Proteolytic processing regulates receptor specificity and activity of VEGF-C

Abstract

The recently identified vascular endothelial growth factor C (VEGF-C) belongs to the platelet-derived growth factor (PDGF)/VEGF family of growth factors and is a ligand for the endothelial-specific receptor tyrosine kinases VEGFR-3 and VEGFR-2. The VEGF homology domain spans only about one-third of the cysteine-rich VEGF-C precursor. Here we have analysed the role of post-translational processing in VEGF-C secretion and function, as well as the structure of the mature VEGF-C. The stepwise proteolytic processing of VEGF-C generated several VEGF-C forms with increased activity towards VEGFR-3, but only the fully processed VEGF-C could activate VEGFR-2. Recombinant 'mature' VEGF-C made in yeast bound VEGFR-3 (K[D] = 135 pM) and VEGFR-2 (K[D] = 410 pM) and activated these receptors. Like VEGF, mature VEGF-C increased vascular permeability, as well as the migration and proliferation of endothelial cells. Unlike other members of the PDGF/VEGF family, mature VEGF-C formed mostly non-covalent homodimers. These data implicate proteolytic processing as a regulator of VEGF-C activity, and reveal novel structure-function relationships in the PDGF/VEGF family.

Downregulation of VEGF-C expression in lung and colon cancer cells decelerates tumor growth and inhibits metastasis via multiple mechanisms

“…We found that VEGF-C downregulation was accompanied by reappearance of certain traits of epithelial phenotype and a decrease in expression of mesenchymal markers that was observed in both A549 ( Figure 6) and HCT116 cells (Supplementary Immature forms of VEGF-C bind only to VEGFR3; mature form binds to VEGFR3 with higher affinity than immature forms, and additionally interacts with VEGFR2 (Joukov et al, 1997). a-tubulin protein was analyzed as loading control.…”

Targeting lymphangiogenesis to prevent tumour metastasis

“…Subsequently, the propeptides can be proteolytically removed to generate mature forms consisting of VHD dimers. The full-length forms of both growth factors bind the lymphangiogenic receptor VEGFR-3 but the mature forms do so with greater affinity (Joukov et al, 1997;Stacker et al, 1999), suggesting that the degree of proteolytic processing of VEGF-C and VEGF-D may in part determine the extent of lymphangiogenesis induced by these proteins in a tumour. Once VEGF-C is processed to the mature form it acquires the capacity to bind VEGFR-2 (Joukov et al, 1997), a cell surface receptor tyrosine kinase thought to signal for angiogenesis.…”

“…The full-length forms of both growth factors bind the lymphangiogenic receptor VEGFR-3 but the mature forms do so with greater affinity (Joukov et al, 1997;Stacker et al, 1999), suggesting that the degree of proteolytic processing of VEGF-C and VEGF-D may in part determine the extent of lymphangiogenesis induced by these proteins in a tumour. Once VEGF-C is processed to the mature form it acquires the capacity to bind VEGFR-2 (Joukov et al, 1997), a cell surface receptor tyrosine kinase thought to signal for angiogenesis. In the case of VEGF-D, the affinity for VEGFR-2 is increased approximately 290-fold by proteolytic conversion of the full-length to the mature form (Stacker et al, 1999).…”

Vascular endothelial growth factors C and D and lymphangiogenesis in gastrointestinal tract malignancy

“…In vitro studies have shown that VEGF-C and VEGF-D exhibit mitogenic effects for vascular and lymphatic endothelial cells and survival-promoting abilities for lymphatic endothelial cells through VEGFR3 Achen et al, 1998;Marconcini et al, 1999;Veikkola et al, 2001). Both growth factors promote angiogenesis in in vitro assays (Joukov et al, 1996;Joukov et al, 1997;Marconcini et al, 1999). Vascular endothelial growth factor-C promotes the formation of capillary-tube structures by lymphatic endothelial cells, but not blood vascular endothelial cells, in a collagen sandwich assay (Podgrabinska et al, 2002).…”