Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The ability of a variety of compounds to disrupt normal endocrine homeostasis, and potentially, the physiological and reproductive capacity of an organism, has gained worldwide attention in recent years. In an attempt to identify such compounds, and to examine the mechanism(s) by which they may exert their actions, we have constructed reporter plasmid vectors that contain the firefly luciferase gene under hormone-inducible control of estrogen-, androgen-, or retinoic acid-responsive DNA enhancer elements. Transient transfection of these vectors into appropriate receptor-containing cell lines revealed their ability to respond to their respective hormones with the induction of luciferase. Here, we describe development and optimization of a recombinant human ovarian carcinoma (BG-1) line, which has been stably transfected with the estrogen responsive luciferase reporter plasmid. The resulting recombinant cell line (BG1Luc4E(2)) responds to 17beta-estradiol at concentrations as low as 1 pM. The utility of BG1Luc4E(2) cells as a bioassay screening system for environmental estrogens was demonstrated by their response to known xenoestrogens, and also by the putative identification of two polychlorinated biphenyls (2,3',4, 4,'-tetrachlorobiphenyl and 2,2',3,5',6-pentachlorobiphenyl) as novel estrogenic chemicals. These cell bioassay systems have applications for rapid screening, identification, and characterization of endocrine disrupting chemicals.
In Vitr Mol Toxicol 2000
PMID:Recombinant cell bioassays for endocrine disruptors: development of a stably transfected human ovarian cell line for the detection of estrogenic and anti-estrogenic chemicals. 1090 Apr 8

Adrenomedullin (AM) gene expression was analysed in 60 cases of epithelial ovarian cancer, (29 serous, 14 mucinous, 13 endometrioid, three clear cell, and one undifferentiated) using reverse transcription-polymerase chain reaction (RT-PCR); 10 of the cases were of low malignant potential; 25 were stage I; three were stage II; 27 were stage III; and five were stage IV. The level of AM gene expression was described in terms of the relative yield of the AM gene to the beta2-microglobulin gene. AM gene expression ranged from 0.04 to 1.57 (median 0.36). The association between histological grade and AM gene expression was significant (P: = 0.027), however, the association with other clinico-pathological features, i.e. patients' age at diagnosis, stage of disease, residual tumour mass after initial surgery, and histological subtype were not significant. Survival data were available for all patients and univariate Cox regression analysis showed that the AM gene expression was significantly associated with a poor prognosis (P: = 0.019). Immunohistochemical studies showed that AM was localized in the outer cell membrane or the cytoplasm of the carcinoma cells and in the endothelial cells of the tumour stroma. The AM gene expression level may play a key role in the biology of epithelial ovarian cancer and may define a more aggressive tumour phenotype.
Mol Hum Reprod 2000 Oct
PMID:Expression of the adrenomedullin gene in epithelial ovarian cancer. 1100 13

Protein synthesis is regulated in response to environmental stimuli by covalent modification, phosphorylating the components of the translational machinery. Phosphorylation of the alpha subunit of eIF-2 is one of the best-characterized mechanisms for down-regulating protein synthesis in higher eukaryotes in response to various stress conditions. One of mammalian eIF-2alpha kinases is a heme-regulated inhibitor kinase (HRI), which is activated by heme deficiency and plays an important role in translational control. In this work, we have analyzed the differentially expressed genes between epithelial ovarian cancer and normal ovary. We have screened a total of 1,408 genes isolated from a human dermal papilla cell cDNA library by cDNA array hybridization. Among many differentially expressed genes, eIF2alpha kinase, a heme regulated inhibitor was down-regulated in ovarian epithelium cancer. The down-regulation of hHRI was also confirmed in other ovarian cancer tissues by Northern blot hybridization. The hHRI gene is 2,887 bp in length and the amino acid sequence deduced from the cDNA clone encodes a protein of 630 amino acids with molecular mass of 73 kDa. It contains all 12 catalytic domains of the protein kinases with consensus sequences of the protein-serine/threonine kinases. The expression pattern of hHRI mRNA showed approximately 3.0 kb bands which were expressed ubiquitously in all human tissues examined, which indicates that eIF-2alpha kinase could play an important role in the translational regulation of nonerythroid tissues.
Mol Cells 2000 Oct 31
PMID:Cloning of hHRI, human heme-regulated eukaryotic initiation factor 2alpha kinase: down-regulated in epithelial ovarian cancers. 1110 Nov 52

