Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.24.3 (collagenase)
18,340 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In the present paper we report on an improved procedure for the preparation of free uterine cells which avoids the use of trypsin and employs very low concentration of collagenase. The cells released mechanically from the digested tissue are constantly removed from the enzyme containing medium, thus minimizing exposure to collagenase. 60%-70% of the cells which make up the intact uterus are obtained as free cells and 95% of these cells are viable for at least 15 hours at 37 degrees. Metabolic integrity was assessed by measuring the cell's ability to oxidize glucose and synthesize proteins over extended periods of time. The membrane leucine carrier protein and the membrane Na+/K+ ATPase were found to be fully functional. Electron microscopic analysis of the cells confirmed their structural integrity. Data are presented illustrating that with this system the estrogen binding protein is stable at physiological temperatures. The cells contain approximately 30,000 specific estrogen binding sites, with an apparent KA of 5--6 x 10(9) M-1. At 37 degrees 80% of the hormone receptor complexes were in the nuclear fraction, 20% in the cytoplasm. The similarity of the estrogen receptor binding parameters with those measured in the intact tissue after in vivo hormone adminsistration, together with the cells' structural and metabolic integrity make this procedure for the preparation of uterine cell suspensions in high yields particularly suitable for studies in which minimal cell injury is an essential prerequisite.
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PMID:An improved procedure for the preparation of rat uterine cell suspensions. 22 Jul 54

Basement membranes serve as significant barriers to the passage of tumor cells but ones which metastatic cells can pass. This involves the production of a cascade of proteases leading to the activation of a specific collagenase that degrades the unique collagen network in basement membrane. Breast cancer cells, when estrogen dependent, show a requirement for estrogen for invasive activity. However, when these cells progress to an estrogen independent state and increased malignancy, they express an invasive phenotype constitutively. Studies with various anti-estrogens suggest that these responses are mediated via the estrogen receptor. Anti-estrogens lacking agonist activity suppress invasiveness as well as growth of the breast cancer cells.
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PMID:Factors regulating basement membrane invasion by tumor cells. 290 53

Flow cytometric determination of tumor ploidy and S-phase fraction following collagenase dissociation and thymidine labeling was performed on 75 consecutive breast cancers. Estrogen and progesterone receptor levels and routine histologic examination also were obtained on each tumor. Cell viability following collagenase dissociation varied from 13 to 95% with a mean of 71%. Thirty-six tumors were diploid, four tetraploid, and four hypertetraploid, and the remainder had DNA indices between 1.1 and 1.9. There was no significant correlation between tumor ploidy and tumor size or estrogen receptor positivity or negativity. The percentage of cells in S-phase varied from 1.2 to 20.0% with a mean of 6.0% utilizing a rectilinear model for histogram analysis that integrated a 10-contiguous channel sample containing the lowest number of cells in S-phase (S-pFL). The mean S-pFL of diploid carcinomas (3.43%) was significantly lower than that of hyperdiploid carcinomas (8.38%). There was good correlation between S-phase fraction determined by thymidine-labeling index (TLI) and S-pFL (r = 0.772, p = 0.0001). S-pFL predicted whether a tumor would be above or below median TLI with an accuracy of 90.5%. Estrogen receptor-negative cancers tended to have higher TLIs and S-pFLs than estrogen receptor-positive cancers; however, there was no correlation between progesterone receptor positivity or negativity and TLI and S-pFL.
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PMID:A comparison of human breast cancer cell kinetics measured by flow cytometry and thymidine labeling. 298 50

The tumorigenic properties of human rheumatoid arthritis synovial cells in culture were investigated. The synovial cells developed good colonies and secreted plasminogen activator (PA) and collagenase in the cell cultures, as do Hela cells. Since PA and progesterone receptor (PgR) are considered to be end products of estradiol action in breast cancer cells, the estrogen receptor (ER) and PgR content in these cells was also assayed. Large amounts of ER and PgR were detected in the synovial cells in culture, even though these cells are not targets for sex steroids. Study of the cytomorphologic changes in the synovial cells in culture revealed many characteristics generally observed in neoplastic cells. Whether any or all of these observations have any implication in prognosis or therapy in this disease remains to be studied.
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PMID:Expression of tumor cell properties in synovial cells in culture. 302 23

