Characterization of cysteine proteases and their endogenous inhibitors in MCF-7 and adriamycin-resistant MCF-7 human breast cancer cells.
The expression of three lysosomal cysteine proteases was examined in a lowly metastatic, MCF-7 human breast cancer cell line and its highly metastatic, Adriamycin-resistant variant, MCF-7/AdrR. While levels of cathepsin H activity were similar in all cell lines at each stage of growth, intracellular cathepsin B and L activities were highest in MCF-7/AdrR. These high levels were accompanied by growth-related increases in acid/pepsin-activatable cathepsin activity in the culture medium. Analyses of endogenous cathepsin B inhibitor activity in control and heat-treated cell homogenates after fractionation by fast protein liquid chromatography suggested that alterations in cystatin-like, cysteine protease inhibitor activities contribute to increased levels of cathepsin activities in metastatic MCF-7/AdrR cells.
Department of Biological Sciences, University of Windsor, Ont., Canada.
P B
PB
Scaddan
M J
MJ
Dufresne
D001943:Breast Neoplasms / Q000201:enzymology* / Q000473:pathology; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D015853:Cysteine Proteinase Inhibitors / Q000378:metabolism; D004317:Doxorubicin / Q000494:pharmacology; D004351:Drug Resistance; D006801:Humans; D009362:Neoplasm Metastasis; D014407:Tumor Cells, Cultured
D015853:Cysteine Proteinase Inhibitors; D004317:Doxorubicin; D003546:Cysteine Endopeptidases