title: Regulation of membrane-type matrix metalloproteinase-1 expression by growth factors and phorbol 12-myristate 13-acetate.
abstract: Overexpression of membrane-type matrix metalloproteinase (MT-MMP-1) results in the activation of both endogenous and exogenous 72-kDa gelatinase. To understand the effects of MT-MMP-1 on 72-kDa gelatinase activation, we analyzed its expression in human fibroblasts and HT-1080 fibrosarcoma cells. Both cell types expressed the MT-MMP-1 mRNA constitutively at a considerable level and treatment of cells with PMA enhanced the expression about 2-3-fold. Concanavalin A treatment increased MT-MMP-1 mRNA levels in fibroblasts about 4-fold. Induction of MT-MMP-1 by phorbol 12-myristate 13-acetate (PMA) required protein synthesis as shown by cycloheximide inhibition. The induction was also inhibited by dexamethasone. Analysis of MT-MMP-1 mRNA stability using actinomycin D indicated that the half-life was rather long and not affected by PMA, suggesting transcriptional regulation. Only HT-1080 cells had significant 72-kDa gelatinase processing activity after treatment with PMA or concanavalin A, while fibroblasts were virtually negative. Immunoblotting analysis of fibroblast lysates indicated that MT-MMP-1 was present mainly in a 60-kDa form. PMA and concanavalin A caused 2-4-fold increases in its protein levels, while in HT-1080 cells PMA, concanavalin A, or overexpression of MT-MMP-1 did not significantly enhance the level of the 60-kDa protein. Instead, an immunoreactive, proteolytically processed 43-kDa form was observed, and its appearance correlated to 72-kDa gelatinase processing activity. Thus 72-kDa gelatinase activation, while enhanced by MT-MMP-1 expression, needs additional co-operating factors.
authors.affiliation: Department of Virology, University of Helsinki, Finland.
authors.forename: J
authors.initials: J
authors.lastname: Lohi
authors.forename: K
authors.initials: K
authors.lastname: Lehti
authors.forename: J
authors.initials: J
authors.lastname: Westermarck
authors.forename: V M
authors.initials: VM
authors.lastname: Kähäri
authors.forename: J
authors.initials: J
authors.lastname: Keski-Oja
mesh_terms: D001483:Base Sequence; D000001:Calcimycin / Q000494:pharmacology; D002460:Cell Line; D017364:Collagenases / Q000096:biosynthesis*; D003208:Concanavalin A / Q000494:pharmacology; D003513:Cycloheximide / Q000494:pharmacology; D016207:Cytokines / Q000494:pharmacology*; D017931:DNA Primers; D003907:Dexamethasone / Q000494:pharmacology; D004789:Enzyme Activation; D004815:Epidermal Growth Factor / Q000494:pharmacology; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology; D005347:Fibroblasts; D005354:Fibrosarcoma; D018093:Gelatinases / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects*; D006133:Growth Substances / Q000494:pharmacology*; D006801:Humans; D015151:Immunoblotting; D007375:Interleukin-1 / Q000494:pharmacology; D008168:Lung; D020781:Matrix Metalloproteinase 1; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000096:biosynthesis; D011994:Recombinant Proteins / Q000494:pharmacology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D014158:Transcription, Genetic / Q000187:drug effects*; D016212:Transforming Growth Factor beta / Q000494:pharmacology; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
chemical_list: D016207:Cytokines; D017931:DNA Primers; D006133:Growth Substances; D007375:Interleukin-1; D012333:RNA, Messenger; D011994:Recombinant Proteins; D016212:Transforming Growth Factor beta; D014409:Tumor Necrosis Factor-alpha; D016222:Fibroblast Growth Factor 2; D003208:Concanavalin A; D000001:Calcimycin; D004815:Epidermal Growth Factor; D003907:Dexamethasone; D003513:Cycloheximide; D017364:Collagenases; D018093:Gelatinases; D020781:Matrix Metalloproteinase 1; D013755:Tetradecanoylphorbol Acetate