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PubMed2000

Matrix Gla protein is differentially expressed during the deposition of a calcified matrix by vascular pericytes.

PCR-based subtractive hybridisation was used to identify genes up-regulated when pericytes undergo osteogenic differentiation and deposit a calcified matrix. cDNA pools were generated from confluent pericytes and from pericyte cultures containing calcified nodules. A pericyte cDNA library was screened with the product of the subtraction procedure (calcified minus confluent cDNA) and the majority of the positive clones were identified as matrix Gla protein (MGP). Northern analysis and immunohistochemistry demonstrated that MGP was only expressed by pericytes in calcified nodules. Antibodies to MGP inhibited the deposition of a calcified matrix by pericytes, suggesting that MGP regulates both cell differentiation and calcification.

Amino Acid Sequence↗

PubMed2002

Immunohistochemical study of membrane type-matrix metalloproteinases (MT-MMPs) and matrix metalloproteinase-2 (MMP-2) in dermatofibroma and malignant fibrous histiocytoma.

Matrix metalloproteinases (MMPs) play an important role in tumor invasion and metastasis. Enhanced expression of matrix metalloproteinase-2 (MMP-2) has been demonstrated in dermatofibroma (DF) and malignant fibrous histiocytoma (MFH). MMP-2 has been shown to be activated by membrane-type MMPs (MT-MMPs). To study the role of MT-MMP in the activation of MMP-2, skin specimens of DF (five cases) and MFH (three cases) were immunohistochemically studied using in situ zymography and the antibodies against matrix metalloproteinase-2 (MMP-2) and membrane type 1-3-MMPs (MT1-3-MMPs). Both MMP-2 activity and its expression were significantly activated in the tumor cells in DF and MFH. Anti-MT2-MMP strongly reacted with tumor cells of all cases of DF and MFH, whereas anti-MT1 or 3-MMP antibody showed a weak reaction in some cases of DF and MFH. Double immunofluorescence labeling demonstrated that the immunoreactive cells with anti-MMP-2 antibody in DF and MFH consistently reacted with anti-MT2-MMP antibody. The results suggest that the activation of MMP-2 in the benign and malignant fibrous tumors is related to the activation of MT-MMPs.

Adolescent↗

PubMed1997

Membrane type 1 matrix metalloproteinase digests interstitial collagens and other extracellular matrix macromolecules.

Membrane type 1 matrix metalloproteinase (MT1-MMP) is expressed on cancer cell membranes and activates the zymogen of MMP-2 (gelatinase A). We have recently isolated MT1-MMP complexed with tissue inhibitor of metalloproteinases 2 (TIMP-2) and demonstrated that MT1-MMP exhibits gelatinolytic activity by gelatin zymography (Imai, K., Ohuchi, E., Aoki, T., Nomura, H., Fujii, Y., Sato, H., Seiki, M., and Okada, Y. (1996) Cancer Res. 56, 2707-2710). In the present study, we have further purified to homogeneity a deletion mutant of MT1-MMP lacking the transmembrane domain (DeltaMT1) and native MT1-MMP secreted from a human breast carcinoma cell line (MDA-MB-231 cells) and examined their substrate specificities. Both proteinases are active, without any treatment for activation, and digest type I (guinea pig), II (bovine), and III (human) collagens into characteristic 3/4 and 1/4 fragments. The cleavage sites of type I collagen are the Gly775-Ile776 bond for alpha1(I) chains and the Gly775-Leu776 and Gly781-Ile782 bonds for alpha2(I) chains. DeltaMT1 hydrolyzes type I collagen 6.5- or 4-fold more preferentially than type II or III collagen, whereas MMP-1 (tissue collagenase) digests type III collagen more efficiently than the other two collagens. Quantitative analyses of the activity of DeltaMT1 and MMP-1 indicate that DeltaMT1 is 5-7.1-fold less efficient at cleaving type I collagen. On the other hand, gelatinolytic activity of DeltaMT1 is 8-fold higher than that of MMP-1. DeltaMT1 also digests cartilage proteoglycan, fibronectin, vitronectin and laminin-1 as well as alpha1-proteinase inhibitor and alpha2-macroglobulin. The activity of DeltaMT1 on type I collagen is synergistically increased with co-incubation with MMP-2. These results indicate that MT1-MMP is an extracellular matrix-degrading enzyme sharing the substrate specificity with interstitial collagenases, and suggest that MT1-MMP plays a dual role in pathophysiological digestion of extracellular matrix through direct cleavage of the substrates and activation of proMMP-2.

