Reactive oxygen species-mediated mitochondrial dysfunction is involved in apoptosis in human nasopharyngeal carcinoma CNE cells induced by Selaginella doederleinii extract

Authors Liu, Huanhai; Peng, Hu; Ji, Zhenhua; Zhao, Shuwei; Zhang, Yinfang; Wu, Jian; Fan, Jingping; Liao, Jianchun

Journal JOURNAL OF ETHNOPHARMACOLOGY , OCT 31 2011,1:138

DOI 10.1016/j.jep.2011.08.072 PubMed 21924341

Abstract Ethnopharmacological relevance: A traditional Chinese medicine Selaginella doederleinii Hieron has been combined with radiotherapy for the treatment of human nasopharyngeal carcinoma in clinic in China. However, the detailed mechanism of anti-tumor effect of Selaginella doederleinii remains elusive.Aim of the study: This study was designed to investigate the anti-tumor effect of ethanol extract of Selaginella doederleinii (SDE) on human nasopharyngeal carcinoma and its possible mechanisms.Materials and methods: Viability, apoptosis and protein expression of tumor cells were analyzed by MTT, Annexin V staining and Western blot, respectively. Formation of intracellular reactive oxygen species was determined using dichlorofluorescin fluorescence. The in vivo anti-tumor effect was evaluated by measuring tumor volume changes and TUNEL staining in nude mice.Results: SDE significantly inhibited the growth and induced apoptosis in human nasopharyngeal carcinoma CNE cells. In addition, SDE triggered the mitochondrial/caspase apoptotic pathway indicated by enhanced Bax-to-Bcl-2 ratio, loss of mitochondrial membrane potential, cytochrome c release, and caspase cascade. Moreover, SDE provoked the generation of reactive oxygen species in CNE cells, while the antioxidant N-acetyl cysteine almost completely blocked SDE-induced disruption of mitochondrial membrane potential, caspases activation and apoptosis. Furthermore, a transplantable nude mice model was utilized to estimate the effectiveness of SDE in vivo. The treated mice displayed decreased tumor size, which was associated with enhanced apoptotic cell death.Conclusions: These results, offering solid evidence of the induction of mitochondria-related apoptosis in tumor cells, provide the molecular theoretical basis of clinical application of Selaginella doederleinii for the treatment of human nasopharyngeal carcinoma. (C) 2011 Elsevier Ireland Ltd. All rights reserved.