Inhibition of PI3K abrogates the TRAF6 protective effect. Double-transduced endothelial cells (as labeled) were treated with LPS (100 ng/mL) and CHX (50 μg/mL) for 8 hours following a 60-minute pretreatment with vehicle or specific inhibitor as indicated. Apoptotic cells were quantitated by labeling with Alexa 594-conjugated annexin V. Results shown are the increase in percentage of annexin V-positive cells over CHX treatment alone, and represent the mean plus or minus SEM of 3 independent experiments. ^*P < .05.