Degradation of extracellular-matrix proteins by human cathepsin B from normal and tumour tissues - PubMed (original) (raw)

Comparative Study

. 1992 Feb 15;282 ( Pt 1)(Pt 1):273-8.

doi: 10.1042/bj2820273.

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Comparative Study

Degradation of extracellular-matrix proteins by human cathepsin B from normal and tumour tissues

M R Buck et al. Biochem J. 1992.

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.

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References

    1. Arch Biochem Biophys. 1989 Sep;273(2):367-74 - PubMed
    1. FEBS Lett. 1990 Aug 20;269(1):189-93 - PubMed
    1. J Biol Chem. 1986 Oct 25;261(30):14245-55 - PubMed
    1. Exp Cell Biol. 1987;55(4):209-24 - PubMed
    1. Biochem J. 1986 May 1;235(3):731-4 - PubMed

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