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)

The 33-kDa matrix protein BM-40 (SPARC, osteonectin) consists of an acidic N-terminal domain I, a central cysteine-rich follistatin-like module, and a C-terminal extracellular calcium-binding (EC) module. Previous studies attributed collagen IV and high affinity calcium binding of BM-40 to its EC module, which was shown by x-ray crystallography to consist of an EF-hand pair surrounded by several alpha-helical and loop segments. This module was now shown by surface plasmon resonance assay to bind with similar affinities to collagens I, III, and V. Cleavage of recombinant BM-40 and its EC module by collagenase-3, gelatinases A and B, matrilysin, and stromelysin-1 showed similar fragment patterns, whereas collagenase-1 was inactive. Some differences were, however, observed in cleavage rates and the preference of certain cleavage sites. Edman degradation of fragments demonstrated only three to four major cleavage sites in the central region of domain I and a single uniform cleavage in helix C of the EC module. Cleavage is accompanied by a 7-20-fold increase in binding activity for collagens I, IV, and V but revealed only small effects on calcium-dependent alpha-helical changes in the EC module. The data were interpreted to indicate that helix C cleavage is mainly responsible for enhancing collagen affinity by exposing the underlying helix A of the EC module. A similar activation may also occur in situ as indicated previously for tissue-derived BM-40.
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PMID:Limited cleavage of extracellular matrix protein BM-40 by matrix metalloproteinases increases its affinity for collagens. 908 57

Activation of the matrix metalloproteinase 2 (MMP-2) has been shown to play a major role in the proteolysis of extracellular matrix (ECM) associated with tumor invasion. Although the precise mechanism of this activation remains elusive, levels of the membrane type 1-MMP (MT1-MMP) at the cell surface and of the tissue inhibitor of MMP-2 (TIMP-2) appear to be two important determinants. Induction of MMP-2 activation in cells cultivated on collagen type I gels indicated that the ECM is important in the regulation of this process. In this study, we show that SPARC/osteonectin, a small ECM-associated matricellular glycoprotein, can induce MMP-2 activation in two invasive breast cancer cell lines (MDA-MB-231 and BT549) but not in a noninvasive counterpart (MCF-7), which lacks MT1-MMP. Using a set of peptides from different regions of SPARC, we found that peptide 1.1 (corresponding to the NH2-terminal region of the protein) contained the activity that induced MMP-2 activation. Despite the requirement for MT1-MMP, seen in MCF-7 cells transfected with MT1-MMP, the activation of MMP-2 by SPARC peptide 1.1 was not associated with increased steady-state levels of MT1-MMP mRNA or protein in either MT1-MMP-transfected MCF-7 cells or constitutively expressing MDA-MB-231 and BT549 cells. We did, however, detect decreased levels of TIMP-2 protein in the media of cells incubated with peptide 1.1 or recombinant SPARC; thus, the induction of MMP-2 activation by SPARC might be due in part to a diminution of TIMP-2 protein. We conclude that SPARC, and specifically its NH2-terminal domain, regulates the activation of MMP-2 at the cell surface and is therefore likely to contribute to the proteolytic pathways associated with tumor invasion.
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PMID:SPARC/osteonectin induces matrix metalloproteinase 2 activation in human breast cancer cell lines. 985 90

Proteolytic cleavage at single sites in the extracellular calcium-binding module of BM-40/SPARC/osteonectin either by an unknown endogenous protease (L197-L198) or several matrix metalloproteinases (E196-L197) was previously shown to enhance collagen binding activity 10-fold. Polyclonal rabbit antibodies were now obtained against synthetic peptide antigens containing either an N-terminal L197 or L198 and characterized by radioimmunoassay, ELISA, immunoblots and immunohistology. These neoepitope-specific antibodies reacted with proteolytically processed but not with uncleaved mouse and human BM-40. The cross-reaction between the two different neoepitopes was < 1%, indicating the immunodominant role of the N-terminal residues. Analysis of a basement membrane producing mouse tumor demonstrated extensive cleavage at the L198 site, which correlated with a calcium-dependent binding to the matrix. A variable degree of this cleavage was also detected in BM-40 obtained from adult mouse bone and several other tissues. Negligible or much lower levels of conversion were detected at the MMP-specific L197 site, however. Immunogold staining of mouse heart and a basement membrane-producing mouse tumor showed a distinct extracellular labeling for BM-40 and the L198 neoepitope but only a very weak reaction for the L197 neoepitope. This strongly indicates that these neoepitopes are generated in vivo and emphasizes a specific biological role for the proteolytic activation of BM-40.
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PMID:Immunochemical and tissue analysis of protease generated neoepitopes of BM-40 (osteonectin, SPARC) which are correlated to a higher affinity binding to collagens. 1060 37

