Isolation of infectious EB virus from the epithelial tumour cells of nasopharyngeal carcinoma

Trumper, Paul; Epstein, M. A.; Giovanella, Beppino C.; Finerty, S.

doi:10.1002/ijc.2910200503

Cited by 79 publications

(25 citation statements)

References 37 publications

(41 reference statements)

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“…It is also observed that there is a ''spike'' in circulating EBV DNA levels immediately after the first treatment (5), suggesting an alternate hypothesis of the activation of EBV into a lytic phase. This hypothesis is supported by the detection of infectious EBV in NPC cells (26), the presence of the linear form of the EBV genome suggestive of a productive lytic cycle (27), and observations of BRLF1 expression in NPC biopsy samples along with circulating BRLF1 antibodies in NPC patients (28). Our current study supports the concept that EBV activation could contribute to the observed increased levels of circulating EBV after treatment.…”

Section: Discussionsupporting

confidence: 84%

Nuclear Factor-Y and Epstein Barr Virus in Nasopharyngeal Cancer

Chia

Leung

Krushel

et al. 2008

Clinical Cancer Research

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Purpose: The Epstein Barr virus (EBV) is intimately associated with nasopharyngeal cancer (NPC) in a latent state expressing a limited number of genes.The process of switching from latency to replication is not well understood, particularly in response to DNA stress; hence, the focus of this study is on an EBV-positive NPC model. Experimental Design: C666-1 cells were exposed to radiation (2-15 Gy) or cisplatin (0.1-50 Ag/mL) assayed subsequently for relative EBV copy number (BamHI) and lytic gene expression (BRLF1 and BZLF1) using quantitative real-time PCR. Chromatin immunoprecipitation was conducted to assess the interaction of the transcription factor nuclear factor-Y (NF-Y) with promoter sequences. Results: Radiation-induced and cisplatin-induced BamHI expression, along with increased levels of BRLF1 and BZLF1 in a dose-dependent and time-dependent manner, associated with the immediate nuclear transactivation of the transcription factor NF-Y and its own increased transcription of NF-Y subunits 8 h posttreatment. In silico analysis revealed three putative NF-Y consensus-binding sequences in the promoter region of BRLF1, which all interacted with NF-Y in response to radiation and cisplatin, confirmed using chromatin immunoprecipitation. Introduction of dominant-negative NF-YA reduced BRLF1 expression after radiation and cisplatin by 2.8-fold; in turn, overexpression of NF-YA resulted in a 2-fold increase in both BRLF1 and BZLF1 expression. Conclusions: These results show that NF-Y is an important mediator of EBV stress response in switching from a latent to lytic state. This novel insight could provide a potential therapeutic strategy to enhance NPC response to radiation and cisplatin.

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Section: Discussionsupporting

confidence: 84%

Nuclear Factor-Y and Epstein Barr Virus in Nasopharyngeal Cancer

Chia

Leung

Krushel

et al. 2008

Clinical Cancer Research

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“…Indeed some NPC biopsies appear to express transcripts usually associated with entry of cells into the productive cycle Tugwood et al, 1987) and the passage of NPC cells in nude mice in some cases leads to full virus replication in a small proportion of the cells (Trumper et al, 1977). However, in the present experiments we could find no detectable expression of lytic cycle antigens in NPC biopsies using either a selected human serum or the EA(D)-specific MAb R3 (Fig.…”

Section: Discussioncontrasting

confidence: 53%

Epstein--Barr Virus Gene Expression in Nasopharyngeal Carcinoma

Lw¹,

Dawson²,

Clark³

et al. 1988

Journal of General Virology

433

236

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SUMMARYEpstein-Barr virus (EBV), an agent with growth transforming potential for human B cells, is associated with certain B cell lymphomas in man and also with an epithelial tumour, undifferentiated nasopharyngeal carcinoma (NPC). Since B cell growth transformation is associated with the constitutive expression of a small number of EBV-coded latent proteins, the nuclear antigens EBNA 1, EBNA 2, EBNA 3 and EBNA-LP and the latent membrane protein (LMP), the present work sought to determine whether this same pattern of virus gene expression occurred in NPC. Tumour biopsies were taken from NPC patients from three areas of differing tumour incidence (Kenya, Algeria, Britain) and immediately snap-frozen, as were biopsies of non-EBV-related carcinomas for controls. Immunoblotting of PAGE-separated proteins with selected human sera identified 24 NPC biopsies clearly expressing EBNA 1. When the analysis was extended using selected human sera with antibodies against the other EBNAs, there was no detectable expression of EBNA 2, EBNA 3 or EBNA-LP in any of these 24 biopsies; their EBNA 2-negative status was confirmed using a monoclonal antibody (MAb) PE2 which was reactive in immunoblotting and in immunoprecipitation with EBNA 2A and EBNA 2B proteins. Similar experiments with two different LMP-specific MAbs, CS1 to 4 and S12, revealed heterogeneity between NPC biopsies; 9/24 biopsies were demonstrably LMP-positive, the degree of expression varying considerably between individual tumours in a manner which was not related to the level of EBNA 1 expression. None of the 24 NPC biopsies expressed detectable amounts of EBV lytic cycle antigens. A nude mouse-passaged NPC cell line, C15, likewise expressed EBNA 1 and LMP but none of the other EBV latent proteins nor lytic cycle antigens. This work identifies a novel type of EBV-cell interaction in NPC cells which is distinct from that seen in in vitro transformed B cell lines and from that seen to date in EBV-positive B cell lymphomas.

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“…A more likely explanation for the tumor is that long-term passage of this tumor in vivo has resulted in expression alterations, including up-regulation of genes that break the latent expression pattern. There is indeed evidence in the literature that EB virus can be isolated from NPC xenografts (40). However, cross-hybridization cannot be totally excluded in that long exposures with the H-242 probe also showed some hybridization to the 5-kb rRNA.…”

Section: Resultsmentioning

confidence: 99%