Characterization of the estrogen receptor and its dynamics in MCF-7 human breast cancer cells using a covalently attaching antiestrogen

Journal Article · Sun Jul 01 04:00:00 EDT 1984 · Endocrinology; (United States)

DOI:https://doi.org/10.1210/endo-115-1-143· OSTI ID:6472430

Monsma, Jr, F J; Katzenellenbogen, B S; Miller, M A; Ziegler, Y S; Katzenellenbogen, J A

The authors have used a covalently attaching antiestrogen, tamoxifen aziridine TA to analyze the structure and dynamics of the estrogen receptor in MCF-7 human breast cancer cells. The labeling of receptor with (/sup 3/H)TA is specific, being blocked only by estrogens and antiestrogens, and the labeling is very efficient in that TA labels covalently the same number of receptors that are labeled reversibly by estradiol. In cells exposed to (/sup 3/H)TA for 1 h, most of the covalently associated radioactivity is found in the 0.6 M KCl extract of the nuclear fraction; this receptor has an apparent mol wt of 63,000 +/- 2000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and a pI of 5.7 by gel isoelectric focusing in the presence of 8 M urea. The mol wt and pI of cytosol receptor labeled with (/sup 3/H) TA are identical. In cells labeled with (/sup 3/H)TA (20 nM) for 1 h and then exposed to a chase of 10(-6) M estradiol, (3H)TA-labeled nuclear receptor disappears with a half-life of 4 h. Affinity labeled receptor interacts with several monoclonal antibodies to MCF-7 estrogen receptor, and it can be purified extensively by immunoadsorbent chromatography. The findings of similar mol wt and isoelectric points for soluble cytosol and nuclear extracted receptors under strongly denaturing and disaggregating conditions reveal that nuclear localization of receptor after ligand binding is not associated with major structural alterations in the receptor component labeled by TA.

• Research Organization: Univ. of Illinois, Urbana
• OSTI ID: 6472430
• Journal Information: Endocrinology; (United States), Journal Name: Endocrinology; (United States) Vol. 115:1; ISSN ENDOA
• Country of Publication: United States
• Language: English

Related Subjects

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59 BASIC BIOLOGICAL SCIENCES
ANIMAL CELLS
ANTIBODIES
BODY
ESTROGENS
GLANDS
HORMONES
LABELLED COMPOUNDS
MAMMARY GLANDS
MOLECULAR STRUCTURE
MOLECULAR WEIGHT
MONOCLONAL ANTIBODIES
ORGANS
RECEPTORS
STEROID HORMONES
TRITIUM COMPOUNDS
TUMOR CELLS