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Cancer development and progression is often associated with inflammation. Late diagnosis of inflammation that directly leads to the development of neoplasm—cancer is associated with a reduction in the chance of successful treatment or is associated with therapeutic difficulties. A panel of chromogenic substrates was used for the qualitative determination of the specific activity of enzymes in urine of patients with confirmed inflammatory reaction and/or epithelial neoplasms in particular tumours at various stages of development. Urine of people with excluded inflammation was used as a control group. Proteolytic activity was determined in urine samples collected from patients with epithelial neoplasms and/or inflammation. What is more, we determine human neutrophil elastase activity-related inflammation based on the examination of urine samples. We suspect that the proteolytical activity of urine samples is due to neutrophil response to inflammation, which is directly related to cancer. This is the first study to determine elastolytic activity in bladder cancer urine samples. It supports wider use of urine for inflammation screening. [ABSTRACT FROM AUTHOR]

The function of neutrophil protease 3 (PR3) is poorly understood despite of its role in autoimmune vasculitides and its possible involvement in cell apoptosis. This makes it different from its structural homologue neutrophil elastase (HNE). Endogenous inhibitors of human neutrophil serine proteases preferentially inhibit HNE and to a lesser extent, PR3. We constructed a single-residue mutant PR3 (I217R) to investigate the S4 subsite preferences of PR3 andHNEand used the best peptide substrate sequences to develop selective phosphonate inhibitors with the structure Ac-peptidylP(O-C6H4-4-Cl)2. The combination of a prolyl residue at P4 and an aspartyl residue at P2 was totally selective for PR3. We then synthesized N-terminally biotinylated peptidyl phosphonates to identify the PR3 in complex biological samples. These inhibitors resisted proteolytic degradation and rapidly inactivated PR3 in biological fluids such as inflammatory lung secretions and the urine of patients with bladder cancer. One of these inhibitors revealed intracellular PR3 in permeabilized neutrophils and on the surface of activated cells. They hardly inhibited PR3 bound to the surface of stimulated neutrophils despite their low molecular mass, suggesting that the conformation and reactivity of membrane-bound PR3 is altered. This finding is relevant for autoantibody binding and the subsequent activation of neutrophils in granulomatosis with polyangiitis (formerly Wegener disease). These are the first inhibitors that can be used as probes to monitor, detect, and control PR3 activity in a variety of inflammatory diseases. [ABSTRACT FROM AUTHOR]