Inhibition of Epstein-Barr virus-induced growth proliferation by a nuclear antigen EBNA2-TAT peptide.
Epstein-Barr virus (EBV) causes infectious mononucleosis and is associated with cancers in immunocompromised populations. Antiviral drugs targeted against lytic viral replication have limited efficacy in these disease settings. EBV infection of peripheral blood mononuclear cells induces growth proliferation and the EBV latency Epstein-Barr virus-encoded nuclear antigen (EBNA)2 transcriptional transactivator (TAT) is essential for this response. EBNA2 targets the cellular DNA-binding protein CBF1 to mimic activated Notch signaling. A 10-aa peptide from the CBF1 interaction domain of EBNA2 was synthesized as a fusion with the protein transduction domain of HIV-1 TAT. The EBNA2-TAT peptide blocked EBNA2-CBF1 interaction in an in vitro GST affinity assay and labeling with fluorescein confirmed that the EBNA2-TAT peptide efficiently entered cultured B cells. Neither EBNA2-TAT, nor a mutant peptide with a 2-aa substitution that was unable to block the EBNA2-CBF1 interaction, significantly affected the growth of non-EBNA2-expressing EBV(-) B cells or Burkitt's lymphoma Akata cells. However, treatment of an EBV-immortalized lymphoblastoid cell line with the EBNA2-TAT peptide stopped cell growth and reduced cell viability. RT-PCR analyses of gene expression in the peptide-treated lymphoblastoid cell line cultures revealed that EBNA2-TAT treatment down-regulated the EBNA2-responsive viral LMP1 and LMP2 genes and cellular CD23, intercellular adhesion molecule 1, BATF, and Cdk1 genes while up-regulating expression of the cyclin-dependent kinase inhibitor p21. EBV-induced outgrowth of B cells from cultured peripheral blood mononuclear cells was also blocked in a dose-responsive manner by the EBNA2-TAT peptide. This study suggests that cell-permeable EBNA2 peptides may have potential as novel anti-EBV therapeutics.
Farrell
Christopher J
CJ
Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, 1650 Orleans Street, Baltimore, MD 21231, USA.
Lee
Jae Myun
JM
Shin
Eui-Cheol
EC
Cebrat
Marek
M
Cole
Philip A
PA
Hayward
S Diane
SD
D001483:Base Sequence; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D017931:DNA Primers; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D019309:Epstein-Barr Virus Nuclear Antigens / Q000502:physiology*; D015870:Gene Expression; D015696:Gene Products, tat / Q000502:physiology*; D004854:Herpesvirus 4, Human / Q000254:growth & development / Q000502:physiology*; D006801:Humans; D051819:Immunoglobulin J Recombination Signal Sequence-Binding Protein; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000493:pharmacokinetics / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction
D017931:DNA Primers; D004268:DNA-Binding Proteins; C438197:EBNA4 antigen; D019309:Epstein-Barr Virus Nuclear Antigens; D015696:Gene Products, tat; D051819:Immunoglobulin J Recombination Signal Sequence-Binding Protein; D009687:Nuclear Proteins; D010446:Peptide Fragments; C497570:RBPJ protein, human