HIGH-LEVELS OF PROTEOLYTIC-ENZYMES IN THE ASCITIC FLUID AND PLASMA OFRATS BEARING THE YOSHIDA AH-130 HEPATOMA

Plasma and ascitic fluid of rats bearing the Yoshida ascites hepatoma AH-130 were shown to contain high levels of proteolytic enzymes belong ing to different classes active at neutral and acidic pH. Relative to those measured in control rat plasma, in tumor-bearing animals, the ac tivity levels of lysosomal cathepsins B and L, in their latent, acidic -activatable form, were approximately 5-fold higher in plasma and 9-fo ld higher in ascitic fluid, and cathepsin D activity was about 5-fold higher in both plasma and ascitic fluid. Plasma and ascitic fluid of t umor-bearing rats also contained novel neutral and acidic gelatinolyti c activities. The latter, as revealed by zymographic analysis conducte d at pH 6.0, in the presence of dithiothreitol and in the absence of d ivalent metal ions, was sensitive to iodoacetamide inhibition but not to EDTA, showed a molecular mass of approximately 90 kD on SDS-PAGE, a nd was lost upon limited proteolysis with pepsin. Therefore, this enzy me is not identifiable as cathepsin B or L or their related latent for ms and may represent a novel, so far undescribed, gelatinase. Its pres ence exclusively in the body fluids of AH-130-bearing rats suggests it s possible use as a tumor marker.