Proportionality of protease activities in malignant cells to their metastatic potentials

It has been suggested that the activities of type IV collagenase and/or ectopeptidases possessed by malignant cells are related to their metastatic potentials. In the present study, we examined the activities of three aminopeptidases, two serine proteases, as well as type IV collagenase, in three kinds of cell lines of malignant cells. The activities of the aminopeptidases and serine proteases, rather than of type IV collagenase, were found to be proportionate to the metastatic potentials of those cell lines. Such activities of aminopeptidases were effectively suppressed by the addition of low molecular weight inhibitors.