Collagenase dissociation, performed on 40 human breast cancers, yielded between 1 million and 50 million cells from less than 1 g of tissue from each tumor. Approximately 60% of cells (mean) was considered viable as judged by trypan blue exclusion and phase microscopy. On subsequent flow cytometric analysis, 20 cancers (50%) were considered diploid, three were tetraploid, and the remainder, hyperdiploid. Thymidine labeling (TLI) and flow cytometry following mechanical dissociation also were performed on 23 of these 40 tumors. Among this group of 23 cases, the median percentage of S-phase cells obtained by collagenase dissociation was 5.4, by TLI was 5.7, and by mechanical dissociation was 9.7. There was excellent correlation between the percentage of S-phase cells obtained by collagenase and TLI (r = 0.847, p = 0.0001) but only fair correlation between the percentage of S-phase cells obtained by mechanical dissociation and TLI (r = 0.597, p = 0.0027). The percentage of S-phase cells obtained by either collagenase or mechanical dissociation predicted whether a tumor was above or below median TLI in 19 of 23 cases (p = 0.0018). Estrogen receptor positivity or negativity did not predict whether a tumor was above or below median TLI (r = 0.283, p = 0.130) or above or below median S-phase fraction following collagenase dissociation (r = 0.218, p = 0.182), nor did quantitative estrogen receptor correlate significantly with TLI (r = 0.283, p = 0.13) or S-phase fraction (r = 0.218, p = 0.18).
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PMID:A method for dissociation of viable human breast cancer cells that produces flow cytometric kinetic information similar to that obtained by thymidine labeling. 632 21

Epithelial cells isolated from the mammary glands of virgin Sprague-Dawley rats and treated with 7,12-dimethylbenz[a] anthracene (DMBA) acquire an indefinite life span and anchorage-independent (AI) growth and form carcinomas in athymic nu/nu mice. Epithelial cells separated from fibroblasts and lipocytes by density-gradient centrifugation after collagenase digestion of the fat pads are grown in a hormone-supplemented medium. Control mammary epithelial cells survived approximately 30 days. After 2 days in culture, the mammary epithelial cells were treated with DMBA (1 microM) for 24 hr allowing for maximum oxidative metabolism of the hydrocarbon. DMBA-treated cells acquired an extended life span and grew in AI medium; however, in most cases, they were nontumorigenic and eventually ceased dividing. A pool of mammary epithelial cells, ME 10CL1, treated with DMBA has grown indefinitely, exhibited AI growth, and after 195 days in culture formed adenocarcinomas when 5 X 10(6) cells were injected into athymic nu/nu mice. When the tumor promoter, 12-O-tetra-decanoylphorbol-13-acetate (100 ng/ml), was added to another pool (ME 11CL2) of DMBA-treated mammary epithelial cells which had been in culture for 110 days, an irreversible increase in cell growth rate and a significant morphological alteration resulted. The 12-O-tetradecanoylphorbol-13-acetate-treated cells also formed colonies in AI medium after 140 days and poorly differentiated carcinomas in athymic nu/nu mice. Inhibition of tumor cell proliferation by tamoxifen is consistent with the mammary origin of the epithelial cells and suggests the presence of a viable estrogen receptor. The results demonstrate in vitro neoplastic transformation of rat mammary epithelial cells by DMBA or promotion of DMBA-initiated cells by 12-O-tetradecanoylphorbol-13-acetate resulting in two different epithelial tumor cell lines.
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PMID:Carcinogen-induced phenotypic alterations in mammary epithelial cells accompanying the development of neoplastic transformation. 640 Nov 65

An estrogen-responsive mouse Leydig cell tumor line (Tumor 124958) has been shown to contain only a low-affinity binder for estradiol in the cytosol fraction. This differed from the putative estrogen receptor in terms of its hormone-binding specificity as well as affinity. In addition, the possibility that an estrogen receptor-like molecule exists in the nuclei even without hormonal stimuli was examined using purified nuclei. Scatchard plot analyses showed that these nuclei possessed a large amount of estrogen binder having a high affinity for estradiol and diethylstilbestrol. The content of this nuclear binding component was not diminished by using molybdate, a potent inhibitor for receptor activation, and in vitro incubation of collagenase-dispersed cells with estradiol did not cause significant increase in the number of nuclear binding sites when compared with the values obtained by direct incubation of isolated nuclei with estradiol. These results support the view that this nuclear estrogen binder is not due to artificial migration of the cytosol receptor into nuclei during homogenization. The characterization of this nuclear binding component under cell-free conditions revealed that its affinity for estradiol in Mg2+-containing buffer was temperature dependent (Kd 3 nM at 30 degrees and 12 nM at 0 degrees) without significant alteration in the number of maximum binding sites. Introduction of a chelating agent (ethylenediaminetetraacetate) into the buffer system abolished the temperature effect on the affinity, resulting in high affinity for estradiol at both low and high temperatures. These Mg2+ and temperature effects were reversible. In addition, when compared with putative nuclear estrogen receptors, this nuclear binding was observed to be relatively resistant to high salt or micrococcal nuclease treatments in relation to solubilization from nuclei. However, trypsin digestion was found to result in a marked decrease in the nuclear binding sites, indicating that this unique nuclear binding component contains a protein unit(s). These results suggest the possibility that this tumor line contains a unique unoccupied nuclear estrogen binder which might be able to transmit estrogen signals to tumor cell nuclei with regard to tumor growth.
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PMID:Characterization of a unique nuclear estrogen-binding component in an estrogen-responsive mouse Leydig cell tumor. 687 50

