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Biomedical subjects

S Iacobelli

Publications and source records attributed to S Iacobelli.

At least 109 records · Page 6Linked to original sources
PubMed1985

Elevated serum levels of creatine kinase BB in breast cancer.

Creatine kinase BB serum levels were evaluated by radioimmunoassay in patients with benign or malignant breast pathology. Elevated enzyme levels were observed in 6 out of 20 (30%) patients with primary breast cancer. After surgery the levels fell to normal values only in patients without nodal involvement. Six out of 28 (21%) patients with benign breast lesions and 4 out of 38 (13%) patients with metastatic breast cancer also showed increased levels of the enzyme. Most of the patients with high creatine kinase BB serum levels were found to have estrogen and progesterone receptor-positive tumors. These findings suggest that creatine kinase BB can barely be considered a marker of malignancy in breast pathology, but rather an indicator of hormone dependency in breast cancer.

Adult↗
PubMed1984

Estrogen stimulates cell proliferation and the increase of a 52,000 dalton glycoprotein in human breast cancer cells.

In an estrogen supersensitive variant of the MCF-7 cell line, CG-5, estrogen was found to stimulate the labelling of a glycoprotein released into the culture medium which has the same electrophoretic migration pattern as that previously reported in MCF-7 cells (Biochem. Biophys. Res. Commun., 90: 410-416, 1979). To test the possibility that the 52 K is a marker of estrogen-dependent breast cancer cell proliferation, we have correlated the effect of estrogen and antiestrogen on protein labelling and cell proliferation under different experimental conditions. In cells cultured in the presence of 5% charcoal-treated fetal calf serum, physiological concentrations (0.1-1 nM) of estradiol stimulated in a dose- and time-related fashion both 52 K labelling and cell proliferation. However at high concentrations (10-100 nM) estrogen decreased 52 K labelling while it still stimulated cell proliferation. Concentrations of the tamoxifen derivative, 4-hydroxytamoxifen, which effectively prevented estrogen-stimulated cell proliferation also blocked estrogen-stimulated increase of 52 K labelling. Time-course experiments suggest that the estrogen-stimulated increase of 52 K labelling (detectable after 22 h of hormone exposure) precedes the effect of cell proliferation (detectable after 3 days of hormone exposure). In cells cultured under serum-free conditions there was no effect of estradiol at any of the concentrations and times used on either 52 K labelling or cell proliferation.

Breast Neoplasms↗
PubMed1984

Creatine kinase BB in normal, hyperplastic and neoplastic endometrium.

We measured creatine kinase BB activity in normal, hyperplastic and neoplastic endometrium. Creatine kinase BB levels were higher in secretory than in proliferative endometrium. High levels were also found in hyperplastic tissue. In endometrial cancer creatine kinase BB activity was higher in well differentiated than in poorly differentiated tumors.

Creatine Kinase↗
PubMed1984

Tamoxifen induced membrane alterations in human breast cancer cells.

It was previously shown that proliferation of CG-5 cells, an estrogen supersensitive variant of the MCF-7 cell line, is inhibited by tamoxifen starting three days after addition to culture medium. In this paper we report here on the effect of tamoxifen on CG-5 cell membrane morphology using scanning electron microscope. The addition of the antiestrogen to CG-5 cells causes marked alterations of cell surface, consisting of reduction in the length and the number of microvilli. Moreover, cells appear flattened and of reduced thickness. These modifications are more pronounced in cells plated at low density, but they are observed also in nearly confluent monolayers. In this case alterations are more evident in the center of cell islands, while at the periphery there is a certain mobility as reflected by the persistence of few microvilli and philopodia. These early effects of tamoxifen on cell membrane raise the possibility that parallel modifications in membrane function may occur which are responsible for alterations impairing transport mechanisms.

Breast Neoplasms↗
PubMed1984

Estrogen-responsive creatine-kinase in the reticulo-epithelial cells of rat thymus.

We have evaluated the presence of the so-called "estrogen-induced protein" (IP) in the thymus of immature rat. IP is one of the earliest proteins synthesized in response to estrogen in rat uterus and has recently been identified as the BB-isozyme of creatine-kinase (J. Biol. Chem. 256 (1981) 5741). Estrogen-exposed tissues were labelled with [35S]methionine and the soluble proteins separated by SDS-polyacrylamide gel electrophoresis followed by fluorography. It was observed that estrogen stimulated the labelling of a thymic protein with electrophoretic mobility identical to that of uterine IP. The effect was dose-related and specific for estrogen receptor ligands. Thymic IP, like that of the uterus, was immunoprecipitated equally well by either anti-IP antiserum from rat uterus or anti-BB-creatine-kinase antiserum from rat brain. After purification by ion-exchange and affinity chromatography, there was a parallel increase in the extent of recovery of IP and BB-creatine-kinase activity in both the thymus and the uterus. Using the immunohistochemical peroxidase-antiperoxidase method with anti-IP serum, the immune-reaction product was localized in a few cells identified as reticulo-epithelial cells. The thymocytes were always free of any reaction product. These data demonstrate that the reticulo-epithelial cells of rat thymus are a target for estrogens.

Animals↗
PubMed1983

Two new estrogen-supersensitive variants of the MCF-7 human breast cancer cell line.

