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Query: UMLS:C0006142 (breast cancer)
 160,383 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Isolated adrenal cells were obtained surgically from patients with primary aldosteronism, breast cancer, or Cushing's syndrome. They were prepared by the modification of Sayers method, and incubated at 37 degrees C for 2 hours under 95% O-2-5% CO-2, in the medium of calcium-free Krebs-Ringer bicarbonate buffer containing 0.2% glucose and 0.5% bovine serum albumin, to which various doses of calcium, ACTH, dibutyryl cyclic AMP or cycloheximide were added. Steroid production was measured by the method of Silber et al. In isolated normal adrenocortical cells, 11-OHCS was produced by calcium alone in the absence of ACTH or dibutyryl cyclic AMP, while it was not produced by ACTH alone without calcium. 11-OHCS production by ACTH was decreased in the high concentration of calcium (10.16 mM, 12.70 mM). Cycloheximide partially blocked an increase in 11-OHCS synthesis induced by calcium. These data suggest that adenyl cyclase of human adrenocortical cells may be stimulated by calcium alone, supporting the notion that calcium is a second messenger. The ratio of 11-OHCS production by calcium alone to that by dibutyryl cyclic AMP was higher in adenoma cells than in normal cells. This may account for the character of autonomic steroid production in adrenocortical adenoma cells.
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PMID:[Effect of calcium on steroidogenesis in isolated human adrenal cells (author's transl)]. 16

The present experiment was planned to verify the effect of calcium on adenyl cyclase in isolated human adrenal cells. Normal adrenal glands were obtained surgically from patients with primary aldosteronism and advanced breast cancer. Isolated adrenal cells were prepared by the modified Haning's method. They were incubated at 37C under a gas mixture of 95 percent O2: 5 percent CO2 in calcium-free Krebs-Ringer bicarbonate buffer solution containing 0.2 percent glucose and 0.5 percent fatty acid-free bovine serum albumin, to which various doses of CaCl2 or ACTH were added. Thirty minutes later, cyclic-AMP was measured by cyclic-AMP assay kit (The Radio-chemical Center, Amersham). 11-OHCS was estimated fluorometrically by the modified Silber's method after incubation for 2 hours. In the calcium-free incubation medium, productions of 11-OHCS and cyclic-AMP were negligible. In the concentration of 2.54 mM/L of calcium, 11-OHCS production increased with significant difference statistically, while the increase of cyclic-AMP production was not significant. In the concentration of 12.70 mM/L of calcium, however, cyclic-AMP production increased remarkably. When ACTH was added to the incubation medium containing 2.54 mM/L of calcium, productions of 11-OHCS and cyclic-AMP also increased remarkably. These results indicate that adenyl cyclase of human adrenocortical cells is directly stimulated by calcium and suggest that calcium acts as the second messenger of ACTH.
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PMID:[The effect of calcium on steroidogenesis in isolated human adrenal cells (author's transl)]. 20 11

Patients with breast cancer and bone destruction were found to have a pattern of calcium metabolism which was broadly similar to that found in other malignancies, but different from that in primary hyperparathyroidism. Thus, they tended to have reduced absorption of calcium from the intestine, elevated endogenous faecal calcium and normal or reduced urinary cyclic AMP excretion. Since prostaglandin synthetase inhibitors have been shown to inhibit breast cancer-induced osteolysis in vitro we have attempted to reduce bone destruction and serum calcium in patients with hypercalcaemia complicating breast cancer using these agents. High doses failed to reduce the serum calcium or the urinary hydroxyproline: creatinine ratio in ten patients with skeletal metastases, four of whom had hypercalcaemia.
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PMID:Calcium metabolism in breast cancer. 87 Sep 1

