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)

Previous investigations have shown that culture of freshly isolated hepatocytes under conventional conditions, i.e., on dried rat tail collagen in the presence of growth factors, facilitates cell growth but also causes an extensive down-regulation of most liver-specific functions. This dedifferentiation process can be prevented if the cells are cultured on a reconstituted basement membrane gel matrix derived from the Englebreth-Holm-Swarm mouse sarcoma tumor (EHS gel). To gain insight into the mechanisms regulating this response to extracellular matrix, we are analyzing the activities of two families of transcription factors, C/EBP and AP-1, which control the transcription of hepatic and growth-responsive genes, respectively. We demonstrate that isolation of hepatocytes from the normal quiescent rat liver by collagenase perfusion activates the immediate-early growth response program, as indicated by increased expression of c-jun, junB, c-fos, and c-myc mRNAs. Adhesion of these activated cells to dried rat tail collagen augments the elevated levels of these mRNAs for the initial 1 to 2 h postplating; junB and c-myc mRNA levels then drop steeply, with junB returning to normal quiescence and the c-myc level remaining slightly elevated during the 3-day culture period. Levels of c-jun mRNA and AP-1 DNA binding activity, however, remain elevated from the outset, while C/EBP alpha mRNA expression is down-regulated, resulting in a decrease in the steady-state levels of the 42- and 30-kDa C/EBP alpha polypeptides and C/EBP alpha DNA binding activity. In contrast, C/EBP beta mRNA production remains at near-normal hepatic levels for 5 to 8 days of culture, although its DNA binding activity decreases severalfold during this time. Adhesion of hepatocytes to the EHS gel for the same period of time dramatically alters this program: it arrests growth and inhibits AP-1 DNA binding activity and the expression of c-jun, junB, and c-myc mRNAs, but, in addition, it restores C/EBP alpha mRNA and protein as well as C/EBP alpha and C/EBP beta DNA binding activities to the abundant levels present in freshly isolated hepatocytes. These changes are not due merely to growth inhibition, because suppression of hepatocyte proliferation on collagen by epidermal growth factor starvation or addition of transforming growth factor beta does not inhibit AP-1 activity or restore C/EBP alpha DNA binding activity to normal hepatic levels. These data suggest that expression of the normal hepatic phenotype requires that hepatocytes exist in a G0 state of growth arrest, facilitated here by adhesion of cells to the EHS gel, in order to express high levels of hepatic transcription factors such as C/EBP alpha.
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PMID:Cell-extracellular matrix interactions can regulate the switch between growth and differentiation in rat hepatocytes: reciprocal expression of C/EBP alpha and immediate-early growth response transcription factors. 806 19

By applying Western blot analysis using anti-phosphotyrosine antibodies, primary human dermal fibroblasts were examined after having been cultured on type I collagen-coated surfaces or in free-floating type I collagen gels. In both systems cells showed enhanced tyrosine phosphorylation of a M(r) 120,000 protein (pp120) and of a M(r) 42,000 protein (pp42). Phosphorylation was apparent 6 h at the latest after initiation of the culture and was only slightly induced on polylysine or on plastic. In contrast to pp42, pp120 was rapidly dephosphorylated in cells suspended by trypsinization or released from collagen gels by collagenase treatment, but regained phosphorylation in cells cultured in/on type I collagen. Two human sarcoma cell lines (HT-1080 and RD) exhibited identical tyrosine phosphorylation of pp120 but not of pp42. pp120 is identical with pp125FAK, a novel tyrosine kinase localized in focal adhesions, as proved by immunological cross-reactivity with anti-pp125FAK antibodies. Our results suggest that tyrosine phosphorylation is involved in signal transduction triggered by two- and three-dimensional type I collagen-fibroblast contact.
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PMID:Three-dimensional contact with type I collagen mediates tyrosine phosphorylation in primary human fibroblasts. 812 56

