title: Reversible and permanent effects of tobacco smoke exposure on airway epithelial gene expression.
abstract: BACKGROUND
  Tobacco use remains the leading preventable cause of death in the US. The risk of dying from smoking-related diseases remains elevated for former smokers years after quitting. The identification of irreversible effects of tobacco smoke on airway gene expression may provide insights into the causes of this elevated risk.
  
  
  RESULTS
  Using oligonucleotide microarrays, we measured gene expression in large airway epithelial cells obtained via bronchoscopy from never, current, and former smokers (n = 104). Linear models identified 175 genes differentially expressed between current and never smokers, and classified these as irreversible (n = 28), slowly reversible (n = 6), or rapidly reversible (n = 139) based on their expression in former smokers. A greater percentage of irreversible and slowly reversible genes were down-regulated by smoking, suggesting possible mechanisms for persistent changes, such as allelic loss at 16q13. Similarities with airway epithelium gene expression changes caused by other environmental exposures suggest that common mechanisms are involved in the response to tobacco smoke. Finally, using irreversible genes, we built a biomarker of ever exposure to tobacco smoke capable of classifying an independent set of former and current smokers with 81% and 100% accuracy, respectively.
  
  
  CONCLUSIONS
  We have categorized smoking-related changes in airway gene expression by their degree of reversibility upon smoking cessation. Our findings provide insights into the mechanisms leading to reversible and persistent effects of tobacco smoke that may explain former smokers increased risk for developing tobacco-induced lung disease and provide novel targets for chemoprophylaxis. Airway gene expression may also serve as a sensitive biomarker to identify individuals with past exposure to tobacco smoke.
authors: Bioinformatics Program, Boston University, Cummington Street, Boston, MA 02215, USA. jbeane@bu.edu
authors: Jennifer
authors: J
authors: Beane
authors: Paola
authors: P
authors: Sebastiani
authors: Gang
authors: G
authors: Liu
authors: Jerome S
authors: JS
authors: Brody
authors: Marc E
authors: ME
authors: Lenburg
authors: Avrum
authors: A
authors: Spira
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers; D004848:Epithelium / Q000187:drug effects; D005786:Gene Expression Regulation; D006801:Humans; D008875:Middle Aged; D020411:Oligonucleotide Array Sequence Analysis; D015203:Reproducibility of Results; D012137:Respiratory System / Q000187:drug effects*; D012906:Smoke; D012907:Smoking; D014028:Tobacco Smoke Pollution / Q000009:adverse effects*; D014132:Trachea / Q000187:drug effects*; D014026:Nicotiana
chemical_list: D015415:Biomarkers; D012906:Smoke; D014028:Tobacco Smoke Pollution