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

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.