Locally generated VGVAPG and VAPG elastin-derived peptides amplify melanoma invasion via the galectin-3 receptor

Melanomas containing more elastin are associated with higher stages of the disease. The interaction between elastin-derived peptides and melanoma cells appears to play an important role in the progression of melanomas. The effects of the elastin-derived peptides VGVAPG and VAPG have been investigated on the migration, invasion, adhesion and angiogenesis of human melanoma cells of different invasive potential. Elastin, tropoelastin and VGVAPG peptide were demonstrated at the invasion site of melanoma using histochemistry and immunohistochemistry. Not only the VGVAPG elastin-derived peptide, which exhibits the XGXXPG consensus sequence in its primary structure, but also the shorter VAPG bind directly to 3 cell surface receptors: galectin-3, integrin alpha v beta 3 and elastin-binding protein. Our results suggest that the increased levels of elastin-derived peptides facilitate the invasion of melanoma cells: (i) VGVAPG and VAPG elastin-derived peptides are chemotactic for melanoma cells; (ii) they can increase the migration of melanoma cells and the expression of CXCR-4 and CXCL-12 chemokines; (iii) they enhance the expression of the elastin-degrading MMP-2 and MMP-3; (iv) they increase the attachment of melanoma cells and the expression of different adhesion molecules; (v) they increase the expression of the lymphangiogenic VEGF-C and (vi) the galectin-3 receptor can mediate all these effects. Clinical and therapeutic aspects are also discussed.