Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0006142 (breast cancer)
 160,383 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The nitrogen mustard derivatives of 4-phenylbutyric acid and L-phenylalanine, called chlorambucil (Chl) and melphalan (Mel), respectively, have been incorporated into several peptide hormones, including luteinizing hormone-releasing hormone (LH-RH). The alkylating analogues of LH-RH were prepared by linking Chl, as an N-acyl moiety, to the complete amino acid sequence of agonistic and antagonistic analogues. These compounds, in particular the antagonistic analogues, showed much lower potency than their congeners carrying other acyl groups. To obtain highly potent alkylating analogues of LH-RH, the D enantiomer of Mel was incorporated into position 6 of the native hormone and some of its antagonistic analogues. Of the peptides prepared, [D-Mel6]LH-RH (SB-05) and [Ac-D-Nal(2)1,D-Phe(pCl)2,D-Pal(3)3,Arg5,D-Mel6,D-Ala10++ +]LH-RH [SB-86, where Nal(2) is 3-(2-naphthyl)alanine and Pal(3) is 3-(3-pyridyl)alanine] possessed the expected high agonistic and antagonistic activities, respectively, and also showed high affinities for the membrane receptors of rat pituitary cells, human breast cancer cells, human prostate cancer cells, and rat Dunning R-3327 prostate tumor cells. These two analogues exerted cytotoxic effects on human and rat mammary cancer cells in vitro. Thus these two D-Mel6 analogues seem to be particularly suitable for the study of how alkylating analogues of LH-RH could interfere with intracellular events in certain cancer cells.
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PMID:Highly potent analogues of luteinizing hormone-releasing hormone containing D-phenylalanine nitrogen mustard in position 6. 254 7

The effects of 17 beta-estradiol treatment versus tamoxifen on the metabolism of human breast cancer T47D-clone 11 cells were studied by noninvasive 31P and 13C nuclear magnetic resonance techniques. 31P nuclear magnetic resonance spectra revealed differences between estrogen and tamoxifen treated cells. The steady state content of phosphorylcholine and of the nucleoside diphosphates was higher in the tamoxifen treated cells by 33 and 140%, respectively, relative to estrogen treated cells. The intracellular pH of 7.2 and the content of the nucleoside triphosphates, Pi, phosphocreatine, glycerolphosphorylcholine, and glycerolphosphorylethanolamine and uridine diphosphoglucose remained the same in both treatments. Glucose utilization and subsequent lactate, glutamate, alanine, and glycerol 3-phosphate synthesis were monitored on line following administration of specifically labeled [13C]glucose. In estrogen treated cells the rate of lactate production via glycolysis was 560 fmol/cell/h and the initial rate of 13C labeling of the glutamate pool via the Krebs cycle was 6.8 fmol/cell/h. In the tamoxifen treated cells these rates were 2-fold lower, at 250 and 2.9 fmol/cell/h for lactate and glutamate labeling, respectively. In estrogen treated cells, the calculated content of glutamate (19 fmol/cell), alanine (11 fmol/cell), and glycerol 3-phosphate (8 fmol/cell) was higher than in tamoxifen treated cells, where only glutamate labeling was detected (13 fmol/cell). The observed differences in the in vivo kinetics of glucose metabolism may provide a sensitive measure for detecting the response of human breast cancer cells to estrogen versus tamoxifen treatments.
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PMID:Metabolic studies of estrogen- and tamoxifen-treated human breast cancer cells by nuclear magnetic resonance spectroscopy. 256 27

Of the numerous gonadotropin-releasing hormone (GnRH) analogues that have been produced in the past decade, agonists with substitutions of a hydrophobic unnatural aminoacid at position 6 retain the highest biologic activity. Nafarelin is derived from GnRH by substitution of 3-(2-naphthyl)-alanine in the 6th position. In this study, 47 regularly menstruating women used daily intranasal nafarelin for contraception for 6 months in either 125 mcg or 250 mcg doses. Ovulation was inhibited during 261 of the 262 treatment months analyzed and no pregnancies occurred. The initial rise in estradiol concentrations was most prominent with the higher dose, but these differences evened out over time. The mean estradiol concentration for the study group as a whole during the 6th month of treatment was 162 pmol/1, which is within the range for the early follicular phase of the normal menstrual cycle. There was a mean time of 43 days after discontinuation of nafarelin for ovulatory menstruation to occur. Histopathologic examination revealed that the endometrium became thin and inactive in most subjects treated with nafarelin. During nafarelin treatment, serum cholesterol increased by 5-6% and high-density lipoprotein increased by 8-9%. It is possible that the disruption of hypothalamic-pituitary-ovarian function caused by GnRH analogue treatment could afford protection against diseases such as endometrial and breast cancer that are promoted by hormonal changes of the menstrual cycle. Before GnRH superagonists are considered as contraceptives, however, more research is needed on their adverse endometrial effects and the risk of bone loss during longterm use.
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PMID:Peptide contraception by inhibition of ovulation with intranasal GnRH superagonist: clinical and metabolic aspects. 294 48

