title: Effects of estrogens on MCF-7 cells: positive or negative regulation by the nature of the ligand-receptor complex.
abstract: The present study demonstrates that the nature of the binding of estrogens to the hormone-binding domain of the estrogen receptor (ER) modifies the responses of estrogen-dependent cells. We report here that 10 nM estradiol (E2) forms noncovalent associations with the ER, increases the level of ER and Progesterone Receptors (PR) in ER+ MCF-7 human breast cancer cells in culture following short-term or long-term exposure to E2. In contrast, 10 nM 16-alpha-hydroxyestrone (16 alpha-OHE1), a physiological metabolite of E2, in short-term cultures is equivalent to E2, but upon long-term incubation, 16 alpha-OHE1 forms covalent associations with the ER, produces a marked decrease in ER and PR levels reaching values similar to, or below to that of control cells.
authors.affiliation: Rockefeller University, New York, NY 10021.
authors.forename: G E
authors.initials: GE
authors.lastname: Swaneck
authors.forename: J
authors.initials: J
authors.lastname: Fishman
mesh_terms: D001943:Breast Neoplasms / Q000378:metabolism; D002452:Cell Count; D004958:Estradiol / Q000494:pharmacology; D004967:Estrogens / Q000494:pharmacology*; D005260:Female; D006801:Humans; D006894:Hydroxyestrones / Q000494:pharmacology; D008024:Ligands; D011960:Receptors, Estrogen / Q000187:drug effects / Q000378:metabolism*; D011980:Receptors, Progesterone / Q000187:drug effects / Q000378:metabolism; D014407:Tumor Cells, Cultured
chemical_list: D004967:Estrogens; D006894:Hydroxyestrones; D008024:Ligands; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; C026702:16-hydroxyestrone; D004958:Estradiol