia is seen in the Epstein-Barr virus (EBV)-driven process oral hairy leukoplakia, and EBV is known to be involved in the pathogenesis of several other malignancies.

OBJECTIVE

We tested the hypothesis that EBV is involved in MCC.

METHODS

We employed EBV-encoded RNA in situ hybridization (ISH), lytic EBV ISH, latent membrane protein 1 immunohistochemistry, and BamH1Z leftward reading frame 1 immunohistochemistry to detect and localize EBV in paraffin sections of MCC from five patients as well as seven other cutaneous tumors and positive controls for EBV infection.

RESULTS

Positive controls reacted appropriately. However, there was no evidence of latent or lytic EBV in any of the MCC biopsies or other cutaneous tumors.

CONCLUSION

Our findings suggest that EBV is not associated with MCC.

Antibodies to gp350/220 enhance the ability of Epstein-Barr virus to infect epithelial cells

Epstein-Barr virus (EBV) is a persistent, orally transmitted herpesvirus that replicates in B cells and epithelial cells and is associated with lymphoid and epithelial malignancies. The virus binds to CD21 on B cells via glycoprotein gp350/220 and infects efficiently. Infection of cultured epithelial cells has not typically been efficient but can occur in the absence of gp350/220 and CD21 and in vivo is thought to be important to the development of nasopharyngeal carcinoma. We report here that antibodies to gp350/220, which inhibit EBV infection of B cells, enhance infection of epithelial cells. The effect is not mediated by Fc receptor binding but is further enhanced by antibody cross-linking, which may patch gp350/220 in the virus envelope. Saliva from EBV-seropositive individuals has similar effects that can be reversed by depletion of antibody. The results are consistent with a model in which gp350/220 interferes with the access of other important players to the epithelial cell surface. The results may have implications for the development of nasopharyngeal carcinoma in high-risk populations in which elevated titers of antibody to EBV lytic cycle proteins are prognostic.

Chemotherapeutic agents enhance AAV2-mediated gene transfer into breast cancer cells promoting CD40 ligand-based immunotherapy

PURPOSE

Supplementing conventional treatment with gene therapy to induce an immune response might be beneficial to cancer patients. In this study, we evaluated the efficiency of transduction of breast cancer cells with recombinant adeno-associated virus (rAAV) and effects of cytotoxic agents used in chemotherapy. Furthermore, the capacity of tumor cells expressing transgenic CD40 ligand (CD40L) to stimulate dendritic cells was measured.

METHODS

Breast cancer cell lines were infected with a rAAV encoding the enhanced green fluorescent protein (EGFP) or murine CD40L and transgene expression was analyzed by flow cytometry. Stimulation of isolated human dendritic cells by CD40L-expressing tumor cells was quantified by measuring secreted interleukin 12.

RESULTS

Infection with an EGFP-encoding rAAV resulted in variable fractions (14-93%, mean 42%) of transgene-expressing cells. Pre-incubation of MM 157, MM 231, and MCF7 cells with epirubicin or carboplatin substantially increased AAV-mediated transgene expression. rAAV/CD40L was used to generate CD40L-transgenic tumor cells, which specifically activated immature dendritic cells, as confirmed by blocking with an antibody binding to CD40L.

CONCLUSIONS

The efficiency of rAAV-mediated gene transfer into breast cancer cells is significantly higher than previously reported and can be further enhanced by co-administration of chemotherapeutic agents. We also confirmed that breast cancer cells can activate human dendritic cells after infection with a CD40L-encoding rAAV.

TRAF6 is required for TRAF2-dependent CD40 signal transduction in nonhemopoietic cells

