目的 miR-122是一种肝脏特异性miRNA,miR-122过表达可以降低肝脏肿瘤细胞的相关特性,并增强化疗药物的敏感性,但是在放疗方面研究较少。本研究探讨miR-122对肝癌细胞放疗敏感性的影响及其可能的机制。方法通过转染miR-122类似物构建HepG2-miR-122mimic细胞,利用Q-PCR检测miR-122的表达,通过成克隆分析观察miR-122对肝癌细胞放疗敏感性的影响,ELISA方法检测X射线照射后不同时间点细胞内乏氧因子HIF1-α及ROS的表达;蛋白质印迹法检测X射线照射后48h各细胞凋亡相关蛋白Bcl-2、Bax及Bim的表达变化。结果 Q-PCR检测显示,HepG2-miR-122mimic细胞中miR-122的表达较HepG2细胞增加了约8.2倍。成克隆分析显示,HepG2细胞转染miR-122mimic后放疗敏感性增高,与HepG2组相比,准域剂量Dq的放疗增敏比(SER)为1.52。ELISA分析显示,HepG2细胞在0hHIF-1α表达量为5.20ng/mL。X射线照射后HepG2细胞中HIF-1α升高,至48h升至最高,为6.69ng/mL。而HepG2-miR-122mimic细胞在0h的表达量为4.7ng/mL,X射线照射后HIF-1α的含量进一步下降,至48h下降至3.41ng/mL。48h时miR-122 mimic转染情况对HIF-1α的表达差异有统计学意义,F=70.819,P<0.001;X射线暴露对HIF-1α的表达差异有统计学意义,F=132.436,P<0.001;miR-122mimic的转染情况及X射线暴露之间存在交互作用,F=4.290,P=0.039。ROS含量在X射线照射后表现为轻度升高,在0h HepG2组和HepG2-miR-122mimic组ROS表达量分别为116.21和121IU/mL,X射线照射后ROS进一步升高,至48h升至最高,分别为130和192IU/mL。48h时miR-122mimic转染情况对ROS的表达差异有统计学意义,F=98.189,P<0.001;X射线暴露对ROS的表达差异有统计学意义,F=145.373,P<0.001;miR-122mimic的转染情况及X射线暴露之间存在交互作用,F=6.548,P=0.012。蛋白质印迹法检测结果显示,HepG2-miR-122mimic细胞中BCL-2的表达量为HepG2的56.32%,X射线照射后48hHepG2细胞中BCL-2的表达量降至原来的55.01%,而HepG2-miR-122mimic细胞则降至23%。HepG2-miR-122mimic细胞中Bax和Bim的表达量分别为HepG2细胞的170.21%和140.35%,X射线照射后,HepG2细胞中Bax和Bim的表达量分别升至HepG2的220.12%和178.34%,而HepG2-miR-122mimic细胞中,Bax和Bim的表达量则分别升至HepG2细胞的240%和260%。miR-122mimic转染情况对BCL-2、Bax和Bim的表达差异均有统计学意义,均P<0.01。X射线暴露对BCL-2、Bax及Bim的表达差异均有统计学意义,均P<0.01。miR-122mimic转染情况及X射线暴露对Bcl-2、Bim及Bax的表达均不存在交互作用。结论 miR-122可以上调肝癌细胞HepG2的放射敏感性,其机制可能与调节HIF-1α和ROS及凋亡相关蛋白有关。 Purpose miR-122 is a liver-specific miRNA. Overexpression of miR-122 can reduce the relevant characteristics of liver tumor cells and enhance the sensitivity of chemotherapeutics. However, there are few studies on radiotherapy. This study was to investigate the effect of miR-122 on the radiosensitivity of hepatoma cells and its possible mechanism. Methods HepG2-miR-122mimic cells were transfected with miR-122 analogs. The expression of miR-122 was detected by Q-PCR. The effect of miR-122 on radiosensitivity of hepatocellular carcinoma cells was observed by clonogenic assay. The expression of hypoxia factor HIF1-α and ROS were detected at different time points after irradiation. The expressions of apoptosis-related proteins Bcl-2, Bax and Bim were detected by Western blotting 48 hours after X-ray irradiation. Results Q-PCR showed that the expression of miR-122 in HepG2-miR-122mimic cells increased by about 8.2-fold compared with HepG2 cells. Clone analysis showed that the radiosensitivity of HepG2 cells transfected with miR-122mimic increased, compared with HepG2 group, quasi-domain dose Dq radiosensitization ratio (SER) of 1.52. ELISA analysis showed that the expression of HepG2 cells at 0hHIF-1α was 5.20ng / mL. After X-ray irradiation, HIF-1αin HepG2cells increased to the highest at 48h, which was 6.69ng / mL. The expression of HepG2-miR-122mimic cells at 0h was 4.7ng / mL, and the content of HIF-1α further decreased after X-ray irradiation and decreased to 3.41ng / mL at 48h. The expression of HIF-1α in miR-122 mimic transfection group was significantly different at 48h (F = 70.819, P <0.001). There was significant difference in HIF-1α expression by X-ray exposure 0.001; there was interaction between miR-122mimic transfection and X-ray exposure, F = 4.290, P = 0.039. ROS levels showed a slight increase after X-ray irradiation. At 0h, the ROS levels in HepG2 group and HepG2-miR-122mimic group were 116.21 and 121 IU / mL, respectively. The ROS level increased further after X-ray irradiation and reached the peak at 48h , Respectively 130 and 192 IU / mL. There was a significant difference in the expression of ROS between miR-122mimic transfection group at 48h (F = 98.189, P <0.001). There was a significant difference in the expression of ROS between X-ray exposures and F = 145.373, P < Transfection and X-ray exposure, F = 6.548, P = 0.012. The results of Western blotting showed that the expression of BCL-2 in HepG2-miR-122mimic cells was 56.32% of that in HepG2 cells, and the expression of BCL-2 in HepG2 cells decreased to 55.01% at 48h after X-ray irradiation. However, HepG2-miR -122 mimic cells decreased to 23%. The expression levels of Bax and Bim in HepG2-miR-122mimic cells were 170.21% and 140.35% of HepG2 cells, respectively. After X-ray irradiation, the expression levels of Bax and Bim in HepG2 cells increased to 220.12% and 178.34% of HepG2 cells, respectively In HepG2-miR-122mimic cells, the expression of Bax and Bim increased to 240% and 260% of HepG2 cells, respectively. There was significant difference in the expression of BCL-2, Bax and Bim between miR-122mimic transfection cases, all P <0.01. There were significant differences in the expression of BCL-2, Bax and Bim between X-ray exposure, all P <0.01. There was no interaction between miR-122mimic transfection and X-ray exposure on Bcl-2, Bim and Bax expression. Conclusion miR-122 can up-regulate the radiosensitivity of HepG2 cells, which may be related to the regulation of HIF-1α, ROS and apoptosis-related proteins.