title: Mechanisms of heparanase inhibition by the heparan sulfate mimetic PG545 and three structural analogues.
abstract: The tetrasaccharide heparan sulfate (HS) mimetic PG545, a clinical anti-cancer candidate, is an inhibitor of the HS-degrading enzyme heparanase. The kinetics of heparanase inhibition by PG545 and three structural analogues were investigated to understand their modes of inhibition. The cholestanol aglycon of PG545 significantly increased affinity for heparanase and also modified the inhibition mode. For the tetrasaccharides, competitive inhibition was modified to parabolic competition by the addition of the cholestanol aglycon. For the trisaccharides, partial competitive inhibition was modified to parabolic competition. A schematic model to explain these findings is presented.
authors.affiliation: Progen Pharmaceuticals, Darra, QLD 4076, Australia.
authors.forename: Edward
authors.initials: E
authors.lastname: Hammond
authors.forename: Paul
authors.initials: P
authors.lastname: Handley
authors.forename: Keith
authors.initials: K
authors.lastname: Dredge
authors.forename: Ian
authors.initials: I
authors.lastname: Bytheway
keywords: Cancer; ECM, extracellular matrix; HS, heparan sulfate; HSPG, heparan sulfate proteoglycan; Heparanase; Inhibitor; Kinetics; PG545; SE, standard error; SS, sum of squares; WST-1, 4-[3-(4-iodophenyl)-2-(4-nitrophenyl)-2H-5-tetrazolio]-1,3-benzene disulfonate