title: Inhibition of aromatase expression by a psoralen-linked triplex-forming oligonucleotide targeted to a coding sequence.
abstract: The cytochrome P450 enzyme aromatase (P450arom) is an important target in breast cancer treatment. We have designed a 20-base pyrimidine oligodeoxynucleotide (ODN) which forms a sequence-specific triple helix (triplex) with a purine-rich tract in the P450arom coding sequence. The psoralen-linked ODN (Pso20T) formed photo-induced cross-linked products with target double-stranded DNA. Cross-linked adducts formed in vitro between ODNs and P450arom expression constructs were used to transfect COS and human MCF-7 breast cancer cells. Levels of aromatase transcripts and enzyme activity were significantly lower in cultures transfected with Pso20T-treated cDNA relative to controls. Pso20T had a lesser inhibitory effect on aromatase expression from a mutant P450arom construct, consistent with predicted effects of the mutations on triplex formation. These results are compatible with triplex-mediated interruption of transcription within intact cells.
authors.affiliation: Chester Beatty Laboratories, Institute of Cancer Research, London, UK.
authors.forename: V M
authors.initials: VM
authors.lastname: Macaulay
authors.forename: P J
authors.initials: PJ
authors.lastname: Bates
authors.forename: M J
authors.initials: MJ
authors.lastname: McLean
authors.forename: M G
authors.initials: MG
authors.lastname: Rowlands
authors.forename: T C
authors.initials: TC
authors.lastname: Jenkins
authors.forename: A
authors.initials: A
authors.lastname: Ashworth
authors.forename: S
authors.initials: S
authors.lastname: Neidle
mesh_terms: D001141:Aromatase / Q000096:biosynthesis*; D001483:Base Sequence; D001665:Binding Sites; D005363:Ficusin / Q000378:metabolism*; D006801:Humans; D008969:Molecular Sequence Data; D009841:Oligonucleotides / Q000494:pharmacology*; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology*; D014407:Tumor Cells, Cultured
chemical_list: D009841:Oligonucleotides; D011500:Protein Synthesis Inhibitors; D001141:Aromatase; D005363:Ficusin