Collagen↗

PubMed1995

Dual role for the latent transforming growth factor-beta binding protein in storage of latent TGF-beta in the extracellular matrix and as a structural matrix protein.

The role of the latent TGF-beta binding protein (LTBP) is unclear. In cultures of fetal rat calvarial cells, which form mineralized bonelike nodules, both LTBP and the TGF-beta 1 precursor localized to large fibrillar structures in the extracellular matrix. The appearance of these fibrillar structures preceded the appearance of type I collagen fibers. Plasmin treatment abolished the fibrillar staining pattern for LTBP and released a complex containing both LTBP and TGF-beta. Antibodies and antisense oligonucleotides against LTBP inhibited the formation of mineralized bonelike nodules in long-term fetal rat calvarial cultures. Immunohistochemistry of fetal and adult rat bone confirmed a fibrillar staining pattern for LTBP in vivo. These findings, together with the known homology of LTBP to the fibrillin family of proteins, suggest a novel function for LTBP, in addition to its role in matrix storage of latent TGF-beta, as a structural matrix protein that may play a role in bone formation.

Animals↗

PubMed2005

Extracellular matrix remodelling in human aortic valve disease: the role of matrix metalloproteinases and their tissue inhibitors.

AIMS: Aortic valve diseases are characterized by pathological remodelling of valvular tissue but the cellular and molecular effectors involved in these processes are not well known. The role of matrix metalloproteinase (MMP)-2, MMP-9, MMP-3, MMP-7, and tissue inhibitor of matrix metalloproteinase (TIMP)-1 and TIMP-2 are investigated here. METHODS AND RESULTS: Histological analysis of pathological valves [aortic stenosis (AS) (n=49), aortic regurgitation (AR) (n=23)] and control valves (n=8) was performed. The main tissue abnormalities (calcification, inflammatory cells, and capillaries) observed in AS were less severe or absent in AR. However, both groups of pathological valves displayed similar histological signs of extracellular matrix (ECM) remodelling. Biochemical analysis of MMPs and TIMPs (gelatin and casein zymography and ELISA) was performed on valve extracts. MMP-2 activity was not significantly different in control and pathological valves. Increases in MMP-9 and MMP-3 in AS demonstrated an inflammatory state. Finally, there was a four- to seven-fold increase of TIMP-1 in pathological valves. TIMP-1, TIMP-2, and MMP-2 were synthesized by the valvular interstitial cells in primary culture. CONCLUSION: This study demonstrates the involvement of the MMP/TIMP system in ECM remodelling of both AS and AR. These findings provide evidence of inflammatory injury more severe in AS than in AR and involvement of mesenchymal cell response.

Adult↗

PubMed2001

Matrix metalloproteinase-2 in dentin matrix mineralization.

In the serum-free culture medium of bovine odontoblasts we detected active gelatinolytic metalloproteinases, matrix metalloproteinase (MMP)-2 and MMP-9 (gelatinases A and B). The activity of MMP-2, in particular, appeared suddenly around day 21 in the culture, coinciding with the development of odontoblastic cell processes and the loss of alkaline phosphatase. Reverse transcriptase-polymerase chain reaction analysis of these odontoblasts demonstrated that messages of MMP-2 but not MMP-9 increased significantly between day 15 and day 21. The in vitro observation indicates that medium conditioned by these odontoblasts and containing significant amounts of MMP-2 degrades not only the collagenous substrates but also purified dentin phosphophoryn as well. We have also observed that dephosphorylated dentin phosphoprotein becomes a better substrate for casein kinase II after limited proteolysis with MMP-2. These results support our working hypothesis that MMP-2-mediated proteolytic processing is an important step in accelerating the process of dentin matrix maturation, which includes phosphorylation and subsequent mineralization. As has been suggested previously, extracellular phosphorylation of matrix proteins is an important step in biomineralization both in bone and in dentin (Mikuni-Takagaki et al., J Bone Miner Res 1995;10:231-42; Zhu et al., Biochem J 1997; 323:637-43). Our present histochemical analysis in MMP-2 knockout mice confirms the concept with the delayed formation of mineralized tissues, dentin, and bone.