The cellular response to cisplatin involves activation of multiple signal transduction pathways, including the mitogen-activated protein (MAP) kinase pathways. In this study, we compared the cisplatin-induced activation of two MAP kinases, c-jun N-terminal kinase 1 (JNK1) and extracellular signal-regulated protein kinases 1 and 2 (ERK1/2), in the cisplatin-sensitive ovarian carcinoma cell line A2780 and its derivative cisplatin-resistant cell lines CP70 and C200. Dose-dependent and time-dependent activation of JNK1 and ERK1/2 occurred in each of the three cell lines in response to cisplatin treatment. The requirement of higher concentrations of cisplatin for induction of maximum activation of JNK1 and ERK1/2 was correlated with increased levels of cisplatin resistance. In addition, inhibition of cisplatin-induced ERK activation, using the MAP/ERK kinase 1 synthetic inhibitor PD98059, resulted in enhanced sensitivity to cisplatin in all three cell lines. These results suggest that cisplatin-induced ERK1/2 activity is not responsible for the acquired cisplatin resistance in CP70 and C200 cells but rather provides a general cytoprotective effect in both cisplatin-sensitive and cisplatin-resistant cell lines. In conclusion, different patterns of cisplatin-induced JNK1 and ERK1/2 activation are observed in cell lines with different levels of cisplatin sensitivity, and inhibition of cisplatin-induced ERK1/2 activation enhances sensitivity to cisplatin in both cisplatin-sensitive and cisplatin-resistant cell lines.
Mol Carcinog 2000 Dec
PMID:Cisplatin-induced response of c-jun N-terminal kinase 1 and extracellular signal--regulated protein kinases 1 and 2 in a series of cisplatin-resistant ovarian carcinoma cell lines. 1117 Feb 60

The U6 expression system was explored for efficient expression of a ribozyme against the human proto-oncogene c-neu. A hammerhead ribozyme (neuRz) and the control mutant ribozyme (MRz) were targeted to cleave c-neu mRNA at the tyrosine kinase domain. In vitro cleavage showed that neuRz was very active while MRz was not. Near-maximal target cleavage observed at a low ribozyme:target ratio (0.1) suggests that neuRz has good activity and turnover capability under physiological conditions, i.e., <5 mM MgCl(2) and 37 degrees C. Chimeric U6 ribozyme was expressed at about 5 x 10(6) copies/cell at 48 h in the ovarian carcinoma cell line SKOV-3.ip1. Partial down-regulation of c-neu mRNA and protein was observed in a dose-dependent manner in cells transiently transfected with U6neuRz- but not with MRz-containing plasmid. Sorted transient transfectants demonstrated dramatic growth inhibition with the neuRz-expressing cells. Our results demonstrate that the U6 expression system is very efficient and suitable for the expression of a hammerhead ribozyme. Moreover, nonviral delivery of the neuRz-expressing plasmid resulted in specific down-regulation of c-neu and, subsequently, growth inhibition of ovarian cancer cells overexpressing c-neu.
Mol Ther 2001 Feb
PMID:Specific down-regulation of HER-2/neu mediated by a chimeric U6 hammerhead ribozyme results in growth inhibition of human ovarian carcinoma. 1123 73

Functional significance has been demonstrated in vitro for the exon 3 T-->C Tyr113His amino acid substitution polymorphism of the microsomal epoxide hydrolase (EPHX) gene. The higher activity or fast TT genotype was previously reported to be associated with an increased risk of ovarian cancer, and this association may reflect enhanced activation of endogenous or exogenous substrates to more reactive and mutagenic derivatives. Components of cigarette smoke are examples of exogenous substrates subject to such bioactivation, and smoking exposure may thus modify the risk associated with the EPHX polymorphism. We examined 545 cases of epithelial ovarian cancer and 287 unaffected controls for this EPHX T-C genetic variant to investigate whether, in the Australian population, the TT genotype was associated with (i) specific ovarian tumor characteristics; (ii) risk of ovarian cancer, overall or for specific subgroups; and (iii) risk of ovarian cancer in smokers specifically. Genotyping was carried out using the Perkin-Elmer ABI Prism 7700 Sequence Detection System for fluorogenic polymerase chain reaction allelic discrimination. Stratification of the ovarian cancer cases according to tumor behavior (low malignant potential or invasive), grade, stage, and p53 immunohistochemical status failed to show any heterogeneity with respect to the genotype defined by the EPHX polymorphism. There was a suggestion of heterogeneity with respect to histologic subtype (P=0.03), largely due to a decreased frequency of the TT genotype in endometrioid tumors. EPHX genotype distribution did not differ significantly between unaffected controls and ovarian cancer cases (overall, low malignant potential, or invasive) either overall or after stratification by smoking status. However, the TT genotype was associated with a decreased risk of invasive ovarian cancer of the endometrioid subtype specifically (age-adjusted odds ratio=0.38, 95% confidence interval=0.17-0.87). The results suggest that the proposed EPHX-mediated bioactivation of components of cigarette smoke to mutagenic forms is unlikely to be involved in the etiology of ovarian cancer in general but that a greater rate of EPHX-mediated detoxification may decrease the risk of endometrioid ovarian cancer. Mol. Carcinog. 30:71-78, 2001.
Mol Carcinog 2001 Jan
PMID:The microsomal epoxide hydrolase Tyr113His polymorphism: association with risk of ovarian cancer. 1125 66

