The antiadhesive activity of TRAIL is mediated by down-regulation of chemokines. Differential chemokine gene expression was assessed by cDNA microarray analysis in HUVECs, either left untreated or pretreated with TRAIL for 3 days, before stimulation with TNF-α. (A) Ratios represent TNF-α (▪) or TRAIL (3 days) plus TNF-α (▨) values divided by untreated values. The cut-off of 2-fold of induction is shown as a vertical line. Arrows indicate the genes most significantly down-modulated by the TRAIL pretreatment. (B) Microarray results were validated by semiquantitative RT-PCR (1-4, serial scalar dilutions of the RNA templates; GAPDH, housekeeping gene). (C) Chemokine release by HUVECs either left untreated or pretreated with TRAIL for 3 days, before stimulation with TNF-α, was measured by ELISA. Results are expressed as means ± SD of 3 independent experiments, each performed in triplicate. ^*P < .05.