Specific down-regulation of an engineered human cyclin D1 promoter by a novel DNA-binding ligand in intact cells.
Cyclin D1 is expressed at abnormally high levels in many cancers and has been specifically implicated in the development of breast cancer. In this report we have extensively analyzed the cyclin D1 promoter in a variety of cancer cell lines that overexpress the protein and identified two critical regulatory elements (CREs), a previously identified CRE at -52 and a novel site at -30. In vivo footprinting experiments demonstrated factors binding at both sites. We have used a novel DNA-binding ligand, GL020924, to target the site at -30 (-30-21) of the cyclin D1 promoter in MCF7 breast cancer cells. A binding site for this novel molecule was constructed by mutating 2 bp of the wild-type cyclin D1 promoter at the -30-21 site. Treatment with GL020924 specifically inhibited expression of the targeted cyclin D1 promoter construct in MCF7 cells in a concentration-dependent manner, thus validating the -30-21 site as a target for minor groove-binding ligands. In addition, this result validates our approach to regulating the expression of genes implicated in disease by targeting small DNA-binding ligands to key regulatory elements in the promoters of those genes.
Laurance
M E
ME
Genelabs Technologies Inc., 505 Penobscot Drive, Redwood City, CA 94063, USA. barrys@genelabs.com
Starr
D B
DB
Michelotti
E F
EF
Cheung
E
E
Gonzalez
C
C
Tam
A W
AW
Deikman
J
J
Edwards
C A
CA
Bardwell
A J
AJ
D001665:Binding Sites / Q000235:genetics; D001667:Binding, Competitive; D019938:Cyclin D1 / Q000235:genetics*; D004247:DNA / Q000235:genetics / Q000378:metabolism; D015536:Down-Regulation / Q000187:drug effects; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D008156:Luciferases / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D009842:Oligopeptides / Q000378:metabolism / Q000494:pharmacology*; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics; D017384:Sequence Deletion; D014157:Transcription Factors / Q000378:metabolism; D014407:Tumor Cells, Cultured
C424464:GL020924; D009842:Oligopeptides; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; D019938:Cyclin D1; D004247:DNA; D008156:Luciferases