A Low Molecular Weight Protein from the Sea Anemone Anemonia viridis with an Anti Angiogenic Activity

Sea anemones are a remarkable source of active principles due to a decentralized venom system. Blood vessel formation or angiogenesis is a very promising target against cancer, but the few available anti-angiogenic compounds have a limited efficacy. In this study, a protein fraction was purified from tentacles of Anemonia viridis able to limit endothelial cells proliferation and vessel network formation or angiogenesis at low concentration (14 nM). The sequences in this protein fraction were determined with Edman degradation and Mass Spectrometry In Source Decay and revealed homologies with BDS sea anemones. The presence of a two turn alpha helix observed with Circular Dichroism and a trypsin activity inhibition suggested that the active principle could be a Kunitz-type inhibitor, which may interact with an integrin due to a RGD motif well exposed to the solvent as revealed by Molecular Modeling. This active principle could improve antiangiogenic therapy from existing antiangiogenic compounds binding on the VEGF.