Two lambda gt11 libraries containing complementary DNAs from human breast cancer MCF7 cells were screened by expression with monoclonal antibodies to the secreted 52K protein and with a 36-mer oligonucleotide derived from the N-terminal amino acid sequence of the secreted 52K protein. Four overlapping clones were sequenced, and found to be extensively homologous to the cathepsin D of normal human kidney, except for 5-point mutations resulting in one amino acid change (Ala to Val) in the profragment of cathepsin D. Northern blot analysis showed the 2.2 kilobase (kb) cathepsin D mRNA to be induced by estradiol in MCF7 cells and produced constitutively at high levels in the estrogen-receptor-negative BT20 cell line. A simple restriction pattern consistent with the restriction map of cathepsin D cDNA was obtained in Southern blot analysis of MCF7 cell DNA. In situ hybridization of the 52K-9 cDNA probe on normal lymphocytes assigned the 52K cathepsin D gene at the extremity of the short arm of chromosome 11, in the p15 band, close to the H-ras gene and in the region whose deletion increases the risk of invasive breast cancer. We conclude that the estrogen induced 52K protein has the same sequence as normal pro-cathepsin D and we propose that the 52K protein correspond to the only pro-cathepsin D expressed in MCF7 cells.
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PMID:Cloning and sequencing of the 52K cathepsin D complementary deoxyribonucleic acid of MCF7 breast cancer cells and mapping on chromosome 11. 339 49

A continuous monitoring by chromatographic determination of 10 free serum amino acids was carried out in 21 breast cancer patients. The results show, that the pretherapeutic levels of asparagine, glutamine, alanine, isoleucine, leucine, tyrosine and phenylalanine are significantly elevated if the disease progressed within the next two years. Asparagine, glutamine, glycine, alanine, tyrosine and phenylalanine are significantly elevated if no progression could be observed. In patients without progression the level of free serum amino acid went back to normal during one year. The determination of free serum amino acid is qualified for monitoring the treatment results in breast cancer patients.
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PMID:[Free serum amino acids for monitoring the therapy of female patients with breast cancer]. 375 16

21 unilateral breast cancer patients taking different combinations of chemotherapeutic agents (cyclophosphamide, methotrexate, 6-fluorouracil, vincristine, and prednisone) were studied to determine how chemotherapy affected their granulocytes. It is widely believed that in cancer patients chemotherapeutic agents increase susceptibility to infection. Therefore, luminol-enhanced chemiluminescence was used to evaluate leukocyte function since the chemiluminescence response has been correlated to bacterial killing. the chemiluminescence response in cancer patients (6-week treatment) was significantly reduced (approximately 50%; p less than 0.01) compared to nontreated volunteers. Preliminary studies using 3H-formyl-methionyl-leucyl-phenyl alanine binding showed similar decreases. We postulate that chemotherapy for 6 weeks may affect granulocyte precursor cells in bone marrow, thereby weakening peripheral granulocytes and reducing both their bactericidal capacity and 3H-formyl-methionyl-leucyl-phenyl alanine receptors.
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PMID:Effect of cancer chemotherapeutic agents on the chemiluminescence of human granulocytes. 661 46

The multidrug resistance (MDR) phenotype induces cross-resistance to many chemotherapeutic agents in cancer cells. Protein kinase C (PKC) has been implicated in the regulation of the MDR phenotype. In order to determine the role of specific PKC isoenzymes in regulating the MDR phenotype, the expression and activity of PKC isoenzymes in the human breast cancer cell line, MCF-7-WT, and an MDR subline, MCF-7-MDR, were examined. The MDR phenotype was associated with a 10-fold increase in calcium-dependent PKC activity as well as a 10-fold decrease in calcium-independent activity was due to a selective increase in the activity was due to a selective increase in the expression of PKC alpha as determined by Western blot analysis and hydroxylapatite chromatography. This increase in expression of PKC alpha was regulated at the message level as demonstrated by Northern blot analysis. The decrease in calcium-independent activity was caused by a decrease in the expression of PCK delta and epsilon. The significance of the increase in PKC alpha expression was then demonstrated by a commensurate 11-fold increase in the basal and stimulated phosphorylation of the myristolated alanine-rich C kinase substrate. Phosphorylation of P-glycoprotein, the cellular mediator of the MDR phenotype, was increased > 20-fold in the unstimulated MCF-7-MDR cell line and its phosphorylation was further increased 2-fold in response to phorbol 12-myristate 13-acetate. These changes paralleled the increases in P-glycoprotein pump function and the MDR phenotype underscoring the role for PKC alpha in regulating P-glycoprotein phosphorylation and function.
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PMID:Selective regulation of expression of protein kinase C (PKC) isoenzymes in multidrug-resistant MCF-7 cells. Functional significance of enhanced expression of PKC alpha. 809 47

