Endothelial network formation and proliferation is mediated via the ERK1/2 pathway. (A) Endothelial network formation and (B) proliferation in HUVECs treated with V CM or P CM in the absence/presence of inhibitors of ERK1/2 (PD98059), mTOR (rapamycin) or PI3K (wortmannin or LY294002). (C) Endothelial network formation and (D) proliferation in HUVECs treated with vehicle or recombinant FGF2 protein (50 ng/ml) in the absence/presence of rapamycin. Data are expressed as percentage increase over control V CM (where V CM = 100%, not shown) and presented as mean ± SEM. (* represents statistical significance P < 0.05).