title: EBV latency III immortalization program sensitizes B cells to induction of CD95-mediated apoptosis via LMP1: role of NF-kappaB, STAT1, and p53.
abstract: Epstein-Barr virus (EBV) induces CD95 expression and the CD95 gene (FAS) is regulated by NF-kappaB, STAT1, and/or p53. To understand the contribution of these factors in the regulation of CD95 by EBV in lymphoblastoid cell lines (LCLs), we cloned dominant-active IkappaBalpha, active (STAT1alpha) and inactive (STAT1beta) forms of STAT1, p53, a dominant-negative mutant of LMP1, and wild-type LMP1 into a novel double-inducible episomal vector, pRT-1. These plasmids were stably transfected either into wild-type LCLs or EREB2-5 cells, an LCL with an estrogen-regulatable EBNA2 protein. Inhibition of LMP1 signaling decreased expression of CD95, whereas overexpression of LMP1 markedly increased it. Induction of the latency III program in EREB2-5 cells correlated with activation of NF-kappaB, STAT1, and p53. CD95 expression was regulated by these 3 transcriptional systems. STAT1 and p53 activation were secondary to NF-kappaB activation. CD95 surface expression sensitized EBV-infected B cells to the induction of CD95-mediated apoptosis. In vitro inhibition of CD95-CD95 ligand interaction was found to reverse T-cell killing of EBV-infected B cells. Therefore, LMP1 activation of NF-kappaB sensitizes infected B cells to CD95-mediated apoptosis and renders EBV latency III-immortalized B cells susceptible to elimination by the immune system, contributing to the establishment of a host/virus equilibrium.
authors.affiliation: Centre National de la Recherche Scientifique, Unité Mixte de Recherche (UMR) CNRS 6101, Faculté de Médecine de Limoges, Université de Limoges, Centre Hospitalier Universitaire (CHU) Dupuytren, Laboratoire d'Hématologie, Limoges, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Le Clorennec
authors.forename: Ibtissam
authors.initials: I
authors.lastname: Youlyouz-Marfak
authors.forename: Eric
authors.initials: E
authors.lastname: Adriaenssens
authors.forename: Jean
authors.initials: J
authors.lastname: Coll
authors.forename: Georg W
authors.initials: GW
authors.lastname: Bornkamm
authors.forename: Jean
authors.initials: J
authors.lastname: Feuillard
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics; D001402:B-Lymphocytes / Q000378:metabolism* / Q000821:virology; D045744:Cell Line, Tumor; D002472:Cell Transformation, Viral / Q000187:drug effects / Q000235:genetics; D020031:Epstein-Barr Virus Infections / Q000235:genetics / Q000378:metabolism* / Q000821:virology; D019309:Epstein-Barr Virus Nuclear Antigens / Q000235:genetics / Q000378:metabolism; D004967:Estrogens / Q000494:pharmacology; D053222:Fas Ligand Protein; D005786:Gene Expression Regulation / Q000187:drug effects; D005799:Genes, Dominant / Q000235:genetics; D005822:Genetic Vectors / Q000378:metabolism; D004854:Herpesvirus 4, Human / Q000378:metabolism*; D006801:Humans; D020672:I-kappa B Proteins / Q000235:genetics / Q000378:metabolism; D050832:Interferon-Stimulated Gene Factor 3 / Q000235:genetics / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000378:metabolism; D009154:Mutation; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000378:metabolism; D010957:Plasmids / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D013601:T-Lymphocytes / Q000378:metabolism / Q000821:virology; D048069:Tumor Necrosis Factors / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism; D014763:Viral Matrix Proteins / Q000235:genetics / Q000378:metabolism; D014764:Viral Proteins; D019014:fas Receptor / Q000096:biosynthesis
chemical_list: C402641:EBNA-2 protein, Human herpesvirus 4; C037662:EBV-associated membrane antigen, Epstein-Barr virus; D019309:Epstein-Barr Virus Nuclear Antigens; D004967:Estrogens; C505661:FASLG protein, human; D053222:Fas Ligand Protein; D020672:I-kappa B Proteins; D050832:Interferon-Stimulated Gene Factor 3; D008562:Membrane Glycoproteins; D016328:NF-kappa B; C000606204:NFKBIA protein, human; D048069:Tumor Necrosis Factors; D016159:Tumor Suppressor Protein p53; D014763:Viral Matrix Proteins; D014764:Viral Proteins; D019014:fas Receptor; C079868:gamma interferon activation factor; D000072000:NF-KappaB Inhibitor alpha