Abstract
Tobacco-related diseases are leading causes of death worldwide, and many are associated with expression of matrix metalloproteinase-1 (MMP-1). We have reported extracellular signal-regulated kinase (ERK)1/2-dependent induction of MMP-1 by cigarette smoke in lung epithelial cells. Our objectives were to define regions of the human MMP-1 promoter required for activation by smoke, to identify differences in responses of the 1G/2G -1607 polymorphic promoters to smoke, and to identify relevant transcription factors whose activity in airway epithelial cells is increased by smoke. The responses of deletion and mutant promoter constructs were measured in transfected cells during exposure to cigarette smoke extract (CSE). DNA oligonucleotide arrays were used to identify transcription factors activated after smoke exposure. CSE activated the MMP-1 promoter, and this induction was prevented by PD98059 blockade of ERK1/2 phosphorylation. Deletion studies revealed the distal 1kb promoter region (-4438 to -3280 upstream of the transcription start site) is essential for CSE induction of MMP-1, and confers activation of a minimal promoter. Studies of 1G and 2G MMP-1 polymorphic promoter variants revealed higher 2G allele basal and CSE-responsive activities than the 1G allele. Cotransfection, mithramycin, and electrophoretic mobility shift assay studies identified activating and repressive roles for Sp1 and PEA3 transcription factors, respectively. Oligonucleotide DNA arrays confirmed activation of Sp1 and PEA3 by CSE. These data demonstrate that the MMP-1 promoter is a direct target of cigarette smoke in lung epithelial cells. This characterization of a smoke response region in the distal MMP-1 promoter has implications for smoking-related diseases such as cancer, heart disease, and emphysema.