Matrix metalloproteinases, their tissue inhibitors and colorectal cancer staging

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Abstract
Background: Matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) are important in tumour invasion and metastasis. The levels of MMPs, TIMPs and total MMP activity were compared in paired colorectal tumour (n = 50) and normal tissue (n = 49) samples and correlated with clinical and pathological staging. Methods: Gelatin zymography (MMP-2 and MMP-9), enzyme-linked immunosorbent assays (MMP-1, MMP-3, TIMP-1 and TIMP-2) and quenched fluorescent substrate hydrolysis (total MMP activity) were employed in resection specimens from 50 patients, four with adenomas and 46 with colorectal cancer. Results: The levels of active MMP-2 and MMP-9 and total MMP-1, MMP-3 and TIMP-1 were significantly greater in tumour tissue than in normal colon (e.g. TIMP-1 tumour median 72 (range 25–351) versus normal 26 (4–107) ng per mg total protein content; P < 0·05); however, TIMP-2 levels were significantly greater in normal tissue (P < 0·05). Total MMP activity was significantly greater in tumour than in normal tissue (15 025 (1750–174 400) versus 7250 (750–354 650) pmol l−1 min−1 mg protein−1; P < 0·05). Correlations were found between both MMP and TIMP levels and pathological tumour staging. MMP-1 appeared to be most important as its concentration correlated positively with Dukes staging, tumour differentiation and lymphatic invasion. Conclusion: The levels of the studied MMPs and total MMP activity were upregulated in colorectal tumours. MMP-1 is important in colorectal cancer progression.