Abstract
Increased matrix metalloproteinase (MMP) activity has been implicated in the pathogenesis of lymphangioleiomyomatosis (LAM). The objective of this study was to investigate how tuberous sclerosis complex (TSC) 1 or TSC2 deficiency alters MMP expression and regulation. We studied immortalized cells that lack TSC2 derived from an angiomyolipoma of a patient with LAM, a TSC2 addback derivative, and murine embryonic fibroblast cells that lack Tsc1 or -2 and respective controls. Global gene expression analysis was performed in the angiomyolipoma and derivative cell lines. MMP levels in the conditioned media from these cells were analyzed by zymography and ELISA. We found increased MMP-2 expression in cells lacking TSC1/TSC2 compared with their respective controls by zymography. MMP-2 overproduction by these cells was not affected by rapamycin treatment. Gene expression analysis confirmed increased MMP-2 gene expression that was not affected by rapamycin. Furthermore, multiple other genes were found to be overexpressed in rapamycin-treated TSC2-deficient cells compared with TSC2(+) cells. We conclude that TSC1/TSC2 deficiency leads to MMP-2 overproduction that is rapamycin-insensitive, and that several genes exhibit similar patterns, suggesting that TSC1/TSC2-dependent, but mammalian target of rapamycin-independent, pathways may be involved in the pathogenesis of LAM.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Cell Line
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Cell Line, Tumor
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Gene Expression Profiling
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Humans
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Lung Neoplasms / etiology
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Lung Neoplasms / genetics*
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Lung Neoplasms / metabolism*
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Lymphangioleiomyomatosis / etiology
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Lymphangioleiomyomatosis / genetics*
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Lymphangioleiomyomatosis / metabolism*
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Matrix Metalloproteinase 2 / biosynthesis
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Matrix Metalloproteinase 2 / genetics*
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Mechanistic Target of Rapamycin Complex 1
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Mice
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Monomeric GTP-Binding Proteins / metabolism
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Multiprotein Complexes
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Neuropeptides / metabolism
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Protein Kinases / metabolism
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Proteins
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RNA, Messenger / genetics
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RNA, Messenger / metabolism
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RNA, Small Interfering / genetics
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Ras Homolog Enriched in Brain Protein
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Sirolimus / pharmacology
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TOR Serine-Threonine Kinases
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Tissue Inhibitor of Metalloproteinases / genetics
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Transcription Factors / metabolism
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Tuberous Sclerosis Complex 1 Protein
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Tuberous Sclerosis Complex 2 Protein
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Tumor Suppressor Proteins / deficiency*
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Tumor Suppressor Proteins / genetics
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Tumor Suppressor Proteins / metabolism
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Up-Regulation / drug effects
Substances
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Multiprotein Complexes
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Neuropeptides
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Proteins
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RHEB protein, human
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RNA, Messenger
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RNA, Small Interfering
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Ras Homolog Enriched in Brain Protein
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TSC1 protein, human
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TSC2 protein, human
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Tissue Inhibitor of Metalloproteinases
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Transcription Factors
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Tsc1 protein, mouse
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Tsc2 protein, mouse
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Tuberous Sclerosis Complex 1 Protein
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Tuberous Sclerosis Complex 2 Protein
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Tumor Suppressor Proteins
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Protein Kinases
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MTOR protein, human
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mTOR protein, mouse
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Mechanistic Target of Rapamycin Complex 1
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TOR Serine-Threonine Kinases
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MMP2 protein, human
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Matrix Metalloproteinase 2
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Monomeric GTP-Binding Proteins
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Sirolimus