Heparan sulfate (HS) is an endogenous anionic glycosaminoglycan that resides on nearly all mammalian cell surfaces and in the extra-cellular matrix. HS helps facilitate numerous biological processes from cell proliferation and differentiation to angiogenesis and anti-coagulation. HS is also known to play a role in many disease states, including cancer, Alzheimer's, and viral invasion. In all HS-mediated biological processes, HS interacts with specific proteins. It is known that HS and the structurally similar heparin bind to over 200 biologically active proteins. Because HS displays an immense range of biological activity over twenty different therapeutic applications have been proposed for molecules to block HS-protein interactions. Current research toward therapeutic candidates of proposed clinical applications has focused on heparin-like (agonistic) polyanions such as sulfated carbohydrates and small molecules. This approach has yielded only highly charged molecules that suffer from non-specific binding and poor oral bioavailability. In the studies here, charge-reduced heparin derivatives were prepared by incorporating non-anionic aromatic moieties at the carboxylate groups of uronic acids within heparin and low molecular weight heparins (LMWHs). A series of aromatic amines were coupled to the carboxylate groups in heparin and LMWHs to form carboxyamides. The resulting aryl amides of heparin and LMWHs were evaluated in competition binding studies for binding to growth factors FGF-1, FGF-2, and VEGF. These binding studies resulted in the discovery of 4-phenoxyaniline amides of heparin and LMWHs showing enhanced affinity for VEGF over heparin. The 4-phenoxyaniline amide of heparin has an EC50 value 4.3 + 1.3 muM for binding to VEGF, which is 2.8-fold lower than that of heparin. The biphenyl amide of LMWH centaxarin has an EC50 value 0.35 + 0.11 muM for binding to VEGF. 4-phenoxyaniline amides of other endogenous glycosaminoglycans ( i.e. dermatan sulfate, chondroitin sulfates) also demonstrated enhanced affinity for FGF-2, particularly the 4-phenoxyaniline amide of chondroitin 6-sulfate.An AB15 pH meter from Fisher Scientifiic was used with an accumetAr combination MicroProbeAr, which has a 254 mm stem with a 3 mm diameter and a Calomel reference. 4.4 Carbazole Assay Procedure Briefly, stock solutions wereanbsp;...
|Title||:||Aryl Amides of Uronic Acid Containing Oligosaccharides as Bind and Block Antagonists of Heparin-binding Proteins|
|Author||:||Christopher M. Hattan|
|Publisher||:||ProQuest - 2008|