title: Cathepsin A activity in primary and metastatic human melanocytic tumors.
abstract: Several lysosomal proteases including cathepsins B, D, H and L have been found to play a role in the metastasis of tumor cells. However, up to now no information on the role of cathepsin A, a lysosomal multifunctional peptidase, in the proliferative, invasive, and metastatic potential of malignant tumors has been available. In the present study we compared the activity of cathepsin A in lysates of 34 human melanocytic tumors: primary (n = 12) and metastatic (n = 5) malignant melanoma, dysplastic pigmented nevi (n = 6) and pigmented nevi without evidence of dysplastic melanocytes (n = 11). The carboxypeptidase activity of cathepsin A was assayed at pH 5.0 with its specific substrate Cbz-Phe-Ala. The amount of released C-terminal alanine was measured by the ninhydrin method. We found that lysates of primary malignant melanoma lesions exhibited significantly higher cathepsin A activity than lysates of dysplastic and normal pigmented nevi. The cathepsin A activity in lysates of metastatic lesions of malignant melanoma was significantly higher than in primary focus lysates. It seems that cathepsin A may play a role in malignant transformation and metastatic dissemination of malignant melanoma.
authors.affiliation: Department of Oncology, Medical Academy, Bialystok, Poland. oncomed@polbox.com.pl
authors.forename: L
authors.initials: L
authors.lastname: Kozlowski
authors.forename: M Z
authors.initials: MZ
authors.lastname: Wojtukiewicz
authors.forename: H
authors.initials: H
authors.lastname: Ostrowska
mesh_terms: D002268:Carboxypeptidases / Q000378:metabolism*; D043402:Cathepsin A; D006801:Humans; D008545:Melanoma / Q000201:enzymology* / Q000556:secondary
chemical_list: D002268:Carboxypeptidases; C468629:CTSA protein, human; D043402:Cathepsin A