The emerging role of CD40, a tumor necrosis factor (TNF) receptor family member, in immune regulation, disease pathogenesis, and cancer therapy necessitates the analysis of CD40 signal transduction in a wide range of tissue types. In this study we present evidence that the CD40-interacting proteins TRAF2 and TRAF6 play an important physiological role in CD40 signaling in nonhemopoietic cells. Using mutational analysis of the CD40 cytoplasmic tail, we demonstrate that the specific binding of TRAF2 to CD40 is required for efficient signaling on the NF-kappaB, Jun N-terminal protein kinase (JNK), and p38 axis. In fibroblasts lacking TRAF2 or in carcinoma cells in which TRAF2 has been depleted by RNA interference, the CD40-mediated activation of NF-kappaB and JNK is significantly reduced, and the activation of p38 and Akt is severely impaired. Interestingly, whereas the TRAF6-interacting membrane-proximal domain of CD40 has a minor role in signal transduction, studies utilizing TRAF6 knockout fibroblasts and RNA interference in epithelial cells reveal that the CD40-induced activation of NF-kappaB, JNK, p38, and Akt requires the integrity of TRAF6. Furthermore, we provide evidence that TRAF6 regulates CD40 signal transduction not only through its direct binding to CD40 but also indirectly via its association with TRAF2. These observations provide novel insight into the mechanisms of CD40 signaling and the multiple roles played by TRAF6 in signal transduction.

Activation of CD40 in Cervical Carcinoma Cells Facilitates CTL Responses and Augments Chemotherapy-Induced Apoptosis

In this study, we describe the expression and function of CD40, a TNF receptor family member, in cervical carcinomas. CD40 was present at very low levels in normal cervical epithelium but was overexpressed in human papillomavirus-infected lesions and advanced squamous carcinomas of the cervix. The stimulation of CD40-positive cervical carcinoma cell lines with soluble CD40L (CD154) resulted in activation of the NF-kappaB and MAPK signaling pathways and up-regulation of cell surface markers and intracellular molecules associated with Ag processing and presentation. Concomitantly, the CD154-induced activation of CD40 in carcinoma cells was found to directly influence susceptibility to CTL-mediated killing. Thus, CD40 stimulation in cervical carcinoma cell lines expressing a TAP-dependent human papillomavirus 16 E6 Ag epitope resulted in their enhanced killing by specific CTLs. However, CD154 treatment of carcinoma cells expressing proteasome-dependent but TAP-independent Ags from the EBV-encoded BRLF1 and BMLF1 failed to increase tumor cell lysis by specific CTLs. Moreover, we demonstrate that chemotherapeutic agents that suppress protein synthesis and reverse the CD40-mediated dissociation of the translational repressor eukaryotic initiation factor 4E-binding protein from the initiation factor eukaryotic initiation factor 4E, such as 5-fluorouracil, etoposide, and quercetin, dramatically increase the susceptibility of cervical carcinoma cells to CD40L-induced apoptosis. Taken together, these observations demonstrate the functional expression of CD40 in epithelial tumors of the cervix and support the clinical exploitation of the CD40 pathway for the treatment of cervical cancer through its multiple effects on tumor cell growth, apoptosis, and immune recognition.

Epstein-Barr virus and cancer

EBV was the first human virus to be directly implicated in carcinogenesis. It infects >90% of the world's population. Although most humans coexist with the virus without serious sequelae, a small proportion will develop tumors. Normal host populations can have vastly different susceptibility to EBV-related tumors as demonstrated by geographical and immunological variations in the prevalence of these cancers. EBV has been implicated in the pathogenesis of Burkitt's lymphoma, Hodgkin's disease, non-Hodgkin's lymphoma, nasopharyngeal carcinoma, and lymphomas, as well as leiomyosarcomas arising in immunocompromised individuals. The presence of this virus has also been associated with epithelial malignancies arising in the gastric region and the breast, although some of this work remains in dispute. EBV uses its viral proteins, the actions of which mimic several growth factors, transcription factors, and antiapoptotic factors, to usurp control of the cellular pathways that regulate diverse homeostatic cellular functions. Recent advances in antiviral therapeutics, application of monoclonal antibodies, and generation of EBV-specific CTLs are beginning to show promise in the treatment of EBV-related disorders.

Use of gHgL for attachment of Epstein-Barr virus to epithelial cells compromises infection

Epstein-Barr virus (EBV) is a lymphotropic herpesvirus. However, access to B lymphocytes during primary infection may be facilitated by replication in mucosal epithelial cells. Attachment and penetration of EBV into these two cell types are fundamentally different. Both the distribution of receptors and the cellular origin of the virus impact the efficiency of infection. Epithelial cells potentially offer a wide range of receptors with which virus can interact. We report here on analyses of epithelial cells expressing different combinations of receptors. We find that the stoichiometry of the virus glycoprotein complex that includes gHgL and gp42 affects the use of gHgL not just for entry into epithelial cells but also for attachment. Penetration can be mediated efficiently with either a coreceptor for gp42 or gHgL, but the use of gHgL for attachment as well as penetration greatly compromises its ability to mediate entry.

