Molecular changes in multiple signaling pathways that regulate oxidative stress, inflammation and xenobiotic metabolism are frequently observed in diseased lung. The purposes of this study were: 1) to assess differential gene expression profiles in human lung tissue or cells of non-smokers and smokers with and without lung cancer or COPD and 2) to compare gene expression changes induced by smoke in in vitro cultures of NHBE cells to expression profiles from ex vivo lung tissue samples.

Gene expression profiles were evaluated with the Affymetrix HG_U133 Plus 2.0 GeneChip Microarray. First, expression profiles which distinguished normal tissues from non-smokers and smokers were represented by 115 statistically significant probe sets (genes). Pathway and gene ontology analyses identified several ontologies containing overrepresented genes in smokers, including those involved in immune response and T cell activation. Second, gene profiles (7880 probe sets) and molecular pathways that distinguished malignant lung of smokers from the paired normal tissue were associated with immune response, cell cycle regulation and tryptophan metabolism. Third, comparisons of bronchial brushings from non-smoker, smoker and COPD (GOLD 0 - II) yielded 63 unique probe sets. NADPH quinone oxidoreductase (NQO1), mucin 5AC and glutamate decarboxylase 1 were among notable targets, and the top pathways represented oxidative stress, xenobiotic metabolism and hypoxia.

Finally, as we previously reported, the top responders in the NHBE cells exposed to repeated applications of cigarette smoke condensate (CSC) were represented by 241 consistently regulated probe sets with significant deregulation of genes involved in oxidative stress, xenobiotic and tryptophan metabolism. Bioinformatic analyses were further employed to identify correlations with smoke and disease-impact in ex vivo lung samples. The gene profiles that were significantly modified in both CSC-exposed NHBE cells and COPD lung brushings included aldo-keto reductases (AKR1B10, AKR1C1, AKR1C2), cytochrome P450 1B1 (CYP1B1), NQO1, glutathione peroxidase 2 (GPX2) and SLC7A11, an amino acid transporter. Probe sets significantly regulated in both CSC-exposed NHBE cells and the cancerous and smoking-exposed lung were osteopontin (OPN/Spp1), dedicator of cytokinesis 10 (DOCK10), glycerol kinase (GK), kynureninase (KYNU) and transforming growth factor beta 2 (TGFB2).

Collectively, the data suggest that smoke-induced expression profiles in in vitro lung cell models are phenotypically relevant to lung modifications in vivo and may serve as potential biomarkers of effect.