Different metastatic aggressiveness by murine TS/A clones: ultrastructure, extracellular glycoproteins and type IV collagenolytic activity.

Cell ultrastructure, extracellular matrix glycoproteins, and type IV collagenolytic activity have been examined in four murine TS/A clones characterized by different metastatic aggressiveness. In vitro, highly metastatic clones (E) exhibited slightly less differentiated ultrastructure, and high type IV collagenolytic activity, while low metastatic clones (F) showed a more differentiated cytotype, with either high and low collagenolytic activity. Type IV collagen, laminin, and fibronectin were expressed without correlation with the metastatic efficiency; keratin was slightly more evident in E than in F cells. The morphological differences between E and F clones were less evident in the tumors produced by subcutaneous injection, and markedly reduced in the relative metastases composed only of the less differentiated cytotype; differences were also reduced in cells cultured on extracellular-matrix-coated flasks. The present study shows that no general correlation is observed between the studied parameters and metastatic aggressiveness.