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

The effects of 17 beta-estradiol and tamoxifen (TAM) on the proliferation of responsive MCF-7 and unresponsive HBC-4 human breast cancer cells were studied in a defined culture medium containing insulin (2 micrograms/ml), transferrin (2 micrograms/ml), ethanolamine (2 microM), and selenite (25 nM). MCF-7 cells grew at a population-doubling rate of 2.0 days in serum-free medium and at a rate of 1.7 days in the medium containing 1 mg/ml of the 55-70% ammonium sulfate fraction of bovine serum or 1% dextrancoated charcoal-treated fetal bovine serum. Increasing concentrations of the ammonium sulfate fraction and/or dextran-coated charcoal-treated fetal bovine serum increasingly inhibited the growth of MCF-7 cells but did not inhibit HBC-4 cell growth, indicating that such serum preparations contain some growth inhibitor specific for estradiol-responsive MCF-7 cells. A sufficiently high concentration of exogenous estradiol (100 pM) had the dual action of neutralizing the growth inhibition by the 55-70% ammonium sulfate fraction of bovine serum and dextran-treated charcoal-treated fetal bovine: serum and enhancing directly the MCF-7 cell growth maximally 2-fold. Bovine serum albumin fraction V containing globulin remnants also inhibited growth, but globulin-free bovine serum albumin did not. Eliminating growth inhibition by the use of globulin-free bovine serum albumin enabled us to develop an ideal medium for assaying the direct effects of estradiol and TAM on MCF-7 cells. With this medium, we clearly identified (a) a direct mitogenic effect of exogenous estradiol on MCF-7 cells which was initiated at 3 pM and maximized at 0.2 to 10 nM, (b) an acute lethal effect of 1 microM TAM and its prevention by 100 pM estradiol, and (c) a nearly 50-fold increase in the concentration of exogenous estradiol (10 nM) required for maximum growth enhancement in the presence of 1 microM TAM than without TAM (0.2-0.3 nM).
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PMID:Mechanisms of estrogen action on the proliferation of MCF-7 human breast cancer cells in an improved culture medium. 281 16

The mechanism of action of prolactin in target cells and the role of prolactin in human breast cancer are poorly understood phenomena. The present study examines the effect of human prolactin (hPRL) on the synthesis of unique proteins by a human breast cancer cell line, T-47D, in serum-free medium containing bovine serum albumin. [35S]Methionine-labeled proteins were analysed by sodium dodecyl sulfate-polyacrylamide slab gel electrophoresis and fluorography. Treatment of cells with hPRL (1-1000 ng/ml) and hydrocortisone (1 microgram/ml) for 36 h or longer resulted in the synthesis and secretion of three proteins having molecular weights of 11,000, 14,000, and 16,000. Neither hPRL nor hydrocortisone alone induced these proteins. Of several other peptide hormones tested, only human growth hormone, a hormone structurally and functionally similar to hPRL, could replace hPRL in causing protein induction. These three proteins were, therefore, referred to as prolactin-inducible proteins (PIP). Each of the three PIPs was purified to homogeneity by preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and specific antibodies were generated to them in rabbits. By immunoprecipitation and immunoblotting (Western blot) of proteins secreted by T-47D cells, it was demonstrated that the three PIPs were immunologically identical to one another. In addition, the 16-kDa and 14-kDa proteins (PIP-16 and PIP-14), and not the 11-kDa protein (PIP-11), incorporated [3H]glycosamine. Furthermore, 2-deoxyglucose (2 mM) and tunicamycin (0.5 micrograms/ml), two compounds known to inhibit glycosylation, blocked the production of PIP-16 and PIP-14, with a concomitant increase in the accumulation of PIP-11. These results indicate PIP-16 and PIP-14 are glycosylated variants of PIP-11. Finally, in vitro translation of poly(A)+ messenger RNA followed by immunoprecipitation revealed a 12.5-kDa protein, possibly the precursor form of PIPs. In addition, T-47D cells treated with hPRL plus hydrocortisone contained 10-fold more mRNA for PIPs than control cells, suggesting that the hormones' action is at the level of gene expression. Our finding represents a first demonstration of prolactin regulation of gene expression in human target cells. The human breast cancer cells, T-47D, appear to be an excellent model to afford future studies on the molecular action of prolactin and on the possible role of prolactin in human breast cancer.
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PMID:Prolactin-inducible proteins in human breast cancer cells. 286 72

