p53基因对食管癌细胞的作用

目的 观察野生型p53基因对不同放射敏感性食管癌细胞的作用，探索p53基因治疗与放射治疗联合应用的价值。方法 以人食管癌细胞株TE－13及经反复照射后改变了放射敏感性的细胞TE－13R50为实验对象，将载有人野生型p53cDNA并含巨细胞病毒（CMV)启动子的重组腺病毒（Ad5CMV-p53）感染上述两种细胞及肿瘤组织并加用放射，在体、离体实验比较观察Ad5CMV-p53对不同放射敏感性食管癌细胞的影响。结果 TE－13细胞及TE－13R50细胞的放射敏感性明显不同（D0值分别为1.38、2.48Gy）；当联合应用Ad5CMV-p53时明显增加了它们的放射敏感性，TE－13R50细胞的提高幅度较大，接近了亲代细胞的水平（D0值分别为0.97、1.14Gy）。放射合并瘤内注射Ad5CMV-p53与单纯放射相比，荷瘤裸鼠的肿瘤生长速度明显受到抑制，对TE－13R50细胞的作用更大。结论 Ad5CMV-p53可提高食管癌细胞的放射敏感性，在一定程度上消除了食管癌细胞的放射抗拒性。

Wild-type p53 gene expression sensitizes radioresistant esophageal cancer cell lines

Objective To define the radiosensitizing effect of wild type p53 (Wt p53) on human radioresistant esophageal cancer cell lines and the application of p53 genetherapy combined with radiotherapy.Methods The human esophageal cancer cell lines TE 13 and its radioresistant variant TE 13R50 derived from repeated irradiation were initially transfected with Ad5CMV p53, a recombined adenovirus vector containing human Wt p53 cDNA and cytomegalovirus (CMV) promoter. The impact of Ad5CMV p53 expression on radiation sensitivity was observed and analyzed both after transfected cell lines (in vitro) and their transplanted tumors (in vivo) had been irradiated.Results Significant difference in radiosensitivity between the TE 13 (D 0= 1.38 Gy)and TE 13R50 (D 0=2.48 Gy) cell lines was confirmed. When Ad5CMV p53 had been transfected and expressed in there cells,their sensitivity to irradiation was enhanced obviously,with declined D 0 values of 0.97 Gy and 1.14 Gy ,respectively. On the other hand, the growth rate of transplanted tumors in nude mice was more suppressed by combined radiation and injection of Ad5CMV p53, as compared with irradiation alone, especially for TE 13R50.Conclusion The potentiation of adenovirus mediated wt p53 gene expression has a significant impact on improving the radiosensitivity of esophageal cancer cell lines.