Alkaline Phosphatase↗

PubMed2002

Gelatin zymography and substrate cleavage assays of matrix metalloproteinase-2 in breast carcinoma cells overexpressing membrane type-1 matrix metalloproteinase.

Gelatin zymography is the common method for examining matrix metalloproteinase-2 (MMP-2) in cells and media samples. Activation of the latent MMP-2 zymogen involves its binding to the cell surface MT1-MMP*TIMP-2 (membrane type-1 matrix metalloproteinase/tissue inhibitor of matrix metalloproteinase-2) complex with subsequent cleavage of proMMP-2 by TIMP-2-free adjacent MT1-MMP. This is followed by autolytic maturation of the activation intermediate and the release of the mature MMP-2 species from cell surfaces into the extracellular milieu. To observe the MMP-2 activation pathway in more detail, proMMP-2-deficient MCF7 breast carcinoma cells expressing MT1-MMP were incubated with excess proMMP-2 to saturate the available MT1-MMP*TIMP-2 surface receptors. After removal of the unbound material, the kinetics of proMMP-2 activation and MMP-2 release from cells into media was monitored by gelatin zymography and substrate cleavage. Our observations demonstrate that gelatin zymography is insufficient for providing meaningful information about the status of MMP-2. The proteolytically competent mature MMP-2 moiety alone, but not in its complex with TIMP-2, was released from the cells. In tissue culture conditions, the enzyme's proteolytic activity was suppressed in the next 30 to 60 minutes by tissue inhibitors of MMPs, especially by TIMP-1. The picture emerges that there is a likely temporal regulation of MMP-2 activity by TIMPs in tumor cells. These relatively rapid changes of the MMP-2 status cannot be detected by gelatin zymography. Additional studies are needed to examine the significance of this phenomenon in vivo.

Breast Neoplasms↗

PubMed2003

Collagen of chronically inflamed skin is over-modified and upregulates secretion of matrix metalloproteinase 2 and matrix-degrading enzymes by endothelial cells and fibroblasts.

In order to investigate the properties of collagen in chronically inflamed tissue, we isolated collagen from the ear skin of mice with chronic contact dermatitis and examined its biochemical characteristics and the functions that regulate the secretion of matrix metalloproteinase 2 and collagen-degrading enzymes from endothelial cells and fibroblasts. Collagen in skin with chronic contact dermatitis comprised 60% type I collagen and 40% type III collagen, which latter is higher than the content of type III collagen in control skin (35%). The denaturation temperature was higher (42 degrees C) than that of control skin (39 degrees C). The alpha2 chain of type I collagen was over-hydroxylated at both proline and lysine residues. Segment-long-spacing crystallites of type I collagen were unusually connected in tandem. Collagen of chronically inflamed skin was less susceptible to matrix metalloproteinase 2 after heat denaturation. Endothelial cells and fibroblasts secreted an increased amount of matrix metalloproteinase 2 when cultured on a gel formed from the collagen of chronically inflamed skin. Collagen-degrading activity secreted from fibroblasts was also upregulated when cells were in contact with collagen of chronically inflamed skin. These results suggest that the collagen in chronically inflamed tissue has altered biochemical characteristics and functions, which may affect the pathogenesis of the chronic skin disease.

Animals↗

PubMed2001

Matrix-dependent mechanism of neutrophil-mediated release and activation of matrix metalloproteinase 9 in myocardial ischemia/reperfusion.

