Collagenolytic activities in methylcholanthrene-induced fibrosarcomas in mice

Summary

Methylcholanthrene-induced fibrosarcomas in mice were found to possess two kinds of collagenolytic activities towards [³H]collagen, one having a pH- optimum of 4.2 and the other of pH 7.4. These two activities could be separated on a column of Celite 545 by a reverse ammonium sulfate gradient. Activity at pH 4.2 was enhanced by cysteine and EDTA and inhibited by the chloromethylketones of tosyllysine and tosyl-phenylalanine, iodoacetate, and p-hydroxymercuribenzoate. Activity at pH 7.4 was inhibited by cysteine and EDTA and enhanced by Ca²⁺. Both enzymes were inhibited by α₂-macroglobulin but neither one by α₁-antitrypsin. An electrophoretic examination of the products produced from collagen by the pH 4.2 and pH 7.4-active enzymes revealed that the former caused extensive degradation of collagen, whereas the latter yielded products of limited cleavage (β^A, α^A and α^B) characteristic of mammalian collagenases. When tumor cells were cultured in vitro, the pH 7.4 activity appeared in the medium, whereas the pH 4.2 activity remained bound to the tumor cells. An enzyme capable of hydrolyzing 4-phenylazobenzoyloxycarbonyl-L-Pro-L-leu-Gly-L-Pro-D-Arg (designated as Pz-peptide) was also present but could be seperated from the other two activities. Since all three of these activities were highest in the periphery or invasion zone of the tumor, they could play a role in the invasive property of the tumor.