title: Oestrogens Downregulate Tissue Factor Pathway Inhibitor through Oestrogen Response Elements in the 5'-Flanking Region.
abstract: Oestrogens influence the pathology and development of hormone-sensitive breast cancers. Tissue factor pathway inhibitor (TFPI) has been shown to be associated with breast cancer pathogenesis. Recently, we found TFPI mRNA levels to be significantly reduced by oestrogens in a breast cancer cell line (MCF7), a process mediated through the oestrogen receptor alpha (ERα). The aim of the present study was to investigate the mechanism(s) by which oestrogens may regulate TFPI at the transcriptional level. The TFPI 5'-flanking region contains three oestrogen response element (ERE) half-sites at positions -845, -769 and -50. Constructs containing the wild type or mutated ERE half-sites of the TFPI 5'-flanking region were generated in a luciferase reporter gene vector and transiently co-transfected with an ERα expression vector into HEK293 cells and subsequently treated with oestrogens. We found that luciferase activity was significantly downregulated after oestrogen stimulation in cells transfected with the wild type construct, an effect that was abolished by mutating either ERE half-sites. Electrophoretic mobility shift assay suggested direct and specific interaction of ERα with the ERE half-sites in the TFPI 5'-flanking region. Chromatin immunoprecipitation showed that ERα was recruited to the region -899 to -578 of the TFPI 5'-flanking region in vivo, where the ERE half-sites -845 and -769 are located. Our results indicate that ERα can interact with all three ERE half-sites in the TFPI 5'-flanking region and thus participate in the repression of oestrogen mediated TFPI transcription in breast cancer cells.
authors.affiliation: Department of Haematology, Oslo University Hospital, Oslo, Norway.|Research Institute of Internal Medicine, Oslo University Hospital, Oslo, Norway.|Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
authors.forename: Huda Omar
authors.initials: HO
authors.lastname: Ali
authors.affiliation: Department of Haematology, Oslo University Hospital, Oslo, Norway.|Research Institute of Internal Medicine, Oslo University Hospital, Oslo, Norway.
authors.forename: Benedicte
authors.initials: B
authors.lastname: Stavik
authors.affiliation: Department of Haematology, Oslo University Hospital, Oslo, Norway.|Research Institute of Internal Medicine, Oslo University Hospital, Oslo, Norway.
authors.forename: Christiane Filion
authors.initials: CF
authors.lastname: Myklebust
authors.affiliation: Department of Haematology, Oslo University Hospital, Oslo, Norway.|Research Institute of Internal Medicine, Oslo University Hospital, Oslo, Norway.|Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Andersen
authors.affiliation: Research Institute of Internal Medicine, Oslo University Hospital, Oslo, Norway.|Institute of Clinical Medicine, University of Oslo, Oslo, Norway.|Department of Haematology, Akershus University Hospital, Nordbyhagen, Norway.
authors.forename: Anders E A
authors.initials: AE
authors.lastname: Dahm
authors.affiliation: Department of Medical Genetics, Oslo University Hospital, Oslo, Norway.
authors.forename: Nina
authors.initials: N
authors.lastname: Iversen
authors.affiliation: Department of Haematology, Oslo University Hospital, Oslo, Norway.|Research Institute of Internal Medicine, Oslo University Hospital, Oslo, Norway.|Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
authors.forename: Per Morten
authors.initials: PM
authors.lastname: Sandset
authors.affiliation: Department of Haematology, Oslo University Hospital, Oslo, Norway.|Research Institute of Internal Medicine, Oslo University Hospital, Oslo, Norway.
authors.forename: Grethe
authors.initials: G
authors.lastname: Skretting
mesh_terms: D024506:5' Flanking Region / Q000235:genetics*; D001665:Binding Sites; D045744:Cell Line, Tumor; D015536:Down-Regulation / Q000187:drug effects*; D024202:Electrophoretic Mobility Shift Assay; D047628:Estrogen Receptor alpha / Q000378:metabolism; D004967:Estrogens / Q000494:pharmacology*; D055785:Gene Knockdown Techniques; D006801:Humans; D008074:Lipoproteins / Q000235:genetics* / Q000378:metabolism; D009687:Nuclear Proteins / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects; D020218:Response Elements / Q000235:genetics*; D016329:Sp1 Transcription Factor / Q000378:metabolism; D018808:Transcription Factor AP-1 / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: C506487:ESR1 protein, human; D047628:Estrogen Receptor alpha; D004967:Estrogens; D008074:Lipoproteins; D009687:Nuclear Proteins; D016329:Sp1 Transcription Factor; D018808:Transcription Factor AP-1; C051928:lipoprotein-associated coagulation inhibitor