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Modulation of topoisomerase IIalpha expression by a DNA sequence-specific polyamide

Daniel Hochhauser1, Minal Kotecha, Caroline O'hare

  • 1Department of Oncology, Royal Free and University College Medical School, University College London, 91 Riding House Street, London W1W 7BS, United Kingdom. d.hochhauser@ucl.ac.uk

Molecular Cancer Therapeutics
|January 24, 2007
PubMed

Insights

A novel polyamide, JH-37, successfully blocks transcription factor NF-Y binding to the topoisomerase IIalpha promoter. This increases topoisomerase IIalpha expression, enhancing cancer cell sensitivity to etoposide chemotherapy.

Area of Science:

  • Molecular Biology
  • Cancer Research
  • Drug Development

Background:

  • Topoisomerase IIalpha (topo IIalpha) is a key target for chemotherapy drugs like etoposide.
  • Confluent cells exhibit low topo IIalpha levels and resistance to etoposide.
  • NF-Y transcription factor binding to the topo IIalpha promoter represses its transcription in confluent cells.

Purpose of the Study:

  • To investigate if a polyamide (JH-37) can inhibit NF-Y binding and restore topo IIalpha expression.
  • To determine if modulating topo IIalpha levels impacts cancer cell chemosensitivity.

Main Methods:

  • Design of polyamide JH-37 to target CCAAT sites in the topo IIalpha promoter.
  • Electrophoretic mobility shift assays and DNase I footprinting to confirm JH-37 binding.
  • Chromatin immunoprecipitation assays to assess in vivo NF-Y binding.
  • Comet assay to evaluate DNA double-strand breaks and cell viability assays.

Main Results:

  • JH-37 effectively occupied target CCAAT sites in the topo IIalpha promoter.
  • In vivo assays confirmed JH-37 inhibited NF-Y binding to the promoter.
  • JH-37 treatment led to increased topo IIalpha mRNA and protein expression.
  • Increased topo IIalpha expression correlated with enhanced etoposide-induced DNA damage and reduced cell viability.

Conclusions:

  • Polyamides can be designed to modulate gene expression by targeting specific transcription factor binding sites.
  • JH-37 demonstrates potential for overcoming chemoresistance by restoring target gene expression.
  • This approach offers a novel strategy for enhancing cancer chemotherapy efficacy.

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