The effect of a number of steroids, growth factors, and peptides on aromatase activity in two estrogen receptor positive breast cancer cell lines (MCF7 and T47D) was investigated. The cells were incubated in Dulbecco's minimum essential medium containing phenol red and 10% fetal calf serum. Pronounced differences in basal aromatase activity and different responses to the addition of experimental agents were found in the two cell lines. Aromatase activity in MCF7 cells was significantly stimulated by phorbol 12,13-diacetate [PDA], dibutyryl cyclic AMP [(Bu)2cAMP], transforming growth factor alpha, and epidermal growth factor individually and PDA and (Bu)2cAMP in combination, while it was inhibited by dexamethasone and unaffected by transforming growth factor beta, fibroblast growth factor, platelet-derived growth factor, prolactin, and tamoxifen. Addition of cortisol to MCF7 cells had no effect on aromatase activity at 1 nM, caused suppression of activity at 10 nM and stimulated activity at 100 nM. Aromatase activity in T47D cells was stimulated by transforming growth factor alpha, epidermal growth factor, platelet-derived growth factor, prolactin, dexamethasone, and cortisol individually and PDA and (Bu)2cAMP in combination. It was unaffected by transforming growth factor beta, PDA, (Bu)2cAMP, and fibroblast growth factor. These findings suggest that aromatase activity is induced by agents which stimulate cyclic AMP-dependent protein kinases [e.g., (Bu)2cAMP] and that this effect is potentiated by factors which stimulate protein kinase C [e.g., PDA]. The effect on aromatase activity of growth factors, the actions of which are believed to be mediated by receptors linked to tyrosine kinase activity, is not as clearly defined, with a factor causing stimulation, inhibition, and no change in activity depending on the tissue concerned. Further insight into these differences will require resolution of the molecular mechanisms that mediate the actions of stimulatory and repressive growth factors on aromatase activity of oestrogen-producing cells.
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PMID:Steroid and growth factor modulation of aromatase activity in MCF7 and T47D breast carcinoma cell lines. 131 30

The human breast cancer cell line T 47 D expresses calcitonin (CT) receptors that are coupled to adenylate cyclase and which reveal a dose-dependent cyclic AMP response to CT. We used this model to establish an in vitro bioassay for synthetic human CT (hCT) preparations to overcome some of the obstacles of the standard rat hypocalcemia in vivo bioassay. The detection limit of the in vitro bioassay was 1 x 10(-10) M hCT (EC 50: 8.7 pM +/- 26%) compared to 7.3 x 10(-9) M (EC 50: 7.2 microM +/- 32%) for the in vivo bioassay. The relative potencies of test preparations revealed a good correlation (r = 0.89) and several hCT-related substances produced comparable results when tested by the two methods. The standard deviations of precision and accuracy, however, were significantly smaller (P less than 0.05) for the in vitro bioassay. According to these data the T 47 D in vitro bioassay is more sensitive, superior in precision and accuracy, and comparable in specificity to the rat hypocalcemia bioassay.
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PMID:A new in vitro bioassay for human calcitonin: validation and comparison to the rat hypocalcemia bioassay. 131 97

A specific CGRP-binding protein of M(r) 60,000 has been identified in the human neuroblastoma cell line SK-N-MC. After N-deglycosylation a M(r) of 48,000 was found. The M(r) were indistinguishable from those determined in the human cerebellum. Receptor binding of CGRP is coupled to cyclic AMP formation. The latter is antagonized by hCGRP-I8-37. CT and DAPamide interact only minimally with the CGRP receptor, whereas CGRP and DAPamide are full agonists in T47D cells. The CT receptor on human breast cancer cell line T47D is clearly different from the human CGRP receptor.
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PMID:Comparison of a calcitonin gene-related peptide receptor in a human neuroblastoma cell line (SK-N-MC) and a calcitonin receptor in a human breast carcinoma cell line (T47D). 132 87