The aim of this study was to characterize the cellular phenotypes of articular cartilage and meniscus in rabbits with experimentally induced osteoarthritis (OA), by histological and molecular biological techniques. OA was induced by severing the anterior cruciate ligament of the knee and rabbits were killed 2, 4 or 9 weeks following surgery. Our histological observations show a progressive destruction of extracellular matrix in both tissues. To determine whether these morphological changes could be related to alterations in the regulation of gene expression for a subset of relevant molecules, levels of mRNA for proteinases and one inhibitor (MMP-1, -3 and -13, aggrecanase-1 and -2 and TIMP-1), matrix molecules and one chaperone (type II and X collagens, aggrecan, osteonectin, betaig-h3 and BiP) were assessed by reverse transcription-polymerase chain reaction. Our results indicate that for most markers expression profiles were similar in both tissues. In particular, matrix protein gene expression remained stable or varied little during progression of OA, suggesting a poor repair capacity of the tissues. MMP gene expression increased rapidly whereas aggrecanase gene expression remained stable. These findings suggest that differential regulation of mRNA levels of MMP-1, -3 and -13 on the one hand and aggrecanase-1 and -2 on the other, occurs during OA.
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PMID:Matrix metalloproteinase-1, -3, -13 and aggrecanase-1 and -2 are differentially expressed in experimental osteoarthritis. 1132 36

Osteoarthritis (OA) is the most common of all joint diseases to affect mankind and is characterized by the degradation of articular cartilage. The low availability of normal and pathologic human cartilage and the inability to study the early stages of the disease in humans has led to the development of numerous animal models of OA. The aim of our study was to establish gene expression profiles during the progression of a rabbit model of OA induced by anterior cruciate ligament (ACL) section. Semiquantitative RT-PCR was used to follow expression of several relevant molecules (type II and X collagens, aggrecan, osteonectin, betaig-h3, BiP, TIMP-1, MMP-1, -3, -13, aggrecanase-1, -2) during development of OA in articular cartilage. In parallel, we monitored the activities of collagenase, caseinase, phospholipase A2 and glycosyltransferases (xylosyl-, galactosyl-, glucuronyl- and N-acetyl-galactosaminyl-transferase). Novel cDNA clones for rabbit type X collagen, aggrecanase-1 and -2, osteonectin and BiP were constructed to obtain species-specific primers. Ours result show that MMP-13 (collagenase-3) gene expression increased dramatically early after ACL surgery and remained high thereafter. An increase in MMP-1 (collagenase-1) and MMP-3 expression was also noted with an absence of variation for TIMP-1 expression. In addition, the global MMPs activities paralleled the MMP gene expression. These data together characterize at the molecular level the evolution of OA in this rabbit model. Furthermore, we have undertaken a search for identifying differentially expressed genes in normal and OA cartilage in this model, by differential display RT-PCR. We present here preliminary results with the determination of the best technical conditions to obtain reproducible electrophoresis patterns of differential display RT-PCR.
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PMID:Differential gene expression analysis in a rabbit model of osteoarthritis induced by anterior cruciate ligament (ACL) section. 1208 87

Secreted protein acidic and rich in cysteine (SPARC) is highly expressed in human gliomas and promotes glioma invasion. We have shown by cDNA array analysis that SPARC upregulates membrane type 1-matrix metalloproteinase (MT1-MMP) and matrix metalloproteinase-2 (MMP-2) transcripts. To confirm these findings at the protein level and determine whether SPARC expression correlates with increased MMP activity, we used Western blot to assess the levels of MT1-MMP, and gelatin zymography to assess MMP-2 levels and activity. We also examined the expression, secretion, and cleavage of galectin-3, a target of MT1-MMP and MMP-2. Our data confirm that SPARC upregulates MT1-MMP levels and MMP-2 activity. There was also an increase in secreted galectin-3, as well as an increase in the proteolytically processed form of galectin-3. Previous studies have demonstrated that MT1-MMP, MMP-2, and galectin-3 are increased in gliomas. Our results suggest that their upregulation and activation may be a consequence of increased SPARC expression. These data provide a provisional mechanism whereby SPARC contributes to brain tumor invasion.
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PMID:SPARC upregulates MT1-MMP expression, MMP-2 activation, and the secretion and cleavage of galectin-3 in U87MG glioma cells. 1749 Aug 12

