Plasminogen activators, kallikrein-like proteinase and type I and type IV collagenases at various stages of oncogenic transformation.

Comparative studies of membrane-associated, intracellular and secreted activities of serine (uPA, kallikrein-like proteinase) and metalloproteinases (type I and IV collagenases) were carried out on rat embryo fibroblasts, sequentially immortalized and transformed by two different genes. Using this experimental model it was shown that (1) activity of uPA was expressed at the stage of immortalization solely; (2) intracellular and secreted activity of type I and IV collagenases decreased during process of transformation, (3) kallikrein-like proteinase activity was not revealed either in the primary or in transformed cells, (4) Z-Phe-Arg-MCA hydrolysis was the result of the action of cysteine proteinases alone; the increase in this activity was correlated with the stages of oncogenic transformation of fibroblasts.