Autocrine effects of VEGF-D on endothelial cells after transduction with AD-VEGF-DΔNΔC

Endothelial cells in tumor vessels display unusual characteristics in terms of survival and angiogenic properties which result from the increased expression of VEGF-D and its autocrine effect. To evaluate mechanisms by which VEGF-D leads to such abnormal phenotype, we searched for proteins with modified expression in HUVECs enriched in the recombinant mature VEGF-D (VEGFDΔNΔC) delivered by adenovirus. Expression of membrane proteins in endothelial cells was characterized by FACS using anti-human IT-Box-135 antibodies. HUVECs transduced with Ad-VEGF-DΔNΔC revealed markedly increased expression of proteins involved in adhesion and migration such as (a) integrins (αVβ5, α2β1, α5β1, αMβ2, αLβ2), (b) matrix metalloproteinases (MMP-2, MMP-9, and MMP-14), (c) components of fibrinolytic system (PAI-1, u-PAR), and (d) CD45, CD98, CD147. Interestingly, there also were numerous proteins with significantly reduced expression, particularly among surface exposed membrane proteins. Thus, it can be concluded that to induce proangiogenic phenotype and facilitate migration of HUVECs, VEGF-DΔNΔC not only upregulates expression of proteins known to participate in the cell-matrix interactions but also silences some membrane proteins which could interfere with this process.