Epigenetic alternation of lung cancer AND the effect of 14-3-3sigma of cisplatin-quercetin induced cell proliferation and apoptosis in lung cancer cell line

• Main Authors: Chih-Wen, 張智雯
• Other Authors: Li-Sung Hsu
• Format: Others
• Language: en_US
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/09047164656831688779

碩士 === 中山醫學大學 === 生化暨生物科技研究所 === 93 === Epigenetic inactivation of tumor suppressor genes by aberrant promoter methylation is frequently observed in lung carcinomas and seems so play an important role in the pathogenesis of this tumor type. Hypermethylation has been shown in the promoter region of the endothelin receptor B (EDNRB) gene in several human tumors, but its role in lung cancer formation is unclear. In this study, genomic DNA from lung cancer patients was subjected to methylation-specific PCR to determine the methylation status of the EDNRB gene in lung cancer. Aberrant methylation of the EDNRB gene was detected in 32.9% (26 of 79) lung cancer patients. Treatment H1355 (human lung cancer cell line) with 5’-aza-2’-deoxycytidine (demethylation reagent) to determine the relationship between hypermethylation of the promoter region and the activation of EDNRB gene. Our results suggest that inactivation of the EDNRB gene through epigenetic alteration may play an important role in lung cancer tumorigenesis. Of the 7 14-3-3 isoforms, 14-3-3σ has been linked to cancer most directly, and its acts as a tumor suppressor gene. Cisplatin is widely used anti-cancer agents in the treatment of various tumors. The natural product Quercetin has been shown to sensitize cells to the cytotoxic potential of Cisplatin. In this study, we use MTT assay, DNA fragmentation, Western blotting and flow cytometry to analyze the cellular response of overexpressed 14-3-3σ that treat with Cisplatin and Quercetin alone or combination. The rusult of MTT assay and flow cytometry showed that after treated with DNA damage reagent overexpressed 14-3-3σ induct cell apoptosis and promote cell cycle arrest at G2/M phase.