Front-cell-specific expression of membrane-type 1 matrix metalloproteinaseand gelatinase a during cohort migration of colon carcinoma cells induced by hepatocyte growth factor/scatter factor

Migration of tumor cells is usually assessed as single cell locomotion in v itro using Boyden chamber type assays. In vivo, however, carcinoma cells fr equently invade the surrounding tissue as coherent clusters or nests of cel ls, We have called this type of movement "cohort migration" and developed a two-dimensional in vitro cohort migration model, in which human rectal wel l-differentiated adenocarcinoma cells (L-IO) migrate from piled-up cell isl ands as coherent sheets of cells when stimulated with hepatocyte growth fac tor/scatter factor. In this study, we examined whether there is a cohort mi gration-specific way of expression of matrix metalloproteinases (MMP) and w hether degradation of extracellular matrix is necessary for this type of mi gration. Production of membrane-type 1-MMP (MT1-MMP) and gelatinase A (MMP- 2) by L-10 cells was demonstrated by gelatin zymography, immunoblotting, an d reverse transcription-PCR When cohort migration was induced with hepatocy te growth factor/scatter factor, MMT1-MMP and MMP-2 were immunolocalized pr edominantly in the leading edges of the front cells of migrating cell sheet s, with the following cells being negative. In addition, during the cohort migration on gelatin-coated substratum, the gelatin matrix was degraded by the cells, in a very organized manner, causing radially arrayed lysis of ge latin matrix at the sites of leading edges. BB94, a synthetic inhibitor spe cific to MMPs, tissue inhibitor of metalloproteinases-l and -2, and the COO H-terminal hemopexin-like domain of MMP-2 inhibited the migration on gelati n matrix. Thus, these data demonstrate that gelatin matrix is reorganized t o suit cell migration via leading-edge-of-front-cell-specific localization of MT1-MMP and MMP-2 during cohort migration and suggest that the reorganiz ation is essential for this type of migration.