中文摘要：

目的探讨脆性组胺酸三联体基因转染对肿瘤细胞辐射敏感性的影响。方法首先构建了含有FHIT基因编码序列的真核表达质粒pcDNA／FHIT，并转染人肝癌细胞株Hep G2得到表达正常FHIT蛋白的细胞株Hep G2，FHIT。然后利用CCK-8和流式细胞仪等方法研究了Hep G2／FHIT细胞接受^60Coγ射线电离辐射后细胞周期、增殖和凋亡的改变。结果研究表明人肝癌细胞Hep G2重新表达FHIT后其对电离辐射的敏感性增加，表现为接受电离辐射后细胞存活率下降，凋亡细胞增加。细胞周期检测发现Hep G2重新表达FHIT后接受电离辐射后发生G2期阻滞的程度减轻。结论FHIT基因缺失的肿瘤细胞重新表达正常的FHIT蛋白可以提高其辐射敏感性，并且辐射敏感性提高可能是和FHIT基因抑制了ATR／CHK1通路活性有关。FHIT基因．电离辐射联合治疗肿瘤，具有一定的协同作用，可以作为一个较好的肿瘤基因治疗的靶点。

英文摘要：

Objective To evaluate the potential of the combination of fragile histidine triad （FHIT） gene therapy and radiation treatment. Methods A plasmid （pcDNA/FHIT） containing an open reading frame of FHIT gene was estabilished, and then the plasmid was transfected into a human hepatocellular carcinoma cell line （Hep G2 ）. Using G418 for selection, a cell line （Hep G2/FHIT） was generated which stably expressing FHIT gene. Using cell counting kit-8 and flow cytometry, the survival fraction, cell cycle and apoptosis of the Hep G2/ FHIT cells after exposure to ^60Co γ-ray were measured. Results The transfection of FHIT gene enhanced the radiosensitivity of the Hep G2 cell. The Hep G2 cells without FHIT showed stronger G2 checkpoint response, which indicated that enhanced radiosensitivity was due to the FHIT gene＇ s role in the ATR/CHK 1 pathway. Conclusions Combining T-rays with FHIT transfection might be an effective way to treat the radioresistant cancer and FHIT might be a potential gene target for tumor treatment.