Among human viruses etiologically linked to human cancer, the Epstein Barr virus (EBV) is unusual because of the diverse assortment of malignancies with which it is associated, if only sporadically. Our long term objective is to understand how a ubiquitous and persistent viral pathogen that normally achieves a lasting rapport with its host becomes pathogenic years after primary infection. Emerging possibilities that more fully acknowledge EBV opportunism in the context of the life-long carrier state include viral reactivation with entry into cells made more prone to infection and EBV-enhanced malignant progression by pre-existing molecular alterations. Here, we examine EBV tumorigenesis within a new conceptual framework of chance infection of neoplastic cells by virus endogenous to the host, with possible viral DNA loss from some tumors after EBV contribution to growth has been made.
Aim 1 will use the pattern of EBV distribution and clonality in human tumor biopsies, as discerned by laser capture microdissection and single cell quantitative PCR, to establish a time frame for infection, subsequent clonal evolution, and EBV DNA loss.
Aim 2 will determine how variably reiterated EBV terminal repeat (TR) sequences, comprising the first intron of the LMP2A gene, govern expression levels of this EBV oncoprotein. With TRs a commonly employed viral marker of tumor clonality, information obtained may implicate TR number per se in a process of cell selection that drives the transition from polyconal infection of a few tumor cells to monoclonal outgrowth of a subset with the highest LMP2A expression.
Aim 3 will define the genomics of EBV redundancy and loss. In a newly devised in vitro system of transient infection, we will establish whether EBV transit through a cell produces epigenetic gene silencing as a component of the multistep process of carcinogenesis. The public health relevance of this research is that it will answer fundamental biological questions on the nature of EBV's erratic association with an ever expanding array of human tumors. Does EBV have the capability to initiate every tumor in which it is found as currently presupposed on the basis of EBV clonality or does it contribute instead to late stages of disease, entering cells more prone to infection and malignant progression by prior molecular mishaps? The information gained will further elucidate EBV's role in human cancer, its prognostic significance, and future therapeutic approaches. ? ? ?

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA114416-02
Application #
7247107
Study Section
Virology - B Study Section (VIRB)
Program Officer
Daschner, Phillip J
Project Start
2006-07-01
Project End
2011-05-31
Budget Start
2007-06-01
Budget End
2008-05-31
Support Year
2
Fiscal Year
2007
Total Cost
$283,896
Indirect Cost
Name
Louisiana State University Hsc Shreveport
Department
Microbiology/Immun/Virology
Type
Schools of Medicine
DUNS #
095439774
City
Shreveport
State
LA
Country
United States
Zip Code
71103
Birdwell, Christine E; Queen, Krista J; Kilgore, Phillip C S R et al. (2014) Genome-wide DNA methylation as an epigenetic consequence of Epstein-Barr virus infection of immortalized keratinocytes. J Virol 88:11442-58
Queen, Krista J; Shi, Mingxia; Zhang, Fangfang et al. (2013) Epstein-Barr virus-induced epigenetic alterations following transient infection. Int J Cancer 132:2076-86
Shi, Mingxia; Gan, Yan-Jun; Davis, Timothy O et al. (2013) Downregulation of the polyamine regulator spermidine/spermine N(1)-acetyltransferase by Epstein-Barr virus in a Burkitt's lymphoma cell line. Virus Res 177:11-21
Jiang, Ru; Scott, Rona S; Hutt-Fletcher, Lindsey M (2011) Laser capture microdissection for analysis of gene expression in formalin-fixed paraffin-embedded tissue. Methods Mol Biol 755:77-84
Ikuta, Kazufumi; Ding, Mingyu; Zhang, Fangfang et al. (2011) Epithelial cell retention of transcriptionally active, P3HR-1-derived heterogeneous Epstein-Barr virus DNA with concurrent loss of parental virus. J Virol 85:7634-43
Repic, Allison M; Shi, Mingxia; Scott, Rona S et al. (2010) Augmented latent membrane protein 1 expression from Epstein-Barr virus episomes with minimal terminal repeats. J Virol 84:2236-44
Ikuta, Kazufumi; Srinivas, Shamala K; Schacker, Tim et al. (2008) Points of recombination in Epstein-Barr virus (EBV) strain P3HR-1-derived heterogeneous DNA as indexes to EBV DNA recombinogenic events in vivo. J Virol 82:11516-25
Li, Haiyan; Ikuta, Kazufumi; Sixbey, John W et al. (2008) A replication-defective gammaherpesvirus efficiently establishes long-term latency in macrophages but not in B cells in vivo. J Virol 82:8500-8