BACKGROUND: A key component of reperfusion of myocardial infarction is an immediate inflammatory response, which enhances tissue repair. Matrix turnover is crucial to tissue repair, and matrix metalloproteinases (MMPs) are key enzymes involved in matrix degradation. The hypothesis tested is that one inflammation-based effector of tissue repair is the secretion and activation of MMP-9 by infiltrating neutrophils. METHODS AND RESULTS: Cardiac lymph and tissue were assayed for atent and active MMP-2 and MMP-9 by zymography and immunochemistry. Dual-labeling immunofluorescence determined the cellular source of MMP-9 protein. Isolated canine neutrophils were incubated with preischemic and postischemic cardiac lymph in the presence and absence of collagen-fibronectin pads, and the supernatants were assayed for latent and active MMP-9. MMP-9 increased during the first hours of reperfusion in both lymph supernatants and myocardial extracts, and this increase was of neutrophil origin. MMP-9 in the cardiac lymph remained latent but was activatable. In contrast, MMP-9 in the myocardium was in both latent and active forms. In situ zymography demonstrated that activated MMP-9 surrounded the infiltrated neutrophils. When postischemic cardiac lymph was incubated with neutrophils in vitro, MMP-9 secretion and activation occurred only in the presence of a collagen-fibronectin substrate; preischemic cardiac lymph did not induce significant secretion or activation. CONCLUSIONS: Infiltrating neutrophils are an early source of MMP-9 after reperfusion, and a portion of MMP-9 in the myocardium is active. Infiltrating neutrophils may localize MMP-9 activation by secreting MMP-9 and as a source of activating proteases.

Animals↗

PubMed2003

Matrix metalloproteinase inhibition modulates fibroblast-mediated matrix contraction and collagen production in vitro.

PURPOSE: To investigate the effect of matrix metalloproteinase (MMP) inhibition on fibroblast-mediated matrix contraction and production. METHODS: Free-floating fibroblast-populated type I collagen lattices were prepared with human Tenon's capsule fibroblasts. Lattice areas were photographed and digitally analyzed to indicate the degree of lattice contraction. Quantitative competitive reverse transcription-polymerase chain reaction (QCRT-PCR) and enzyme-linked immunosorbent assay (ELISA) were used to quantify mRNA and protein respectively for MMP-1, -2, and -3 by fibroblasts during lattice contraction. Gelatin zymography demonstrated activity of MMPs released into the conditioned medium of contracting lattices. Concentrations of the broad-spectrum MMP inhibitors ilomastat, CellTech (Slough, UK), and BB-94 were added to the contracting fibroblast-populated collagen lattices. Secreted C-terminal propeptide of type I collagen was measured in conditioned medium of contracting lattices by ELISA. Fibroblast proliferation in the presence of concentrations of ilomastat was measured by using the reagent water-soluble tetrazolium-1 (WST-1). RESULTS: During contraction of type I collagen lattices, Tenon's capsule fibroblasts expressed MMP-1, -2, and -3 mRNA and protein. Zymography demonstrated the release of four gelatinolytic species into the conditioned medium of contracting lattices (57, 72, 91, and 100 kDa). Inclusion of MMP inhibitors in the zymogram-developing buffer reduced the proteolytic activity of the detected bands. MMP inhibition (1-100 microM) significantly reduced fibroblast-mediated collagen lattice contraction (P < 0.05), and this effect was found to be reversible. Ilomastat also significantly inhibited production of collagen in a dose-dependent manner (P < 0.05). No effect on fibroblast proliferation was found in the presence of ilomastat. CONCLUSIONS: MMPs are produced during Tenon's capsule fibroblast-mediated collagen lattice contraction. Broad-spectrum MMP inhibition significantly reduced matrix contraction and production without cell toxicity. Future clinical use of MMP inhibitors may be possible, because MMP inhibition significantly reduces fibroblast functions associated with contractile scarring.

Cell Division↗

PubMed2001

Extracellular matrix molecules improve periodontal ligament cell adhesion to anorganic bone matrix.

