Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.24.35 (matrix metalloproteinase 9)
 2,207 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Matrix metalloproteinases (MMP) are a family of zinc-dependent enzymes which degrade various components of the extracellular matrix (ECM) and play an important role in facilitating neoplastic cell invasion and metastasis. Structural changes in the extracellular matrix are necessary for cell migration during tissue remodeling and tumor invasion. Expression of MMP-2, -3, -9, -10, and -13 was investigated in both spontaneous and xenografted (cells derived from an established cell-line [DAOY#3]) childhood medulloblastomas (MEDs)/primitive neuroectodermal tumors (PNETs) employing an indirect alkaline phosphatase conjugated immunocytochemical technique. Evaluation of the results was based on (a) the percent of neoplastically transformed tissue that reacted positively and (b) a measure of staining intensity [graded from A (highest) to D]. The two forms of stromelysin (SL), types 1 (MMP-3) and 2 (MMP-10), share 82% sequence homology, but exhibit differences in cellular synthesis and inducibility by cytokines and growth factors in vitro. Strong overall expression of MMP-3 and -10 was found only in the spontaneous MEDs/PNETs, especially in the ECM adjacent to blood vessels. Positive immunoreactivity could be seen for these two MMPs in the ECM surrounding over 90% of the neoplastically transformed cells in the spontaneous cases, and the staining intensity was also the strongest possible (A,B). Focal (surrounding less than 10% of the neoplastically transformed cells) but strong (A,B) immunoreactivity for collagenase-3 (MMP-13) was also only detected in spontaneous MEDs/PNETs, an endopeptidase characterized by a potent degrading activity against a wide spectrum of substrates. Weak (surrounding anywhere between 10% and 90% of the neoplastically transformed cells, and of B and B,C intensity) expression of MMP-2 (gelatinase A) and MMP-9 (gelatinase B), two cytokine-induced MMPs, was also observed in the spontaneous cases. Staining for MMP-2 was negative in the xenografted MEDs/PNETs. The only positive immunoreactivity in the xenografted MEDs/PNETs was observed in the case of MMP-9, with expression of strong intensity in the ECM surrounding over 90% of the neoplastically transformed xenografted MED/PNET cells (++++; A,B). It is clear that the activation of MMPs and their inhibitors occurs in a very well orchestrated manner. The data presented here suggest that there are significant differences in the pathophysiology of spontaneous and xenografted human neoplasms, which further establishes the already detected limitations of such models in preclinical cancer research.
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PMID:Significant differences in the matrix metalloproteinase expression profiles of spontaneous medulloblastomas/primitive neuroectodermal tumors as compared with their xenografted, established tumor cell line derived counterparts. 1121 45

Matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) have been implicated in the immense invasive potential and neovascularization of primary brain tumors. We investigated the gene expression profiles of MMPs 1, 2, 3, 7, 9, 12, 13, 14, 16 and of TIMPs 1, 2, 3, and 4 in various primary brain tumors (astrocytoma WHO grade I-III, glioblastoma, PNET, ependymoma III and oligoastrocytoma II) using novel RNase protection assay probe sets. In addition, we determined the level and cellular source of gelatinolytic activity and localized gelatinase B and TIMP-1 RNA. Distinct expression patterns of the MMP and TIMP genes were found in the various brain tumors tested. While the WHO grade I and II tumors had MT1/MT3 ratios below 1, the malignant (grade III and IV) tumors had ratios above 1. Strong expression of TIMP-1 RNA was observed in all malignant tumors and in grade I pilocytic astrocytomas and localized to the walls of neovessels. Quantitative analysis of enzymatic activity in the soluble fraction of protein extracts revealed that in most tumors gelatinases remained in the inactive pro-form. In situ zymography revealed net gelatinolytic activity in neurons of normal brain and in tumor cells and vessel walls of all tumors tested. Immunohistochemistry demonstrated that gelatinase B was localized to vessel walls, to neutrophils in areas of hemorrhage, and in glioblastomas to macrophages. Together these data demonstrate that the different primary brain tumors show distinct regulation of MMP and TIMP genes. The localization of the soluble gelatinase B indicates an association with neovascularization, whereas membrane-bound MMPs may account for the invasive potential of the glial tumor cells.
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PMID:Distinct expression patterns and levels of enzymatic activity of matrix metalloproteinases and their inhibitors in primary brain tumors. 1139 36