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目的 构建缺氧及辐射双敏感性启动子 ,增强缺氧条件下放射诱导的抑瘤素M (OSM)表达水平 ,提高肺癌放射 基因治疗效果。方法 利用基因重组构建缺氧及辐射双敏感性缺氧反应元件早期生长反应基因 (HRE Egr)启动子及其调控的OSM表达载体 ;以脂质体转染肺癌A5 4 9细胞 ,给予照射 ( 6Gy)和 (或 )缺氧 ( 1%氧浓度 )处理 ,观察其OSM表达水平及细胞存活率的变化。利用肺癌移植瘤观察不同处理后的抑瘤效应。结果 HRE Egr启动子具有辐射及缺氧双重敏感性 ,它可使照射后的肺癌细胞OSM表达水平在缺氧条件下显著提高 ,为常氧条件下的 3倍。在缺氧条件下 ,重组质粒 pHEO转染合并照射处理后细胞存活率 [( 9 5± 2 8) % ]显著低于常氧组 [( 34 8± 3 6 ) % ;χ2 =11 375 ,P =0 0 0 3]。HRE Egr启动子转染合并照射可明显抑制肺癌移植瘤 ,并可使 6 0 %的移植瘤完全消退。结论 用HRE Egr启动子提高OSM表达水平 ,可增强肺癌移植瘤放射 基因治疗疗效
OBJECTIVE: To construct dual hypoxia and radiosensitive promoters to enhance the expression of radiation-induced oncogene M (OSM) under hypoxia and to improve the radiotherapy effect of lung cancer. Methods HRE Egr promoter and its regulated OSM expression vector were constructed by gene recombination. A549 cells were transfected with A549 cells by lipofectamine and irradiated with 6 Gy ) And / or hypoxia (1% oxygen concentration), the changes of OSM expression and cell survival were observed. Lung cancer xenografts were used to observe the antitumor effect of different treatments. Results The HRE Egr promoter had the dual sensitivity of radiation and hypoxia. It could significantly increase OSM expression in irradiated lung cancer cells under hypoxia, which was three times of that under normoxia. Under hypoxic condition, the cell viability after transfection with recombinant plasmid pHEO was significantly lower than that in the normoxia group [(34 8 ± 36)%; χ2 = 11 375, P = 0 0 0 3]. HRE Egr promoter transfection combined irradiation can significantly inhibit lung cancer xenografts, and 60% of the xenografts completely subsided. Conclusion The use of the HRE Egr promoter to enhance the expression of OSM can enhance the efficacy of radiation gene therapy for lung cancer xenografts