【摘要】 目的评价野生型抑癌基因（正常）ｐ５３对人胃癌细胞系放射敏感性的控制作用。方法用流式细胞仪分析４Ｇｙ照射后８和２４小时４种不同ｐ５３状态的人胃癌细胞系细胞周期分布和凋亡的反应。以４Ｇｙ细胞存活份数和１０Ｇｙ照射后的肿瘤生长曲线比较４种细胞的放射敏感性。结果照射４Ｇｙ后８小时和２４小时的ｐ５３正常的ＢＧＣ８２３细胞出现强烈的Ｇ１期阻滞（分别占原细胞总数的６７．９％和６１．１％），比无照射的该细胞Ｇ１期比例有显著的增高（Ｐ＜０．０５），并出现明显的预示凋亡的亚Ｇ１峰（ＳｕｂＧ１），凋亡细胞比例分别达１３．０％和１５．３％；同样条件下其他３种ｐ５３异常的细胞Ｇ１期比例没有显著的变化（Ｐ＞０．０５），都没有出现亚Ｇ１峰，凋亡细胞比例均为０．０％。ｐ５３正常的ＢＧＣ８２３细胞４Ｇｙ的存活份数明显低于其它３种细胞（Ｐ＜０．０５）；且细胞移植肿瘤１０Ｇｙ照射后比其它３种的生长受到更明显抑制（Ｐ＜０．０５）。结论以上的结果证实了野生型ｐ５３基因促进了照射后肿瘤细胞的Ｇ１期阻滞和凋亡，从而明显地提高肿瘤细胞的放射敏感性。更多还原

【Abstract】 Objective To assess the role of p53 tumor suppressor gene ( wildtype p53 ) in radiosensitivity of human gastric carcinoma cell lines. Methods Cell cycle distribution and apoptosis were analyzed by flow cytometry of four human gastric carcinoma cell lines with different p53 statuses at H 8 and H 24 following irradiation of 4Gy. Surviving fraction of the four cell lines after 4 Gy irradiation was counted. Relative volume of implanted tumor of the four cell lines in nude mice was observed after irradiation of 10Gy. Results The BGC823 cells (wtp53) containing normal p53 showed strong arrest in G1 phase at H 8 and H 24 following 4 Gy irradiation (67.9% and 61.1% of original population) while the other three cell lines contained unnormal p53 had no arrest in G1 in H 8 and H 24 following irradiation at 4Gy. In the BGC823 cells (wtp53), a sub G1 peak of apoptosis was observed at H 8 and H 24 after 4 Gy irradiation, apoptotic cell rate 13.0% and 15.3% respectively. The other three cell lines gave no apoptotic response at H 8 and H 24 following 4 Gy irradiation.Surviving fraction of BGC823 cells (wtp53) radiated at 4Gy significantly smaller than other three cell lines’ ( P <0.05). Tumor of BGC823 cells (wtp53) after 10 Gy irradiation was significantly was inhibited than the other three cell lines ( PTBZ<0.05). Conclusions These results suggest that wildtype p53 promotes G1 phase arrest and apoptosis of tumor cells following irradiation and,therefore, enhances intrinsic radiosensitivity of tumor cells.更多还原