Inhibition of PMN-elastase activity by semisynthetic glucan sulfates

Abstract

Proteolysis of connective tissue by enzymes such as PMN-elastase(PMNE) is a crucial step during inflammation and metastasis.Semisynthetic sulfated carbohydrates (SC) were shown toexhibit potent antiinflammatory and antimetastatic activity invivo. The aim of the present study was to examine whetherinterferences with PMN-elastase may contribute to theseeffects. Therefore, the interactions of these compounds withPMNE were evaluated in various test systems. Besides semisyntheticα-1,4/1,6- and β-1,3-glucan sulfates, UFH, a LMWH andpentosan polysulfate (PPS) were included in the study. Theinhibitory activity of SC improves not only with increasing molecular weight (MW 10 - 250 kDa: 37 - 54% inhibition at0.25 µg/ml) and degree of sulfation (DS 0.25 - 2.0: 16 - 50%inhibition at 0.25 µg/ml), but depends also on their genuinepolysaccharide structure (IC50 β-1,3-glucan sulfate 0.18 /a-1,4/1,6-glucan sulfate 0.25 / UFH 0.5 µg/ml). Using physiologicalsubstrate assays (collagen, elastin), β-1,3- and α-1,4/1,6-glucansulfates are more active than UFH (inhibition at 1.5 µg/ml:41 / 32 / 12%). According to enzyme-inhibitor binding studies,SC exhibit structure dependent affinity to the enzyme (Kd forPMNE: β-1,3 < α-1,4/1,6 < UFH). Finally, SC were shown toinhibit cancer cell-mediated elastinolysis.