Two new estrogen-sensitive variants of MCF-7 human breast cancer cells, CG-4 and CG-5, are described in this report. These cells were derived from a casual contamination by MCF-7 cells of primary cultures from a human adenocarcinoma of the breast and a pleural effusion of a patient with advanced breast cancer, respectively. Careful characterization of these variants revealed chromosomal properties highly similar to and alloenzyme phenotypes identical to those of MCF-7 cells which were simultaneously cultured in the laboratory. MCF-7, CG-4 and CG-5 cells were tested for estrogen responsiveness under identical growth conditions, that is in the presence of culture medium supplemented with 5% charcoal-treated serum. While the number of MCF-7 cells increases by about 40% over the controls in the presence of physiological concentrations of estradiol, the number of CG-4 cells doubles and the number of CG-5 cells triples. All these cell lines have approximately the same number of estrogen, androgen, glucocorticoid, and progesterone receptor sites/cell. Since several difficulties arise in demonstrating the estrogen responsive growth stimulation of currently available human breast cancer cells, these two new variants, characterized by a high and reproducible estrogen responsiveness, afford a new model for studying the mechanisms by which estrogen regulates cell proliferation. The problems related to the careful characterization of every established cell line are discussed.

Adenocarcinoma↗
PubMed1983

Presence and steroid inducibility of glutamine synthetase in human leukemic cells.

Glutamine synthetase (EC 6.3.1.2; GS) is present in lymphoblasts from patients with acute lymphoblastic leukemia (ALL) as well as in normal peripheral blood lymphocytes. In 16 out of 20 ALL patients studied exposure of the cells to physiological concentrations of dexamethasone in vitro increased enzyme activity above the control levels. The increase was specific for glucocorticoid receptor ligands. A direct correlation was found between the magnitude of glucocorticoid-mediated increase of GS activity and the cellular levels of specific glucocorticoid receptors assayed in the same cell specimen. Moreover, the basal levels of the enzyme measured in cells prior to exposure to dexamethasone correlated negatively with receptor density. It is suggested that the presence of steroid-inducible GS in ALL cells may prove to be a marker for functional receptor sites.

Enzyme Induction↗
PubMed1981

Glucocorticoids inhibit the stimulatory effect of epidermal growth factor on the initiation of DNA synthesis.

Confluent, quiescent Swiss 3T3 cells in culture can be stimulated to initiate DNA synthesis and divide by addition of growth factors to the culture medium. Here we show that hydrocortisone and other steroids which have glucocorticoid activity inhibit the stimulation of these cells by epidermal growth factor (EGF) in contrast to their reported enhancement of stimulation by fibroblast growth factor (FGF). Binding studies using [3H]-triamcinolone acetonide show that Swiss 3T3 cells contain a single class of glucocorticoid receptor of uniform affinity (KD = 2.0 nM), and about 34,000 receptor sites per cell. Those steroids which displace bound [3H]-triamcinolone acetonide are also effective in inhibiting the stimulation of DNA synthesis by EGF in the presence or absence of insulin, and the concentration of triamcinolone acetonide required for one-half maximal biological effect is in the same range as the KD. A similar concentration is required for one-half maximal enhancement of the effect of FGF. These results suggest that both the inhibitory and stimulatory effects of glucocorticoids may be mediated via these receptors, the different effects thus being due to differences in the intracellular events triggered by each growth factor.

Animals↗
PubMed1981

Steroid-induced proteins in human endometrium.

The synthesis of soluble proteins in human endometria at various phases of menstrual cycle was evaluated by polyacrylamide gel electrophoresis of [35S]methionine-labeled proteins. Densitometric analysis of the gels revealed alterations in the rate of synthesis of single protein bands throughout the cycle. Administration of conjugated estrogens (Premarin) to women undergoing hysterectomy, or exposure, in vitro, of the endometrial tissue to 17 beta-estradiol produced an increased incorporation of [35S]methionine into a specific protein which migrated on SDS-polyacrylamide gels at a molecular weight of about 55 000. Induction of this protein was observed only in those endometria showing a secretory histological appearance. The protein was resolved into at least 2 different spots in two-dimensional gel electrophoresis. An increase in the rate of synthesis of another endometrial protein with an apparent molecular weight of 51 000 was observed in tissues exposed in vitro to medroxyprogesterone acetate. These steroid-induced proteins may be a useful marker for studying hormone action in both normal and neoplastic endometria.

Electrophoresis, Polyacrylamide Gel↗
PubMed1981

Glucocorticoid receptors and in vitro corticosensitivity of peanut-positive and peanut-negative human thymocyte subpopulations.

In 6 human thymus glands, the immature subset of thymocytes was separated from the more mature one, by differential peanut lectin agglutination. These 2 cell subpopulations were analyzed for glucocorticoid receptor content by using a whole cell assay, with (3H)-triamcinolone acetonide as tracer. The unagglutinated thymocytes (peanut negative) contained about 2 times more receptor sites per cell than agglutinated (peanut positive) ones (7650 +/- 1550 S.D. verus 3195 +/- 896 S.D.). The affinity for steroid was similar in both cell subsets, as was the stereospecificity for glucocorticoids, the time-course of steroid-receptor association, and cytoplasmic to nuclear translocation. Despite the greater number of glucocorticoid receptor sites, the peanut-negative thymocyte subpopulation did not differ from the peanut-positive one in its sensitivity to the inhibitory effects of triamcinolone acetonide, as determined by measurements of the incorporation of radiolabeled precursors of protein and DNA. Moreover, the peanut-negative subset appeared more resistant in vitro to the steroid-induced cell lysis as compared to the peanut-positive one. Thus, our data suggest that glucocorticoid receptor density and corticosensitivity are not directly correlated and that the number of glucocorticoid receptor sites may be dependent on the degree of immunologic maturation.

Binding Sites↗