Sulfated Hyaluronan Binds to Heparanase and Blocks Its Enzymatic and Cellular Actions in Carcinoma Cells

We examined whether sulfated hyaluronan exerts inhibitory effects on enzymatic and biological actions of heparanase, a sole endo-beta-glucuronidase implicated in cancer malignancy and inflammation. Degradation of heparan sulfate by human and mouse heparanase was inhibited by sulfated hyaluronan. In particular, high-sulfated hyaluronan modified with approximately 2.5 sulfate groups per disaccharide unit effectively inhibited the enzymatic activity at a lower concentra-tion than heparin. Human and mouse heparanase bound to immobilized sulfated hyaluronan. Invasion of heparanase-positive colon-26 cells and 4T1 cells under 3D culture conditions was signifi-cantly suppressed in the presence of high-sulfated hyaluronan. Heparanase-induced release of CCL2 from colon-26 cells was suppressed in the presence of sulfated hyaluronan via blocking of cell surface binding and subsequent intracellular NF-κB-dependent signaling. The inhibitory effect of sulfated hyaluronan is likely due to competitive binding to the heparanase molecule, which antag-onizes the heparanase-substrate interaction. Fragment molecular orbital calculation revealed a strong binding of sulfated hyaluronan tetrasaccharide to the heparanase molecule based on electro-static interactions, particularly characterized by interactions of (−1)-and (−2)-positioned sulfated sugar residues with basic amino acid residues composing the heparin-binding domain-1 of hepara-nase. These results propose a relevance for sulfated hyaluronan in the blocking of heparanase-me-diated enzymatic and cellular actions.