The tumor-bearing state is associated with an increase in gluconeogenesis which may contribute to the development of cancer cachexia. The purpose of this study was to determine if tolbutamide, a drug known to decrease gluconeogenesis in diabetes, could decrease gluconeogenesis in hepatocytes isolated from tumor-bearing rats. Hepatocytes from 24-hr fasted normal and methylcholanthrene-induced sarcoma-bearing rats (5-10% tumor burden) were isolated by in situ collagenase liver perfusion. Hepatocytes (n = 12 samples) from non-tumor-bearing (NTB) controls and tumor-bearing (TB) rats were incubated with lactate (10 mM) and alanine (10 mM) with and without 1 mM tolbutamide. Supernatant glucose concentration was measured at 30-min intervals for 2 hr. Rates of gluconeogenesis (+/- standard error) were calculated by linear regression and are expressed as nmole glucose/10(6) cells/min. Comparisons were made by two-way analysis of variance and significance defined as P < 0.05. TB hepatocytes had an increased rate of gluconeogenesis (P < 0.0001) from alanine and lactate (3.8 +/- 0.30 and 2.2 +/- 0.10, respectively) compared with NTB hepatocytes (0.66 +/- 0.10 and 1.2 +/- 0.04, respectively). TB hepatocytes treated with tolbutamide had a decreased (P < 0.0001) rate of gluconeogenesis from alanine and lactate (3.1 +/- 0.10 and 1.1 +/- 0.10, respectively) compared with untreated TB hepatocytes (5.3 +/- 0.10 and 2.1 +/- 0.10, respectively). Tolbutamide inhibits gluconeogenesis from lactate and alanine in tumor-influenced hepatocytes.
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PMID:Tolbutamide inhibits gluconeogenesis in the tumor-influenced hepatocyte. 823 Nov 77

The vascular endothelium normally is maintained in a quiescent state, but under certain conditions it is induced to undergo marked changes in behavior and form new vascular structures. A complex interaction among various growth and differentiation factors and the extracellular milieu regulates this behavior. One series of signals affecting endothelial behavior is provided by laminin, a major structural protein of basement membrane. These signals have been studied using Matrigel, a reconstituted basement membrane preparation from the murine Englebreth-Holm-Swarm sarcoma, in an in vitro assay of endothelial cell differentiation. Three biologically-active sequences from the laminin molecule have been evaluated. Synthetic peptides that include the sequences -RGD-, -YIGSR-, and -SIKVAV- mediate, respectively, cell binding to Matrigel, alterations in cell morphology, and induction of migration and collagenase activity. Preliminary data indicate that observations made with this system may be relevant to endothelial function in vivo. Endothelial cell differentiation on Matrigel may thus be a useful in vitro model for the study of certain steps in angiogenesis.
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PMID:Role of laminin in endothelial cell recognition and differentiation. 843 60

There has been an increasing interest in the measurement of carotenoids, retinoids, and tocopherols in human tissues because some of these micronutrients have been shown to have chemopreventive activity. Since clinical tissue samples obtained for analysis are usually small in quantity, a sensitive analytical procedure that can simultaneously measure all the micronutrients of interest in one small piece of human tissue is necessary. Moreover, some solid tissues, such as skin, are very difficult to homogenize unless they are first saponified in alcoholic KOH, but the saponification often causes substantial destruction of some micronutrients. Thus, a nonsaponification procedure using collagenase to facilitate homogenization was developed. Solid tissues are first incubated in a collagenase solution, homogenized, then incubated in a protease solution, followed by precipitation of tissue proteins and extraction with hexane. Collagenase digestion facilitates homogenization, and protease digestion increases the extractable amounts of the micronutrients from certain tissue samples. In this study, the recovery and precision (coefficient of variation) of the new procedure was determined. In addition, the extracted amounts of seven carotenoids, two retinoids, and two tocopherols from human skin, cervical/ovarian tissue, as well as sarcoma and kidney tumors using the new procedure and a commonly applied saponification procedure were compared.
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PMID:A nonsaponification method for the determination of carotenoids, retinoids, and tocopherols in solid human tissues. 846 48

