Spontaneous capillary tube migration of metastatic rat mammary adenocarcinoma cells.

The spontaneous capillary tube migration of metastatic MAT 13762 rat mammary adenocarcinoma cells has been measured and compared with that of a non-metastatic variant, TGR. MAT 13762 cells migrated to a greater extent in the presence than in the absence of serum, and in both cases migration areas were considerably greater than for TGR cells. Different clones of hybrids, formed by fusing metastatic and non-metastatic variants, showed migration areas ranging from those of the metastatic to those of the non-metastatic parent cells. Despite their differing migrations, all of these clones were either non or only slightly metastatic. Treatment of TGR cells with trypsin enhanced their migration to that of MAT 13762 cells, whereas trypsin-treated MAT 13762 cells showed a slightly decreased migration. Although MAT 13762 cells, unlike TGR cells, produced large amounts of plasminogen activator (PA), no evidence was obtained for the direct involvement of PA in the high migration rate of MAT 13762 cells.