Glutathione S-transferase A1 mediates nicotine-induced lung cancer cell metastasis by promoting epithelial-mesenchymal transition.

The present study aimed to investigate the effect of glutathione S-transferase A1 (GSTA1) on lung cancer cell viability, invasion and adhesion in the presence of nicotine in vitro. Furthermore, the effect of GSTA1 on the epithelial-mesenchymal transition (EMT), a process strongly associated with lung cancer metastasis, was examined. Human lung carcinoma A549 cells were treated with various concentrations of nicotine (0.01, 0.1, 1 and 10 mu M) and levels of GSTA1 mRNA and protein were measured by reverse transcription-quantitative polymerase chain reaction and western blot analysis, respectively. To knock down GSTA1 expression, GSTA1-small interfering RNA was transfected into A549 cells. Cell viability, invasion and adhesion abilities were determined by MTT, Transwell-Matrigel invasion and cell adhesion assays, respectively. The expression of the epithelial cell markers E-cadherin and keratin, and the mesenchymal cell markers vimentin and N-cadherin in A549 cells were examined by western blot analysis. The current study indicated that the expression of GSTA1 was increased in A549 cells following nicotine treatment. GSTA1 suppression inhibited the viability, invasion and adhesion of lung cancer cells. In addition, the increase in lung cancer cell viability, invasion and adhesion by nicotine was suppressed following GSTA1 knockdown. Furthermore, GSTA1 affected the expression of EMT markers in nicotine-treated or untreated lung cancer cells. Thus the present study demonstrates that GSTA1 promotes lung cancer cell invasion and adhesion and mediates the effect of nicotine on lung cancer cell metastasis in vitro. Furthermore, the results demonstrated that GSTA1 exerts its effect on lung cancer cell metastasis by promoting the EMT.