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

We have examined the interaction of dexamethasone with the ZR75-1 human breast cancer cell line to determine if glucocorticoids might directly inhibit growth of breast cancer cells. Growth of these cells in serum-free medium was stimulated significantly by physiological concentrations of insulin (0.1 to 1.0 nM). Pharmacological concentrations of dexamethasone (10 nM) reduced cell number below that found in controls and nearly abolished the effect of insulin after several days in culture. Thymidine and uridine, but not leucine, incorporation into macromolecules or acetate incorporation into fatty acids were similarly inhibited by dexamethasone in the presence of absence of insulin. Dexamethasone did not inhibit insulin effects by altering insulin receptor affinity or concentration, as determined by Scatchard analyses of insulin binding. Net thymidine uptake into the trichloroacetic acid-soluble fraction of the cell was stimulated by insulin and inhibited by dexamethasone also inhibited thymidine kinase activity multiple potential sites of glucocorticoid action that directly oppose the effects of insulin. They also suggest that glucocorticoids have a direct inhibitory effect on proliferation of human breast cancer cells, which may help explain breast tumor regression following pharmacological glucocorticoid therapy.
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PMID:Direct inhibition of growth and antagonism of insulin action by glucocorticoids in human breast cancer cells in culture. 44 41

The mechanisms of steroid and peptide hormone action in human breast cancer are poorly understood. We have previously characterized a cell line of human breast cancer in long-term tissue culture that possesses various steroid hormone receptors and responses, providing a model for the study of steroid hormone action. The present studies describe a human breast cancer in vitro that responds to physiologie concentrations of insulin with an increased rate of macromolecular synthesis and growth. Thymidine and uridine incorporation in cells in serum-free medium are stimulated by 10(-11) M insulin and are maximal with 10(-8) M. Leucine incorporation is stimulated by 5 X 10(-11) M insulin and is maximal with 10(-9) M. Significant stimulation of uridine and leucine incorporation is evident by 3 hr and maximal by 10 hr. A 10-hr lag period exists for insulin stimulation of thymidine incorporation, which is maximal form 14 to 24 hr. The effect of 10(-8) M insulin on macromolecular synthesis is accompanied by a 69% increase above controls in the number of cells after 24 hr. The effect on macromolecular synthesis is observed in glucose-free medium. Insulin's effect on protein synthesis is not blocked by inhibition of RNA synthesis with actinomycin D. Glucocorticoids partially inhibit the action of insulin in these cells. This system provides a model for studying insulin action, and suggests that some human breast cancer may show growth regulation by insulin.
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PMID:Hormone responsive human breast cancer in long-term tissue culture: effect of insulin. 107 4

The purpose of our study was to evaluate the effects of 5 alpha-dihydrotestosterone (DHT) and hydroxyflutamide (HF), alone or in combination, on androgen receptor (AR) dynamics and on cellular growth in cultured breast cancer cells (EVSA-T). The incubation of cells with DHT increased the concentration of nuclear AR after 24 and 48 h. HF was also able to promote the nuclear accumulation of AR after 24 and 48 h of treatment. When HF-treated cells are incubated with DHT, the nuclear AR concentration is lower than that found in cells treated with DHT alone. We conclude that HF acts by increasing nuclear accumulation of receptor-antiandrogen complexes. Moreover, DHT stimulates cell growth while HF has an inhibitory effect. Thymidine incorporation in cells also increased after DHT treatment and decreased after HF incubation. The HF-induced inhibition of cell growth persisted both after renewal of the medium and after the addition of DHT to cultures. It may be hypothesized that either DHT is converted to inactive metabolites or that HF exerts a persistent inhibitory effect. In the latter case, the antiandrogen action of HF could be exerted by retention of high levels of antiandrogen in cells or by such a depressed protein synthesis that the renewal of growth is slower than the 48 h period studied.
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PMID:Effects of dihydrotestosterone and hydroxyflutamide on androgen receptors in cultured human breast cancer cells (EVSA-T). 161 84

Recently, it was reported that bombesin/gastrin-releasing peptide (GRP) have mitogenic effects on some human breast cancer cell lines. In this study, we investigated the effects of bombesin/GRP and its receptor antagonist (RC-3095) on the proliferation of three breast cancer cell lines, MDA-MB-231, MCF-7 MIII, and MCF-7. Stimulation by bombesin and inhibition by RC-3095 of cell growth were found in MDA-MB-231 and MCF-7 MIII cells cultured in phenol red-free medium with 5% heat-inactivated and dextran-coated charcoal-treated fetal bovine serum (DCC-FBS). A stimulatory effect by bombesin was not observed in the presence of untreated FBS. [3H]Thymidine incorporation into DNA in these cells was suppressed by RC-3095. MCF-7 cells failed to respond to bombesin and RC-3095 in the presence of either FBS or DCC-FBS. GRP-like immunoreactivity was found in the cell extracts and FBS, but it was undetectable in DCC-FBS. It appears that the stimulatory effect of bombesin on cell proliferation of MCF-7 MIII and MDA-MB-231 cell lines could be obtained because of reduction in the levels of some serum factors in DCC-FBS. These results suggest that bombesin/GRP can act as growth factors through bombesin/GRP receptors in some human breast cancers.
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PMID:Stimulation by bombesin and inhibition by bombesin/gastrin-releasing peptide antagonist RC-3095 of growth of human breast cancer cell lines. 164 47

