MATRIX METALLOPROTEINASE-2 AND TISSUE INHIBITOR OF METALLOPROTEINASE-2 EXPRESSION AND SYNTHETIC MATRIX METALLOPROTEINASE-2 INHIBITOR BINDING IN OVARIAN CARCINOMAS AND TUMOR-CELL LINES

Enhanced matrix metalloproteinase-2 (MMP-2/72-kd type IV collagenase) action correlates with invasion in neoplasia. MMP-2 is inhibited in vi vo by tissue inhibitors of metalloproteinases (TIMPs)-TIMP-1 and, espe cially, TIMP-2. A synthetic, biotinylated inhibitor specific for activ ated MMP-2 in solution phase, and immunohistochemistry were used to de tect MMP-2 and TIMP-2 expression in cell lines and ovarian tumors and to analyze the surface-binding capacity of the inhibitors, which are p otential therapeutic agents. Characterization of novel monoclonal anti bodies to MMP-2 and TIMP-2 is described together with immunocytochemic al staining of 83 paraffin-embedded ovarian tumors (67 malignant, 7 bo rderline, 9 benign) and 9 cell lines. Synthetic MMP-2 inhibitor bindin g under controlled conditions was visualized by immunofluorescence and avidin-biotin complex immunoperoxidase methods in cell lines and cryo stat sections of ovarian tumors. MMP-2 and TIMP-2 showed heterogenous immunoreactivity, with enhanced staining on high-grade tumors, specifi cally at the invasive front and in vascular invasion. TIMP-2 immunorea ctivity was maximal in malignant cell cytoplasm and less intense in de smoplastic fibroblasts. One monoclonal antibody to MMP-2 showed membra ne immunoreactivity, apically polarized in benign and low-grade tumors but depolarized and strong in 37 of 44 cases of high-grade invasive t umors. Eleven of eighteen ovarian carcinomas and six of nine cell line s showed membrane localization of the synthetic inhibitor. Maximal bin ding occurred in the ovarian cell line OVCA 432 and the breast cell li nes MCF 7 and MDA MB 435, all of which were immunoreactive for MMP-2. Cell lines propagated on type I collagen showed no enhancement in inhi bitor binding. This study demonstrates cell surface binding of a synth etic MMP-2 inhibitor and provides new evidence of MMP-2 and TIMP-2 imm unoreactivity in ovarian carcinomas and cell lines.