氨甲蝶呤辐射增敏作用与RAD51的相关性研究

Correlation of RADSI and radiosensitization of methotrexate

目的探讨同源重组修复蛋白RAD51与氨甲蝶呤辐射增敏作用的相关性。方法分别采用Westernblot和RT—PCR法，观察γ射线、氨甲蝶呤及二者联合应用对人骨肉瘤细胞RAD51表达的影响，克隆形成实验观察氨甲蝶呤对RAD51高表达前后骨肉瘤细胞辐射增敏作用的影响。结果氨甲蝶呤在蛋白质和RNA水平抑制RAD51的表达，氨甲蝶呤和射线联合应用可明显降低RAD51的表达水平；HOS细胞和RAD51高表达的HOS-RAD51细胞加药前后的辐射增敏比分别为1．51和0．99，表明氨甲蝶呤对HOS细胞具有较好的放射增敏性。结论RAD51可能参与了氨甲蝶呤的辐射增敏作用。

Objective To evaluate the correlation between protein RAD51 and methotrexate-enhanced radiosensitivity. Methods homologous recombination repair Western blot and RT-PCR assays were used to detect RAD51 expression in HOS osteosarcoma cells exposed to γ-ray irradiation alone and in combination with methotrexate. Colony formation assay was used to test the survival fraction of HOS cells exposed toγ-rays and methotrexate. Results Methotrexate inhibited both protein and RNA expressions of RAD51, and the combination of radiation and methotrexate enhanced the inhibition of RAD51 expression. Moreover, transfeetion of cells with RAD51 gene decreased cellular sensitivity to methotrexate and γ-rays. The sensitizer enhancerment ratios after irradiation in combination with methotrexate were 1.51 and 0. 99, respectively. Methotrenate was a preferred radiosensitizer to HOS cell. Conclusions RAD51 might be involved in the methotrexate-enhanced radiosensitivity.