The pharmacokinetics and metabolism of medroxyprogesterone acetate (MPA) were studied in patients with advanced breast cancer after i.v. injection and oral administration of [3H]MPA. MPA was distributed very rapidly into three compartments after i.v. injections, revealing half-lives of 4-7 h. Using a nonlinear model fitting metabolic clearance rates (MCR) were found to be 652 1/day before and 601 1/day during MPA treatment, and distribution volumes (V0) 5.9 and 3.41 respectively. The major metabolite of MPA following i.v. injection was a glucuronide of MPA, presumably of the 3-enol form. After oral administration the radioactivity in serum increased rapidly and reached a plateau of about 1% of the dose per litre serum after approx 2 h. About 80-90% of the radioactivity was found in the water phase after hexane extraction, persumably as glucuronides of metabolites more polar than MPA. Radioimmunoassay (RIA) of MPA in untreated serum samples showed 3-8-fold greater MPA values as compared to measurements in hexane extracts of serum. Ethanol extraction did not remove these interfering substances. Extraction of serum with a low polar solvent before RIA of MPA is essential in order to prevent great overestimation, as the glucuronidated polar metabolites most likely will crossreact in an assay with an antiserum raised against a MPA-3-O-carboximethyloxime coupled to bovine serum albumin.
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PMID:Pharmacokinetics and metabolism of medroxyprogesterone acetate in patients with advanced breast cancer. 297 41

Mammary carcinoma tissue from 514 primary breast cancer patients were all biochemically and histochemically analyzed for both estrogen receptors and progesterone receptors. The dextran-coated charcoal (DCC) method measured the ER and PR as defined by Scatchard analysis, ligand competition experiments and target organ specificity. The ligands, estradiol-6-carboxymethyloxime-BSA-fluoresceine isothiocyanate and hydroxyprogesteronehemisuccinate-BSA-tetramethylrhodamine isothiocyanate, used for histochemistry, did not bind to either ER or PR and were mainly bound to the membrane fraction of isolated breast cancer cells. Fluorescence was not specifically inhibited by estrogens or progestogens. In addition, "estrogenic" always coincided with "progestogenic" fluorescence. The binding of the fluoresceine compounds to tissue slides depended on the large steroid hormone substitution on the bovine serum albumin molecule. Clinical parameters, known to be related to ER and PR did not correlate with the histochemical results. The observations indicated the impossibility of specific steroid receptor detection by the histochemical method. Therefore, up to the present, evaluation of hormone dependency and prognosis in human breast cancer cannot be based on this approach.
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PMID:Biochemical and histochemical analysis of steroid hormone binding sites in human primary breast cancer. 298 19

A fluorescent estradiol macromolecular complex was used to study and to characterize steroid binding to membranes of living target cells. Ligand binding to plasma membranes was quantitated with a sensitivity of 0.1 nM. In this way, we found two types of estradiol-binding sites on hormone sensitive MCF-7 cells. Type A sites (8000-16000 sites per cell) were rapidly saturated at low concentrations of the estradiol-bovine serum albumin-fluorescein isothiocyanate macromolecular complex (E2-BSA-FITC). They had a greater affinity for the complex than did the type B sites for which a phenomenon of cooperative fixation was shown. The complex binding was displaced by estrogenic molecules, but not by non-estrogenic compounds, such as cortisol or progesterone. We also studied complex binding on another breast cancer cell line, MDA-MB-231 (MDA), without intracellular estrogen receptors. These cells showed a specific plasma membrane binding system for estrogen, but lacked the high affinity type A binding site. Then, we report the effects of enzyme treatments (trypsin, phospholipase A2 and neuraminidase) on E2-BSA-FITC binding to MCF-7 cell membranes. The quantity of complex bound to membranes decreased after phospholipase and neuraminidase treatments and increased after trypsin. But, in the three cases, the binding was no longer specific because it could not be displaced by E2-BSA or by estradiol. The enzymatic effects were reversible and specific binding was totally restored within 24 h. However, in the presence of the protein synthesis inhibitor, cycloheximide, no restoration of specific binding occurred on trypsin-treated cells. Estrogen binding to MCF-7 and MDA cell plasma membranes thus possesses the three characteristics of all mediated transport processes across biological membranes: saturability, substrate specificity, and specific inhibition. However, the high affinity type A binding site was found only on the estrogen-sensitive cell line, MCF-7.
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PMID:Estradiol membrane binding sites on human breast cancer cell lines. Use of a fluorescent estradiol conjugate to demonstrate plasma membrane binding systems. 302 20

