PubMed · 5329622
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I Syrový. 1966. [Cathepsins].. https://pubmed.ncbi.nlm.nih.gov/5329622/
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Bladder tumors comprise a spectrum of neoplastic diathesis. Some behave in a benign fashion, and others are highly aggressive and lead rapidly to metastatic disease and death. The metastasizing potential, often described as a sequence of interrelated steps, involve 1) tumor cell adhesion to basement membranes, 2) degradation of basement membranes and underlying connective tissue stroma, and 3) migration of tumor cells through the destroyed stroma into blood and lymphatic vessels. Each of these processes involves the expression of molecular and biochemical factors identified with tumor cells. With better understanding of the molecular basis of these factors, novel prognostic and potential therapeutic agents can be generated and applied to the clinical arena.
We have used a new approach to test the possible participation of lysosomes in the degradation of long-lived proteins. Rat liver lysosomal proteins were introduced, via multilamellar liposomes, into L-132 cells. Viability and protein synthesis were not impaired by this treatment. The liposomal content was released into the lysosomes of the cultured cells, as revealed by ferritin uptake and electron microscopy. Degradation rates of long-lived proteins increased with the uptake of lysosomal proteases. However, the increased protein degradation of chloroquine and leupeptin, in contrast to the inhibition by these reagents of the increased protein degradation of cells 'starved' of serum (step-down conditions). This approach opens a new way of investigating the degradation of intracellular proteins in cultured cells.
Lysosomal cysteine proteinases (cathepsin H, B + L) and metalloproteinase (MMP7-ase) activities were measured from early gestational period (6-12 weeks) in frozen, non-cultivated chorionic villi. The mean activity of cathepsin H was 50.99 mU/mg protein, of cathepsin B + L, 71.16 mU/mg protein, and of MMP7-ase, 16.16 mU/mg protein. The MMP7-ase enzyme activities showed a correlation with gestational age. There was a significant correlation between the activities of cathepsin H and MMP7-ase.