CATHEPSIN B-LIKE ACTIVITY IN VIABLE TUMOR-CELLS ISOLATED FROM RODENT TUMORS

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  • 1 January 1985
    • journal article
    • research article
    • Vol. 45  (8) , 3636-3641
Abstract
The cathepsin B-like cysteine proteinase activity which has been implicated in tumor malignancy has been attributed to several cellular sources, including viable tumor cells, necrotic tumors cells, necrotic tumor cells, and host-inflammatory cells. Subpopulations of cells from 8 rodent tumors [mouse melanomas B16a, B16-013, B16-BL6 and B16-B15b; mouse Lewis lung carcinoma 3LL; rat Walker carcinoma W-256; mouse reticulum cell sarcoma M5076; and mouse mammary adenocarcinoma 15091A] of 5 histological types were isolated using centrifugal elutriation. The cellular composition of the subpopulations cytologically was verified. Of the cathepsin B-like activity 92% plus was associated with the isolated fractions containing .gtoreq. 95% tumor cells of 86 .+-. 2% (SE) viability (.beta. fractions). The isolated fractions consisting of necrotic tumor cells and inflammatory cells (.alpha. fraction) apparently contain a cysteine proteinase inhibitor, since both cathepsin B-like and cathepsin H activities in the .beta. fraction of B16 amelanotic melanomas could be inhibited by addition of the .alpha. fraction.