Bone replacement graft (BRG) materials are used in periodontal therapy to encourage new bone formation. Extracellular matrix proteins may improve periodontal ligament fibroblast (PDLF) attachment to these materials. We demonstrate that PDLFs adhere well to the extracellular matrix (ECM) proteins fibronectin, vitronectin, laminin, and collagen types I and IV. PDLFs express numerous ECM-receptor integrin subunit transcripts (alpha1, alpha2, alpha3, alpha4, alpha5, alpha11, beta1, beta5, and beta8) at high levels, while others (alpha6, alpha9, alphaV, beta3, beta6, and beta7) are expressed at reduced levels. Despite the fact that PDLFs adhere well to fibronectin and collagen type IV bound to plastic, and express integrins that recognize these ECM proteins, they do not attach well to anorganic bovine bone matrix (ABM) coated with these same proteins. However, the addition of vitronectin, laminin, or collagen type I to these same ABMs substantially increased PDL cell attachment. Thus, selective use of ECM proteins may be clinically useful in promoting cell attachment to ABM and bone regrowth.

Adsorption↗

PubMed2000

A novel hydra matrix metalloproteinase (HMMP) functions in extracellular matrix degradation, morphogenesis and the maintenance of differentiated cells in the foot process.

As a member of Cnidaria, the body wall of hydra is structurally reduced to an epithelial bilayer with an intervening extracellular matrix (ECM). Biochemical and cloning studies have shown that the molecular composition of hydra ECM is similar to that seen in vertebrates and functional studies have demonstrated that cell-ECM interactions are important to developmental processes in hydra. Because vertebrate matrix metalloproteinases (MMPs) have been shown to have an important role in cell-ECM interactions, the current study was designed to determine whether hydra has homologues of these proteinases and, if so, what function these enzymes have in morphogenesis and cell differentiation in this simple metazoan. Utilizing a PCR approach, a single hydra matrix metalloproteinase, named HMMP was identified and cloned. The structure of HMMP was similar to that of vertebrate MMPs with an overall identity of about 35%. Detailed structural analysis indicated some unique features in (1) the cysteine-switch region of the prodomain, (2) the hinge region preceding the hemopexin domain, and (3) the hemopexin domain. Using a bacterial system, HMMP protein was expressed and folded to obtain an active enzyme. Substrate analysis studies indicated that recombinant HMMP could digest a number of hydra ECM components such as hydra laminin. Using a fluorogenic MMP substrate assay, it was determined that HMMP was inhibited by peptidyl hydroxamate MMP inhibitors, GM6001 and matlistatin, and by human recombinant TIMP-1. Whole-mount in situ studies indicated that HMMP mRNA was expressed in the endoderm along the entire longitudinal axis of hydra, but at relatively high levels at regions where cell-transdifferentiation occurred (apical and basal poles). Functional studies using GM6001 and TIMP-1 indicated that these MMP inhibitors could reversibly block foot regeneration. Blockage of foot regeneration was also observed using antisense thio-oligo nucleotides to HMMP introduced into the endoderm of the basal pole using a localized electroporation technique. Studies with adult intact hydra found that GM6001 could also cause the reversible de-differentiation or inhibition of transdifferentiation of basal disk cells of the foot process. Basal disk cells are adjacent to those endoderm cells of the foot process that express high levels of HMMP mRNA. In summary, these studies indicate that hydra has at least one MMP that is functionally tied to morphogenesis and cell transdifferentiation in this simple metazoan.

Amino Acid Sequence↗

PubMed1993

Production of matrix metalloproteinase 1 (interstitial collagenase) and matrix metalloproteinase 2 (gelatinase A: 72 kDa gelatinase) by ovine endometrial cells in vitro: different regulation and preferential expression by stromal fibroblasts.