HER-2neu alterations (amplification and overexpression), proliferative activity (3H-Thymidine-Labeling Index, 3H-Tdr-LI) and tumor ploidy (flow-cytometry) were analyzed in a human breast cancer series. Overexpressed tumors showed a significantly higher median 3H-Tdr-LI than normally expressed (p = 0.04), as also did amplified/overexpressed with respect to non-amplified/normally expressed (p less than 0.04). These differences were confirmed only in N-primary tumors. In fact, high expressed cases demonstrated a median 3H-Tdr-LI of 5.5% with respect to 1.9% for low expressed cases (p = 0.04) and amplified/overexpressed had a 3H-Tdr-LI of 9% with respect to 2% for non amplified/low expressed (p = 0.009). HER-2/neu alterations were not correlated with tumor DNA content.
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PMID:Biological correlation between HER-2/neu and proliferative activity in human breast cancer. 168 96

Synchronization of mammalian cells is essential for investigations involving cell proliferation. A simple method for obtaining synchrony in all types of cells, through several cycles and with minimal overall metabolic perturbations, has not yet been available. We describe a procedure for synchronizing normal as well as tumor cells reversibly in the G1 phase of the cell cycle using Lovastatin, an inhibitor of 3-hydroxy-3-methylglutaryl-coenzyme A reductase. This method of synchronization was successful with all cell lines tested, including normal and tumor cells of mouse, hamster, and human origins. For example, when MCF-7 human breast cancer cells were synchronized with Lovastatin and released by the addition of mevalonic acid (the product of the reaction catalyzed by 3-hydroxy-3-methylglutaryl-coenzyme A reductase), 3 phases of accelerated thymidine incorporation into DNA corresponding to 3 S phases of the cell cycle occurred during a 90-h period of cell replication. Thymidine incorporation was decreased to less than or equal to 4% during the initial lag of 18 h before the first S phase, and maximum incorporation was then achieved after only 6 h. The antibody Ki-67, which detects a nuclear antigen associated with proliferation, was present in cells arrested with Lovastatin. This fact, together with the lack of thymidine incorporation during the initial lag time, indicates that the cells were arrested in the G1 and not in the G0 phase of the cell cycle. Furthermore, in synchronized tumor-derived human breast epithelial cells, histone H4 RNA was low after Lovastatin release and increased with the onset of DNA synthesis. Concomitant synthesis of DNA and histone H4 RNA expression could be observed for 2 cycles. Minimal perturbations of general metabolic functions occurred since the rate of RNA, protein, and initial DNA synthesis were unaffected by Lovastatin, as evidenced by [3H]uridine, [3H]leucine, and initial [3H]thymidine incorporation. Finally, while the Lovastatin-induced synchronization was overcome by mevalonic acid, addition of squalene or cholesterol-ethanol had no such effect. Thus, Lovastatin appears to prevent formation of an early intermediate in the cholesterol pathway that is essential for progression of cells through early G1 phase.
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PMID:Synchronization of tumor and normal cells from G1 to multiple cell cycles by lovastatin. 171 13

The fraction of tumor cells in the DNA synthesis (S) phase of the cell cycle is a strong prognostic indicator in human breast cancer. Most studies measuring S-phase in primary tumors have used either in vitro labeling with 3H thymidine or DNA flow cytometry. The former involves a cumbersome and time-consuming radioactive assay, while the latter is heavily dependent on the quality of the preparation and the effectiveness of the algorithms used. In this study, in vivo or in vitro labeling with bromodeoxyuridine (BrdUrd) was compared with in vitro labeling using 3H thymidine in a series of 33 human breast tumors. Thymidine labeling showed strong correlation with both in vitro (r = 0.96) and in vivo (r = 0.83) BrdUrd incorporation. The reliability between observers was higher for BrdUrd counting (r = 0.94) than for thymidine counting (r = 0.87). The mean labeling index of 15 tumors labeled in vivo with BrdUrd was 5.9% compared to 4.7% for 18 tumors labeled in vitro (p = 0.34). There was poor correlation between flow cytometric and microscopic analysis of BrdUrd incorporation (r = 0.37). We conclude that microscopic analysis of in vivo or in vitro BrdUrd incorporation is a rapid and reliable method to estimate breast tumor proliferation.
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PMID:A comparison between bromodeoxyuridine and 3H thymidine labeling in human breast tumors. 172 86

