外源性p53基因对人胃癌细胞的放射增敏作用

目的:评价外源性p53基因对人胃癌细胞放射敏感性的影响.方法:以复制缺陷型重组腺病毒为载体,将人野生型p53基因导入不同p53状态的4种人胃癌细胞系,用免疫组化法及Western blot法检测p53基因在胃癌细胞中的表达;用细胞存活份数来表示细胞的生长抑制情况;用流式细胞计数、细胞DNA片段化分析和TUNEL检测细胞凋亡.结果:[ HTSS 在高效靶比病毒剂量下,外源p53基因在4种胃癌细胞的胞核中均高效表达,并可使细胞产生明显的G2/M 阻滞和凋亡,使细胞存活份数明显减少.而且这种作用不依赖细胞内在的p53基因状态.单独照射4 Gy,对野生型p53细胞的生长抑制和致凋亡效应明显,而对其它3种细胞的作用较弱 .照射4 Gy结合Ad-p53时,外源p53基因可显著增强照射引起的G2/M期阻滞和凋亡及生长抑制作用,对4种胃癌细胞放射增效比高达2.3～3.6.结论:腺病毒载体介导的野生型p53基因转染4种胃癌细胞后有明显的放射增敏作用.

Enhancement of radiosensitivity of human gastric ca rcinoma cell lines by adenovirus-mediated delivery of the p53 gene

Objective: To determine the radiosensitization efficacy of adenovirus mediated wild type p53 gene (Ad p53)on human gastric carcinoma cell lines. Methods: Human wild type p53 gene was transfected into gastric carcinoma cell lines with different p53 status by recombinant adenovirus. Its expression product was detected by immunohistochemistry assay and Western blot assay. Cell growth assay was carried out using cell survival ratio. Cell apoptosis was detected by flow cytometric analysis and DNA fragment analysis and TUNEL assay. Results: p53 gene could be efficiently expressed in four gastric carcinoma cell lines, which could greatly induce G 2/M arrest and cell apoptosis and suppress cell growth. Its function didn't depend on the intrinsic p53 genetic status of gastric carcinoma cell lines. After only 4 Gy irradiation, its function of inducing G 1 arrest and apoptosis and suppressed cell growth on cell line W was much stronger than the others. Combination of irradiation and p53 transfection was more effective than either treatment alone to four cell lines. p53 gene could greatly enhance radiation induced G 2/M arrest and apoptosis and growth inhibition, which sensitive enhancement ratio was 2.3 3.6. Conclusion: The results demonstrated that adenovirus mediated p53 gene significantly increased the radiosensitivity of human gastric carcinoma cell lines.