The cyclo-oxygenase 2 promoter is induced in nontarget cells following adenovirus infection, but an AU-rich 3'-untranslated region destabilization element can increase specificity.

Academic Article

Abstract

  • BACKGROUND: Cyclo-oxygenase 2 (Cox-2) is expressed in many types of tumors, but typically undetectable in normal tissues. However, Cox-2 is known to be induced following infection by many microbial agents, which might threaten the tumor selectivity of the Cox-2 promoter in the context of virotherapy or viral gene delivery. Cox-2 expression is regulated in part post-transcriptionally by stimulation or inhibition of mRNA degradation by 3'-untranslated region (3'-UTR) AU-rich elements. In the present study, we investigated the induction of the Cox-2 promoter both in normal and tumor cells after adenovirus infection and explored the utility of AU-rich elements for regaining promoter selectivity. METHODS: Nontumor and tumor cells were transfected in vitro and in vivo with plasmids containing the Cox-2 or cytomegalovirus immediate early promoter driving luciferase (with or without 3'-UTR elements) followed by adenoviral infection. Selectivity and activity of the promoters and 3'-UTR elements were analysed by luciferase assay and in-vivo imaging. RESULTS: The Cox-2 promoter was induced in both normal and tumor cells following infection with E1 containing replicative adenoviruses but not in the absence of E1. Utilization of AU-rich elements counteracted promoter induction in vitro and in vivo in nonmalignant cells but not in cancer cells, thus increasing the selectivity of the approach ten-fold without loss of potency. CONCLUSIONS: Adenoviral infection induces the Cox-2 promoter in normal and tumor cells, which might compromise specificity of the promoter. Utilization of AU-rich destabilization elements can rescue the tumor selectivity of the promoter.
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    Keywords

  • 3' Untranslated Regions, Adenovirus Infections, Human, Cell Line, Tumor, Cyclooxygenase 2, DNA Primers, Gene Expression Regulation, Humans, Luciferases, Plasmids, Promoter Regions, Genetic, Transfection
  • Digital Object Identifier (doi)

    Authorlist

  • Särkioja M; Hakkarainen T; Eriksson M; Ristimäki A; Desmond RA; Kanerva A; Hemminki A
  • Start Page

  • 744
  • End Page

  • 753
  • Volume

  • 10
  • Issue

  • 7