SPARC (osteonectin/BM40) is a secreted protein that modifies the interaction of cells with extracellular matrix (ECM). When we added SPARC to cultured rabbit synovial fibroblasts and analyzed the secreted proteins, we observed an increase in the expression of three metalloproteinases--collagenase, stromelysin, and the 92-kD gelatinase--that together can degrade both interstitial and basement membrane matrices. We further characterized the regulation of one of these metalloproteinases, collagenase, and showed that both collagenase mRNA and protein are upregulated in fibroblasts treated with SPARC. Experiments with synthetic SPARC peptides indicated that a region in the neutral alpha-helical domain III of the SPARC molecule, which previously had no described function, was involved in the regulation of collagenase expression by SPARC. A sequence in the carboxyl-terminal Ca(2+)-binding domain IV exhibited similar activity, but to a lesser extent. SPARC induced collagenase expression in cells plated on collagen types I, II, III, and V, and vitronectin, but not on collagen type IV. SPARC also increased collagenase expression in fibroblasts plated on ECM produced by smooth muscle cells, but not in fibroblasts plated on a basement membrane-like ECM from Engelbreth-Holm-Swarm sarcoma. Collagenase was induced within 4 h in cells treated with phorbol diesters or plated on fibronectin fragments, but was induced after 8 h in cells treated with SPARC. A number of proteins were transiently secreted by SPARC-treated cells within 6 h of treatment. Conditioned medium that was harvested from cultures 7 h after the addition of SPARC, and depleted of residual SPARC, induced collagenase expression in untreated fibroblasts; thus, part of the regulation of collagenase expression by SPARC appears to be indirect and proceeds through a secreted intermediate. Because the interactions of cells with ECM play an important role in regulation of cell behavior and tissue morphogenesis, these results suggest that molecules like SPARC are important in modulating tissue remodeling and cell-ECM interactions.
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PMID:SPARC, a secreted protein associated with morphogenesis and tissue remodeling, induces expression of metalloproteinases in fibroblasts through a novel extracellular matrix-dependent pathway. 850 59

The aim of the study was to assess the activities of the collagenases type IV (matrix metalloproteinase type 2 [MMP-2] and matrix metalloproteinase type 9 [MMP-9]), also known as gelatinases, and the local activity of interstitial collagenase (matrix metalloproteinase type I[MMP-1]) in tissue extracts from a case of the botryoid sarcoma, a rare and very malignant tumour of the female genital tract. Zymography revealed that botryoid sarcoma does not express the 92-kDa form of type IV collagenase activity in Triton extract and only weak activity in Heat extract when compared to values found in extracts from striated muscle and fibroma uteri. MMP-1 appeared in the latent form only in the Triton extract of botryoid sarcoma and its activity was lower than those found in the control tissues. These results indicate that the very rapid local invasion and systemic metastases associated with botryoid sarcoma do not depend on the activity of tumour-derived gelatinases.
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PMID:Local activity of matrix metalloproteinases in a case of botryoid sarcoma. 884 7

Forty-seven cases of giant cell tumor (GCT) of bone were reviewed pathologically to elucidate the origin of spindle-shaped stromal cells or the histogenesis of mononuclear histiocytic stromal cells and osteoclast-like giant cells (OCGC). To clarify the histogenesis of OCGC, eight cases of sarcoma associated with OCGC were reviewed for a comparative study. Spindle-shaped stromal cells sometimes produced minute focl of osteoid matrix. Proliferating cell nuclear antigen (PCNA) was observed in spindle-shaped stromal cells and mononuclear histiocytic stromal cells, but not in OCGC. Matrix metalloproteinase (MMP)-9 was expressed by mononuclear histiocytic stromal cells and OCGC, and its expression was correlated with the lung metastasis rate. In both GCT and sarcomas with OCGC, mononuclear histiocytic stromal cells and OCGC expressed CD68, parathyroid hormone-like protein (PTH-LP), MMP-1 and MMP-9. Immunoreactivity of mononuclear histiocytic stromal cells and OCGC to CD68, PTH-LP, MMP-1 and MMP-9 was similar between GCT and sarcomas with OCGC. These observations may suggest that mononuclear histiocytic stromal cells and OCGC are reactively induced with several cytokines acting in an autocrine or paracrine fashion and that these cells are closely related with the biologic aggressiveness of GCT.
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PMID:Giant cell tumor of bone: an immunohistochemical comparative study. 970 42