Cerebral palsy (CP) is a nonprogressive central nervous system lesion clinically characterized by impairment of voluntary movement related to spasticity, time of activation, and strength of skeletal muscle. Altered muscular control may act on tendon structure and influence extracellular matrix homeostasis, in particular, collagen. The effect of spasticity on collagen turnover in CP patients' tendons has not been described previously. We studied collagen turnover related genes in the gracilis and semitendinosus tendons of diplegic (n = 6) and quadriplegic (n = 15) patients, compared to normal subjects (n = 7). In particular, using real time RT-PCR, we analyzed the mRNA levels of the major extracellular matrix (ECM) components collagen type I (COL-I, alpha 2 chain COL1A2), the matrix metalloproteinase-1 (MMP-1) and the tissue inhibitor of MMP (TIMP-1), the enzyme responsible for collagen maturation lysyl hydroxylase 2b (LH2b), of the matricellular protein involved ECM remodelling (secreted protein acidic and rich in cysteine, SPARC), and the transforming growth factor-beta1 (TGF-beta1), a multipotent cytokine involved in collagen turnover. Our results show that gene expression profiles are quite different in CP samples compared to normal ones. In fact, spasticity induces relevant modifications of tendons at the molecular level, which modify their phenotypes to respond to the higher mechanical loading and increased functional demands. Interestingly, hypertonic quadriplegic subjects displayed the highest mRNA levels of COL1A2, LH2b, TGF-beta1, and SPARC, suggesting that their tendons undergo higher mechanical loading stimulation.
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PMID:Expression profiling of genes involved in collagen turnover in tendons from cerebral palsy patients. 1944 61

Abnormal expression of SPARC (osteonectin), cwcv and kazal-like domains proteoglycan 2 (SPOCK2) plays a significant role in the development and progression of various human cancers, yet a relationship between SPOCK2 and endometrial cancer (EC) has not been reported. Here, we assessed the potential role and mechanism by which SPOCK2 acts in the pathogenesis and progression of EC. First, protein expression of SPOCK2 in EC tissue from patients was detected by immunohistochemistry and associated clinical data were analyzed. Then, HEC-1A and Ishikawa cells were transfected with an adenoviral vector containing an SPOCK2 recombinant fragment and the biological behavior of transfected cells was observed. Finally, the expression of membrane type 1 matrix metalloproteinase (MT1-MMP) and MMP2 in the transfected cells was detected by Western blot and zymography gel assay to analyze the effect of SPOCK2 on the regulation of the MT1-MMP/MMP2 pathway. We found that there was significantly less SPOCK2 protein expression in the EC tissue than in the normal endometrium tissue, and lack of SPOCK2 protein expression in EC tissue was associated with distant metastasis and myometrial invasion. Upregulation of SPOCK2 in HEC-1A and Ishikawa cells inhibited cell proliferation, invasion, adhesion, and apoptosis. Upregulation of SPOCK2 inhibited the expression of MT1-MMP and MMP2 and activation of MMP2 in HEC-1A and Ishikawa cells. Collectively, our data indicated that SPOCK2 contributed to the progression of EC by regulating the biological behavior of cancer cells, which is achieved partly through regulating protein expression of MT1-MMP and MMP2 and activation of MMP2.
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PMID:SPOCK2 Affects the Biological Behavior of Endometrial Cancer Cells by Regulation of MT1-MMP and MMP2. 3083 59

Abnormal expression of SPARC (osteonectin), cwcv and kazal-like domains proteoglycan 2 (SPOCK2) plays a significant role in the development and progression of various human cancers, yet a relationship between SPOCK2 and endometrial cancer (EC) has not been reported. Here, we assessed the potential role and mechanism by which SPOCK2 acts in the pathogenesis and progression of EC. First, protein expression of SPOCK2 in EC tissue from patients was detected by immunohistochemistry and associated clinical data were analyzed. Then, HEC-1A and Ishikawa cells were transfected with an adenoviral vector containing an SPOCK2 recombinant fragment and the biological behavior of transfected cells was observed. Finally, the expression of membrane type 1 matrix metalloproteinase (MT1-MMP) and MMP2 in the transfected cells was detected by Western blot and zymography gel assay to analyze the effect of SPOCK2 on the regulation of the MT1-MMP/MMP2 pathway. We found that there was significantly less SPOCK2 protein expression in the EC tissue than in the normal endometrium tissue, and lack of SPOCK2 protein expression in EC tissue was associated with distant metastasis and myometrial invasion. Upregulation of SPOCK2 in HEC-1A and Ishikawa cells inhibited cell proliferation, invasion, adhesion, and apoptosis. Upregulation of SPOCK2 inhibited the expression of MT1-MMP and MMP2 and activation of MMP2 in HEC-1A and Ishikawa cells. Collectively, our data indicated that SPOCK2 contributed to the progression of EC by regulating the biological behavior of cancer cells, which is achieved partly through regulating protein expression of MT1-MMP and MMP2 and activation of MMP2.
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PMID:SPOCK2 Affects the Biological Behavior of Endometrial Cancer Cells by Regulation of MT1-MMP and MMP2. 3243 Jul 15