[The effect of leukocyte elastase on high molecular weight kininogen from human plasma in the presence of alpha-1 protease inhibitor. Analysis of proteolytic degradation]. / Deistvie leikotsitarnoi élastazy na vysokomolekuliarnyi kininogen plazmy krovi cheloveka v prisutstvii al'fa-1-proteinaznogo ingibitora. Analiz proteoliticheskoi degradatsii.

Degranulation of polymorphonuclear leukocytes (neutrophils) and releasing of leukocyte elastase during inflammation occur not only in injured tissue but in plasma in the presence of considerable excess of alpha-1 proteinase inhibitor (alpha-1PI). However, in spite of the absence of free elastase in patients' plasma, even in such severe inflammation as peritonitis and septicaemia, degradation of the connective tissue structures and plasma proteins may be determined. However the reasons of such destructive action are not yet determined. In this paper the action of leukocyte elastase on human plasma high molecular weight kininogen (HMWK) was studied in the absence or in the presence of different concentrations of alpha-1PI. The results showed that degradation of the intact molecules of HMWK occurred under the action of elastase during 1-2 hours of combined incubation even if the concentration of alpha-1PI in the mixture in 3-5 fold exceeds the molar elastase concentration. The rate of elastase inhibition by alpha-1PI in the presence of HMWK did not depend on an order of enzyme and inhibitor addition to the incubation medium. HMWK degradation by elastase in the presence of alpha-1PI was accompanied by impairments in its adhesion function although high tolerance of HMWK inhibitory activity with respect to SH-proteinases preserved. Thus, total inhibition of leukocyte elastase by alpha-1PI, in the presence of high molecular weight kininogen develops during relatively long time interval. The pronounced destruction of intact HMWK molecules takes place during this period of gradual elastase inhibition. This fact seems to be very important in pathogenesis of thrombo-haemorrhage syndrome as a complication of severe inflammation.

Expression of matrix metalloproteinases and the metastasis-associated gene S100A4 in human neuroblastoma and primitive neuroectodermal tumor cells.

BACKGROUND: Matrix metalloproteinases (MMPs) and their endogenous inhibitors (tissue inhibitors of MMPs; TIMPs) have been shown to correlate with in vitro invasiveness and clinical outcome in several adult malignancies. The importance of MMP and TIMP expression in neuroblastoma (NB) and primitive neuroectodermal tumors (PNET) is incompletely understood. The aim of the current study was to relate in vitro invasion of NB and PNET cell lines with MMP and TIMP expression and evaluate the effect of a synthetic MMP inhibitor. Furthermore, S100A4 levels were determined because recent reports have suggested a possible association between MMPs, TIMPs, and the metastasis-associated gene S100A4. METHODS: Expression of MMPs, TIMPs, and S100A4 was evaluated at both mRNA and protein levels in 2 human NB and 2 PNET cell lines. In vitro invasion and effects of the synthetic MMP inhibitor Marimastat were assessed in the Transwell chamber assay. RESULTS: The most invasive cells expressed the highest levels of MMPs and S100A4. Marimastat reduced invasion by 30%. CONCLUSIONS: In vitro invasion correlated with MMP and S100A4 expression. The fact that Marimastat reduced in vitro invasion is encouraging for further studies on a possible therapeutic application for proteinase inhibitors.