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)

Previous studies have shown that the administration of cadmium causes extensive necrosis of the testes and, eventually, a high incidence of interstitial cell tumors. However, the interactions of cadmium with interstitial cells of the testes have not been well defined. Therefore, this study was designed to assess the uptake of cadmium into this potential target cell of cadmium carcinogenesis. Interstitial cells were prepared by collagenase dispersion of decapsulated Wistar rat testes and separated from seminiferous tubules by unit gravity sedimentation. Such preparations showed a high exclusion rate of trypan blue. The interstitial cell preparations were incubated at 33 degrees with various concentrations of cadmium (1.0 to 100 microM) for periods ranging from 0.5 to 60 min. At the end of the incubation, cellular cadmium was separated from cadmium in the media by centrifugation through an oil layer. Initial experiments showed three distinct phases of cadmium influx into interstitial cells, a primary rapid velocity phase (V0; 0 to 1.5 min), a second intermediate velocity phase (V1; 3 to 12 min), and a third low velocity phase (V2; 15 to 60 min). V2 appeared to have both influx and efflux components, as efflux experiments indicated an approximate 20% loss of cadmium from 15 to 60 min. The initial phase was found to be nonsaturable and was not decreased by inclusion of potassium cyanide (1.0 mM), N-ethylmaleimide (1.0 mM), or zinc (100 microM) in the incubation mixture. However, V1 was found to be saturable between 50 and 100 microM cadmium and was substantially decreased by the inclusion of potassium cyanide, N-ethylmaleimide or zinc during incubation. These data suggest that cadmium is taken up into interstitial cells by a transport system that may normally function in zinc uptake and may possibly constitute carrier mediated or active transport.
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PMID:Interactions of cadmium with interstitial tissue of the rat testes. Uptake of cadmium by isolated interstitial cells. 401 91

Selenium is an essential dietary trace element which has anticancer properties. Among its effects in rats, selenium has been shown to inhibit the development of carcinogen-induced mammary tumors by interfering with the postinitiation, promotion phase of carcinogenesis. We studied the effects of selenium on the growth of rat mammary tumor cells in primary culture. Our objective was to determine whether selenium had any direct influence on cell growth which might explain its influence on tumor development. Rat mammary tumors were induced by N-nitrosomethylurea. Tumor epithelium was prepared by collagenase dispersion and the cells were separated by Ficoll gradient centrifugation. The tumor epithelium was grown in primary culture using a defined serum-free medium. The addition of low concentrations of sodium selenite, less than 1.0 micrograms/ml, stimulated tumor cell proliferation. Protein synthesis and the production of type IV collagen increased within the first hour of exposure, prior to any measurable increase in DNA synthesis. Concentrations of selenite greater than 1.0 micrograms/ml inhibited cell proliferation, the synthesis of protein, and the replication of DNA in a dose-related manner. These studies demonstrated that selenium has the potential to influence the postinitiation phase of rat mammary tumorigenesis by directly altering the growth of tumor cells, possibly through the regulation of protein synthesis.
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PMID:Influence of selenium on the growth of N-nitrosomethylurea-induced mammary tumor cells in culture. 403 31

