Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.24.23 (MMP)
 4,246 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Glucosamine and chondroitin sulphate in many animal and human trials has improved joint health. In vitro studies are beginning to clarify their mode of action. The objective of this research was to: 1) determine at what concentrations glucosamine-HCl (GLN) and/or chondroitin sulphate (CS) would inhibit the cytokine-induced catabolic response in equine articular cartilage explants and 2) to determine if a combination of the 2 was more effective at inhibiting the catabolic response than the individual compounds. Articular cartilage was obtained from carpal joints of horses (age 1-4 years). Cartilage discs (3.5 mm) were biopsied and cultured. Explants were incubated with lipopolysaccharide (LPS) in the presence of varying concentrations of GLN, CS, or both. Control treatments included explants with no LPS and LPS without GLN or CS. Media were analysed for nitric oxide (NO), prostaglandin E2 (PGE2) and keratan sulphate. Cartilage was extracted for analysis of metalloproteinases (MMP). Four experiments were conducted. In all experiments, GLN at concentrations as low as 1 mg/ml decreased NO production relative to LPS stimulated cartilage without GLN over the 4 day period. In general, CS at either 0.25 or 0.5 mg/ml did not inhibit NO production. The addition of CS to GLN containing media did not further inhibit NO production. GLN at concentrations as low as 0.5 mg/ml decreased PGE2 production, whereas CS did not effect on PGE2. The combination of GLN/CS decreased MMP-9 gelatinolytic activity but had no effect on MMP-2 activity. The combination in 2 experiments tended to decrease MMP-13 protein concentrations and decreased keratan sulphate levels in media. Overall, the combination of GLN (1 mg/ml) and CS (0.25 mg/ml) inhibited the synthesis of several mediators of cartilage degradation. These results further support the effort to understand the role of GLN and CS in preserving articular cartilage in athletic horses.
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PMID:Inhibition of articular cartilage degradation by glucosamine-HCl and chondroitin sulphate. 1240 91

Tumor-stroma interactions play a significant role in tumor development and progression. Alterations in the stromal microenvironment, including enhanced vasculature (angiogenesis), modified extracellular matrix composition, inflammatory cells, and dys-balanced protease activity, are essential regulatory factors of tumor growth and invasion. Differential modulation of stromal characteristics is induced by epithelial skin tumor cells depending on their transformation stage when grown as surface transplants in vivo. Tumor cells can regulate the development of a "tumor-stroma" via the aberrant expression of growth factors or induction of growth factor receptors in the stromal compartment. In this context, secretion of the hematopoietic growth factors G-CSF and GM-CSF, constituitively expressed in enhanced malignant tumors, may be good candidates for induction of a tumor stroma through their effect on inflammatory cells. Upon its induction, the tumor stroma will reciprocally influence the differentiation status of tumor cells resulting in a normalization of benign tumor epithelia and the maintenance of a malignant phenotype, respectively. In the HaCaT model for squamous cell carcinoma of the skin, stromal activation and angiogenesis are transient in pre-malignant transplants, however they remain persistent in malignant transplants where progressive angiogenesis is closely correlated with tumor invasion. While continued expression of VEGF and PDGF are associated with benign tumor phenotypes, activation of VEGFR-2 is a hallmark of malignant tumors and accompanies ongoing angiogenesis and tumor invasion. As a consequence the inhibition of ongoing angiogenesis by blocking VEGFR-2 signalling resulted in dramatically impaired malignant tumor expansion and invasion. Comparably, tumor vascularization and invasion was blocked by disturbing the balance of matrix protease activity caused by a lack of PAI-1 in the stromal cells of the knockout mouse hosts. A similar inhibition of tumor vascularization was caused by TSP-1 over-expression in skin carcinoma cells, which also blocked tumor invasion and expansion. On the other hand, when granulation tissue and angiogenesis were only transiently activated as a result of stable transfection of PDGF into non-tumorigenic HaCaT cells, the target cells formed benign, but not malignant, tumors. Collectively, these data show that tumor vascularization, providing intimate association of blood vessels with tumor cells, is a prerequisite for tumor invasion. A potential mechanism for this interrelationship may be the differential regulation of MMP-expression in tumors of different grades of malignancy. In vitro MMP expression did not discriminate between benign and malignant tumor cells unless they were co-cultured with stromal fibroblasts. However, in vivo regulation of MMP expression was clearly dependent on tumor phenotype. While MMP-1 and MMP-13 were down-regulated in benign transplants, they were persistently up-regulated in malignant ones. A tight balance between proteases and their inhibitors is crucial for both the formation and infiltration of blood vessels and for tumor cell invasion, thus again emphasizing the importance of the stromal compartment for the development and progression of carcinomas.
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PMID:Tumor-stroma interactions directing phenotype and progression of epithelial skin tumor cells. 1249 91

