Involvement of Egr-1 in cocaine-induced expression of PDGF-BB. (A) Whole cell lysates from HBMECs transfected with either Egr-1/nonsense (Non) siRNAs subject to Western blot analysis. (B) Egr-1 siRNA but not nonspecific siRNA inhibited cocaine-mediated induction of PDGF-BB. (C) DN-MEK but not WT-MEK inhibited cocaine-mediated induction of PDGF-BB. (D) Schematic illustration of Egr-1 binding consensus sequence on the PDGF-B promoter region. (E) ChIP assay demonstrating cocaine-mediated binding of Egr-1 to the PDGF-B promoter. Histone lane: positive control; IgG lane: negative control. All data are presented as mean ± SD of 3 separate experiments. *P < .05, **P < .01 vs control group.