Epstein-Barr virus small RNAs potentiate tumorigenicity of Burkitt lymphoma cells independently of an effect on apoptosis

J Virol. 2000 Nov;74(21):10223-8. doi: 10.1128/jvi.74.21.10223-10228.2000.

Abstract

The tumorigenic potential of the Burkitt lymphoma (BL) cell line Akata is dependent on the restricted latency program of Epstein-Barr virus (EBV) that is characteristically maintained in BL tumors. Within these cells, EBV-mediated inhibition of apoptosis correlates with an up-regulation of BCL-2 levels in concert with a down-regulation in c-MYC expression that occurs under growth-limiting conditions. Here we addressed whether EBV's effects on apoptosis and tumorigenicity are mediated by the EBV small RNAs EBER-1 and EBER-2. Stable expression of the EBERs in EBV-negative Akata BL cells, at levels comparable to those in EBV-positive cells, significantly enhanced the tumorigenic potential of EBV-negative BL cells in SCID mice, but did not fully restore tumorigenicity relative to EBV-positive Akata cells. Furthermore, wild-type or greater levels of EBER expression in EBV-negative Akata cells did not promote BL cell survival. These data therefore suggest that EBV can contribute to BL through at least two avenues: an EBER-dependent mechanism that enhances tumorigenic potential independent of a direct effect on apoptosis, and a second mechanism, mediated by an as-yet-unidentified EBV gene(s), that offsets the proapoptotic consequences of deregulated c-MYC in BL.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Apoptosis*
  • Burkitt Lymphoma / pathology
  • Burkitt Lymphoma / virology*
  • Cell Line, Transformed
  • Herpesvirus 4, Human / genetics
  • Herpesvirus 4, Human / pathogenicity*
  • Humans
  • Mice
  • Mice, SCID
  • RNA, Viral / genetics
  • RNA, Viral / metabolism*
  • Tumor Cells, Cultured

Substances

  • Epstein-Barr virus encoded RNA 1
  • Epstein-Barr virus encoded RNA 2
  • RNA, Viral