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Abstract

Metastatic rat colon cancer cells but not normal rat hepatocytes showed activity of cathepsin B on their plasma membranes. Activity was visualized in living cells with a new fluorogenic substrate, [Z-Arg]2-cresyl violet, and confocal microscopy. When these cancer cells were injected into the portal vein of rats, the animals developed tumors in the liver in a heterogeneous fashion. Three- to four-fold more tumors were found in the small caudate lobe than in the other three large lobes of the liver. Oral treatment with a selective water-soluble inhibitor of extracellular cathepsin B, Mu-Phe-homoPhe-fluoromethylketone, resulted in 60% reduction of the number of tumors and 80% reduction of the volume of tumors in the three large lobes whereas tumor development was not affected in the small caudate lobe. This study supports the conclusions that (a) extracellular cathepsin B plays a crucial but complex role in liver colonisation by rat colon carcinoma cells in vivo, (b) its selective inhibition suppresses tumor growth heterogeneously in the liver and (c) the caudate lobe of the liver is a relatively large risk factor for tumor development.

Podocyte Migration during Nephrotic Syndrome Requires a Coordinated Interplay between Cathepsin L and α3 Integrin

“…2c). Next, to visualize the subcellular sites of cathepsin L activity, we used a fluorogenic substrate CV-(FR) 2 , which emits fluorescence light upon cleavage by cathepsin L (36). In nontreated podocytes, we found a low baseline activity in lysosomes (Fig.…”

“…Fluorescence was recorded every 10 min for 1 h using a Wallac fluorometer with a 355-nm excitation filter and a 460-nm emission filter. Cathepsin L activity in living cells was visualizing with cresyl violet as a substrate (36).…”

“…In brief, ␣ 3 integrin defiant podocyte rescued by human ␣ 3 integrin expression, and differentiated wild type podocytes were incubated with ␣ 3 integrin monoclonal antibody P1B5 (5 g/ml) for 1 h at 37°C. Then, the activity of cathepsin L was analyzed in living cells using fluorophore cresyl violet as a substrate (36). In control experiments, mouse monoclonal anti-synaptopodin was used.…”

Down-regulation of cathepsin B expression impairs the invasive and tumorigenic potential of human glioblastoma cells

“…It has also been demonstrated that cathepsin B not only degrades components of the ECM such as laminin, collagen, and ®bronectin and structures of basement membranes (Buck et al, 1992), but also activates other proteolytic enzyme systems (Kobayshi et al, 1993;Schmitt et al, 1992). A recent study has shown that inhibition of extracellular cathepsin B inhibits the growth and metastasis of rat colon cancer cells (Van Noorden et al, 1998), providing further evidence for the involvement of cathepsin B in tumor invasion. Cells transfected with antisense cathepsin B cDNA exhibited a decrease in cathepsin B activity, which resulted in a reduced invasion and motility of treated cells (Krueger et al, 1999).…”

Ala-Pro-Cresyl Violet, a Synthetic Fluorogenic Substrate for the Analysis of Kinetic Parameters of Dipeptidyl Peptidase IV (CD26) in Individual Living Rat Hepatocytes

“…Examples are turnover alyzed quantitatively in individual cells by capturing of collagen (7)(8)(9), activation of the immune system (10), series of images in time. Production of fluorescence arthritis (11,12), and metastasis of cancer (13,14). For strates for proteases containing cresyl violet was syn-Cresyl violet-dependent fluorescence appeared in a similar way when cells were analyzed by flow cytome-thesized.…”