γ射线照射对IER5基因mRNA表达的影响

IER5 gene＇s mRNA expression after irradiation

目的应用实时PCR技术分析^60Coγ射线照射正常人淋巴母细胞（AHH1）、宫颈癌细胞（HeLa）与接种人肿瘤细胞的裸鼠后IER5基因表达的影响。方法对于离体培养的AHH1、HeLa与BALB／c—nu裸鼠，按照不同剂量（0．5、2、4、6、10、15Gy）与照射后不同时间点（2、4、8、12、24h）进行分组进行提取mRNA、反转录与IER5基因表达量测试。结果在相同条件下AHH1对照射比HeLa更灵敏，其表达量的峰值对应的剂量比HeLa的要低。对于AHH1细胞，对2Gy低剂量的照射反应比10Gy的高剂量反应要快，而HeLa细胞，对于2Gy的低剂量与10Gy的高剂量的照射反应没有太大差异，在照射后2h都出现基因表达的最大值。此外，人肝肿瘤的IER5基因对照射比较敏感，而人肺与脑肿瘤的IER5基因不敏感。结论IER5基因有可能成为宫颈癌与肝肿瘤新的辐射损伤生物分子的一个标记物，对肝肿瘤放疗具有潜在的应用价值。

Objective To explore the effect of irradiation on IER5 gene expression. Methods Two kinds of cells （AHH-1 and HeLa） and the BALB/c-nu mice inoculated with tumor cells were exposed to ^60 Co γ- rays and analyzed by real-time PCR. The above-mentioned irradiated objects were firstly divided into groups by different doses and post-radiation time, then mRNA were extracted and reverse-transcripted to DNA before real- time PCR test. Results Under the same condition, AHH-1 was more sensitive to radiation than HeLa. The dose level corresponding to the expression peak of AHH-1 was less than that of HeLa. For AHH-1 cells, the response to 2 Gy irradiation was earlier than that to 10 Gy. But there was not remarkable difference for HeLa response between 2 and 10 Gy, and the top transcriptional levels for both cells nearly simultaneously appeared at 2 h after irradiation. In addition, the IER5 gene of human liver tumor was more sensitive than that of lung cancer and brain tumor. Conclusions IER5 might be a candidate biomarker of radiation injury, and had the potential value in radiation-therapy for liver tumor.