ORIGINAL PAPER E. Hrabec ® M. Strek ® D. Nowak ® J. Greger M. Suwalski ® Z. Hrabec Activity of type IV collagenases (MMP-2 and MMP-9) in primary pulmonary carcinomas: a quantitative analysis Received: 2 November 2001 / Accepted: 11 December 2001 / Published online: 22 January 2002 Ó Springer-Verlag 2002 Abstract Purpose: Matrix metalloproteinases MMP-2 and MMP-9 are implicated in invasion and metastasis of malignant tumors. We investigated the expression and activation of MMP-2 and MMP-9 in lung cancer com- pared with normal lung parenchyma, and looked for a potential marker of malignancy. Methods: Thirty-six pulmonary carcinomas and paired normal lung speci- mens were analyzed by gelatin zymography and com- puter-assisted image analysis for the expression of MMP-2 and MMP-9. Results: We showed that expres- sion of both type IV collagenases was remarkably higher in carcinoma samples than in lung parenchyma. The MMP-9 levels in lung cancer were over twofold higher than in normal lung tissues. The levels of latent and active forms of MMP-2 in lung cancer samples were, correspondingly, 3.8- and 17-fold higher than in lung parenchyma. The tumor/normal (T/N) ratios of MMP-2 were negatively correlated with the hemoglobin levels and erythrocytes number. Conclusions: A high level of the active form of MMP-2 in almost all of the carcino- mas and the near lack of its activation in normal lung parenchyma shows that MMP-2 activation is associated with the malignant phenotype and may serve as a good marker of malignancy. The correlation between low hemoglobin level and T/N ratio of MMP-2 may indicate significance of MMP-2 for angiogenesis. Keywords MMP-2 ® MMP-9 ® Lung cancer ® Gelatin zymography ® Type IV collagenases Introduction The extracellular matrix (ECM) is a network of proteins and proteoglycans determining the architecture of tissues and playing an essential role in cell adhesion, migration, proliferation, and differentiation (Judware and Culp 1997). In mature tissues the turnover of the ECM pro- ceeds relatively slowly but it accelerates during tissue remodeling that accompanies many pathological pro- cesses such as inflammation or tumor invasion (Noe¨ l et al. 1994; Stuve et al. 1997). Degradation of ECM requires the participation of different proteolytic enzymes in- cluding matrix metalloproteinases (MMPs), cysteine proteinases, and serine proteinases (Krepela et al. 1995; Noguchi-Takino et al. 1996; Go¨ hring et al. 1996). Tumor metastasis is a multistep process consisting of several sequential events including detachment of malignant cells from the primary tumor, invasion to surrounding tissue, intravasation into the circulatory system, adhesion to vascular endothelial cells at distant sites, and extravasation through endothelial basement membrane to colonize new tissues. Among these steps, degradation or remodeling of the basement membranes is conceived to be one of the most critical steps in tumor invasion (Matsui et al. 1995). Therefore, MMPs – en- zymes capable of degrading all constituents of the basement membrane – are a particularly interesting object of study (Noe¨l et al. 1994). MMPs comprise a family of over 20 structurally related, calcium-activated endopeptidases containing zinc at a highly conserved active site (Borkakoti 1998). These enzymes are regu- lated at various intra- and extracellular levels and the net enzymatic activity is the final result of events including the regulation of gene expression, activation of latent enzyme and inhibition of enzymatic activity by tissue inhibitors of matrix metalloproteinase (TIMPs) mole- cules (Crawford and Matrisian 1996; DeClerck and J Cancer Res Clin Oncol (2002) 128: 197–204 DOI 10.1007/s00432-001-0320-3 E. Hrabec (&) ® M. Strek ® J. Greger ® Z. Hrabec Department of Medical Biochemistry, Medical University of Lodz 90-131, Lodz Lindleya 6, Poland E-mail: ehrabec@go2.pl Fax: +48-42-6782465 D. Nowak Department of Experimental and Clinical Physiology, Medical University of Lodz, Mazowiecka 6/8, Poland M. Suwalski District Chest Hospital, Surgery Ward, Tuszynek, Poland