Abstract
Tumor cells produce various types of matrix-degrading proteinases which play essential roles in tumor cell invasion through basement membranes and connective tissues. Highly sensitive analysis of proteinases by zymography on gelatin- or casein-containing gels has shown that tumor cells frequently secrete matrix metalloproteinases (MMPs) including gelatinases A and B, interstitial collagenase, stromelysin and matrilysin, as well as the serine proteinase trypsin. On the other hand, analysis by reverse zymography has revealed that tumor cells also secrete various kinds of inhibitors for MMPs and trypsin. These results suggest that extracellular proteolysis has been regulated by a balance between various kinds of proteinases and their inhibitors. The zymography and reverse zymography can be widely applied to studies on proteinases present in various biological fluids and tissues.
