| Oestradiol synthesis from oestrone in malignant breast epithelial cells: studies on a high affinity, 80 kDa form of oestradiol dehydrogenase. | |
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MedLine Citation:
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PMID: 1525049 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Previous studies have shown that in the breast there are multiple forms of the enzyme oestradiol dehydrogenase (E2DH), responsible for the interconversion of oestrone (E1) to oestradiol (E2). We have now re-examined oestrogen metabolism in the breast cancer cell lines (T47D and MCF-7) and have shown that steroids previously shown to inhibit the conversion of E1 to E2 in normal breast tissue failed to do so when added to growing monolayers of these malignant cells. In contrast to earlier estimates in normal breast tissues, the apparent Km for this conversion in monolayers of these malignant cells is shown here to be considerably lower, at around 50 nM. Cell free studies on these cell lines have revealed the presence of a high affinity (for E1) form of this enzyme of Mw approximately 80 kDa. The ability to detect this enzyme in soluble cell fractions appears to be critically dependent on buffer composition. Normal breast epithelial cells and adipose tissue appear to be devoid of this form of E2DH. As this form of E2DH has the highest affinity for the substrate E1 of all the forms in the breast, it is probable that this 80 kDa enzyme is responsible for the conversion of E1 to E2 in cell monolayers. If the observation holds that the 80 kDa enzyme is absent in the normal tissues, then the possibility arises that this E2DH may be linked with the neoplastic process in some breast tumours containing malignant epithelial cells of a similar type as studied here. |
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Authors:
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C J Newton; A Butta; J Nicholls; M Dowsett |
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Publication Detail:
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Type: Journal Article |
Journal Detail:
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Title: The Journal of steroid biochemistry and molecular biology Volume: 42 ISSN: 0960-0760 ISO Abbreviation: J. Steroid Biochem. Mol. Biol. Publication Date: 1992 Sep |
Date Detail:
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Created Date: 1992-10-22 Completed Date: 1992-10-22 Revised Date: 2004-11-17 |
Medline Journal Info:
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Nlm Unique ID: 9015483 Medline TA: J Steroid Biochem Mol Biol Country: ENGLAND |
Other Details:
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Languages: eng Pagination: 891-900 Citation Subset: IM |
Affiliation:
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Department of Academic Biochemistry, Royal Marsden Hospital, London, England. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Adipose Tissue
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enzymology Breast / enzymology Breast Neoplasms / metabolism* Cell-Free System Epithelium / enzymology Estradiol / biosynthesis* Estradiol Dehydrogenases / isolation & purification, metabolism* Estrone / metabolism* Female Humans Kinetics Molecular Weight Tumor Cells, Cultured |
| Chemical | |
Reg. No./Substance:
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50-28-2/Estradiol; 53-16-7/Estrone; EC 1.1.1.62/Estradiol Dehydrogenases |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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