Proteolytic enzymes as new tumor markers in chemical carcinogenesis of intestinal tumors.
Because the role of proteolytic enzymes in carcinogenesis is not yet well understood, we studied two arylamidases cleaving Boc-(Ala)2-p-nitroanilide and Bz-Lys-p-nitroanilide in the sera of rats during azoxymethane (AOM)-induced development of bowel carcinomas. Both proteolytic activities exhibited similar patterns: During administration of the carcinogen they increased up to 2.1-fold (Boc-[Ala]2-Nan) and 1.7-fold (Bz-Lys-Nan) the activity of the control group (P less than 0.05). Subsequently they decreased, passing the normal range between weeks 16 and 20 after the first AOM treatment and then diminishing continuously with increasing manifestation of tumors. At week 24 when the last animals were sacrificed enzyme activities were only 36.5% and 43.7% of the controls (P less than 0.05). The early increase may be related to direct effects of the carcinogen. The decrease of serum activity in the further course, however, seems to be a typical event of invasive tumor growth, because a similar loss of activity was also observed in rats with benzopyrene sarcomas. We conclude that both arylamidases may become useful as nonspecific tumor markers.
D000626:Aminopeptidases / Q000097:blood*; D000818:Animals; D001397:Azoxymethane; D007414:Intestinal Neoplasms / Q000139:chemically induced / Q000175:diagnosis / Q000201:enzymology*; D008297:Male; D051381:Rats; D011916:Rats, Inbred F344
D000626:Aminopeptidases; D001397:Azoxymethane