MCF-7 human breast cancer cells propagated in vitro were treated with adenosine derivatives added to the culture medium. The effects on cell proliferation, glycolysis, and glutaminolysis were investigated. Of all adenosine derivatives tested, AMP was the most efficient inhibitor of cell proliferation. In AMP-treated cells, DNA synthesis decreased, whereas RNA and protein syntheses rose normally with time. In terms of carbohydrate metabolism, lactate production from glucose was drastically reduced; therefore, most of lactate produced must have been derived from glutamine. Increases in the enzyme activities involved in glutamate degradation and in the malate-aspartate shuttle were observed. In contrast, actual glycolytic flux rates declined, whereas key glycolytic enzyme activities increased. Metabolites such as fructose 1,6-bisphosphate and pyruvate accumulated in AMP-arrested cells. Based on the lowered NAD level in the AMP-treated cells, lactate dehydrogenase, but not malate dehydrogenase, was impaired; thereby the whole of glycolysis was inhibited. In compensation, glutamine catabolism was increased. NAD concentrations fell drastically because of the known inhibition of P-ribose-PP synthesis through heightened intracellular AMP levels. A hypothetical metabolic scheme to explain these results and to show how extracellular AMP may influence carbohydrate metabolism and cell proliferation is presented.
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PMID:In vitro effect of extracellular AMP on MCF-7 breast cancer cells: inhibition of glycolysis and cell proliferation. 144 15

Extrahepatic synthesis and secretion of transferrin (Tf), the major iron-carrying protein, have been described in normal and tumoral tissues suggesting a potential role for paracrine or autocrine function. In breast tumor cell MCF-7, we have previously shown a Tf secretion stimulated by estradiol which might confer selective growth advantages of these rapidly proliferating cells. The present work refers to possible additional Tf functions related to differentiation of breast tumor cells. We induced MCF-7 cell differentiation by the cyclic AMP derivative, dibutyryl cAMP (dB cAMP) and studied Tf secretion in different culture conditions after labeling with [35S] methionine. Our results demonstrate that dB cAMP stimulates Tf secretion only in culture environment that permits access to the basolateral surface and caters to the polarity requirements of the cell. These results suggest that Tf may also act as a modulator of cellular differentiation in breast cancer cells.
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PMID:Cyclic AMP stimulation of transferrin secretion by breast cancer cell grown on extracellular matrix or in two-compartment culture chambers. 171 42

Cyclic AMP binding proteins were measured in the primary tumour from 100 patients with non-disseminated breast cancer selected on the basis that sufficient tumour material was available for analysis. These measurements have been related to factors of established prognostic value and to the patients' disease-free interval and survival. There was a wide variation in amounts of binding proteins in different tumours. Values were significantly higher (P less than 0.05) in oestrogen receptor-negative tumours but no statistically significant correlations were apparent between levels and tumour grade or whether the patients had lymph node metastasis or adjuvant treatment. However, levels were significantly higher in patients whose disease recurred within 3 years of primary treatment as compared with those who remained disease-free. Using a retrospectively determined cut off point of 8 pmol mg-1 cytosol protein, it was shown that patients with tumour cyclic AMP binding in excess of this value had a significantly greater chance of developing recurrent disease and poorer survival rates (P less than 0.001 by Cox analysis) than those with lower levels. This remained true when other prognostic factors were taken into account in a multivariate analysis. It is suggested that the level of tumour cyclic AMP binding may be an independent prognostic factor for patients with early breast cancer.
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PMID:Cyclic AMP binding proteins and prognosis in breast cancer. 215 42

The activity of metabolic enzymes, adenosine and thymidine, has been studied in the blood serum and lymphocytes of healthy people and oncological patients aged 23-80. An increase in the activity of thymidine kinase (EC 2.7.1.2), an enzyme of thymidine biosynthesis, was observed in the blood serum of oncological patients against a background of a sharp decrease in the activity of thymidine phosphorylase (EC 2.4.2.4), a catabolic enzyme. The revealed enzymic shifts have been observed in breast cancer patients after 36, in patients with the stomach cancer--after 46. It is found that an increase in the activity of adenosine deaminase (EC 3.5.4.4) and 5-nucleotidase of AMP (EC 3.1.3.5) in the blood serum of oncological patients is accompanied by a sharp decrease in the activity of these enzymes in lymphocytes.
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PMID:[Activity of adenosine and thymidine metabolism enzymes in the blood of cancer patients of various ages]. 233 24


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