Cigarette smoking affects all phases of atherosclerosis from endothelial dysfunction to acute occlusive clinical events. We explored activation by exposure to tobacco smoke of two genes, beta-catenin and COX-2, that play key roles in inflammation and vascular remodeling events. Using both in vivo and in vitro smoke exposure, we determined that tobacco smoke (TS) induced nuclear beta-catenin accumulation and COX-2 expression and activity and moreover interacted with IL-1beta to enhance these effects. Exposure of cardiac endothelial cells to tobacco smoke plus IL-1beta (TS/IL-1beta) enhanced permeability of endothelial monolayers and disrupted membrane VE-cadherin/beta-catenin complexes, decreased beta-catenin phosphorylation, and increased phosphorylation of GSK-3beta, Akt, and EGFR. Transfection of endothelial cells with beta-catenin-directed small interfering RNA (siRNA) suppressed TS/IL-1beta-mediated effects on COX-2 modulation. Inhibitors of EGFR and phosphatidylinositol-3-kinase also abolished both the TS/IL-1beta-mediated modulation of the Akt/GSK-3beta/beta-catenin pathway and enhancement of COX-2 expression. Moreover, increased levels of Akt and GSK-3beta phosphorylation, nuclear beta-catenin accumulation, COX-2 expression, and IL-1beta were observed in cardiovascular tissue of ApoE-/- mice exposed to cigarette smoke daily for 2 wk. Our results suggest a novel mechanism by which cigarette smoking can induce proinflammatory and proatherosclerotic effects in vascular tissue.