title: MT1-MMP correlates with MMP-2 activation potential seen after epithelial to mesenchymal transition in human breast carcinoma cells.
abstract: We have previously reported that human breast carcinoma (HBC) cell lines expressing the mesenchymal intermediate filament protein vimentin (VIM+) are highly invasive in vitro, and highly metastatic in nude mice when compared to their VIM- counterparts. Since only VIM+ cell lines can be induced to activate matrix metalloproteinase-2 (MMP-2) upon stimulation with Concanavalin A (Con A), we have examined here membrane type 1 MMP (MT1-MMP), a cell surface activator of MMP-2. Northern analysis reveals baseline expression of MT1-MMP in five of the six VIM+ cell lines studied (MDA-MB-231, MDA-MB-435, BT-549, Hs578T, MCF-7(ADR)), each of which showed variable activation of exogenous MMP-2 after treatment with Con A. In contrast, the four VIM-, poorly invasive HBC cell lines studied (MCF-7, T47D, MDA-MB 468, ZR-75-1) lacked baseline MT1-MMP mRNA expression, and showed no induction of either MT1-MMP expression or MMP-2-activation with Con A. Such differential MT1-MMP expression was confirmed in vivo using in situ hybridization analysis of nude mouse tumor xenografts of representative cell lines. Western analysis of the MDA-MB-231 cells revealed baseline membrane expression of a 60 kDa species, which was strongly induced by Con A treatment along with a weaker band co-migrating with that from MT1-MMP-transfected COS-1 cells (63 kDa), presumably representing latent MT1-MMP. MT1-MMP immunofluorescence strongly decorated Con A-stimulated MDA-MB-231 cells in a manner consistent with membranous staining, but did not decorate the unstimulated MDA-MB-231 cells or MCF-7 cells under either condition. Collectively, the results suggest the constitutive production of active MT1-MMP which is unavailable for either MMP-2 activation or immuno-decoration until Con A treatment. Since VIM expression arises by virtue of the so-called epithelial to mesenchymal transition (EMT) in invasive embryonic epithelia, we propose that this represents a major metastasis mechanism in breast carcinomas. MT1-MMP on the surface of such 'fibroblastoid' carcinoma cells may mediate a paracrine loop for the utilization of stromally produced MMP-2, and contribute to the poorer survival associated with VIM+ breast carcinomas.
authors.affiliation: Lombardi Cancer Center, Georgetown University Medical Center, Washington, DC 20007, USA.
authors.forename: H
authors.initials: H
authors.lastname: Pulyaeva
authors.forename: J
authors.initials: J
authors.lastname: Bueno
authors.forename: M
authors.initials: M
authors.lastname: Polette
authors.forename: P
authors.initials: P
authors.lastname: Birembaut
authors.forename: H
authors.initials: H
authors.lastname: Sato
authors.forename: M
authors.initials: M
authors.lastname: Seiki
authors.forename: E W
authors.initials: EW
authors.lastname: Thompson
mesh_terms: D000818:Animals; D014408:Biomarkers, Tumor / Q000378:metabolism*; D015153:Blotting, Western; D001943:Breast Neoplasms / Q000201:enzymology / Q000378:metabolism* / Q000556:secondary*; D003208:Concanavalin A / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D018093:Gelatinases / Q000378:metabolism*; D006801:Humans; D017403:In Situ Hybridization; D053511:Matrix Metalloproteinase 14; D020778:Matrix Metalloproteinase 2; D053504:Matrix Metalloproteinases, Membrane-Associated; D008666:Metalloendopeptidases / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008819:Mice, Nude; D009361:Neoplasm Invasiveness; D012333:RNA, Messenger / Q000378:metabolism; D014183:Transplantation, Heterologous; D014407:Tumor Cells, Cultured; D014746:Vimentin / Q000378:metabolism*
chemical_list: D014408:Biomarkers, Tumor; C507096:Mmp14 protein, mouse; D012333:RNA, Messenger; D014746:Vimentin; D003208:Concanavalin A; D018093:Gelatinases; D053504:Matrix Metalloproteinases, Membrane-Associated; D008666:Metalloendopeptidases; D020778:Matrix Metalloproteinase 2; D053511:Matrix Metalloproteinase 14