IFN regulatory factor-1 is required for the up-regulation of the CD40-NF-kappa B activator 1 axis during airway inflammation

Recent studies show that NF-kappa B activator 1 (Act1) functions as an important adapter molecule for CD40-mediated signaling in epithelial cells. To explore the physiological function of the CD40-Act1 axis, we studied the regulation of gene expression of CD40 and Act1 both in vivo and in cell culture models. Although CD40 and Act1 are up-regulated in mouse lung upon LPS stimulation, IL-1 plus IFN-alpha, -beta, or -gamma synergistically up-regulate both CD40 and Act1 gene expression in human epithelial A549 cells. Cycloheximide superinduces the Act1 mRNA, whereas actinomycin D completely abolishes the Act1 mRNA, indicating that the induction of Act1 mRNA is at the transcriptional level and does not require protein synthesis. Promoter sequence analyses identified putative IFN regulatory factor (IRF)-1, C/EBP-beta, and AP-1 transcription factor binding sites in the Act1 promoter. Although mutation of any of the three sites abolished the promoter activity, Abs against IRF-1 and C/EBP-beta, but not AP-1, blocked the formation of the DNA-binding complex induced by IL-1 plus IFN-beta stimulation, suggesting cooperative action between IRF-1 and C/EBP-beta in mediating Act1 promoter activity. Importantly, LPS-induced gene expression of CD40 and Act1 in the mouse lung is abolished in IRF-1(-/-) mice, indicating an essential role of transcription factor IRF-1 in the coordinated regulation of these two genes during airway inflammation. The induced expression of the CD40-Act1 axis by inflammatory cytokines in epithelial cells probably plays an important role in priming these cells for their response to CD40 ligand during airway inflammation.

Epstein-Barr virus (EBV)-related oral squamous cell carcinoma in Okinawa, a subtropical island, in southern Japan--simultaneously infected with human papillomavirus (HPV)

Up to now, many authors have reported on the EBV infection and its carcinogenic importance in undifferentiated nasopharyngeal carcinoma (WHO classification, type III), but the infection of the virus in well differentiated oral squamous cell carcinoma has not been well described. We introduce the EBV-related well differentiated oral squamous cell carcinomas in Okinawa, a subtropical island in the southernmost part of Japan. This study aimed to clarify the pathogenesis of this malignancy in this area by carrying out analysis of the histology and the Epstein-Barr (EBV) and human papillomavirus (HPV) infection. In the Department of Oral Surgery, Ryukyu University Hospital Okinawa, 188 cases of oral malignant tumours were encountered from 1996 to 2000. The histopathological examination and the sequence analysis of LMP-1 carboxy terminal region and EBNA2 region of EBV were carried out, as were the analysis of virus subtypes, A and B, BamHI-F and f, and C and D. Additionally, HPV infection in the squamous cell carcinomas were demonstrated using E6 and E7 region primer sets by PCR method. In Okinawa, 94% (177/188) of the cases were squamous cell carcinomas. A surprisingly large number of EBV (72%) and HPV (78%) infections in the oral squamous cell carcinomas were demonstrated. EBV type B virus infection was found in 36% of EBV-related oral squamous cell carcinoma in Okinawa, but in only 2-5% of the mainland cases. In both regions the incidence of the BamHI- f variant infection was very low. The infected virus in 79 out of 80 (39 Okinawan and 41 mainland) cases was BamHI- F type. In Okinawa, the numbers of C and D variants were almost equal, whereas in the mainland the D variant was rare. Further, a 30 bp deletion in LMP-1 gene was frequently demonstrated in Okinawan and mainland cases of type A virus, but not in type B virus. Lastly, single nucleotide mutations in EBNA2 region of type A virus when compared with B95-8 strain were demonstrated in Okinawan cases. The prognosis for (mostly EBV/HPV infected) squamous cell carcinomas in Okinawa was better than that in the mainland where most cases were negative for EBV and/or HPV.