L651582 (Merck Institute for Therapeutic Research, Rahway, NJ) is a novel carboxyamide-amino-imidazole compound originally developed as a coccidiostat (U.S. patent No. 4,590,201). We studied the inhibitory effects of this compound on cancer proliferation, adhesion, and motility in vitro and in vivo in a model of ovarian cancer progression. L651582 reversibly inhibited up to 60% of the autocrine motility factor-stimulated tumor cell motility and tumor cell adhesion to tissue culture plastic. Autocrine motility factor-stimulated phosphoinositide metabolism was reduced significantly by treatment of the cells with 3 microM L651582 (P = .022). Thymidine incorporation and clonogenic growth of A2058 human melanoma, MDA-MB-231 human breast cancer, OVCAR-3 human ovarian cancer, and 5R-transformed rat embryo fibroblast cell lines were inhibited 60%-80% by 1-10 microM L651582. Intraperitoneal injection of OVCAR-3 cells causes malignant ascites, peritoneal carcinomatosis, and serosal and visceral seeding that, if left untreated, are lethal to nude mice. Intraperitoneal L651582 markedly prolonged survival of nude mice heavily laden with ovarian cancer [mean survival time of treated group divided by mean survival time of control group = 220% (P less than .03)]. The apparent mechanism of action of L651582 is via inhibition of the receptor-mediated stimulation of effector enzymes utilizing guanine nucleotide-binding protein signal transduction, which thus makes L651582 a novel anticancer agent. L651582 should be considered for further clinical development.
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PMID:L651582: a novel antiproliferative and antimetastasis agent. 215 5

Thymidine labeling index (TLI) and Ki-67 growth fraction (KGF) are two indicators of proliferative activity in breast cancer. The authors examined the relationship between TLI and KGF in 36 breast lesions (28 invasive ductal carcinomas and 8 benign lesions). TLI and KGF values were determined in separately labeled tissue sections as well as in frozen tissue sections labeled with both Ki-67 and tritiated thymidine. In separately labeled sections of carcinoma mean TLI was 6.8 while mean KGF was 16.0. For double-labeled sections of carcinoma mean TLI and KGF values were 6.1 and 16.4, respectively. Strong correlation between TLI and KGF of malignant tumors was found by both methods: r = 0.90 (P less than 0.001) for separately labeled sections, and r = 0.96 (P less than 0.001) for double-labeled sections. In double-labeled sections of benign lesions strong correlation between TLI and KGF also was observed (r = 0.94, P less than 0.001); however, in separately labeled benign breast tissue there was no significant correlation between TLI and KGF (r = 0.38). This may have been the result of variable sampling of small proliferative foci in separate sections of benign breast tissue. The strong correlation between TLI and KGF in breast carcinoma suggests that KGF may have prognostic implications similar to those of the TLI.
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PMID:Thymidine labeling index and Ki-67 growth fraction in lesions of the breast. 253 20

Various studies support the view that analogs of luteinizing hormone-releasing hormone (LH-RH) exert some direct effects on mammary tumor cells. Recently, new LH-RH antagonists [Ac-D-Nal(2)1,D-Phe(pCl)2,D-Trp3,D-Hci6,D-Ala10]-LH-RH (SB-29) and [Ac-D-Nal(2)1,D-Phe(pCl)2,D-Trp3,D-Cit6,D-Ala10]LH-RH (SB-30), which are devoid of edematogenic effects, were synthesized. In this study, we examined whether these LH-RH antagonists inhibit the proliferation of MDA-MB-231 human mammary tumor cells in culture. [3H]Thymidine incorporation into DNA and cell number were measured. The antagonists induced up to 40% inhibition of [3H]thymidine incorporation in MDA-MB-231 cells. This inhibition was dose-dependent in the 0.3-30 microM range and could be demonstrated after 2 days of incubation in the presence of the peptides. An older antagonist, [Ac-D-Phe(pCl)1,2,D-Trp3,D-Arg6,D-Ala10]-LH-RH (ORG 30276), had a lesser effect, and the agonist des-Gly10-[D-Ser(tBu)6]LH-RH ethylamide (buserelin) had no effect. The antagonists SB-29 and SB-30 also inhibited the rate of cell growth, as measured by cell number, while the LH-RH agonist buserelin had no significant effect. These results support the concept that these new LH-RH antagonists can directly inhibit the growth of human mammary tumors and thus might be suitable for the treatment of breast cancer.
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PMID:Inhibition of growth of human mammary tumor cells by potent antagonists of luteinizing hormone-releasing hormone. 264 41


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