Solid tumors depend on angiogenesis for growth and metastasis. It has been shown that blood vessel density, as determined by counting the number of capillaries in clustered bursts, is a significant prognostic factor in carcinomas. It is unclear, however, whether vessel density is a prognostic factor in sarcomas. In this study, we examined angiogenesis in sarcomas of various grades and compared their vascular patterns to those of carcinomas. Microvessels were identified by von Willebrand factor staining. The matrix of multiple sarcoma and breast carcinoma specimens were extracted and subjected to Western analysis of various angiogenic factors and inhibitors. Metalloproteinase inhibitor presence was also determined by in situ hybridization. In breast carcinomas, capillaries were clustered in bursts within the stroma of the tumor, whereas the sarcoma capillaries were homogeneously distributed in the tumor stroma. Random blood vessel density per high power field in sarcomas did not correlate with patient prognosis. The matrix of sarcomas and carcinomas contained both angiogenic stimulators and inhibitors. Tissue inhibitor of metalloproteinase-1 was found predominantly in fibroblasts and myofibroblasts in the matrix of carcinoma specimens. The difference in the pattern of angiogenesis in sarcomas and carcinomas may be attributable to the presence of fibroblasts and myofibroblasts in carcinomas, resulting in the compartmentalization of bursts of angiogenic factors. The homogeneous appearance of vessel density in sarcomas observed in the present study would be the consequence of the influence of a single compartment.
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PMID:Different patterns of angiogenesis in sarcomas and carcinomas. 1058 66

Primary rat hepatocytes were cultured with an extracellular matrix (ECM) overlay, in order to investigate the effect of an ECM on gene expression in hepatocytes. When hepatocytes, isolated by the collagenase-perfusion method, were cultured on type I collagen-coated dishes, the mRNA levels of liver-specific genes (aldolase B, tyrosine aminotransferase and albumin) decreased continuously, while those of ubiquitously-expressed genes (glyceraldehyde 3-phosphate dehydrogenase and beta-actin) increased. When a dilute ECM derived from the Engelbreth-Holm-Swarm mouse sarcoma (an EHS gel) was added to the above hepatocytes 3 days after plating, the mRNA levels of liver-specific genes increased, while those of ubiquitously-expressed genes decreased. The effects of a rat liver biomatrix (a physiological ECM for rat hepatocytes) on gene expression in primary hepatocytes were similar to those of the EHS gel. A nuclear run-on assay, and 5,6-dichloro-1-beta-d-ribofuranosylbenzimidazole or actinomycin D treatments revealed that the transcriptional rates of liver-specific genes were enhanced by the EHS gel overlay, while the apparent stability of the corresponding mRNAs were unchanged. In contrast, the transcriptional rates of ubiquitously-expressed genes were not greatly affected by an EHS gel overlay, while the apparent stability of their mRNAs were decreased. These data suggest that the ECM plays an important role in the maintenance of the differentiated characteristics of primary hepatocytes by inducing the transcription of liver-specific genes and, also, by destabilizing the mRNAs of ubiquitously-expressed genes.
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PMID:Differential regulation of liver-specific and ubiquitously-expressed genes in primary rat hepatocytes by the extracellular matrix. 1127 81


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