Cooperation between secretory phospholipase A2 and TNF-receptor superfamily signaling: implications for the inflammatory response in atherogenesis

Atherogenesis is the consequence of a variety of effector mechanisms rather than the result of a single functional molecule. In this connection, type IIA secretory phospholipase A2 (sPLA2) is an acute-phase reactant, which accumulates in atherosclerotic arterial walls, elicits several effects on monocytes, and has been related to the development of atherosclerosis. CD40/CD40 ligand pair is also a strong proatherogenic system. sPLA2 produced an increase of the surface expression of CD40 in THP-1 monocytes and enhanced the effect of CD40 ligation on the expression of both Fas and FasL, thus indicating the existence of a positive cooperation between sPLA2 and different elements of the TNF-receptor superfamily. Activation of the CD40/CD40L dyad with anti-CD40 antibody produced a small release of arachidonic acid and lacked any significant effect on the induction of cyclooxygenase-2, whereas the secretion of the chemokine MCP-1 and the surface display of CD11b, the alpha chain of the integrin Mac-1, were upregulated. Engagement of CD40 did not influence the survival of THP-1 monocytes, but coincubation of THP-1 monocytes pretreated with anti-CD40 antibody and Jurkat cells induced a significant increase of the number of Jurkat cells showing binding of annexin-V, and nuclear condensation and fragmentation, thus indicating that this treatment might trigger a juxtacrine/paracrine mechanism of apoptotic death in sensitive cell types. This data indicates the existence of overlapping routes for the response to CD40, TNF-alpha, and sPLA2, thus allowing the development of distinct patterns of response in monocytic cells.

Expression of CD154 on renal cell carcinomas and effect on cell proliferation, motility and platelet-activating factor synthesis

CD40 activation by CD154 may trigger diverse cellular responses, ranging from proliferation and differentiation to growth suppression and cell death, in normal and malignant cells. However, the pathophysiologic role of CD154 expressed by tumor cells remains unclear. We have investigated the expression of the CD40-CD154 system in 24 primary cultures derived from renal cell carcinomas, its correlation with tumor stage and its potential functional significance. We found coexpression of CD40 and CD154 in most of the renal carcinoma cell lines. CD154, but not CD40 expression, significantly correlated with tumor stage. Moreover, renal carcinoma cell lines also released the soluble form of CD154 into the supernatant. CD40 engagement by CD154 did not affect apoptosis or survival. On the contrary, CD154 stimulated cell proliferation, motility and production of PAF, a phospholipid mediator of inflammation with angiogenic properties. Furthermore, the renal carcinoma cell lines expressed PAF-R. Blockade of PAF-R by WEB-2170, a PAF-R antagonist, abolished the CD154-dependent motility, indicating a role for PAF synthesized after CD154 stimulation in renal carcinoma cell motility. In conclusion, this study identifies new functional properties for CD154, which are potentially relevant for the growth and dissemination of renal carcinoma cells.

Role of NF kappa B activator Act1 in CD40-mediated signaling in epithelial cells

CD40, a cell surface receptor in the tumor necrosis factor receptor family, first identified and functionally characterized on B lymphocytes, is also expressed on epithelial and other cells and is now thought to play a more general role in immune regulation. Overexpression of the NF kappa B activator 1 (Act1) leads to the activation of both NF kappa B and Jun kinase in epithelial cell lines. Endogenous Act1 is recruited to the CD40 receptor in human intestinal (HT29) and cervical (HeLa) epithelial cells upon stimulation with CD40 ligand, indicating that Act1 is involved in this signaling pathway. Act1 also interacts with tumor necrosis factor receptor-associated factor 3, a component involved in CD40-activated pathway. Furthermore, transfection of Act1 into C33A cervical epithelial cells, which do not express it, renders these cells sensitive to CD40 ligand-induced NF kappa B activation and protects them from CD40 ligand-induced apoptosis. We conclude that Act1 plays an important role in CD40-mediated signaling in epithelial cells.

