VE-cadherin protects HUVECs from apoptosis. (A) HUVECs (10⁵) grown in 6-well plates were transduced with adenovirus (VE-cadherin [VEC]–-GFP and GFP). Four days later, GFP expression levels were determined by flow cytometry, and GFP autofluorescence was visualized using confocal microscopy. Objective lens used was Plan-Neofluar 40×/1.3 oil (Carl Zeiss). VE-cadherin–GFP localizes to the endothelial cell junctions. (B) To quantify apoptosis, cells were fixed in ethanol and stained for propidium iodide. Sub-G₁ apoptotic nuclei were quantified by flow cytometry. Expression of VE-cadherin–GFP significantly reduces cell death, *P < .05. Values are means plus or minus SEM, n = 7. (C) HUVECs (10⁵) grown in 6-well dish were transduced with adenovirus (VEC-GFP and GFP). After 48 hours, cells were transfected with either control GB or Erg-specific GB (100 nM). After a further 48 hours, cells were fixed in ethanol and stained with propidium iodide to determine apoptosis. Apoptosis induced by Erg inhibition was significantly decreased in the VE-cadherin overexpressing cells, indicating that the survival pathway regulated by Erg involves VE-cadherin. *P < .05, **P < .01. Values are means plus or minus SEM, n = 7.