腺病毒介导p53基因转染增加人胃癌细胞的放射敏感性

目的评价腺病毒介导p53基因(Adp53)转染对人胃癌细胞的凋亡效应和放射增敏作用。方法以重组腺病毒介导p53基因感染4种不同p53状况的人胃癌细胞，用免疫组织化学法和Western blot法检测P53蛋白在胃癌细胞中的表达；用细胞集落形成法检测细胞存活率；用TUNEL法检测细胞凋亡。胃癌细胞感染Adp53后照射4Gy，用流式细胞仪检测细胞周期分布和凋亡；胃癌细胞种植肿瘤内注射Adp53后照射6Gy，以肿瘤相对体积增长曲线观察肿瘤抑制情况。结果1：100效靶比(MOI)Adp53产生细胞高转染率，以及p53基因在4种胃癌细胞中均高表达，并产生G2/M期阻滞、凋亡增加和细胞增殖抑制。如果以凋亡评价放射效应，Adp53转染对4Gy照射4种细胞的凋亡率比值为：W细胞3．0，M细胞3．6，neo细胞2．2，823细胞2．5。体内实验结果显示，Adp53对w细胞肿瘤6Gy照射的抑瘤率比值为1．41，而对M细胞肿瘤为1．91。结论腺病毒介导p53基因转染产生细胞凋亡并提高人胃癌细胞的放射敏感性，这种作用不依赖于细胞内在的p53状况。

Adenovirus-mediated p53 gene transfer increases radiosensitivity of human gastric carcinoma cells

Objective To evaluate the effect of adenovirus-mediated p53 gene ( Adp53) on apoptosis and radiosensitivity of human gastric carcinoma cell lines. Methods Recombinant adenovirus carrying wild-type p53 gene was transferred into four human gastric carcinoma cell lines with different p53 genetic status. P53 protein expression was detected by immunohistochemistry and Western blot assay. Cell survival was assessed using a clonogenic assay. TUNEL assay was used in determination of apoptosis. The four human gastric carcinoma cell line infected with Adp53 were irradiated with 4 Gy,and cell cycle distribution and apoptotic rate were assayed by flow cytometry. Nude mice xenograft models of W and M cell were intratumorally injected with Adp53 and 48 h later were irradiated with 6 Gy. Relative volume in growth curve of tumor was used to observe tumor regression. Results G_2/M arrest ,apoptosis and inhibition of tumor cell proliferation were induced by infection with Adp53 at 100 MOI,which caused high transfer rate of wild-type p53 and strong expression of P53 protein in the four human gastric carcinoma cell line cells. When evaluating radio-biologic efficacy by apoptotic rate,the apoptotic enhencement ratio of Adp53 at 4 Gy was 3.0 for W cell,3.6 for M cell,2.2 for neo cell and 2.5 for 823 cell respectively,in vitro. The antitumor enhencement ratio of Adp53 at 6 Gy was 1.41 for W cell-implanted tumor and 1.91 for M cell-implanted tumor in vivo. Conclusion This study demonstrated that Adp53 transfer increased cellular apoptosis and radiosensitivity of human gastric carcinoma.