beta-Catenin gene mutations and microsatellite instability (MI) have been reported in endometrioid ovarian carcinomas. In colon but not endometrial cancer, beta-catenin gene mutations are associated with a replication error phenotype and MI. In this study the authors investigate whether beta-catenin mutations and MI are two independent oncogenic pathways in endometrioid ovarian carcinomas. They also evaluate the usefulness of these molecular markers in determining the primary origin of simultaneous tumors in the ovary and endometrium. This study was performed on 26 patients diagnosed with primary endometrioid ovarian carcinoma, five of whom also had pathologically diagnosed primary synchronous endometrioid endometrial carcinoma. Immunohistochemical and molecular analyses indicated that there were 25 primary ovarian tumors with four primary synchronous endometrial cancers and one ovarian metastasis of a primary endometrial carcinoma. All studies were performed on formalin-fixed, paraffin-embedded tissue samples. The beta-catenin expression pattern (nuclear vs. membranous) was analyzed immunohistochemically. Mutations in exon 3 of the beta-catenin gene were studied by polymerase chain reaction, single-strand conformational polymorphism, and direct sequencing. MI status was established by studying BAT-26 and BAT-25 mononucleotide repeats. In the group with 21 single ovarian tumors, 18 (85%) had beta-catenin nuclear expression, eight (38%) had beta-catenin gene mutations (always associated with beta-catenin nuclear expression), and four (19%) had MI. Only one case (5%) had both beta-catenin gene mutations and MI. The mutations affected one of the serine/threonine residues targeted for phosphorylation by glycogen synthase kinase-3beta or adjacent residues. At codon 32, a GAC-to-TAC (D32Y) change was found; at codon 33, two TCT-to-TGT (S33C) changes were found; at codon 37, three TCT-to-TTT (S37F) changes and one TCT-to-TGT (S37C) change were found; and, lastly, one ACC-to-GCC change at codon 41 (T41A) was detected. Four of the 25 endometrioid ovarian carcinomas (16%) had an associated synchronous endometrial carcinoma. There was a higher percentage of beta-catenin mutations (n = 3, 75%) in synchronous ovarian carcinomas than in single ones, although with a similar percentage of MI (n = 1, 25%). beta-catenin mutations were S37C in two cases and D32G in one. One of the four endometrial carcinomas showed an S33C beta-catenin mutation, and two carcinomas had MI. None of the four tumors had both beta-catenin gene mutation and MI. beta-catenin gene mutations were always associated with a nuclear beta-catenin expression pattern, whereas MI was associated with a membranous pattern. In one patient both the ovarian and the endometrial carcinomas had beta-catenin gene mutations, in another patient both tumors showed MI, whereas in the remaining two patients the ovarian carcinomas showed beta-catenin gene mutations and the endometrial carcinomas showed MI. To summarize, the results of this study suggest that beta-catenin mutations and MI could represent two independent pathways in endometrioid ovarian carcinomas because they occur simultaneously very infrequently (in 5% of these cases). beta-catenin mutations are always associated with a nuclear beta-catenin expression pattern, whereas cases with a replication error -plus phenotype showed no abnormal beta-catenin subcellular localization. The study of the beta-catenin expression pattern, beta-catenin mutations, and MI, together with conventional clinicopathologic findings, could aid in distinguishing between the metastatic or independent origin of simultaneous endometrioid ovarian and endometrial carcinomas. Tumors with identical immunohistochemical and molecular features should therefore be considered to have a common origin.
Diagn Mol Pathol 2001 Jun
PMID:beta-Catenin expression pattern, beta-catenin gene mutations, and microsatellite instability in endometrioid ovarian carcinomas and synchronous endometrial carcinomas. 1138 21

