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Cytochrome P-450 (CYP) epoxygenases metabolize arachidonic acid to epoxyeicosatrienoic acid (EET) regioisomers, which activate several signaling pathways to promote endothelial cell proliferation, migration, and angiogenesis. Since vascular endothelial growth factor (VEGF) plays a key role in angiogenesis, we assessed a possible role of EETs in the VEGF-activated signal transduction cascade. Stimulation with VEGF increased CYP2C promoter activity in endothelial cells and enhanced CYP2C8 mRNA and protein expression resulting in increased intracellular EET levels. VEGF-induced endothelial cell tube formation was inhibited by the EET antagonist 14,15-epoxyeicosa-5(Z)-enoic-acid (14,15-EEZE), which did not affect the VEGF-induced phosphorylation of its receptor or basic fibroblast growth factor (bFGF)-stimulated tube formation. Moreover, VEGF-stimulated endothelial cell sprouting in a modified spheroid assay was reduced by CYP2C antisense oligonucleotides. Mechanistically, VEGF stimulated the phosphorylation of the AMP-activated protein kinase (AMPK), which has also been linked to CYP induction, and the overexpression of a constitutively active AMPK mutant increased CYP2C expression. On the other hand, a dominant-negative AMPK mutant prevented the VEGF-induced increase in CYP2C RNA and protein expression in human endothelial cells. In vivo (Matrigel plug assay) in mice, endothelial cells were recruited into VEGF-impreghated plugs; an effect that was sensitive to 14,15-EEZE and the inclusion of small interfering RNA directed against the AMPK. The EET antagonist did not affect responses observed in plugs containing bFGF. Taken together, our data indicate that CYP2C-derived EETs participate as second messengers in the angiogenic response initiated by VEGF and that preventing the increase in CYP expression curtails the angiogenic response to VEGF. cytochrome P-450; matrigel plug assay

An unprecedented organocatalytic, enantioselective oxy-Michael addition to achiral [gamma]/[delta]-hydroxy-[alpha],[beta]-enones and its use in the preparation of the structural motif is described. The oxy-Michael adduct formed from (E)-4-hydroxy-1-phenyl-2-buten-1-one and phenylboronic acid under catalysis by quinine-based catalyst has acted as a template for the stereoselective addition of allenylboronic acid to the carbonyl.

The article discusses the asymmetric version of the oxy-Michael-addition-utilizing chiral hemiketals derived from D-glucose and D-fructose in the case of achiral γ/ö-hydroxy-α,ß-enones. The intermediate amine, called a boronate complex, acts as a chiral hydroxide surrogate of synthon. The coordination of the carbonyl by the thiourea and complexation of the tertiary nitrogen to boron will enhance the nucleophilicity of the boronate oxygen.