Expression and role of matrix metalloproteinases MMP-2 and MMP-9 in human spinal column tumors

Matrix metalloproteinases (MMPs) have been implicated in the process of tum or invasion and metastasis formation, Thus, we determined the expression of MMPs in various primary and metastatic spinal tumors in order to assess th e role of these enzymes in spinal invasion, MMP expression was examined by immunohistochemical localization, and quantitative evaluation of MMP protei n content was determined by enzyme-linked immunosorbant assay (ELISA) and W estern blotting. MMP enzyme activity was determined by gelatin zymography. Lung carcinomas and melanomas metastatic to the spine were shown to have hi gher levels of MMP-9 activity than those of breast, thyroid, renal metastas es and primary spinal tumors. Immunohistochemical analysis revealed similar difference in expression of MMP-9 in tissue samples, When the tissue sampl es were subjected to gelatin zymography for examination of MMP-2 and MMP-9 activity and to ELISA and Western blotting for quantitative estimation of p rotein content, the most striking results were obtained for lung carcinomas and melanomas relative to the other tumors. Lung carcinomas and melanomas metastatic to the spine had considerably higher levels of MMP-9 activity th an those of primary spinal tumor or breast, thyroid, acid renal carcinoma m etastases, Within the metastatic tumor category, neoplasms that are known t o be associated with the shortest overall survival rates and most aggressiv e behavior, such as lung carcinomas and melanomas, had the highest levels o f MMP-2 and MMP-9 activity compared to those less aggressive metastatic tum ors such as breast, renal cell, and thyroid carcinomas, Our results suggest that MMPs may contribute to the metastases to the spinal column, and overe xpression of these enzymes may correlate with enhanced invasive properties of both primary and metastatic spinal tumors.