The kidney is a key target tissue in animal and human carcinogenesis, yet there are no established short-term tests for studying the genotoxicity of chemicals in the kidney. We have developed an assay for the measurement of chemically induced DNA repair as unscheduled DNA synthesis (UDS) in isolated rat kidney cells following in vivo treatment. Male Fischer-344 rats were injected intraperitoneally with chemicals dissolved in saline or corn oil. After various treatment times, the kidneys were perfused with a collagenase/trypsin solution (CTS), minced into small pieces, and stirred in CTS at 37 degrees C for 1 hr to dissociate cells. Cultures contain a high proportion of epithelial cells from the proximal and distal tubules. Cultures were incubated for 16-18 hr with 3H-thymidine in Williams' Medium E supplemented with 20% fetal bovine serum. UDS was measured by quantitative autoradiography as net grains/nucleus (NG). The percentage of cells in repair (% IR) was defined as the percentage of cells with greater than or equal to 3 NG. Saline- or corn oil-injected controls consistently produced -3 to -5 NG with less than 1% IR. The time course of DNA repair following treatment with the direct-acting mutagen methylmethane sulfonate (MMS) or the renal carcinogen azaserine showed a peak response at 2 hr after treatment. Azaserine showed a rapid decline in UDS at 12 and 24 hr, whereas MMS exhibited a relatively high UDS level at 24 hr. The renal carcinogens methylazoxymethanol acetate, N-methyl-N-nitrosourea, and streptozotocin all yielded strong positive UDS responses. The liver and intestinal carcinogen 1, 1-dimethylhydrazine at doses up to 50 mg/kg was cytotoxic to kidney cells, but induced less than 0 NG. Treatment with 1,2-dimethylhydrazine, which induces kidney tumors in mice but not rats, also induced less than 0 NG. Treatment with o-anisidine, a weak renal carcinogen, did not induce UDS in the kidney, suggesting that it may be acting as a tumor promoter. These results demonstrate the usefulness of this assay for the detection and study of a variety of genotoxic kidney carcinogens.
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PMID:Measurement of unscheduled DNA synthesis in rat kidney cells following in vivo treatment with genotoxic agents. 406 62

gamma-Glutamyl transpeptidase (gamma GT) positive hepatocytes were isolated from F344 male rats fed 2-acetylaminofluorene. The isolation procedure is rapid and highly selective for cells exhibiting gamma GT on their surface. Suspensions of liver cells obtained from perfusion in situ with a collagenase solution were incubated on Petri dishes coated with affinity purified rabbit anti-gamma GT antibody. gamma GT-positive cells bound to the dish within fifteen minutes and could be recovered as viable cells. Approximately 15% of the gamma GT-positive cells are isolated using this procedure. Novikoff hepatoma cells, a gamma GT-positive cell line, were used to define the parameters of the assay. The binding was both time and temperature dependent. Binding of cells to the anti-gamma GT antibody coated dishes was 50% inhibited by 2.8 mM sodium azide and 86% inhibited by 4.6 mM.
Carcinogenesis 1982
PMID:Isolation of gamma-glutamyl transpeptidase positive hepatocytes during the early stages of hepatocarcinogenesis in the rat. 612 30

The pancreas is a key target tissue in human and animal carcinogenesis, yet few short-term test systems measure genotoxicity in pancreatic cells. A method has been developed for the measurement of DNA repair as unscheduled DNA synthesis (UDS) in primary cultures of rat pancreatic cells (PRP) following in vitro or in vivo exposures to chemicals. PRP were isolated from female Sprague-Dawley (SD) or male Fischer-344 rats by mincing the pancreas in a collagenase solution followed by digestion in dispase. For in vitro exposures, PRP were incubated with 3H-thymidine (3H-TdR) in the presence of genotoxic agents for 18-22 hr. For in vivo exposures, male Fischer-344 rats were treated with genotoxic agents 2 hr prior to sacrifice of the animals, and cells were incubated with 3H-TdR. UDS was measured by quantitative autoradiography as net grains/nucleus (NG). Solvent controls ranged from -1.0 to -2.8 NG. Cells isolated from female SD rats and treated in vitro with methylmethane sulfonate (MMS), ethylmethane sulfonate (EMS), N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), and the pancreatic carcinogen azaserine all yielded over 4.0 NG. Cells treated in vitro with the hepatocarcinogens 2-acetylaminofluorene (2-AAF) and dimethylnitrosamine (DMN) and with the multisite carcinogen benzo[a] pyrene (B[a]P) yielded between -1.0 and -3.3 NG. These results are consistent with the lack of carcinogenic activity of 2-AAF, DMN, and B[a]P in the pancreas and indicate that pancreatic cells are incapable of metabolizing these compounds to genotoxic forms. In vivo treatment with MMS at 100 mg/kg yielded 1.9 NG and with azaserine at 100 mg/kg yielded 8.2 NG. This method should be useful in detecting agents that are genotoxic to the pancreas.
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PMID:Induction of unscheduled DNA synthesis in primary cultures of rat pancreatic cells following in vivo and in vitro treatment with genotoxic agents. 637 85

