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