Epstein-Barr Virus Protein Contributes To Cancer

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Epstein-Barr Virus Protein Contributes To Cancer

_http://www.sciencedaily.com/releases/2008/10/081002204424.htm_

(http://www.sciencedaily.com/releases/2008/10/081002204424.htm)

ScienceDaily (Oct. 3, 2008)

 

— Researchers at the University of Toronto have shown that the EBNA1 protein

of Epstein-Barr virus (EBV) disrupts structures in the nucleus of

nasopharyngeal carcinoma (NPC) cells, thereby interfering with cellular

processes that

normally prevent cancer development. The study describes a novel mechanism by

which viral proteins contribute to carcinogenesis.

 

EBV is a common herpesvirus whose latent infection is strongly associated

with several types of cancer including NPC, a tumor that is endemic in several

parts of the world. With NPC only a few EBV proteins are expressed, including

EBNA1. EBNA1 is required for the persistence of the EBV genomes, however,

whether or not EBNA1 directly contributes to the development of tumors has not

been clear, until now.

 

In this study Frappier and her team examined PML nuclear bodies and proteins

in EBV-positive and EBV-negative NPC cells. Manipulation of EBNA1 levels in

each cell type clearly showed that EBNA1 expression induces the loss of PML

proteins and PML nuclear bodies through an association of EBNA1 with the PML

bodies. PML nuclear bodies are known to have tumor-suppressive effects due to

their roles in regulating DNA repair and programmed cell death, and

accordingly, EBNA1 was shown to interfere with these processes.

 

The researchers conclude that there is " an important role for EBNA1 in the

development of NPC, in which EBNA1-mediated disruption of PML nuclear bodies

promotes the survival of cells with DNA damage. " Since EBNA1 is expressed in

all EBV-associated tumors, including B-cell lymphomas and gastric carcinoma,

these findings raise the possibility that EBNA1 could play a similar role in

the development of these cancers. The cellular effects of EBNA1 in other

EBV-induced cancers will require further investigation.

 

 

 

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Journal reference:

 

Sivachandran N, Sarkari F, Frappier L.

Epstein-Barr Nuclear Antigen 1 Contributes to Nasopharyngeal Carcinoma

through Disruption of PML Nuclear Bodies.

PLoS Pathog, 4(10): e1000170 DOI:

_10.1371/journal.ppat.1000170_

(http://dx.doi.org/10.1371/journal.ppat.1000170)

 

Adapted from materials provided by _Public Library of Science_

(http://www.plos.org/) , via EurekAlert!, a service of AAAS.

 

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