title: A yeast-based assay identifies drugs that interfere with immune evasion of the Epstein-Barr virus.
abstract: Epstein-Barr virus (EBV) is tightly associated with certain human cancers, but there is as yet no specific treatment against EBV-related diseases. The EBV-encoded EBNA1 protein is essential to maintain viral episomes and for viral persistence. As such, EBNA1 is expressed in all EBV-infected cells, and is highly antigenic. All infected individuals, including individuals with cancer, have CD8(+) T cells directed towards EBNA1 epitopes, yet the immune system fails to detect and destroy cells harboring the virus. EBV immune evasion depends on the capacity of the Gly-Ala repeat (GAr) domain of EBNA1 to inhibit the translation of its own mRNA in cis, thereby limiting the production of EBNA1-derived antigenic peptides presented by the major histocompatibility complex (MHC) class I pathway. Here we establish a yeast-based assay for monitoring GAr-dependent inhibition of translation. Using this assay we identify doxorubicin (DXR) as a compound that specifically interferes with the GAr effect on translation in yeast. DXR targets the topoisomerase-II-DNA complexes and thereby causes genomic damage. We show, however, that the genotoxic effect of DXR and various analogs thereof is uncoupled from the effect on GAr-mediated translation control. This is further supported by the observation that etoposide and teniposide, representing another class of topoisomerase-II-DNA targeting drugs, have no effect on GAr-mediated translation control. DXR and active analogs stimulate, in a GAr-dependent manner, EBNA1 expression in mammalian cells and overcome GAr-dependent restriction of MHC class I antigen presentation. These results validate our approach as an effective high-throughput screening assay to identify drugs that interfere with EBV immune evasion and, thus, constitute candidates for treating EBV-related diseases, in particular EBV-associated cancers.
authors.affiliation: Institut National de la Santé et de la Recherche Médicale UMR 1078; Université de Bretagne Occidentale, Faculté de Médecine et des Sciences de la Santé; Etablissement Français du Sang (EFS) Bretagne; CHRU Brest, Hôpital Morvan, Laboratoire de Génétique Moléculaire, Brest F-29200, France.
authors.forename: Cécile
authors.initials: C
authors.lastname: Voisset
authors.forename: Chrysoula
authors.initials: C
authors.lastname: Daskalogianni
authors.forename: Marie-Astrid
authors.initials: MA
authors.lastname: Contesse
authors.forename: Anne
authors.initials: A
authors.lastname: Mazars
authors.forename: Hratch
authors.initials: H
authors.lastname: Arbach
authors.forename: Marie
authors.initials: M
authors.lastname: Le Cann
authors.forename: Flavie
authors.initials: F
authors.lastname: Soubigou
authors.forename: Sébastien
authors.initials: S
authors.lastname: Apcher
authors.forename: Robin
authors.initials: R
authors.lastname: Fåhraeus
authors.forename: Marc
authors.initials: M
authors.lastname: Blondel
mesh_terms: D017951:Antigen Presentation / Q000187:drug effects; D000998:Antiviral Agents / Q000032:analysis / Q000737:chemistry / Q000494:pharmacology*; D001681:Biological Assay / Q000379:methods*; D004249:DNA Damage; D004317:Doxorubicin / Q000737:chemistry / Q000494:pharmacology; D004353:Drug Evaluation, Preclinical; D019309:Epstein-Barr Virus Nuclear Antigens / Q000737:chemistry / Q000378:metabolism; D057809:HEK293 Cells; D004854:Herpesvirus 4, Human / Q000187:drug effects* / Q000276:immunology*; D006801:Humans; D057131:Immune Evasion / Q000187:drug effects*; D014176:Protein Biosynthesis / Q000187:drug effects; D017434:Protein Structure, Tertiary; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology
chemical_list: D000998:Antiviral Agents; D019309:Epstein-Barr Virus Nuclear Antigens; D004317:Doxorubicin; C417029:EBV-encoded nuclear antigen 1
keywords: 5-fluorouracil; Cell-based drug screening; Daunorubicin; Doxorubicin; EBNA1 GAr domain; EBV-associated cancers; Immune evasion; Yeast-based models