Ovine endometrial cells (epithelial plus stromal), prepared from ovariectomized ewes treated with oestrogen and progesterone to mimic the luteal phase of the oestrous cycle were maintained in serum-free medium for 48 h in the presence or absence of phorbol myristate acetate (PMA, 100 nmol l-1), a known stimulus for production of matrix metalloproteinases (MMP) in other cells. Matrix metalloproteinase-1 (MMP-1, interstitial collagenase) and matrix metalloproteinase-2 (MMP-2, gelatinase A) activities were expressed by the cells in the absence of PMA; most were in the latent form and required activation by (4-aminophenyl) mercuric acetate (APMA). Exposure to PMA over 48 h resulted in a significant increase in MMP-1 activity but only a modest and nonsignificant increase in MMP-2 activity. Gelatin zymography demonstrated that proMMP-2 (72 kDa) was produced by both PMA-treated and untreated cells and an active form of 67 kDa was also present. Immunolocalization of MMP-1 and MMP-2 was seen within the cells following treatment with monensin. Highly purified epithelial and stromal cells were similarly cultured and analysis of the conditioned medium showed that MMP-1 and MMP-2 were produced predominantly by stromal rather than epithelial cells. Thus, both MMP-1, which degrades interstitial collagens, and MMP-2, an important enzyme for degradation of type IV and V collagens, are synthesized and released by ovine endometrial stromal cells in culture, but MMP-1 is produced primarily upon stimulation, whereas MMP-2 production is constitutive.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1999

Correlation between expression of matrix metalloproteinase-2 (MMP-2), and matrix metalloproteinase-9 (MMP-9) and angiogenesis in colorectal adenocarcinoma.

Matrix metalloproteinases-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9), which degrade extracellular matrix, are believed to play a crucial role in tumor invasion and metastasis. Angiogenesis is also perceived as an important step in tumor growth and metastasis. To investigate the expression of MMPs and the correlation between the expression of MMPs and angiogenesis in colorectal adenocarcinoma, we studied 72 cases of colorectal adenocarcinoma in Inha University Hospital from 1996 to 1997. We evaluated the expression of MMPs by immunohistochemistry and angiogenesis by counting the microvessels. The expression of MMP-2 was increased according to the Astler-Coller stage (p< 0.05). Angiogenesis in the metastatic group was higher than that of the localized one (p<0.05). The expression of MMP-2 positively correlated with angiogenesis (p<0.05), and marked expression of MMP-9 positively correlated with angiogenesis (p<0.05). The present results suggest that the expression of MMP-2 provides clues for tumor progression and angiogenesis provides significant information to predict whether metastasis is present in colorectal adenocarcinoma.

Adenocarcinoma↗

PubMed2002

The role of matrix metalloproteinase-2 and matrix metalloproteinase-9 in antibody-induced arthritis.

Matrix metalloproteinases (MMPs) are a large group of enzymes responsible for matrix degradation. Among them, the family of gelatinases (MMP-2/gelatinase A and MMP-9/gelatinase B) is overproduced in the joints of patients with rheumatoid arthritis. Because of their degradative effects on the extracellular matrix, gelatinases have been believed to play an important role in progression and cartilage degradation in this disease, although their precise roles are yet to be defined. To clarify these roles, we investigated the development of Ab-induced arthritis, one of the murine models of rheumatoid arthritis, in MMP-2 or MMP-9 knockout (KO) mice. Surprisingly, the MMP-2 KO mice exhibited severe clinical and histologic arthritis than wild-type mice. The MMP-9 KO mice displayed milder arthritis. Recovery from exacerbated arthritis in the MMP-2 KO mice was possible by injection of wild-type fibroblasts. These results indicated a suppressive role of MMP-2 and a pivotal role of MMP-9 in the development of inflammatory joint disease.

Animals↗

PubMed2000

[Effects of heparin on the growth, extracellular matrix and matrix metalloproteinase gene expression in rat hepatic stellate cells].

