Comparison of estrogen receptor systems in estrogen-responsive (Ishikawa) and unresponsive (HEC-50) human endometrial adenocarcinoma cells.
Item
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Title
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Comparison of estrogen receptor systems in estrogen-responsive (Ishikawa) and unresponsive (HEC-50) human endometrial adenocarcinoma cells.
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Identifier
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AAI8821095
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identifier
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8821095
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Creator
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Kassan, Sharon Deborah.
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Contributor
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Adviser: Erlio Gurpide
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Date
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1988
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Language
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English
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Publisher
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City University of New York.
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Subject
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Chemistry, Biochemistry
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Abstract
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Cells from the Ishikawa and HEC-50 human adenocarcinoma cell lines differ in their responsiveness to estrogens; the former, but not the latter, respond to estradiol. This dissertation describes studies conducted in order to investigate possible alterations in the estrogen receptor system that could underlie an insensitivity to estrogens.;Saturation analysis of cytosolic estrogen binders was performed over a wide range of (3H) estradiol concentrations and equilibrium dissociation constants (Kd) were determined graphically from Scatchard plots. No significant differences were noted in the Kd of the high affinity specific binder (approximately 0.7nM) present in each of the two cell lines and in normal endometrium.;The estrogen receptor monoclonal antibody, JS 34/32, was used to search for structural differences in the specific estrogen binders in cytosol and nuclear extracts of the 2 cell lines and endometrial tissue that could be present without affecting binding parameters. Interaction of the antibody with the estrogen receptor of Ishikawa cells and normal endometrium was demonstrated by immunoprecipitation with Protein A-Sepharose beads and by the increase in the sedimentation rate of specifically bound (3H) estradiol in glycerol density gradients. None of these effects were noted with the HEC-50 cells.;The ability of (3H) estradiol receptors to be transformed to nucleophilic forms by interaction of the hormone was assessed by binding to DNA-cellulose. In contrast to the clear transformation of some of the specific binders observed in the estrogen-responsive Ishikawa cells, the HEC-50 cells could not be transformed by estradiol.;These results indicate that the lack of responsiveness of the HEC-50 cells to estrogens might be due to structural alterations resulting in a modification or masking of the antigenic domains of the estrogen receptor and in a loss of its capability to undergo estrogen-directed conformational changes leading to increased affinity for DNA.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