We find that tamoxifen is a potent activator of estrogen receptor (ER)- mediated induction of promoters regulated by AP-1 sites including the human collagenase gene promoter and constructs in which an AP-1 site is fused to the herpes thymidine kinase promoter. This contrasts with the inability of tamoxifen to activate otherwise identical promoters bearing classical estrogen response elements. Tamoxifen agonism at AP-1 sites is cell type specific, occurring in cell lines of uterine, but not of breast, origin. It thus parallels tamoxifen agonism in vivo. AP-1 proteins such as Jun or Jun/Fos are needed for tamoxifen stimulation, and tamoxifen increases the transcriptional efficiency of these proteins even when they are provided at optimal amounts. The DNA binding domain (DBD) of ER is required for tamoxifen activation at AP-1 sites. In contrast, estrogen activation is partially independent of this domain. This suggests the existence of two pathways of ER action at AP-1: an alpha (DBD-dependent) pathway activated by tamoxifen, and a beta (DBD-independent) pathway activated by estrogen. Fusing VP16 transcriptional activation functions to ER potentiates the beta, but not the alpha, pathway. We discuss models for the two pathways and the possibility that the AP-1 pathway is a major route by which ER affects target tissue growth and differentiation in vivo.
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PMID:Tamoxifen activation of the estrogen receptor/AP-1 pathway: potential origin for the cell-specific estrogen-like effects of antiestrogens. 765 88

We investigated how overexpression of human TATA-box-binding protein (TBP) affects the action of estrogen receptor (ER) and compared the response with that of other activators. When ER activates a simple promoter, consisting of a response element and either the collagenase or tk TATA box, TBP overexpression potentiates transcription. TBP potentiates only estrogen-induced and not basal transcription and does so independent of spacing between response element and TATA box. TBP overexpression also reduces autoinhibition by overexpressed ER, suggesting that one target of the autoinhibition may be TBP itself. Both AF-1 and AF-2 domains of ER are potentiated by TBP, and each domain binds TBP in vitro. Like ER, chimeric GAL4/VP16 and GAL4/Tat activators are also potentiated by TBP, as is the synergistic activation by ER and GAL4/VP16 on a complex promoter. Unlike ER, GAL4/Sp1 and GAL4/NF-I become less potent when TBP is overexpressed. Furthermore, synergy between ER and Sp1 or between ER and NF-I, whether these are supplied by transfected GAL4 fusions or by the endogenous genes, is inhibited by TBP overexpression. Thus, ER resembles VP16 in response to TBP overexpression and is different from Sp1 and NF-I, which predominate over ER in setting the response on complex promoters.
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PMID:Transcriptional activators differ in their responses to overexpression of TATA-box-binding protein. 786 48

Clinical evidence suggests that sex hormones affect adipose tissue metabolism and deposition. To investigate the biosynthesis and possible action of estrogen in adipose tissue, we report the use of competitive, specific polymerase chain reaction amplifications to determine levels of estrogen receptor (ER) messenger RNA (mRNA) and cytochrome P450 aromatase mRNA in adipocytes and adipose stromal cells. This extremely sensitive technique uses coamplification of a homologous animal species complementary RNA to control for differences in amplification efficiencies. The DNA amplification products are identified by Southern hybridization with species-specific radiolabeled oligonucleotide probes. Abdominal adipose tissue obtained from female patients during elective abdominoplasty was separated by collagenase digestion and centrifugation into floating adipocytes and pelleted adipose stromal cells. Our results demonstrate higher ER mRNA levels in adipocytes compared to adipose stromal cells, whereas cytochrome P450 aromatase mRNA levels are higher in adipose stromal cells compared to adipocytes. The finding of ER mRNA in adipose tissue suggests the presence of the ER in adipose tissue. In addition the inverse correlation of ER mRNA and cytochrome P450 aromatase mRNA levels in adipocytes and adipose stromal cells suggests a paracrine relationship whereby estrogen produced by adipose stromal cells affects adjacent adipocytes.
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PMID:Determination of estrogen receptor messenger ribonucleic acid (mRNA) and cytochrome P450 aromatase mRNA levels in adipocytes and adipose stromal cells by competitive polymerase chain reaction amplification. 840 52


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