title: The Epstein-Barr virus EBNA2 protein induces a subset of NOTCH target genes in thyroid cancer cell lines but fails to suppress proliferation.
abstract: Epstein-Barr virus is associated with lymphoid and epithelial malignancies and has been reported to infect thyroid cells. The Epstein-Barr virus protein, EBNA2, regulates viral and cellular promoters by binding to RBP-jκ. Similarly, NOTCH1, a tumor suppressor protein in thyroid epithelial cells, competes with EBNA2 for binding to overlapping sites on RBP-jκ. EBNA2 activates a subset of NOTCH-responsive genes in lymphocytes and myocytes; however, the effect of EBNA2 expression on NOTCH targets in epithelial cells is unknown. Here we have explored whether EBNA2 activates NOTCH1 targets in thyroid cancer lines and examined its effect on cellular proliferation.
  
  
  
  Two human thyroid cancer lines, follicular FTC-236 and anaplastic HTh7, were transfected with EBNA2, NOTCH1, or control vectors. Notch targets were measured using quantitative reverse transcriptase polymerase chain reaction. Cellular proliferation was measured by MTT analysis.
  
  
  
  EBNA2 activated only a subset of NOTCH1 targets. Expression of HES1 and HEY1 were increased 10-fold in FTC-236 and HTh7 cells, respectively, but the majority of NOTCH1 targets examined were not affected. In contrast to NOTCH1, EBNA2 did not suppress proliferation.
  
  
  
  EBNA2 does not activate most Notch1-responsive genes or suppress proliferation in human thyroid cancer cells. Instead, EBNA2 may compete with NOTCH1 for limiting amounts of RBP-jκ in epithelial cells and inhibit certain aspects of NOTCH1 signaling.
authors.affiliation: Department of Surgery, University of Wisconsin School of Medicine and Public Health, Madison, WI.
authors.forename: Sean
authors.initials: S
authors.lastname: Golden
authors.affiliation: Department of Oncology, University of Wisconsin School of Medicine and Public Health, Madison, WI.
authors.forename: Xiao-Min
authors.initials: XM
authors.lastname: Yu
authors.affiliation: Department of Surgery, University of Wisconsin School of Medicine and Public Health, Madison, WI.
authors.forename: Scott
authors.initials: S
authors.lastname: Odorico
authors.affiliation: Department of Surgery, University of Wisconsin School of Medicine and Public Health, Madison, WI.
authors.forename: Vansh
authors.initials: V
authors.lastname: Jain
authors.affiliation: Department of Surgery, University of Wisconsin School of Medicine and Public Health, Madison, WI.
authors.forename: Ana
authors.initials: A
authors.lastname: Marin
authors.affiliation: Department of Oncology, University of Wisconsin School of Medicine and Public Health, Madison, WI.
authors.forename: Shidong
authors.initials: S
authors.lastname: Ma
authors.affiliation: Department of Oncology, University of Wisconsin School of Medicine and Public Health, Madison, WI.
authors.forename: Shannon
authors.initials: S
authors.lastname: Kenney
authors.affiliation: Department of Surgery, University of Alabama at Birmingham, Birmingham, AL. Electronic address: herbchen@uab.edu.
authors.forename: Herbert
authors.initials: H
authors.lastname: Chen
mesh_terms: D002352:Carrier Proteins / Q000235:genetics*; D002460:Cell Line; D015967:Gene Expression Regulation, Viral; D004854:Herpesvirus 4, Human / Q000235:genetics*; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics; D016601:RNA-Binding Proteins; D051881:Receptor, Notch1 / Q000235:genetics*; D012494:Sampling Studies; D012680:Sensitivity and Specificity; D015398:Signal Transduction; D013964:Thyroid Neoplasms / Q000235:genetics / Q000821:virology*; D015533:Transcriptional Activation / Q000235:genetics*
chemical_list: D002352:Carrier Proteins; C432687:EBNA1BP2 protein, human; D008565:Membrane Proteins; C497761:NOTCH1 protein, human; D016601:RNA-Binding Proteins; D051881:Receptor, Notch1