Hepatocytes were prepared from rainbow trout by perfusion in situ with collagenase and hyaluronidase. Preparations normally showed high initial viability (95 +/- 5% dye exclusion, 92 +/- 5% lactate dehydrogenase retention) and gradually decreased in viability and glutathione concentration over 5 hours. Cellular metabolism of aflatoxin B1 (AFB1), a potent hepatocarcinogen, was characterized by an investigation of the following parameters: kinetics of AFB1 metabolism and DNA adduct formation, dose response, viabilities of detoxication and activation pathways with time, influence of organic solvents, and effect of variation in cell concentration. The AFB1 metabolites and DNA adducts were resolved and quantitated by high-performance liquid chromatography. From these results a standardized assay procedure was derived which we used to examine AFB1 metabolism and DNA adduct formation in hepatocytes from fish fed dietary substances known to alter the carcinogenic response to this mycotoxin. Dietary beta-naphthoflavone, which strongly inhibits AFB1 carcinogenesis in rainbow trout, dramatically and reproducibly altered AFB1 binding and metabolism in isolated hepatocytes. Overall rate of AFB1 metabolism and rates of detoxication reactions increased, whereas DNA binding decreased. Dietary cyclopropenoid fatty acids, powerful synergists and promoters of AFB1 carcinogenesis in trout, also repressed AFB1-DNA binding. Both dietary factors appeared to depress initial DNA damage by AFB1 but operated through different metabolic pathways to do so.
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PMID:Dietary modification of aflatoxin B1 carcinogenesis: mechanism studies with isolated hepatocytes from rainbow trout. 643 Dec 90

Chromosomal aberrations were investigated in tracheal cells of fetal Syrian hamsters after transplacental administration of N-diethylnitrosamine (DEN). On the 15th day of pregnancy, Syrian hamsters were injected s.c. with a tumorigenic dose of DEN (50, 100 and 200 mg/kg body weight). Two hours later, the fetal tracheae were isolated, the epithelial tissue was separated from the mesenchymal tissue by collagenase-treatment, and then each cell population was transferred to cell culture after Dispase treatment. At 24, 48 and 72 h after the cell cultivation, chromosomal damage was examined. The results clearly showed that a high incidence of chromosomal aberrations, especially chromatid-type exchanges, was seen in the epithelial cells of DEN-treated groups. However, significant induction of chromosomal aberrations was not observed in the mesenchymal cells from DEN-treated groups.
Carcinogenesis 1983 Nov
PMID:Transplacental effect of N-diethylnitrosamine on chromosomal aberrations in fetal tracheal cells of the Syrian hamster: comparison between epithelial and mesenchymal cells. 664 Aug 41

