Department of Dentistry, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan; Department and Graduate Institute of Biochemistry, National Defense Medical Center, Taipei, Taiwan. Electronic address: [Email]
OBJECTIVE : To investigate the effect of nicotine on cell survival and cisplatin resistance in oral cancer and the possible involvement of α7-nicotinic acetylcholine receptors (α7-nAChRs). METHODS : The effects of nicotine on cell survival and cisplatin-induced apoptosis were assessed. Knockdown of α7-nAChRs by short hairpin RNA and the specific antagonist methyllycaconitine (MLA) was used to examine the involvement of α7-nAChRs in modulating the effects of nicotine. Apoptosis signal molecules were examined in nicotine- and cisplatin-treated cells. RESULTS : Nicotine increased the survival of the oral cancer cells YD8 and OEC-M1 in a dose- and time-dependent manner. Nicotine treatment accelerated cell cycle progression in the oral cancer cells, and significantly reduced cisplatin-induced cell apoptosis. In the α7-nAChR-silenced cells, the prosurvival effect of nicotine in the cisplatin-treated cells was attenuated. Co-treatment of cisplatin and nicotine attenuated the effect of cisplatin on Bcl-2 expression. In addition, the effect of nicotine on cell survival under cisplatin treatment was attenuated with the addition of the Bcl-2 inhibitor ABT-737. CONCLUSIONS : Treating oral cancer cells with nicotine increased cell survival and cisplatin resistance, in which α7-nAChRs were involved.