Detection of cathepsin B in tumor cytosol and urine of breast cancer patients.
In order to evaluate the role of cathepsin B (CB) as a proteinase involved in mammary tumor progression and its potential role as a tumor marker, we have measured the CB activity in cytosols of breast cancer tumor tissue using Z-Arg-Arg-AMC as the substrate and found a 23fold increase when compared to distantly located breast tissue from the same patient. In addition, urine of breast cancer patients under adjuvant chemotherapy was screened for CB immunoreactivity with a sandwich type enzyme immunoassay which revealed significant interindividual differences in concentrations with some urines containing immunoreactivity comparable to healthy controls. The urines were also investigated for CB activity but no differences between patients and controls were observed. However, urine contains thiol activatable proteinases causing substrate hydrolysis, which is to a varying extent inhibited by E-64 or Z-Phe-Phe-CHN2.
Dengler
R
R
Medizinische Klinik Innenstadt, Universität München, FRG.
Lah
T
T
Gabrijelcic
D
D
Turk
V
V
Fritz
H
H
Emmerich
B
B
D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000201:enzymology* / Q000652:urine; D002401:Cathepsin B / Q000037:antagonists & inhibitors / Q000378:metabolism* / Q000652:urine; D003374:Coumarins; D003600:Cytosol / Q000201:enzymology; D004151:Dipeptides; D005260:Female; D005456:Fluorescent Dyes; D006801:Humans; D008875:Middle Aged; D013379:Substrate Specificity
D003374:Coumarins; D004151:Dipeptides; D005456:Fluorescent Dyes; C069012:benzyloxycarbonylarginyl-arginine 4-methylcoumarin-7-ylamide; D002401:Cathepsin B