Epstein-Barr Protein Contributes To Cancer

A protein in the Epstein-Barr virus (EBV) interferes with cellular
processes that would normally prevent the preservation of damaged DNA,
thereby promoting cancer development, according to an article released
on October 2, 2008 in the open-access journal PLoS
Pathogens.



EBV is a common herpesvirus in humans. Latent infection with this virus
has previously been associated with several types of cancer. One such
cancer is nasopharyngeal carcinoma (NPC), which affects the upper part
of the throat. In NPC, very few proteins from EBV are actively
expressed, one of which is EBNA1. This product is required to maintain
EVB genomes, but it has never yet been clear how this protein might
contribute to cancer.



In this study, a team at the University of Toronto showed that the
EBNA1 protein disrupts certain structures in the nucleus of NPC cells,
called PML nuclear bodies. These complexes contain the tumor suppressor
promyelocytic leukemia protein, which generally regulate DNA repair and
programmed cell death. By adjusting levels of EBNA1 in each cell type,
EBNA1 induced PML protein and PML body loss in NPC cells.



According to the researchers, 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." Other EBV associated tumors, including B-cell
lymphomas and gastric carcinoma, express EBNA1, indicating that this
gene might play similar roles in the development of each of these
cancers. Further investigation is needed to ascertain the full role of
EBNA1 in these other EBV-induced cancers.



Epstein-Barr
Nuclear Antigen 1 Contributes to Nasopharyngeal Carcinoma through
Disruption of PML Nuclear Bodies.

Sivachandran N, Sarkari F, Frappier L

PLoS Pathog 4(10): e1000170.

doi:10.1371/journal.ppat.1000170

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Written by Anna Sophia McKenney