A ROLE OF SRC‐ACTIVATED STAT‐3 IN 14, 15‐EPOXYEICOSATRIENOIC ACID‐INDUCED VEGF EXPRESSION AND ANGIOGENESIS

Abstract

Previously we have shown that 14,15‐epoxyeicosatrienoic acid (14,15‐EET) induces angiogenesis via PI3K‐Akt‐dependent FGF‐2 expression and mTOR‐S6K1 activation. To understand the molecular mechanisms underlying 14,15‐EET‐induced angiogenesis, here we have studied the role of STAT‐3. 14,15‐EET stimulated the tyrosine phosphorylation of STAT‐3 and its translocation from the cytoplasm to the nucleus in HDMVEC. Adenovirus‐mediated delivery of dominant negative STAT‐3 substantially inhibited 14,15‐EET‐induced HDMVEC migration, and tube formation and Matrigel plug angiogenesis. 14,15‐EET activated Src as measured by its tyrosine phosphorylation and blockade of its activation by adenovirus‐mediated expression of its dominant negative mutant significantly attenuated 14,15‐EET‐induced STAT‐3 phosphorylation in HDMVEC and the migration and tube formation of these cells and Matrigel plug angiogenesis. 14,15‐EET induced the expression of vascular endothelial cell growth factor (VEGF) in a time‐and Src‐STAT‐3‐dependent manner in HDMVEC. Transfac analysis of VEGF promoter revealed the presence of STAT‐binding elements and 14,15‐EET induced STAT‐3 binding to this promoter both in vitro and in vivo and this interaction was inhibited by suppression of Src‐STAT‐3 signaling. Neutralizing VEGF antibodies completely blocked 14,15‐EET‐induced HDMVEC migration and tube formation and Matrigel plug angiogenesis. These results show for the first time that Src‐dependent STAT‐3‐mediated VEGF expression is a major contributing factor in 14,15‐EET‐induced angiogenesis. NIH.