The effects of nicotine on human airway epithelial cells

Objective To investigate the genome changes of primary human airway epithelial cells exposed to nicotine in vitro, and therefore to understand the effect of nicotine on the cellular physiological process and phenotypes. Methods The primary human airway epithelial cells were divided into 4 groups: 4 h experimental group and control group, 48 h experimental group and control group, with 1×108/L cells in each culture. Total RNA was extracted from cells after incubated with nicotine (1×10-5 mol/L) for 4 h or 48 h respectively. The genes expressed differentially were detected by a gene chip, and those related to epithelial mesenchymal transition were selected to undergo real-time PCR for verification. Results Sixty-three up-regulated genes and 44 down-regulated genes were detected in the experimental group incubated with nicotine for 4 h, which were mainly involved in the stress response. There were 860 up-regulated genes and 582 down-regulated genes found in the cells treated with 1×10-5 mol/L nicotine for 48 h, compared with the control. These genes were mainly involved in some important physiological processes and pathways with transdifferentiation, including embryonic development, cell polarity maintaining, cell adhesion, etc. Further analysis revealed that some epithelial markers such as epithelial keratin and epithelial mucin protein were down-regulated, while mesenchymal cell markers including fiber connecting protein 1 and N-cadherin were up-regulated. The results by real-time PCR showed consistency with those by gene chip examination. Conclusion Nicotine could promote a series of changes in genes related to epithelial mesenchymal transdifferentiation process in human airway epithelial cells. Key words: Nicotine; Epithelial cells; Oligonucleotide array sequence analysis; Epithelial mesenchymal transdifferentiation