Cytochemical and biochemical evidence of cathepsin B in malignant, transformed and normal breast epithelial cells.

Abstract

Human breast cancer cell lines, as well as transformed mammary epithelial cells (HBL-100) and growth-stimulated normal breast epithelial cells showed positive cytochemical reaction with the proteinase substrate 2-(N-benzyloxycarbonyl-L-arginyl-L-arginylamido)-4-methoxynapht halene, in the presence of 5-nitrosalicylaldehyde. The reaction product, small fluorescent granules, was distributed throughout the cytoplasm, in the perinuclear zone, in some cytoplasmic projections, and at the cell surface. Using a panel of various proteinase inhibitors, we found that the formation of the reaction product was an enzymic function of a cysteine proteinase. Using the substrate 7-(N-benzyloxycarbonyl-L-arginyl-L-arginylamido)-4-methylcoumarin, we evaluated some biochemical properties of the cysteine proteinase, including pH-activity profile, pH stability, apparent relative molecular mass and sensitivity toward various proteinase inhibitors. We found that the proteinase from the studied breast epithelial cells exhibited characteristics of a mature form of cathepsin B. Taken together, the cytochemical and biochemical data provide evidence that human breast epithelial cells of cancer origin, as well as in the transformed or growth-stimulated state express active cathepsin B and compartmentalize it into specific subcellular sites.

• Authors: E Krepela, J Bártek, D Skalková, J Vicar, D Rasnick, J Taylor-Papadimitriou, R C Hallowes
• Journal: Journal of cell science (J Cell Sci) Vol. 87 ( Pt 1) Pg. 145-54 (Feb 1987) ISSN: 0021-9533 [Print] England
• PMID: 3667710 (Publication Type: Journal Article)

Chemical References

• Cathepsin B

Topics

• Breast (enzymology)
• Breast Neoplasms (enzymology)
• Cathepsin B (metabolism)
• Cell Line
• Cell Transformation, Neoplastic (enzymology)
• Chromatography, Gel
• Epithelium (enzymology)
• Humans
• Microscopy, Fluorescence