Epoxygenase-driven angiogenesis in human lung microvascular endothelial cells

Angiogenesis is one of the most recent physiological functions attributed to products of cytochrome P-450 (CYP450) enymes. To test this at a molecular level in human cells, we used a cloned cDNA for the human endothelial enzyme CYP450 2C9 (CYP2C9) to study growth as well as differentiation of human microvascular endothelial cells from the lung (HMVEC-L). Using adenoviral vectors overexpressing mRNA for CYP2C9, we show that the presence of CYP2C9 doubles thymidine incorporation and stimulates proliferation of primary cultures of endothelial cells compared with Ad5-GFP (control) in 24 h. In addition, there is a significant increase of tube formation in Matrigel after infection of HMVEC-L with Ad5-2C9 than with Ad5-GFP. More interestingly, Ad5-2C9 expressing the antisense product of CYP2C9 (2C9AS) inhibited tube formation compared with both Ad5-GFP as well as the Ad5-2C9 constructs. Finally, we tested the most abundant arachidonic acid metabolite of CYP2C9, 14,15-epoxyeicosatrienoic acid, which induced angiogenesis in vivo when embedded in Matrigel plugs and implanted in adult rats. These data support an important role for CYP2C9 in promoting angiogenesis.