We have recently developed an alkaline elution/rat hepatocyte assay to sensitively measure DNA single-strand breaks induced by xenobiotics in non-radiolabeled rat hepatocytes. Here we have evaluated this assay as a predictor of carcinogenic/mutagenic activity by testing 91 compounds (64 carcinogens and 27 non-carcinogens) from more than 25 diverse chemical classes. Hepatocytes were isolated from uninduced rats by collagenase perfusion, exposed to chemicals for 3 h, harvested, and analyzed for DNA single-strand breaks by alkaline elution. DNA determinations were done fluorimetrically. Cytotoxicity was estimated by glutamate-oxaloacetate transaminase release or by trypan blue dye exclusion. The assay correctly predicted the reported carcinogenic/non-carcinogenic potential of 92% of the carcinogens tested and 85% of non-carcinogens tested. The assay detected a number of compounds, including inorganics, certain pesticides, and steroids, which give false-negative results in other short-term tests. Only 2 rat liver carcinogens were incorrectly identified; the other carcinogens incorrectly identified are weakly or questionably carcinogenic (i.e., they cause tumors only in one species, after lifetime exposure, or at high doses). Some chemicals cause DNA damage only at cytotoxic concentrations; of 16 such compounds in this study, 12 are weak carcinogens suggesting a link between DNA damage caused by cytotoxicity and carcinogenesis. Our data indicate that this assay rapidly, reproducibly, sensitively, and accurately detects DNA single-strand breaks in rat hepatocytes and that the production of these breaks correlates well with carcinogenic and mutagenic activity.
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PMID:Evaluation of the alkaline elution/rat hepatocyte assay as a predictor of carcinogenic/mutagenic potential. 687 65

In a series of transgenic mice, the human tissue collagenase gene was expressed in the suprabasal layer of the skin epidermis. Visually, the mice had dry and scaly skin which upon histological analysis revealed acanthosis, hyperkeratosis, and epidermal hyperplasia. At the ultrastructural level, intercellular granular materials were absent in the transgenic skin epidermis but contact was maintained through the intact desmosomes. Despite a diversity of underlying etiologies, similar morphological hyperproliferative changes in the epidermis are observed in the human skin diseases of lamellar ichthyosis, atopic dermatitis, and psoriasis. Subsequent experiments demonstrate that when the transgenic mouse skin was treated once with an initiator (7,12-dimethyl-benz[a]anthracene) and then twice weekly with a promoter (12-O-tetradecanoylphorbol-13-acetate), there was a marked increase in tumor incidence among transgenic mice compared with that among control littermates. These experiments demonstrate that by overexpressing the highly specific proteolytic enzyme collagenase, a cascade of events leading to profound morphological changes which augment the sensitivity of the skin towards carcinogenesis is initiated in the epidermis.
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PMID:Collagenase expression in transgenic mouse skin causes hyperkeratosis and acanthosis and increases susceptibility to tumorigenesis. 756 25

We have previously reported that two closely related protein kinase C (PKC) isoforms, PKC alpha and PKC beta I, had divergent effects on the growth and transformation of the same parental R6 rat embryo fibroblast cell line (Housey, G. M., Johnson, M. D., Hsiao, W.-L. W. O'Brian, C. A., Murphey, J. P., Kirschmeier, P., and Weinstein, I. B. (1988) Cell 52, 343-354; Borner, C., Filipuzzi, I., Weinstein, I. B., and Imber, R. (1991) Nature 353, 78-80). Whereas cells that overexpress PKC beta I lost anchorage dependence, grew to higher saturation densities, and generated small tumors when injected into nude mice, none of these properties were seen with cells that overexpress PKC alpha. In fact, the latter cells grew even slower and to lower saturation densities as compared to control cells. Here we investigate possible molecular mechanisms underlying the reciprocal effects of PKC alpha and PKC beta I. Overexpression of both isoforms enhanced 12-O-tetradecanoyl phorbol-13 acetate-induced expression of the growth regulatory genes c-jun, c-myc, and collagenase and enhanced feedback inhibition of epidermal growth factor receptor binding and cellular levels of diacylglycerol. However, the cells overexpressing PKC beta I differed from those overexpressing PKC alpha by displaying a decreased requirement for growth factors and by the production of a mitogenic factor. Thus, the basis for enhanced growth and transformation of cells overexpressing PKC beta I may be the establishment of an autocrine growth factor loop. These findings may be relevant to the roles of specific isoforms of PKC in carcinogenesis and tumor growth.
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PMID:Two closely related isoforms of protein kinase C produce reciprocal effects on the growth of rat fibroblasts. Possible molecular mechanisms. 781 23


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