Correction: raloxifene response needs more than an element.
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Estrogen Antagonists↗
Biomedical subjects
S Hardikar
Publications and source records attributed to S Hardikar.
Identification of an estrogen response element activated by metabolites of 17beta-estradiol and raloxifene.
17beta-Estradiol modulates gene transcription through the estrogen receptor and the estrogen response element in DNA. The human transforming growth factor-beta3 gene was shown to be activated by the estrogen receptor in the presence of estrogen metabolites or estrogen antagonists. Activation was mediated by a polypurine sequence, termed the raloxifene response element, and did not require the DNA binding domain of the estrogen receptor. Interaction of the estrogen receptor with the raloxifene response element appears to require a cellular adapter protein. The observation that individual estrogens modulate multiple DNA response elements may explain the tissue-selective estrogen agonist or antagonist activity of compounds such as raloxifene.
Base Sequence↗
Estrogen and raloxifene stimulate transforming growth factor-beta 3 gene expression in rat bone: a potential mechanism for estrogen- or raloxifene-mediated bone maintenance.
Estrogen or raloxifene (LY156758) prevent estrogen deficiency-induced bone loss in animals and humans. We demonstrated in the rat that a 22% reduction in bone mineral density generated by ovariectomy was associated with a 2-fold reduction of transforming growth factor-beta 3 (TGF beta 3) messenger RNA expression in the femur. Administration of 17 beta-estradiol or raloxifene to ovariectomized rats restored both bone mineral density and TGF beta 3 messenger RNA expression in the femur to levels measured in intact animals. In transient transfection assays, the promoter sequence from -38 to + 110 of the human TGF beta 3 gene, which contains no palindromic estrogen response element, was sufficient to mediate 17 beta-estradiol or raloxifene induced-reporter gene expression in presence of the estrogen receptor. Raloxifene activated TGF beta 3 promoter as a full agonist at nanomolar concentrations. In the same cellular system, raloxifene inhibited the estrogen response element-containing vitellogenin promoter expression as a pure estrogen antagonist. In two well characterized osteoclast differentiation models, TGF beta 3 significantly inhibited the differentiation and bone-resorptive activities of murine and avian osteoclasts. These findings suggest that regulation of TGF beta 3 gene expression by raloxifene or estrogen in bone may be an important target to mediate bone maintenance.
Animals↗
Myeloproliferative disorders: usefulness of X-linked probes in diagnosis.
Myeloproliferative disorders are neoplasms of the pluripotent hematopoietic stem cell. Accurate diagnosis and distinction from reactive processes can be difficult therein with cytogenetic analysis only being useful in a minority of patients. Use of X-linked restriction fragment length polymorphism and methylation analysis has enabled clonal analysis to be performed in up to 50% of females, significantly increasing the proportion of analyzable patients over methods dependent on glucose-6-phosphate dehydrogenase heterozygosity. Using hypoxanthine phosphoribosyl transferase and phosphoglycerate kinase probes, we have demonstrated monoclonality of peripheral blood leukocytes in three females with myeloproliferative disorders who had uninformative chromosomal analysis. This technique greatly enhances the diagnosis of early myeloproliferative disorder.
Adult↗