Overexpression of cathepsin D in human breast cancers is associated with a higher risk of relapse and metastasis. Also, pro-enzyme routing is altered in several tumoral mammary cell lines, leading to its hypersecretion. MCF7 cells compared to normal kidney carry a C-->T transition at position 224 in the cathepsin D gene which converts Ala to valine in its pro-fragment. Using polymerase chain reaction-single strand conformational polymorphism analysis (PCR-SSCP), the variant T allele frequency was found to be 23-30%, and equally distributed in cancer and normal cells. Six to nine per cent of genotypes were homozygous T/T, 34-41% were heterozygous T/C and 50-59% were homozygous C/C. Moreover, genotypes were identical in 19 out of 20 matched sets of tumoral mammary cells and normal white blood cells from the same patients. Loss of heterozygosity was noted in 1 case. C/T224 transition is thus not due to a somatic event. However, this missense polymorphism might modify procathepsin D secretion and/or maturation in breast cancer cells.
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PMID:Missense polymorphism (C/T224) in the human cathepsin D pro-fragment determined by polymerase chain reaction--single strand conformational polymorphism analysis and possible consequences in cancer cells. 820 64

Stromelysin-3 (ST3) is a matrix metalloproteinase (MMP) which has been implicated in cancer progression and in a number of conditions involving tissue remodelling. In contrast to other MMPs which are secreted as zymogens requiring extracellular activation, ST3 is found in the extracellular space as a potentially active mature form, suggesting that the activation of the ST3 proform differs from that of other MMPs. We show in the present study that the ST3 proform is not autocatalytically processed in the presence of 4-aminophenylmercuric acetate (APMA). By using ST3/ST2 chimeras, we demonstrate that resistance to APMA is due to properties associated with both the ST3 pro- and catalytic domains. In agreement with the observation made by Pei and Weiss [Pei and Weiss (1995) Nature (London) 375, 244-247], we find that the requirement for activation of the ST3 proform by the furin convertase is entirely contained within a stretch of 10 amino acids located at the junction between the ST3 pro- and catalytic domains. Furin cleaves human and mouse ST3 equally well. However, PACE-4, a furin-like convertase, is much more efficient on the mouse enzyme, suggesting that ST3 protein determinants other than the conserved Ala-Arg-Asn-Arg-Gln-Lys-Arg sequence preceding the furin cleavage site are implicated in PACE-4 action. Finally, we show that processing of the ST3 proform is inhibited by a furin inhibitor in human MCF7 breast cancer cells stably transfected to constitutively express a full-length human ST3 cDNA. Using brefeldin A, we demonstrate that, in these MCF7 cells, the 56 kDa precursor form of ST3 is post-translationally modified in the cis- or media-Golgi into a 62 kDa proform. Thereafter, its processing into the 47 kDa mature form occurs in the trans-Golgi network and is followed by secretion into the extracellular space.
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PMID:Characterization of structural determinants and molecular mechanisms involved in pro-stromelysin-3 activation by 4-aminophenylmercuric acetate and furin-type convertases. 864 82

Progression from G1 to the S-phase of the cell cycle is controlled by a family of low molecular weight cyclin-dependent kinase (CDK) inhibitors. The importance of these proteins in cell growth control is underscored by the observation that some members of this family are deleted or mutated in human cancers. For example, the gene encoding the CDK inhibitor p18 is located on a segment of chromosome 1 that is often abnormal in human breast tumors. We have identified an alanine to proline substitution at codon 72 of the p18 gene in BT-20 human breast cancer cells. This mutation abrogates the ability of p18 to interact with CDK6 and renders p18 deficient in suppressing cell growth in a colony formation assay. Our results suggest that p18 inactivation by point mutations may contribute to deregulated growth control in certain cell lines and/or tumors.
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PMID:A p18 mutant defective in CDK6 binding in human breast cancer cells. 884 Sep 66


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