Triplex forming oligonucleotide targeted to 3'UTR downregulates the expression of the bcl-2 proto-oncogene in HeLa
1Department of Nuclear Medicine and Department of Clinical Chemistry, University of Ulm, Germany.
Abstract:
The bcl-2 proto-oncogene is overexpressed in a variety of human cancers and plays an important role in programmed cell death. Recent reports implied that the 3'-untranslated region (3'UTR) functions effectively in the regulation of gene expression. Here, we attempt to assay the ability of triplex forming oligonucleotides (TFOs) to inhibit expression of a target gene in vivo and to examine the potential of the 3'UTR of the bcl-2 proto-oncogene in the regulation of bcl-2 gene expression. To do this, we have developed a novel cellular system that involves transfection of a Doxycyclin inducible expression plasmid containing the bcl-2 ORF and the 3'UTR together with a TFO targeted to the 3'UTR of the bcl-2 proto-oncogene. Phosphorothioate-modified TFO targeted to the 3'UTR of the bcl-2 gene significantly downregulated the expression of the bcl-2 gene in HeLa cells as demonstrated by western blotting. Our results indicate that blocking the functions of the 3'UTR using the TFO can downregulate the expression of the targeted gene, and suggest that triplex strategy is a promising approach for oligonucleotide-based gene therapy. In addition, triplex-based sequence targeting may provide a useful tool for studying the regulation of gene expression.
Insights
Triplex forming oligonucleotides (TFOs) effectively downregulate bcl-2 gene expression by targeting its 3' untranslated region (3'UTR). This novel triplex strategy shows promise for oligonucleotide-based gene therapy and studying gene regulation.
Area of Science:
- Molecular Biology
- Gene Regulation
- Cancer Biology
Background:
- The bcl-2 proto-oncogene is frequently overexpressed in human cancers, contributing to programmed cell death evasion.
- The 3'-untranslated region (3'UTR) of genes plays a crucial role in regulating gene expression.
- Targeting gene expression offers potential therapeutic strategies for cancer.
Purpose of the Study:
- To investigate the efficacy of triplex forming oligonucleotides (TFOs) in inhibiting target gene expression in vivo.
- To explore the regulatory role of the bcl-2 proto-oncogene's 3'UTR in gene expression.
- To assess the potential of TFOs targeting the bcl-2 3'UTR for therapeutic applications.
Main Methods:
- Development of a novel cellular system using a Doxycycline-inducible expression plasmid containing the bcl-2 open reading frame (ORF) and its 3'UTR.
- Transfection of HeLa cells with the expression plasmid and a phosphorothioate-modified TFO specifically designed to target the bcl-2 3'UTR.
- Validation of bcl-2 gene downregulation using Western blotting analysis.
Main Results:
- The TFO targeting the bcl-2 3'UTR significantly downregulated bcl-2 gene expression in HeLa cells.
- Blocking the regulatory functions of the 3'UTR via TFO intervention effectively reduced target gene expression.
- Western blotting confirmed the reduced protein levels of bcl-2 following TFO treatment.
Conclusions:
- The triplex strategy utilizing TFOs targeting the 3'UTR is a viable approach for downregulating specific gene expression.
- This method holds promise as a potential therapeutic strategy for oligonucleotide-based gene therapy, particularly in cancers with bcl-2 overexpression.
- Triplex-based sequence targeting offers a valuable tool for further research into gene expression regulation mechanisms.
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