MAB3319 Sigma-AldrichAnti-MMP-14 Antibody, catalytic domain, clone 114-6G6

Matrix metalloproteases (MMPs) are proteolytic enzymes contribute to tumor expansion by degrading components of the extracellular matrix. MPPs play a key role in tumor invasion and metastases of various cancers and head and neck carcinoma as well. The aim of this study was to investigate MT1-MMP expression in squamous cell carcinoma of the larynx to relate these levels of expression to clinicohistological features of the tumor and lymph nodes e.g. TNM, nodal micrometastases, tumor front grading and 3- and 5-year survival. MATERIAL AND METHODS: The study included 22 patients with laryngeal cancer surgical treated in ENT Department Medical University of Lódź between 1998 and 1999. The expression of MT1-MMP was evaluated immunohistochemically using monoclonal antibodies anti-MT1-MMP (Mouse Anti-Human MT1-MMP, MAB3319 Chemicon). The polyclonal antibodies anti-CK for developing nodal micrometastases was used as well. RESULTS: Positive MT1-MMP expression in 68.2% cases was observed. Immunoexpression of MT1-MMP in advanced laryngeal carcinoma as indicator for 3-year survival was noted. In addition, levels of staining correlated with number of mitoses in tumor front and plasmocytolymphatic infiltration in its environment. CONCLUSIONS: The expression of MT1-MMP in tumor front appears to play an important role in determining prognosis in patients with carcinoma of the larynx.

The process of cancer cell invasion involves degradation of the extracellular matrix (ECM) by proteases, integrin adhesion and cell motility. The role of ECM degrading proteases on the hypoxia-induced invasion of breast carcinoma cells was investigated. Hypoxia markedly increased the invasion capacity of MDA-MB-231 and MDA-MB-435 breast carcinoma cell lines. Matrix metalloproteinase (MMP) inhibitors blocked the hypoxia-induced invasion, whereas other protease inhibitors had no effect. Antibodies or siRNAs blocking either membrane type-1 MMP (MT1-MMP) or MMP-2 were effective in reducing the hypoxia-induced invasion. Serum-free reconstitution experiments confirmed the involvement of the MT1-MMP/MMP-2/tissue inhibitor of metalloproteinase-2 complex in this hypoxia-induced response. Overexpression of MT1-MMP in a poorly invasive breast cancer cell line, T47-D, promoted hypoxia-induced invasion and MMP-2 activation. Cell surface accumulation and activation of MT1-MMP without apparent regulation at the mRNA or protein levels indicated a post-translational adaptive response to hypoxia. Inhibition of the small GTPase RhoA eliminated the hypoxia-induced invasion and blocked the localization of MT1-MMP to the plasma membrane. Zymographic and molecular analysis of human breast tumors showed a strong correlation between hypoxic microenvironments and MMP-2 activation without changes in MT1-MMP expression. Our studies suggest that hypoxic tumor microenvironments promote breast cancer invasion through an MT1-MMP-dependent mechanism.

We have examined the implications of membrane-type matrix metalloproteinase (MT-MMP) for activation of the zymogen of MMP-2 (proMMP-2) in human gastric carcinoma. Northern blot analysis demonstrated exclusive expression of MT-MMP in the carcinoma tissues. Immunohistochemically, MT-MMP was colocalized in the carcinoma cells in almost all MMP-2-positive cases (13 of 14 cases). Gelatin zymography of the culture media showed a correlation of the proMMP-2 activation with MT-MMP expression in the carcinoma cells. A microdissection study indicated that proMMP-2 activation is caused only in the carcinoma cell nests that express MT-MMP but not in the normal gastric mucosa. These results are the first demonstration of the MT-MMP-assisted activation of proMMP-2 in the human gastric carcinoma.