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E M Berns

Publications and source records attributed to E M Berns.

41 records · Page 3Linked to original sources
PubMed1985

Changes of oestrogen receptor levels in Leydig cells from mice and rats during culture.

Two functional properties of Leydig cells in culture, i.e. LH-stimulated steroidogenesis and nuclear oestrogen receptor levels have been investigated. Leydig cells isolated from testes of immature rats and mature mice maintained their responsiveness to LH during 48-72 h of cell culture, although the mouse Leydig cells appeared to be less responsive to LH after 72 h of culture. In contrast, nuclear oestrogen receptor levels in both types of Leydig cells declined to 10-20% of the initial value after 24 h in culture. In the 48-72 h culture period nuclear oestrogen receptor levels recovered to 75% of the initial value only in Leydig cells from immature rats, whereas the nuclear oestrogen receptor levels in Leydig cells from mature mice remained low. These data demonstrate that during in vitro culture of Leydig cells, preservation of LH responsiveness does not necessarily warrant that other Leydig cell parameters e.g. nuclear oestrogen receptors also remain unaltered.

Animals↗
PubMed1984

Fluorescent androgen derivatives do not discriminate between androgen receptor-positive and -negative human tumor cell lines.

For the evaluation of histochemical procedures for detection of androgen receptors, three human tumor cell lines have been used: PC-93 and NHIK-3025, both biochemically characterized as androgen receptor-positive, and EB-33, biochemically characterized as androgen receptor-negative. The binding of three fluorescent ligands, testosterone-17 beta-hemisuccinate-bovine serum albumin-fluorescein isothiocyanate, testosterone-17 beta-hemisuccinate-fluoresceinamine, and 5 alpha-dihydrotestosterone-17 beta-hemisuccinate-fluoresceinamine, to the cells was evaluated. The relative binding affinities of the ligands for the androgen receptors were low (less than 5% when compared to methyltrienolone). Treatment of the cells with the androgen-fluoresceinamine derivatives resulted in a fluorescent labeling of the cytoplasm in both intact and "freeze-damaged" cells of the three cell lines. This staining was independent of the presence of receptors. Nuclei were not stained. Incubation of intact cels with the protein-linked conjugate did not result in significant cellular fluorescence. Only cells with damaged membranes showed a positive histochemical reaction, both in nucleus and cytoplasm, irrespective of the receptor content of the cells. The fluorescence intensity was not suppressed with excess 5 alpha-dihydrotestosterone or methyltrienolone, which are known to prevent binding of low affinity ligands to androgen receptors. From these results it is concluded that androgen receptors cannot be detected by these fluorescent ligands with low affinity for the receptor. The observed fluorescence of the cells is therefore due to binding of the ligands to other binding sites. The visualization/histochemical demonstration of these binding sites does not appear to be related to the presence of androgen receptors.

Adenocarcinoma↗
PubMed1984

Fluorescent ligands, used in histocytochemistry, do not discriminate between estrogen receptor-positive and receptor-negative human tumor cell lines.

A cell line containing estrogen receptors (MCF-7) and a cell line lacking estrogen receptors (PC-93) were used for a comparison of biochemical and histochemical procedures to detect estrogen receptors. We evaluated three different fluorescent estrogen derivatives: 17 beta-estradiol-6-carboxymethyloxime-bovine serum albumin-fluorescein isothiocyanate, 17 beta-estradiol-17-hemisuccinate-fluoresceinamine, and coumestrol. The main results were: The relative binding affinities of these ligands for the estrogen receptor were between 0.1 and 2% of the affinity of estradiol. Fluorescent staining of the cells showed no relation to the presence of estrogen receptors. Staining was not suppressed with excess estradiol-17 beta, which is known to prevent binding of low affinity ligands to estrogen receptors. Cells with intact membranes were not stained after treatment with the albumin-linked estrogen derivative; only cells with damaged cell membranes were stained. Treatment of cells with 17 beta-estradiol-17-hemisuccinate-fluoresceinamine resulted in a fluorescent labeling of the cytoplasm in intact and artificially damaged cells. Coumestrol caused only fluorescence of the cytoplasm in intact cells. It is concluded that estrogen receptors cannot be detected with these low affinity ligands. Fluorescence of these cells is probably due to binding of the ligands to low affinity binding sites. The presence of these low affinity binding sites appears not to be related to the presence or absence of estrogen receptors and can therefore not be used to discriminate between estrogen receptor-positive and receptor-negative tumor cells.

Breast Neoplasms↗
PubMedDate not supplied

Prognostic value of TP53 protein accumulation in human primary breast cancer: an analysis by luminometric immunoassay on 1491 tumor cytosols.

The tumor suppressor gene TP53 is implicated in the regulation of normal cell growth and division, DNA repair and apoptosis. Mutations in this gene usually give rise to a conformationally altered protein which is stably expressed at high levels. We have studied TP53 protein accumulation in routinely prepared cytosols from 1491 human primary breast cancer specimens (median follow-up of patients alive, 66 months), using a quantitative luminometric immunoassay (LIA). The TP53-LIA values varied between 0 and 153.53 (median 0.20 ng/mg protein). Median TP53 levels were significantly higher in ER- and PgR-negative tumors. In Cox univariate regression analysis, when analyzed as a continuous variable, increasing TP53 levels were related with a poor relapse-free survival (p < 0.01). In multivariate analysis for relapse-free survival, including age, menopausal status, tumor size, nodal status and steroid hormone receptor status, TP53 accumulation, when analyzed as a dichotomized variable, was an independent factor for predicting the rate of relapse with a relative relapse rate (95% confidence limits) of 1.39 (1.19-1.63). In conclusion, the LIA for the TP53 protein can easily be performed on cytosols routinely prepared for steroid hormone receptor analysis, it is a quantitative assay, and it may be useful in establishing the relation of TP53 accumulation and breast cancer prognosis.

Adult↗