OBJECTIVE: To study the effects of heparin on the growth, extracellular matrix and matrix metalloproteinase (MMP) gene expression in rat hepatic stellate cells (HSC). METHODS: Activated HSC was treated by heparin or fetal calf serum without heparin. The cell growth was evaluated by actual cell count and BrdU-labelled immunocytochemical stain. The gene expressions of type I and IV procollagen, fibronectin, MMP-2 and membrane type matrix metalloproteinase (MT-MMP) were investigated by immunocytochemical stain and digoxigenin-labeled in situ hybridization technique, respectively. In addition, the gelatinase activity of MMP-2 was examined by zymography. RESULTS: Heparin could obviously reduce HSC growth, inhibit the synthesis of type I procollagen and fibronectin protein, and the gene expressions of type I procollagen, fibronectin and MT-MMP. The expressions of type IV procollagen, MMP-2 and MMP-2 activity were not affected by heparin. CONCLUSION: The results demonstrate that heparin can inhibit HSC proliferation, down-regulate interstitial collagen synthesis and inhibit MT-MMP gene expression.

Animals↗

PubMed1992

Matrix metalloproteinase 3 (stromelysin) activates the precursor for the human matrix metalloproteinase 9.

Matrix metalloproteinase 9 (MMP-9), also known as 92-kDa gelatinase/type IV collagenase, is secreted from neutrophils, macrophages, and a number of transformed cells in zymogen form. Here we report that matrix metalloproteinase 3 (MMP-3/stromelysin) is an activator of the precursor of matrix metalloproteinase 9 (proMMP-9). MMP-3 initially cleaves proMMP-9 at the Glu40-Met41 bond located in the middle of the propeptide to generate an 86-kDa intermediate. Cleavage of this bond triggers a change in proMMP-9 that renders the Arg87-Phe88 bond susceptible to the second cleavage by MMP-3, resulting in conversion to an 82-kDa form. alpha 2-Macroglobulin binding studies of partially activated MMP-9 demonstrate that the 82-kDa species is proteolytically active, but not the initial intermediate of 86 kDa. This stepwise activation mechanism of proMMP-9 is analogous to those of other members of the MMP family, but the action of MMP-3 on proMMP-9 is the first example of zymogen activation that can be triggered by another member of the MMP family. The results imply that MMP-3 may be an effective activator of proMMP-9 in vivo.

Amino Acid Sequence↗

PubMedDate not supplied

Quantitative estimation of matrix metalloproteinases 2 and 7 (MMP-2, MMP-7) and tissue inhibitors of matrix metalloproteinases 1 and 2 (TIMP-1, TIMP-2) in colorectal carcinoma tissue samples.

BACKGROUND: An essential step in the process of tumor invasion and metastasis involves the degradation of tissue barriers in the extracellular matrix (ECM), particularly in the basal membrane (BM). Matrix metalloproteinases (MMPs) and tissue inhibitors of matrix metalloproteinases (TIMPs), in particular MMP-2, MMP-7, TIMP-1 and TIMP-2, play an important role in the process of ECM and BM degradation in connection with tumor invasion. The aim of our study was to assess the levels of MMP-2, MMP-7, TIMP-1 and TIMP-2 mRNA expression in colorectal carcinoma tissue samples and to correlate them with the stage of the disease. PATIENTS AND METHODS: The study included samples of tumor tissue of 38 patients with colorectal carcinoma and samples of tissue of 11 patients with benign disease. The expression levels of mRNA MMP-2, MMP-7, TIMP-1, TIMP-2 and glyceraldehyde-3-phosphate dehydrogenase (GAPDH), as housekeeping gene, were quantified in tissue samples using the method of reverse transcription real-time PCR. RESULTS: The levels of mRNA expression of MMP-2, MMP-7 and TIMP-1 were significantly higher in tumor tissue samples that in the control tissue (p<0.0005, p<0.0007 and p<0.0004). In addition the presence of mRNA MMP-2, MMP-7, TIMP-1 and TIMP-2 in tumor tissue samples in these parameters was significantly higher than in the control tissue (p<0.003, p<0.0001, p<0.0001 and p<0.05). CONCLUSION: This pilot study demonstrated that a significant difference in the level and in the presence of mRNA MMP-2, MMP-7 and TIMP-1 expressions between tumor colorectal and control colorectal tissues might be helpful for the prognosis of colorectal cancer.

Adult↗