Molecular mechanisms of Epstein-Barr virus-mediated carcinogeneis

Abstract

Epstein-Barr virus (EBV), a ubiquitous human double stranded DNA virus, is associated with a variety of malignancies including Burkitt's lymphoma, Hodgkin's lymphoma, nasopharyngeal carcinoma (NPC) and gastric carcinoma (GC). These EBV-associated cancers are characterized by the proliferation of monoclonal EBV-infected cells, and viral gene expression in these cells is limited to a subset of latent genes, indicating that EBV latent genes contribute to carcinogenesis. Here I describe the mechanisms of carcinogenesis by EBV, focusing on the function of two EBV latent gens, latent membrane protein 2A (LMP2A) and EBV-encoded small RNA (EBER). LMP2A, which is known to mimic the B cell receptor (BCR) signaling, has been reported to contribute to malignant lymphoma development through the modulation of immune signals. Also, it has been demonstrated that LMP2A-mediated intracellular signaling plays significant roles in epithelial carcinogenesis. On the other hand, it has been demonstrated that EBER, which is expected to form double stranded RNA (dsRNA) structure, triggers a signal transduction from host viral RNA sensors RIG-I and TLR3. Activation of innate immune signals by EBER has been reported to contribute to the pathogenesis of EBV-associated diseases, including cancers.