VEGF-D (vascular endothelial growth factor D) is synthesized as a full-length protein with a molecular weight of ~53 kDa. It contains a central VEGF homology domain (VHD) flanked by N- and C-terminal propeptides. Fulllength VEGF-D is secreted and is immediately proteolytically processed outside the cell by plasmin and proprotein converatses, thereby generating a mature form (molecular weight ~21 kDa) with a much higher affinity for VEGFR-2 and –3 compared with the unprocessed form. VEGF-D, also known as c-fos-induced growth factor, is a secreted growth factor consisting of VEGF-homology domain, receptor binding domains, and propeptides in both termini. After secretion into the extracellular space, the C– and N-terminal propeptides are cleaved from full length VEGF-D to form mature VEGF-D. This proteolytic processing increases the affinity of VEGF-D for VEGFR-3, a tyrosine kinase receptor that is mainly located on adult lymphatic endothelium and is implicated in lymphangiogenesis. VEGF-D also interacts with a non-tyrosine kinase receptor Nrp-2, another lymphangiogenesis-associated factor. VEGF-D is expressed in a range of human tumors, and can correlate with lymph node metastasis and poor patient outcome. Clinicopathological as well as experimental data indicate that the VEGF-D signaling pathway may be a therapeutic target for restricting the spread of cancer. Further, it has been proposed that VEGF-D is an alternative mediator of tumor angiogenesis to VEGF-A, that might contribute to mechanisms of resistance to bevacizumab, a widely used anti-cancer drug targeting VEGF-A.
- References to VEGF-D (Vascular Endothelial Growth Factor-D, FIGF)