CD40 activation-induced, Fas-dependent apoptosis and NF-kappaB/AP-1 signaling in human intrahepatic biliary epithelial cells

Fas-mediated mechanisms of apoptosis are thought to be involved in the bile duct loss that characterizes diseases such as primary biliary cirrhosis (PBC). We have previously shown that activation of CD40 on hepatocytes can amplify Fas-mediated apoptosis; in the present study, we investigated interactions between CD40 and Fas in biliary epithelial cells (BEC). We report that the bile ducts in PBC liver tissue frequently express increased levels of Fas, Fas ligand (FasL), and CD40 associated with apoptotic BEC. The portal mononuclear infiltrate contains CD40L+ve T cells and macrophages, thereby demonstrating a potential mechanism for CD40 engagement in vivo. Primary cultures of human BEC also expressed Fas, FasL, and CD40 but not CD40L protein or mRNA. Activation of CD40 on BEC using recombinant CD40L increased transcriptional expression of FasL and induced apoptosis, which was inhibited by neutralizing antibodies to either Fas or FasL. Thus, CD40-induced apoptosis of BEC is mediated through Fas/FasL. We then investigated the intracellular signals and transcription factors activated in BEC and found that NF-kappaB and AP-1 were both activated after CD40 ligation. Increased functional NF-kappaB was seen early after CD40 ligation, but returned to baseline levels after 4 h. In contrast, the rapid up-regulation of AP-1 was sustained over 24 h. This study provides further functional evidence of the ability of CD40 to induce Fas/FasL-dependent apoptosis of liver epithelial cells supporting the importance of cross-talk between tumor necrosis factor (TNF) receptor family members as an amplification step in apoptosis induction. Sustained activation of AP-1 in the absence of NF-kappaB signaling may be a critical factor in determining the outcome of CD40 engagement.

CD40L induces matrix-metalloproteinase-9 but not tissue inhibitor of metalloproteinases-1 in cervical carcinoma cells: imbalance between NF-kappaB and STAT3 activation

Matrix-metalloproteinases (MMPs) are essentially required for tumor cell invasion and metastasis. Production of precursor enzymes is regulated on transcriptional level, while activation of the pro-enzymes is tightly controlled by posttranscriptional mechanisms. The enzyme activity can be blocked by specific tissue inhibitors of MMPs (TIMPs). In cervical carcinomas strong up-regulation of the type IV collagenase MMP-9 had been demonstrated. We show that activation of CD40, a receptor highly expressed on cervical carcinomas, induces MMP-9 in cervical carcinoma cells, whereas TIMP-1 production inhibiting MMP-9 activity was not affected. This gene induction pattern corresponded to the differential activation of the transcription factor nuclear factor kappaB (NF-kappaB) regulating MMP-9, but not signal transducer and activator of transcription 3 (STAT3), which is involved in TIMP-1 gene regulation. Transient expression of the CD40-inducible NF-kappaB subunit p65 was sufficient for MMP-9 induction. Agents that suppressed CD40-mediated NF-kappaB activation also reduced MMP-9 induction, further supporting an important role of NF-kappaB in CD40-mediated MMP-9 induction. Our data suggest that CD40 expression in carcinoma cells might convert a CD40L-dependent immunological defense signal into a tumor-promoting signal. Selective CD40-mediated signaling through NF-kappaB but not STAT3 correlates to a shift of the balance between MMP-9 and TIMP-1 toward the protease.

Human CD154 induces activation of porcine endothelial cells and up-regulation of MHC class II expression

BACKGROUND

CD40 is expressed on a number of antigen-presenting cells and also on vascular endothelium. It has been shown that engagement of CD40 on vascular endothelium by CD154 on platelets and CD154-bearing cell lines leads to the induction of adhesion molecule expression. Having cloned porcine CD40, and shown that it is capable of binding human CD154, we investigate whether human CD154 can activate porcine endothelial cells (EC) through CD40 ligation.

METHODS

Human Jurkat clone D1.1 (CD154+), or clone E6.1 (CD154-), were co-cultured with EC from pig aorta and human aorta and umbilical vein for various times in the presence or absence of blocking antibody to CD154.

RESULTS

Human and pig EC were shown to express CD40 by flow cytometry by using soluble human CD154 (CD154Ckappa). Co-culture of pig EC with CD154-expressing Jurkat D1.1 cells led to the induction of E-selectin by 6 hr (peak 24 hr) and vascular cell adhesion molecule-1 (VCAM-1) by 6 hr (peak 48 hr). Similar results were also observed with human EC. Porcine EC were induced to up-regulate major histocompatibility complex class II at 24 hr by co-culture with Jurkat D1.1 cells through a CD40-dependent mechanism. In contrast, no up-regulation was observed on human EC.

