Angiogenesis plays an important role during embryonic development and in many pathologies including cancer, cardiovascular and inflammatory diseases. Fibroblast growth factors (FGFs) are among the most fundamental regulators of the angiogenic process. These factors induce endothelial cell proliferation, migration and angiogenesis in vitro and in vivo. The FGF family of proteins is presently known to include 23 members closely related. FGF-1 and FGF-2, previously known as acidic and basic fibroblast growth factors, are considered to be representative of the whole family. The FGFs exert its action through the interaction with the FGF receptor (FGFR) family of proteins. These proteins are transmembrane tyrosine kinases that activate signaling networks in the cytoplasm of the target cell. It is well established that the FGFs and its receptors interacts with the glycoside moiety of heparan sulfates proteoglycan of the cell coat and basal membranes. Due to the central role that the FGFs plays in the normal and also in the aberrant angiogenesis associated with several pathologies, inhibition of the action promoted by FGFs seems to be reasonable approach to develop new anti-angiogenic compounds. In this work, following leads previously reported, it has been searched new compounds that inhibit the action of FGFs with a single aromatic ring (compounds derived from benzoic acids). Two assayed compounds (persilate: 2,5 dihidroxi-1,4 benzenedisulfonate and dobesilate: 2,5 dihidroxibenzenesulfonate) showed promising effects that were further characterized in vitro and in vivo. Crystal structures of the complexes FGF-1/persilate and FGF-1/dobesilate are presented and helps rationalizes the in vitro and in vivo results: both inhibitors interacts with the FGF-1 through the heparin binding site of the protein and upon binding, the overall structure of the protein is altered when is compared with the structure of the active state (heparin bonded). Specially, the interfaces known to interact with the FGFR are changed in the structure of the FGF-1 bound to the inhibitors. Evidences of the interaction of the dobesilate molecule with the FGFR, likely through its heparin binding site, are also presented, although no structural result is contributed. From the results exposed in this work, we can conclude that small molecules with a single aromatic ring derived from benzoic acids are good inhibitors of the angiogenic promoting factors FGFs in vitro and in vivo. These effects are promoted by the ability of these compounds (especially dobesilate) of interact with the FGF-1 through its heparin binding site and induce a conformational change in the protein that prevents the interaction with the cellular receptor (FGFR). The novel feature of a FGFs inhibiting compound like dobesilate of interact also with the cellular receptor of FGFs, suggest a dual inhibiting mechanism that make this family of compounds really appealing as lead compounds in the development of new anti-angiogenic drugs.

Tesis Doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Biología Molecular. Fecha de lectura: 20-06-2008