Cathepsin A activity in primary and metastatic human melanocytic tumors.
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.
Kozlowski
L
L
Department of Oncology, Medical Academy, Bialystok, Poland. oncomed@polbox.com.pl
Wojtukiewicz
M Z
MZ
Ostrowska
H
H
D002268:Carboxypeptidases / Q000378:metabolism*; D043402:Cathepsin A; D006801:Humans; D008545:Melanoma / Q000201:enzymology* / Q000556:secondary
D002268:Carboxypeptidases; C468629:CTSA protein, human; D043402:Cathepsin A