CONCLUSIONS

A number of cells can express CD154, including T cells, natural killer cells, and platelets, and these could signal graft EC through the CD40 pathway. These results demonstrate a possible role for the CD40 pathway in the activation of vascular endothelium in the rejection of porcine xenografts.

Biology and disease associations of Epstein-Barr virus

Epstein-Barr virus (EBV) is a human herpesvirus which infects almost all of the world's population subclinically during childhood and thereafter remains in the body for life. The virus colonizes antibody-producing (B) cells, which, as relatively long-lived resting cells, are an ideal site for long-term residence. Here EBV evades recognition and destruction by cytotoxic T cells. EBV is passed to naive hosts in saliva, but how the virus gains access to this route of transmission is not entirely clear. EBV carries a set of latent genes that, when expressed in resting B cells, induce cell proliferation and thereby increase the chances of successful virus colonization of the B-cell system during primary infection and the establishment of persistence. However, if this cell proliferation is not controlled, or if it is accompanied by additional genetic events within the infected cell, it can lead to malignancy. Thus EBV acts as a step in the evolution of an ever-increasing list of malignancies which are broadly of lymphoid or epithelial cell origin. In some of these, such as B-lymphoproliferative disease in the immunocompromised host, the role of the virus is central and well defined; in others, such as Burkitt's lymphoma, essential cofactors have been identified which act in concert with EBV in the evolution of the malignant clone. However, in several diseases in which the presence of EBV has more recently been discovered, the role of the virus is unclear. This review describes recent views on the EBV life cycle and its interlinks with normal B-cell biology, and discusses how this interrelationship may be upset and result in EBV-associated disease.

CD40 is not detected on human prostate cancer cells by immunohistologic techniques

OBJECTIVES

The CD40 antigen is expressed by antigen-presenting cells, many kinds of epithelium, and carcinomas. As signaling through CD40 modulates the differentiation state of CD40-expressing cells, we wanted to investigate whether benign or malignant prostate epithelium expressed CD40.

METHODS

Twenty-two paraffin-embedded and 10 snap-frozen human prostate tissue samples were analyzed by immunohistologic methods, using the basal cell-specific markers, high molecular weight cytokeratin (HMWCK) and keratin-14 (K14), and the luminal cell marker, low molecular weight cytokeratin (LMWCK), together with CD40. Fresh prostate tissue was cultured in vitro and analyzed by immunocytofluorescence.

RESULTS

The pattern of CD40 expression was continuous on basal epithelial cells of normal and hyperplastic prostate glands but discontinuous in glands that featured prostatic intraepithelial neoplasia. Coexpression of CD40 with the basal cell-specific cytokeratins, HMWCK and K14, was confirmed by double labeling. In contrast, glandular epithelial cells in prostate adenocarcinoma did not express CD40 or these cytokeratins. A luminal cell phenotype defined as CAM5.2-positive and HMWCK-negative K14-negative was identified among primary epithelial cells cultured in vitro. Most of the cultured cells (more than 99%) were also CD40-negative.

CONCLUSIONS

Together, our results support the hypothesis that CD40 expression correlates with the basal cell phenotype, which is lost upon malignant transformation of the prostate. Hence, CD40 may be useful diagnostically to distinguish benign from malignant prostate lesions in biopsy material.

Epstein-Barr virus infection in the pathogenesis of nasopharyngeal carcinoma

The association of nasopharyngeal carcinoma (NPC) with the Epstein-Barr virus (EBV) was firmly established as early as 1973. Nevertheless, the role for the virus in the pathogenesis of NPC is still controversial. In this article, the evidence implicating EBV in the development of NPC is reviewed, focusing on the cellular site of EBV persistence, the association of the virus with different NPC histotypes, the tumour cell phenotype in the context of viral latent gene expression, and the possible role of the lymphoid stroma.

Coreceptor restriction within the HLA-DQ locus for Epstein-Barr virus infection

Epstein-Barr virus (EBV) is a ubiquitous human herpesvirus that causes infectious mononucleosis and is etiologically associated with malignancies of multiple origins. EBV enters cells through a cascade of interactions between its envelope glycoprotein gp350 and the gp42-gH-gL complex with cellular receptors. Membrane fusion is catalyzed by the binding of gp42, a member of the C type lectin family, to HLA class II molecule HLA-DR, -DP, or -DQ. Here we demonstrate that only a subset of HLA-DQ alleles mediates EBV entry, indicating that individuals expressing these alleles may offer unique sites for EBV infection and subsequent sequelae. Additionally, the specific site within HLA-DQ determined to be essential for EBV entry is homologous to a site within MHC class I shown by structural studies to bind to the C type-lectin-like natural killer receptor, providing insight into the biochemical nature of the gp42-HLA class II interaction.

