Overexpression of Bcl-2 as a proxy redox stimulus to enhance activity of non-viral redox-responsive delivery vectors

Devika S. Manickam, Aiko Hirata, David A. Putt, Lawrence H. Lash, Fusao Hirata, David Oupický

Research output: Contribution to journalArticlepeer-review

14 Scopus citations


Redox-sensitive non-viral delivery systems exploit intracellular reducing environment to improve the efficacy of the delivery of nucleic acids by selectively releasing the cargo in the subcellular space. Bcl-2 overexpression is frequently observed in human cancers and is closely associated with increased resistance to chemotherapy and radiotherapy. One of the biochemical alterations accompanying Bcl-2 overexpression is the increase in cellular glutathione (GSH) levels. In this study, we hypothesize that such increase of GSH concentration will selectively enhance the transfection activity of redox-sensitive delivery systems in cells overexpressing Bcl-2. Transfection studies were conducted in MCF-7 mammary carcinoma cells and MCF-7 clones overexpressing Bcl-2. It was confirmed that Bcl-2 overexpression resulted in the expected increase in GSH concentration. Redox-sensitive complexes containing plasmid DNA, mRNA, antisense oligodeoxynucleotides, and siRNA exhibited selectively increased activity in cells overexpressing Bcl-2 compared to non-redox complexes. The effect of Bcl-2 overexpression on the selective enhancement of transfection was highly dependent on the type of the delivered nucleic acid, and was most pronounced for mRNA. This study shows that Bcl-2 overexpression can serve as a proxy redox stimulus to enhance the activity of all major classes of potential nucleic acid therapeutics, when delivered using redox-sensitive vectors.

Original languageEnglish (US)
Pages (from-to)2680-2688
Number of pages9
Issue number17
StatePublished - Jun 2008
Externally publishedYes


  • Bcl-2 overexpression
  • Glutathione
  • Non-viral gene delivery
  • Polyplexes
  • Transfection

ASJC Scopus subject areas

  • Bioengineering
  • Ceramics and Composites
  • Biophysics
  • Biomaterials
  • Mechanics of Materials


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