Estrogenic and anti-estrogenic regulation of estrogen receptor in MCF-7 breast-cancer cells: Comparison of immunocytochemical data with biochemical measurements

Autor: Abdelhamid El Khissiin, Hye-Sook Seo, Gilbert Querton, Denis Larsimont, Ioanna Laïos, Guy Leclercq, Nicole Legros
Rok vydání: 1998
Předmět:
Zdroj: International Journal of Cancer. 78:760-765
ISSN: 1097-0215
0020-7136
DOI: 10.1002/(sici)1097-0215(19981209)78:6<760::aid-ijc14>3.0.co;2-u
Popis: Data from immunocytochemical assessment of estrogen receptor (ER) regulation in MCF-7 cells under estrogenic and anti-estrogenic stimulation were compared with those obtained by enzyme immunoassay (Abbott ER-EIA). Similar trends were observed, although ER level variations were less marked when assessed immunocytochemically. We confirmed reports of ER disappearance in the presence of estrogens (Es; E2 and DES) and pure anti-estrogens (AEs; RU 58,668 and ICI 164,384) as well as its increase with partial AEs (4-OH-TAM and RU 39,119). E2-induced ER down-regulation was partly blocked by actinomycin D (AMD), okadaic acid (OK) and cycloheximide (CHX) when assessed by these 2 methods. Down-regulation by pure AEs was not impeded by CHX, indicating that they operate differently from Es (i.e., transformation of ER to a form sensitive to constitutive degradation activity). In situ pre-labeling of the cells with [ 3 H]TAZ indicated that all investigated ligands eliminate pre-existing ER through binding to newly synthetized receptors, since [3H]TAZ co-valently associates with ER; E2 and RU 58,668 were more effective than 4-OH-TAM in this regard. CHX blocked ER disappearance even in the presence of pure AEs, which is in contrast to the data established with cells not pre-exposed to [3H]TAZ. Nuclear location of [3H]TAZ-ER complexes may explain this discrepancy, since pure AE-ER complexes were reported to be incapable of nuclear translocation. Int. J. Cancer 78:760‐765, 1998. r 1998 Wiley-Liss, Inc.
Databáze: OpenAIRE
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