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Cigarette smoke extract inhibits the proliferation of alveolar epithelial cells and induces apoptosis

Jiao Zongxian, Ao Qilin, Xiong Mi

Department of Pathology,Tongji Medical College,Huazhong University of Science and Technology.Wuhan 430030,Hubei

Abstract

Cigarette smoke extract (CSE) contains abundant oxidants/free radicals. Oxidative stress caused by cigarette smoking results in the destruction of the alveolar cell walls and emphysema. However, there exists discrepancy about how CSE works in the process. In the present study, we observed the effect of CSE on the cell growth of alveolar epithelial cell type II-derived A549 cell line, and provided molecular understanding of this effect. The MTT assay results showed that CSE decreased the cell viability of A549 cells in a dose- and time-dependent manner, and cell cycle was arrested in G_(1)/S phase. Furthermore, CSE-induced apoptosis of A549 cells was verified by Hoechst 33258 staining, electronic microscopy in morphology, and the appearance of DNA fragmentation and annexin-FITC/propidium iodide (PI) staining assay. CSE treatment was found to result in the upregulation of Fas/APO-1 receptor and activated caspase-3. Besides, CSE also initiated accumulation of intracellular reactive oxygen species, which was detected by laser confocal microscopy. Taken together, CSE could inhibit the cell growth and induce apoptosis of A549 cells involving Fas receptor pathway, oxidative stress caused by CSE may be the radical factor leading to apoptosis as well as cell growth inhibition of alveolar epithelial cells.

Key words: cigarette smoke;alveolar epithelial cells;Apoptosis;Fas receptor

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Citing This Article：

Jiao Zongxian, Ao Qilin, Xiong Mi. Cigarette smoke extract inhibits the proliferation of alveolar epithelial cells and induces apoptosis. Acta Physiol Sin 2006; 58 (3): (in Chinese with English abstract).