Degradation of extracellular-matrix proteins by human cathepsin B from normal and tumour tissues
Year: 1992
Type: article
Abstract: Our laboratory has previously demonstrated that increased malignancy of several histological types of human and animal tumours is associated with increases in their cathepsin B activity, particularly cathepsin B activity associated with plasma-membrane/endosomal vesicles or shed vesicles. Here we report that cathepsin B from normal or tumour tissues degrades purified extracellular-matrix components, type IV collagen, laminin and fibronectin, at both acid pH and neutral pH. The number and sizes of degradation products were analysed by SDS/PAGE. Cathepsin B from both sources exhibited similar activities towards, and similar patterns of cleavage of, the extracellular-matrix proteins. At neutral pH, cathepsin B from both sources appeared to undergo autodegradation, a process that was decreased in the presence of alternative substrates such as the extracellular-matrix proteins. Cathepsin B readily degraded type IV collagen at 25 degrees C, indicating activity towards native type IV collagen. Fibronectin degradation products of 100-200 kDa and of 18 and 22 kDa were observed. A single 70 kDa fragment was released from laminin under non-reducing conditions and multiple fragments ranging from 45 to 200 kDa under reducing conditions. These results suggest that cathepsin B at or near the surface of malignant tumour cells may play a functional role in the focal dissolution of extracellular matrices.
Source: Biochemical Journal
DOI: 10.1042/bj2820273
Authors: M R Buck, D G Karustis, N A Day, K V Honn, B F Sloane
Institutions: Wayne State University, Harper University Hospital
Language: English
Subfield: Cancer Research
Domain: Life Sciences
Open Access status: bronze
OpenAlex ID: W1805256772