UV irradiation leads to distinct changes in skin connective tissue by degradation of collagen, for example. Many of these alterations in the extracellular matrix are mediated by MMPs (matrix metalloproteinases) with reduced content of their antagonist TIMPs (tissue inhibitors of metalloproteinases). Potential candidates to reduce MMP activity in the skin after solar stimulation were examined. The influence of vitamin C, vitamin E and the flavonoids AGR (alpha-glucosylrutin) and 8-prenylnaringenine on the MMP and TIMP expression was investigated. Human dermal fibroblasts were incubated with these additives and irradiated with UVA [10 J cm(-2)]. The gene expression of MMP-1 (collagenase-1) and TIMP-1, the protein expression of MMP-1, MMP-2 (gelatinase-A), TIMP-1 and TIMP-2 as well as the enzyme activity of MMP-1 and MMP-2 were examined. AGR and vitamins C and E were shown to reduce MMP expression and activity, whereas 8-prenylnaringenine appeared to be responsible for the opposite effect. None of the substances considerably influenced the TIMP levels. AGR represented the most effective additive in reducing the collagenase protein expression to 60% and may be useful to level out the MMP activity in the skin after sun exposure. Furthermore, no protein expression of MMP-8, MMP-9, MMP-12 and MMP-13 could be detected.
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PMID:Influence of flavonoids and vitamins on the MMP- and TIMP-expression of human dermal fibroblasts after UVA irradiation. 1265 86

The membrane type-1 matrix metalloproteinase (MT1-MMP), a protease originally identified in breast carcinoma, is characterized by its capacity to activate other MMPs (MMP-2 and MMP-13) and to degrade extracellular matrix. Our study was undertaken to localize and identify the MT1-MMP expressing cells in human breast adenocarcinomas. A textural analysis of images obtained by immunohistochemistry and in situ hybridization showed precisely the co-expression of alpha smooth muscle actin (alphaSM actin) and MT1-MMP in myofibroblasts. MT1-MMP expression is confined to myofibroblasts in close contact with tumor cells. In sharp contrast, the expression of MMP-2 was more widely distributed in both alphaSM actin positive and negative cells close to and at distance from cancer cell clusters. Our in vitro observations are consistent with the higher level of MT1-MMP expression and of MMP-2 activation observed in alphaSM actin positive fibroblasts derived from breast tumors, as compared to normal breast fibroblasts. Collectively, these results implicate myofibroblasts as major producer of MT1-MMP in breast cancer and emphasize the importance of stromal-epithelial cell interactions in their progression.
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PMID:Restricted expression of membrane type 1-matrix metalloproteinase by myofibroblasts adjacent to human breast cancer cells. 1267 23

A synthetic triterpenoid, 2-cyano-3,12-dioxoolean-1,9-dien-28-oic acid (CDDO), has been reported to have anti-inflammatory properties and to decrease the interleukin-1 (IL-1)-induced expression of matrix metalloproteinase-1 (MMP-1) and MMP-13. We have shown previously that IL-1 induces expression of the inhibitor of NF-kappaB (IkappaB) family member Bcl-3, and that this contributes to MMP-1 expression. To quantify the effects of CDDO on IL-1-induced MMP-1, MMP-13 and Bcl-3 expression, we stimulated the chondrosarcoma cell line SW-1353 and human primary chondrocytes with IL-1, in the presence or absence of CDDO. Harvested RNA was subjected to quantitative real-time reverse-transcriptase polymerase chain reaction. In SW-1353 cells, 300 nM CDDO significantly decreased the induction of MMP-1 and MMP-13 by IL-1. In human primary chondrocytes, 300 nM CDDO inhibited the induction of these genes by IL-1 to an even greater extent. In both cell types, inhibition of MMP-1 required 24 hours of pretreatment with CDDO, whereas MMP-13 could be inhibited when CDDO and IL-1 were added simultaneously to culture. In human primary chondrocytes, IL-1-induced Bcl-3 expression was inhibited when cells were pretreated with CDDO. To determine whether the inhibitory effect of CDDO on MMP worked through inhibition of Bcl-3 gene expression, SW-1353 cells stably transfected with a Bcl-3 expression plasmid were treated with IL-1 and/or CDDO, and MMP gene expression was assayed. Overexpression of Bcl-3 increased MMP-1, but not MMP-13, mRNA levels. Furthermore, overexpressed Bcl-3 could sustain the CDDO-dependent inhibition of IL-1-induced MMP-1 expression. Our data demonstrate that CDDO inhibits IL-1-induced MMP-1 and MMP-13 expression in human chondrocytes. CDDO also inhibits the expression of Bcl-3, an IL-1-responsive gene that preferentially contributes to MMP-1 gene expression.
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PMID:The triterpenoid CDDO inhibits expression of matrix metalloproteinase-1, matrix metalloproteinase-13 and Bcl-3 in primary human chondrocytes. 1293 92