Growth of the MCF-7, T47D, and ZR-75-1 human breast cancer cells was established in a serum-free defined medium (MOM-1) composed of a 1:1 (vol/vol) mixture of Ham's F12 medium and Dulbecco's modified Eagle's medium containing 15 mM HEPES (pH 7.2), 2 mM 1-glutamine, 20 micrograms/ml glutathione, 10 micrograms/ml insulin, 10 micrograms/ml transferrin (Tf), 10 ng/ml selenous acid, 0.3 nM triiodothyronine, 50 micrograms/ml ethanolamine, 20 ng/ml epidermal growth factor, 2.0 nM 17 beta-estradiol, and 1.0 mg/ml bovine serum albumin (BSA). Proliferation in MOM-1 was 50 to 70% of the serum stimulated rate. Deletion of components from MOM-1 gave a medium (Tf-BSA) containing only HEPES, 10 micrograms/ml Tf, and 200 micrograms/ml BSA, which sustained MCF-7 and T47D cells in a slowly dividing and mitogen responsive state; ZR-75-1 cells required Tf plus 1.0 mg/ml BSA. In Tf-BSA, insulin and insulin-like growth factor I (IGF-I) were mitogenic with ED50 values of 2 to 3 ng/ml and 30 to 150 pg/ml, respectively, with MCF-7 cells. The T47D cells were responsive to these factors in Tf-BSA but required 10-fold higher concentrations for ED50. At saturating concentrations, insulin and IGF-I promoted 1.5 to 3.5 cell population doublings over controls in 8 d. At less than or equal to ng/ml concentrations, epidermal growth factor, insulin-like growth factor II, and basic fibroblast growth factor were mitogenic for human breast cancer cells in Tf-BSA. Mitogen activities in uterus and pituitary extracts were assayed readily in Tf-BSA. This new method offers a convenient means of comparing the potencies of growth-promoting factors on human breast cancer cells without interfering activities known to be present in serum.
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PMID:A new serum-free method of measuring growth factor activities for human breast cancer cells in culture. 304 18

Foetal steroid binding protein (FSBP) which is present in normal human serum sometimes exhibits unusual sex-steroid binding; its effects on steroid action are uncertain but potentially important in view of the different levels seen in populations at different risk of breast cancer. Studies of the binding of 5 alpha-dihydrotestosterone to FSBP were conducted at varying concentrations of human serum albumin (HSA) and sex hormone binding globulin (SHBG). The saturable, specific binding of purified FSBP (Ka approximately equal to 5 X 10(8) l/mol), was transformed to a rising, plateau pattern by the addition of HSA. In equilibrium dialysis, FSBP competed with HSA or SHBG in a strictly proportional way when the third protein was absent. In the presence of HSA an initial sharp shift of ligand from SHBG to FSBP was observed with increasing FSBP concentration, but this was reversed as higher levels were reached. Steroid binding by FSBP in vivo may be determined predominantly by its interactions with other binding proteins.
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PMID:Interactions of foetal steroid binding protein with other binding proteins in human serum. 312 1

