IGF1 increases HIF1α protein levels in differentiating embryoid bodies and inhibition of HIF1α with rapamycin decreases VEGF and VEGFR2 expression in embryoid bodies treated with IGF1.

<p>A) HIF1αlevels increase significantly following treatment with IGF1. Rapamycin reduces protein levels when added to cell cultures prior to IGF1 stimulation. * denotes P<0.05 compared to conrol, ** denotes P<0.05 compared to +IGF B) Day 3 EB treated with IGF1 express significantly higher levels of VEGF and VEGFR2 compared with control (# denotes P<0.05 compared with control), which are significantly inhibited by treatment with HIF1α inhibitor rapamycin. (* denotes P<0.05 compared to IGF1 treatment). C) Proposed mechanism of IGF1 and IGF2 stimulated endothelial differentiation.