The matrix metalloproteinases (MMPs) are a family of proteolytic enzymes, which are capable of degradation of the proteins composing the extracellular matrix and basement membrane. Their proteolytic activity depends on their binding to metal Zinc and is controlled by tissue inhibitors of MMP (TIMPs). Degradation of the extracellular matrix and basement membrane is an important component of the process of tumor invasiveness, progression, angiogenesis and metastatic spread. Since MMPs may serve as markers of tumor behavior and as predictors of survival and since synthetic inhibitors of MMP may have a place in the treatment of cancer, researching MMPs and their tissue inhibitors in malignant diseases has attracted growing attention. Studies on MMPs and their tissue inhibitors in malignancies of the female genital tract have shown the following: 1) In ovarian carcinoma and cervical carcinoma, over-expression of MMP-2 and MMP-9 is associated with invasiveness, metastatic spread and poor prognosis; 2) In endometrial carcinoma, MMP-7 (matrilysin) is the main MMP associated with invasiveness, metastatic spread and poor prognosis; 3) In cervical intra-epithelial neoplasia (CIN), measuring MMP-2 can assist in identifying high-risk for progression CIN I and CIN II; 4). In vulvar squamous cell carcinoma, over-expression of MMP-13 is associated with invasiveness, metastatic spread and poor prognosis. It is speculated that using synthetic drugs that inhibit MMPs in combination with conventional chemotherapy may contribute to the improvement of treatment results in cancer patients.
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PMID:[Matrix metalloproteinases and their tissue inhibitors in malignancies of the female genital tract]. 1463 13

VEGF (vascular endothelial growth factor) is not only one of the most important angiogenesis factors, but is involved also in inflammatory processes. Recent studies have shown that VEGF as well as its receptor VEGFR-2 are expressed on osteoarthritic chondrocytes, but not on normal adult chondrocytes. Since mechanical overload is one of the causative factors for osteoarthritis, we studied its effect on VEGF expression on bovine cartilage disks that were compressed once with a strain of 50% and a strain rate of 1/second. Under these conditions, control disks (without pressure) were completely negative for VEGF expression as evidenced by immunocytochemical stainings as well as by enzyme-linked immunosorbent assay (ELISA) measurements. In contrast, 4 days after mechanical overload, the cartilage disks were positive in both detection methods. In addition, after mechanical overload chondrocytes were strongly immunopositive for hypoxia-inducible factor-1alpha (HIF-1alpha), the limiting protein of the dimeric transcription factor HIF-1 that is known to induce VEGF expression. Furthermore, the matrix metalloproteases MMP-1, MMP-3, and MMP-13, could be easily detected in pressure-treated disks by immunohistochemistry whereas staining in controls was low or undetectable. The tissue inhibitors of metalloproteinases (TIMP-1 and -2) could be detected in controls but not in samples treated with mechanical overload. To prove that increased MMP or decreased TIMP expression could be a result of the autocrine action of VEGF on chondrocytes, we repeated the experiments in the presence of a specific inhibitor for the kinase activity of the VEGFR-2. This inhibitor was effective to reduce mechanically induced MMP-1, -3, and -13 immunostaining and to restore TIMP expression. Taking together, these findings indicate that VEGF is induced in chondrocytes by mechanical overload and mediates destructive processes in osteoarthritis as an autocrine factor.
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PMID:Mechanical overload induces VEGF in cartilage discs via hypoxia-inducible factor. 1469 32