A completely serum-free assay method has been used to compare the mitogenic activities of polypeptide growth factors and estrogens with MCF-7 and T47D human breast cancer cells in culture. The lines were maintained in a viable, slowly dividing condition in Ham's F12 and Dulbecco's modified Eagle's medium (1:1) supplemented with sodium bicarbonate (2.2 g/liter), 15 mM 4-(2-hydroxyethyl)-1-piperazineethane-sulfonic acid, human transferrin (10 micrograms/ml), and bovine serum albumin (200 micrograms/ml) (designated Tf/BSA). This medium allowed the assay of mitogenic activities as measured by multiple rounds of cell division and permitted comparisons of the biological potencies of growth factors within functional families as well as of dissimilar mitogens. Insulin-like growth factor I (IGF-I) was the most potent mitogen studied, showing ED50 values of 160 pg/ml and 1.7 ng/ml with the MCF-7 and T47D cells, respectively. Insulin-like growth factor II and insulin were less active, with ED50 values of 0.55 and 1.2 ng/ml with MCF-7 cells and 4.3 and 10 ng/ml with the T47D cell line, respectively. Mitogens sharing epidermal growth factor-like functional properties had ED50 values from 35 pg/ml to 2.5 ng/ml, while transforming growth factor type beta and platelet-derived growth factor had no detectable stimulatory effects. Basic fibroblast growth factor had ED50 values of 0.42 ng/ml and 3.7 ng/ml for the MCF-7 and T47D cells, respectively, while acidic fibroblast growth factor was nearly inactive. In phenol red-free Tf/BSA, 17 beta-estradiol caused a 60% increase in MCF-7 cell numbers over controls in 8 days while having no effect on growth of the T47D cell line. From MCF-7 conditioned Tf/BSA medium, IGF-I was identified by biological activity, by radioimmunoassay (approximately equal to 2 pg/ml) and by estimation of molecular weight (8,000) under dissociating conditions. The concentration of IGF-I was not affected by 17 beta-estradiol treatment. The data indicate that induction of acid stable, low molecular weight autocrine growth factors involved more regulation than defined by estrogens alone. The minimal effects of 17 beta-estradiol in Tf/BSA opened several possibilities including the putative roles of other serum-borne hormones, growth factors and regulators in autocrine growth factor induction.
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PMID:Differential responsiveness of human breast cancer cell lines MCF-7 and T47D to growth factors and 17 beta-estradiol. 328 39

To determine whether the human pituitary contains a previously unidentified, nonprolactin (non-hPRL), non-growth-hormone (non-hGH) factor capable of stimulating mammary development, we tested the effects of whole human pituitary extract (hPE) and pituitary extracts depleted of hPRL and hGH ("stripped hPE") in hypophysectomized, castrated estradiol (E2)-treated male rats and rhesus monkeys. Both whole and stripped hPE significantly stimulated rat mammary development (mean scores = 3.3 and 2.0, respectively, on a scale ranging from 0 to 4) in comparison with controls (mean score = 1.0). Mammary development was not due to minute concentrations of hGH or hPRL remaining in stripped hPE because 30- to 100-fold higher concentrations of hGH (Genentech) and 1000-fold higher concentrations of hPRL were required to stimulate significant mammary development. Non-pituitary extracts of human ovary, muscle, and serum, and bovine serum albumin did not stimulate rat mammary gland growth. Trypsin destroyed the mammary mitogenic activity of whole hPE, indicating that the unidentified factor is likely a protein. Mammary growth and development were also stimulated in hypophysectomized, E2-treated monkeys by stripped hPE (mean histological score = 3.25 vs. 1.35 in control animals). Monkeys receiving stripped hPE had undetectable levels of hGH and hPRL in serum sampled over a 24-hr period. These findings suggest that the human pituitary contains a non-hPRL, non-hGH factor that stimulates mammary growth and may be important in normal mammary growth and development and perhaps in breast cancer.
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PMID:Evidence for a nonprolactin, non-growth-hormone mammary mitogen in the human pituitary gland. 347 80

Methotrexate was administered by IV infusion, 2g (1.19 +/- 0.05 g/m2) over 24 hours, to a homogeneous group of patients undergoing treatment for breast cancer. Three courses were given at three week intervals. Methotrexate and 7-hydroxy-methotrexate plasma and urine pharmacokinetics were investigated. The average terminal half-lives of methotrexate and 7-hydroxy-methotrexate in plasma were 15.02 and 15.19 hours respectively. The area under concentration-time curve was 723.8 +/- 196.4 microM x h for methotrexate and 598.1 +/- 212.5 microM x h for 7-hydroxy-methotrexate. The total average urinary excretions of methotrexate and 7-hydroxy-methotrexate over a 96 hour period were 52% and 5.4% respectively. Urinary clearance of methotrexate was 3.46 +/- 1.4 1/h. In contrast, urinary excretion of 7-hydroxy-methotrexate was not linear. These results confirm the protein binding of metabolite to serum albumin and may suggest that distribution of 7-hydroxy-methotrexate is different from unchanged drug or that the metabolite can be eliminated by another route, such as bile.
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PMID:Pharmacokinetics of methotrexate and 7-hydroxy-methotrexate after methotrexate infusions. 350 54


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