CD40 induces apoptosis in carcinoma cells through activation of cytotoxic ligands of the tumor necrosis factor superfamily

CD40, a tumor necrosis factor (TNF) receptor (TNFR) family member, conveys signals regulating diverse cellular responses, ranging from proliferation and differentiation to growth suppression and cell death. The ability of CD40 to mediate apoptosis in carcinoma cells is intriguing given the fact that the CD40 cytoplasmic C terminus lacks a death domain homology with the cytotoxic members of the TNFR superfamily, such as Fas, TNFR1, and TNF-related apoptosis-inducing ligand (TRAIL) receptors. In this study, we have probed the mechanism by which CD40 transduces death signals. Using a trimeric recombinant soluble CD40 ligand to activate CD40, we have found that this phenomenon critically depends on the membrane proximal domain (amino acids 216 to 239) but not the TNFR-associated factor-interacting PXQXT motif in the CD40 cytoplasmic tail. CD40-mediated cytotoxicity is blocked by caspase inhibitors, such as zVAD-fmk and crmA, and involves activation of caspase 8 and caspase 3. Interestingly, CD40 ligation was found to induce functional Fas ligand, TRAIL (Apo-2L) and TNF in apoptosis-susceptible carcinoma cells and to up-regulate expression of Fas. These findings identify a novel proapoptotic mechanism which is induced by CD40 in carcinoma cells and depends on the endogenous production of cytotoxic cytokines and autocrine or paracrine induction of cell death.

Integrin expression in oral hairy leukoplakia and normal tongue epithelium

OBJECTIVE

To describe the expression of integrins in the epithelium of oral hairy leukoplakia (HL) and compare to that of normal lateral tongue epithelium.

MATERIALS AND METHODS

Immunohistochemistry to identify integrins (alpha 2, alpha 3, alpha 5, alpha 6, alpha v, beta 1) was performed, using a standard biotin-streptavidin-peroxidase technique on five clinically and histologically confirmed frozen biopsy specimens of HL and five normal lateral tongue control tissues.

RESULTS

Expression of integrins alpha 2, alpha 3, alpha 6, alpha v, beta 1 was seen both in HL epithelium and in normal control tissue. alpha 5 expression was not seen in HL or in control tissue epithelium. alpha 2 and alpha 3 were expressed mainly in the basal and suprabasal layers; alpha 6 expression was most intense on the basal surface of the basal cells, alpha v was expressed in the basal and suprabasal layers with more expression seen in the higher differentiated cell layers than the other integrins. beta 1 expression was seen in the basal and suprabasal layers only. No apparent difference between HL and normal oral mucosa was noted in the staining pattern of the various integrins.

CONCLUSION

Integrins alpha 2, alpha 3, alpha 6, alpha v, beta 1 are expressed in HL and the expression pattern is not different from that of normal oral mucosa. alpha 5 is not expressed in HL or in normal oral epithelium.

Epstein-Barr virus infection of renal proximal tubule cells: possible role in chronic interstitial nephritis

Chronic interstitial nephritis frequently accompanies renal diseases of different etiologies. Far less common is the entity of primary interstitial nephritis wherein the glomerular and vascular structures of the kidney are not the primary focus of the disease process. Using in situ hybridization and the polymerase chain reaction, we detected DNA from the Epstein-Barr Virus (EBV) exclusively in renal tissue of patients with the idiopathic variety of chronic interstitial nephritis. The EBV genome, but not that of cytomegalovirus or adenovirus, was detected primarily in renal proximal tubule cells. Furthermore, the CD21 antigen, which serves as the receptor for EBV in B lymphocytes, was detected by immunocytochemistry primarily on proximal tubule cells and was markedly upregulated in the EBV-infected tissue. Western blot analysis of primary cultures of normal proximal tubule cells identified a 140-kDa protein, confirming the expression of the CD21 antigen. Colocalization experiments using proximal and distal tubule markers confirmed that EBV DNA and the CD21 antigen are found primarily in proximal tubule cells. EBV infection of renal proximal tubular cells may participate in evoking a cellular immune response that results in a damaged renal interstitium.

