FIG. 8.

Insulin attenuates VEGF expression and HIF-2 transcriptional activity on VEGF promoter in an mTOR-dependent manner in lung epithelial cells. (A) Western blot analysis of VEGF and HIF-2α in A549 cells treated with insulin and/or rapamycin for 48 h. The right panel shows the densitometric analysis. *, P < 0.05 versus the rapamycin (−)/insulin (−) group (n = 3 for each group). (B and C) Luciferase assays in A549 cells. A549 cells were transfected with a VEGF-luc reporter and expression vectors for HIF-1α, HIF-2α, and ARNT and treated with insulin and/or rapamycin. All experiments were performed in the presence of CoCl₂ to mimic hypoxic conditions. *, P < 0.05 versus the rapamycin (−)/insulin (−) group.