Phosphinic peptides were previously reported to be potent inhibitors of several matrixins (MMPs). To identify more selective inhibitors of MMP-11, a matrixin overexpressed in breast cancer, a series of phosphinic pseudopeptides bearing a variety of P(1)'-side chains has been synthesized, by parallel diversification of a phosphinic template. The potencies of these compounds were evaluated against a set of seven MMPs (MMP-2, MMP-7, MMP-8, MMP-9, MMP-11, MMP-13, and MMP-14). The chemical strategy applied led to the identification of several phosphinic inhibitors displaying high selectivity toward MMP-11. One of the most selective inhibitors of MMP-11 in this series, compound 22, exhibits a K(i) value of 0.23 microM toward MMP-11, while its potency toward the other MMPs tested is 2 orders of magnitude lower. This remarkable selectivity may rely on interactions of the P(1)'-side chain atoms of these inhibitors with residues located at the entrance of the S(1)'-cavity of MMP-11. The design of inhibitors able to interact with residues located at the entrance of MMPs' S(1)'-cavity might represent an alternative strategy to identify selective inhibitors that will fully differentiate one MMP among the others.
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PMID:Evaluation of P1'-diversified phosphinic peptides leads to the development of highly selective inhibitors of MMP-11. 1471 5

MMPs, part of a family of enzymes with >35 known members, play an important role in tissue remodeling and repair, in the biology of neoplasia, and during development. Hydroxamic and carboxylic acid inhibitors of these proteases have long been available, but their specificities are poor and there still exists a desire to find novel chemical structures, which could be modified to optimize specificity and biocompatibility. Established methods for measuring MMP activity are based on the cleavage of MCA-PLGL-A2pr(DNP)-AR, which provides a prompt fluorescent signal when cleaved; however, its absorption/emission properties (325/400 nm) are not best suited for HTS assays. We describe an HTS-compatible method using the peptide substrate PLGLAARK, labeled at N- and C-termini with CyDye fluors Cy3 and Cy5Q, respectively, which is cleavable by MMP-1, -2, -3, -7, -9, and -13. HTS assays for MMP-13 and MMP-9 inhibitors were set up in approximately 20 microl in 384-well plates as a prompt fluorescence readout (excitation/emission = 540/570 nm) using the LEADseeker homogenous imaging system. These assays yielded IC(50) values comparable to standard methods, but with a faster, very sensitive, and normalized readout, thus conserving compound, enzyme (approximately 1.5 ng/well), and time (20 s read/plate). Data quality (Z' approximately 0.9) was such that hit-picking to -25% change in primary screening could be performed with confidence, and the subsequent rate of confirmation and validation in IC(50) determinations of the picked compounds was >60%. Parallel screening of related proteases also permitted immediate specificity comparisons, including evaluation of inactive or weakly active compounds.
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PMID:Development of an assay suitable for high-throughput screening to measure matrix metalloprotease activity. 1509 Jan 79

Matrix metalloproteinases (MMPs) and the related tumor necrosis factor converting enzyme (TACE) are involved in tissue remodeling, cell migration, and processing of signaling molecules, such as cytokines and adhesion molecules. Fluorescence-quenched peptide substrates have been widely used to quantitate the actual enzymatic activity of MMPs. However, the various MMPs have very different specific activities toward these substrates. This restricts their value for the determination of composite proteolytic activity of mixtures of metalloproteinases in biological fluids. The N-terminal elongation of the most widely used MMP substrate (FS-1) with a Lys to the sequence Mca-Lys-Pro-Leu-Gly-Leu-Dpa-Ala-Arg-NH(2) (FS-6) yields a fluorogenic peptide with improved substrate properties. As compared to FS-1, the specificity constant (kcat/Km) of FS-6 for collagenases (MMP-1, MMP-8, MMP-13) and MT1-MMP (MMP-14) is increased two- to ninefold and threefold, respectively, while those for gelatinases and matrilysin remain equally high. Using high-performance liquid chromatography-fluorescence detection, MMP activity can be quantitated in the picomolar range. FS-6 shows up to twofold higher specificity constants (kcat/Km of 0.8x10(6)M(-1)s(-1)) for TACE, as compared to standard substrates Mca-PLAQAV-Dpa-RSSSAR-NH(2) and Dabcyl-LAQAVRSSSAR-EDANS. FS-6 is fully water soluble and thus allows measurement of metalloproteinase activity in tissue culture conditions, e.g., on the surface of viable cells in situ.
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PMID:Characterization of Mca-Lys-Pro-Leu-Gly-Leu-Dpa-Ala-Arg-NH2, a fluorogenic substrate with increased specificity constants for collagenases and tumor necrosis factor converting enzyme. 1511 93


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