CD40 and Bcl2 expression in squamous cell carcinoma of the lung: correlation with apoptosis, survival, and other clinicopathological factors

CD40 is a cell surface receptor which, when ligated, modulates apoptosis in some cell types, perhaps via activation of the expression of members of the Bcl2 gene family. This study sought to determine whether expression of CD40 in a series of 134 squamous cell carcinomas (SCCs) of the lung was related to apoptosis or clinical parameters, either alone or in connection with Bcl2 expression. Sections of SCCs were stained for CD40 and Bcl2 by immunohistochemical techniques. An index was determined for these two markers by counting stained and unstained malignant cells under high power. Sections were also stained by haematoxylin and eosin for determination of the apoptotic index by counting apoptotic bodies. About 40 per cent of SCCs expressed CD40 in at least some of the malignant cells, with about 10 per cent essentially uniformly stained. Similar proportions expressed Bcl2, with a tendency for expression to be mutually excluisve. Apoptosis did not correlate with CD40 expression, nor was there evidence of a co-operative or an antagonistic effect with Bcl2. Bcl2 expression, on the other hand, correlated significantly with the apoptosis score. CD40 expression showed no significant relationship with survival or any other clinicopathological parameter except ploidy. Bcl2 expression, however, correlated with longer survival. It is concluded that CD40 expression in SCC of the lung does not by itself relate to apoptosis, nor is it a useful indicator of prognosis.

Soluble CD40 in the serum of healthy donors, patients with chronic renal failure, haemodialysis and chronic ambulatory peritoneal dialysis (CAPD) patients

CD40 and its ligand CD40L are key players in T cell-B cell interaction and T cell-antigen-presenting cell (APC) interaction. Inhibition of CD40-CD40L interaction leads to severe humoral and cellular immunodeficiency. In this study we examined the presence of soluble CD40 (sCD40) in the serum of haemodialysis (HD) patients, CAPD patients, chronic renal failure (CRF) patients and healthy donors in order to evaluate the possible involvement of CD40 in uraemic immunodeficiency. Soluble CD40 was detected in the serum of healthy donors (n = 41) with a mean of 0.14 +/- 0.12 ng/ml and in the urine of healthy donors with a mean of 1.80 +/- 0.74 ng/ml. Soluble CD40 was highly elevated in all patients with impaired renal function. HD patients (n = 22) had up to 100-fold elevated sCD40 levels with a mean concentration of 8.32 +/- 4.11 ng/ml, whereas CAPD patients (n = 10) had considerably lower levels of sCD40 with a mean of 3.58 +/- 2.40 ng/ml. A strong correlation between sCD40 and serum creatinine levels was noted in CRF patients (n = 66). The highly elevated levels of sCD40 may point to the involvement of CD40 and its ligand CD40L in the clinical manifestation of uraemic immunodeficiency.

CD40 expression in bladder cancer

The CD40 receptor is expressed in many immune cell types and is known to play a central role in both humoral and T-cell-mediated immunity, being a subject of intense research interest in recent years. It is also expressed on a variety of carcinomas and may therefore be of biological significance in the development and treatment of cancer. The expression of CD40 was examined immunohistochemically in a series of 131 bladder transitional cell carcinomas and the correlation with known prognostic markers and clinical outcome assessed. Seventy-eight per cent of the tumours were CD40-positive, with a highly significant association with both lower stage and lower grade (p<0.001). Ta and T1 tumours expressed CD40 in 89 per cent of specimens compared with 62 per cent seen in T2-T4 tumours and in contrast to normal urothelium, which was mainly CD40-negative. CD40 expression was not related to any other clinicopathological variable including Bcl-2 and p53 expression, nor was it an independent prognostic marker. The lack of the relationship with Bcl-2 staining which is normally seen in basal epidermal cells may indicate alternative or abnormal CD40-mediated cell differentiation mechanisms. The diffuse expression seen in Ta bladder tumours may account for its clinically less aggressive behaviour and is likely to be an important factor in the excellent clinical response seen to BCG immunotherapy. It also raises the possibility of the future development of CD40/CD40 ligand-based immunotherapy for bladder cancer.