title: Cathepsin B activity in B16 melanoma cells: a possible marker for metastatic potential.
abstract: In solid s.c. tumors of a variant of the murine B16 melanoma with high metastatic potential (B16F10), there was a 2- to 7-fold elevation of lysosomal cathepsin B activity when compared to the B16F1 variant with low metastatic potential. The highest activities (based on either protein or DNA) of cathepsin B were found in tumors of less than 1 g. When B16F1 and B16F10 melanoma variants were grown in tissue culture, the metastatic differential in cathepsin B activity was lost as the cells were subcultured. However, this differential in cathepsin B activity could be restored by reestablishing the cultured cells as s.c. tumors. The activities of four other lysosomal enzymes (cathepsin D, beta-N-acetylglucosaminidase, beta-glucuronidase, and acid phosphatase) showed little evidence of a positive correlation with the metastatic potential of the B16 melanoma variants. Eighty to 90% of cathepsin B activity has been localized to a fraction containing viable tumor cells which was isolated by centrifugal elutriation. In contrast, only 50% of cathepsin D activity was in the viable tumor cell fraction, and from 30 to 70% of beta-N-acetylglucosaminidase, beta-glucuronidase, and acid phosphatase. Elevated levels of cathepsin B in the high metastatic B16F10 variant are consistent with the idea that cathepsin B may play a direct or a regulatory role in tumor metastasis.
mesh_terms: D000118:Acetylglucosaminidase / Q000378:metabolism; D000135:Acid Phosphatase / Q000378:metabolism; D000818:Animals; D002401:Cathepsin B; D002402:Cathepsin D; D002403:Cathepsins / Q000378:metabolism*; D002460:Cell Line; D005966:Glucuronidase / Q000378:metabolism; D008247:Lysosomes / Q000201:enzymology; D008545:Melanoma / Q000201:enzymology* / Q000473:pathology; D051379:Mice; D009154:Mutation; D009362:Neoplasm Metastasis; D009368:Neoplasm Transplantation; D009374:Neoplasms, Experimental / Q000201:enzymology
chemical_list: D000135:Acid Phosphatase; D005966:Glucuronidase; D000118:Acetylglucosaminidase; D002403:Cathepsins; D002401:Cathepsin B; D002402:Cathepsin D