Possible Mechanisms of Action of the Anticarcinogenic Protease Inhibitors

Protease inhibitors have been shown to possess anticarcinogenic properties. Two synthetic protease inhibitors, tosyl phenylethyl chloro-methyl ketone (TPCK) and tosylarginine methylester (a competitive trypsin substrate), have been demonstrated to block the formation of skin tumors promoted with TPA in mice (1). These studies were repeated using the actinomycete-derived protease inhibitor leupeptin (2), thus establishing an in vivo basis for the involvement of proteases in the mechanism of carcinogenesis.