In order to identify molecular targets of environmental polycyclic aromatic hydrocarbons (PAHs), we have analysed regulation of integrin (ITG) expression in PAH-exposed human macrophages. Among ITG subunits, beta 7 ITG was found to be markedly up-regulated at both mRNA and protein levels in response to the prototypical PAH benzo(a)pyrene (BP). Knock-down of the transcription factor c-maf, known to control beta 7 ITG expression, markedly impaired BP-mediated beta 7 ITG induction. Moreover, chromatin immunoprecipitation and electrophoretic mobility shift assays showed BP-triggered binding of c-maf to a specific maf-responsive element found in beta 7 ITG promoter. Such a binding, and also beta 7 ITG induction, were however abolished in response to chemical inhibition of the aryl hydrocarbon receptor (AhR), to which PAHs bind. Taken together, these data establish beta 7 ITG as a new molecular target of PAHs, whose upregulation by these environmental contaminants most likely requires activation of co-operative pathways involving both AhR and c-maf. (C) 2007 Elsevier Inc. All rights reserved.