The telomerase RNA-protein complex responsible for maintenance of telomeric DNA at chromosome ends, is usually inactive in most primary somatic human cells, but is specifically activated with in vitro immortalization and during tumorigenesis. Although expression of the RNA component of telomerase appears to be constitutive, the expression pattern of human telomerase reverse transcriptase (hTERT), the catalytic subunit of telomerase, is correlated with measured enzyme activity. In particular, a >80% concordance has been reported between telomerase activity and hTERT mRNA expression in ovarian tumors. Accordingly, to learn more about the mechanism regulating hTERT gene expression in ovarian carcinoma, we have performed a detailed analysis of the 5'-flanking promoter region of the hTERT gene. We have reported previously the isolation and analysis of a 5.8-kb genomic fragment containing the human hTERT gene promoter (M. Tzukerman et al., Mol. Biol. Cell, 11: 4381-4391, 2000). Deletion analysis of this promoter was carried out using transient transfection of promoter-reporter constructs in four different telomerase-expressing, ovarian carcinoma-derived cell lines, the tumorigenic properties of which have been characterized, and was compared with telomerase-negative primary human fibroblasts and nontransformed ovarian epithelial cells. These assays have shown that the hTERT promoter is inactive in telomerase-negative cells and is active in telomerase-positive cell lines. A core promoter of 283 bp upstream of the transcription initiation site (TI) was found to be sufficient for maximum promoter activity, suggesting the presence of inhibitory elements within the larger promoter sequence. Gel shift analysis of the core promoter using nuclear extracts from the ovarian and control cell lines revealed specific transcription factor binding using extracts from telomerase-positive cells. Among the binding elements, we identified two E-boxes (CACGTG) as well as a novel element (MT-box), which we identified recently in a number of differentiation systems. Site-directed mutagenesis was used to introduce mutations into this novel transcription factor binding element. These mutations significantly affect the transcriptional activity of hTERT promoter in a cell type-specific manner and suggest that the transcription factors that bind to the E-box and the novel element cooperatively function as major determinants of hTERT expression and telomerase activity in ovarian cancer. Further comparison of promoter activity, telomerase activity, and telomere length among the different ovarian cancer cells indicated that a threshold level of telomerase activity is apparently sufficient to protect telomere integrity and permit the immortal state of the different ovarian cancer cell lines.
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PMID:Human telomerase reverse transcriptase promoter regulation in normal and malignant human ovarian epithelial cells. 1145 3

One of the major problems with ovarian cancer treatment is the clinical development of resistance to cisplatin. Considerable efforts have been directed toward the identification of biological and pharmacological agents that would reverse drug resistance to cisplatin. ALLnL is an inhibitor of the proteasome that can inhibit the ubiquitin-proteasome pathway, which plays an essential role in many processes in cell life. We have recently shown that ALLnL, at concentrations that do not appear harmful, has significantly enhanced DNA platination and decreased DNA repair of cisplatin-DNA adducts in human A2780/CP70 ovarian carcinoma cells. These activities of proteasome inhibition were also associated with substantially increased cisplatin toxicity in these cells. In this communication, we demonstrate that treatment of A2780/CP70 cells with ALLnL blocks cisplatin-induced ERCC-1 mRNA expression in a concentration- and time-dependent manner, as measured by Northern blot analysis. In addition, we showed that the cisplatin-dependent increase in steady-state levels of ERCC-1 mRNA was prevented by pretreatment with lactacystin, a potent and specific inhibitor of proteasome. These results suggest that the effect of proteasome inhibition on cisplatin cytotoxicity, DNA platination, and DNA repair of cisplatin adducts in ovarian cancer cells may be through down-regulating ERCC-1 expression.
Res Commun Mol Pathol Pharmacol
PMID:Proteasome inhibition suppresses cisplatin-dependent ERCC-1 mRNA expression in human ovarian tumor cells. 1158 65

CNS-resident macrophages (microglia and CNS-associated macrophages) are the main immunocompetent cells of the central nervous system (CNS) and respond by rapid activation to brain injury. Molecular events occurring during IFNgamma-activation and identification of potential markers of the CNS-resident macrophage subsets were investigated using microglial-derived clones (EOC) differing in their morphology and their antigen presenting activities for CD4+ and CD8+ T-cells. By applying the subtractive process of cDNA representational difference analysis (cRDA), 16 differentially expressed mRNAs were isolated and sequenced, revealing 8 known and 8 novel molecules; 15 of these messages were unpreviously reported in microglia. Two markers of all activated microglial EOC cells were identified (iNOS; IRG-1) and specific subpopulation markers were highlighted, including molecules known to be closely expressed in perivascular spaces. Moreover, some messages could support the distinct morphology, adhesive characteristics, and potential functions of the different clones.
Mol Cell Neurosci 2001 Oct
PMID:Identification and IFNgamma-regulation of differentially expressed mRNAs in murine microglial and CNS-associated macrophage subpopulations. 1164 Aug 94


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