Abstract
Unstimulated human fibrosarcoma cells (HT1080) constitutively secrete matrix metalloproteinase 2 (MMP 2) as a proenzyme requiring proteolytic cleavage by membrane type-1 MMP (MT1 MMP) for activation. Physiological and pharmacological stimuli induce clustering of MT1 MMP/tissue inhibitor of MMP 2 "receptors", promoting binding and activation of MMP 2. We now report that cholesterol depleted HT1080 cells accumulated MT1 MMP on the cell surface and activated MMP 2. A specific inhibitor of mitogen activated protein kinase kinase 1/2 inhibited both MMP 2 activation and extracellular signal-related kinase phosphorylation induced by cholesterol depletion. Our data indicate that the cholesterol content of unstimulated cells is critical for secretion of MMP 2 as an inactive zymogen and control of pericellular proteolysis.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Cell Line, Tumor
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Cell Membrane / enzymology
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Cholesterol / deficiency*
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Cholesterol / metabolism
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Cholesterol / pharmacology
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Cyclodextrins / antagonists & inhibitors
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Cyclodextrins / pharmacology
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Enzyme Activation / drug effects
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Fibrosarcoma / enzymology*
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Fibrosarcoma / metabolism
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Humans
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MAP Kinase Kinase 1
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MAP Kinase Signaling System
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Matrix Metalloproteinase 2 / metabolism*
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Matrix Metalloproteinase Inhibitors
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Matrix Metalloproteinases, Membrane-Associated
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Metalloendopeptidases / metabolism*
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Mitogen-Activated Protein Kinase Kinases / metabolism*
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Mitogen-Activated Protein Kinases / metabolism
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Phosphorylation
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Protease Inhibitors / pharmacology
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Tissue Inhibitor of Metalloproteinase-2 / pharmacology
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beta-Cyclodextrins*
Substances
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Cyclodextrins
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Matrix Metalloproteinase Inhibitors
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Protease Inhibitors
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beta-Cyclodextrins
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methyl-beta-cyclodextrin
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Tissue Inhibitor of Metalloproteinase-2
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Cholesterol
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Mitogen-Activated Protein Kinases
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MAP Kinase Kinase 1
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MAP2K1 protein, human
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Mitogen-Activated Protein Kinase Kinases
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Matrix Metalloproteinases, Membrane-Associated
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Metalloendopeptidases
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Matrix Metalloproteinase 2