电离辐射对不同放射敏感性细胞中高迁移率簇蛋白B1的诱导表达作用

目的 探讨电离辐射对已建立的宫颈癌放射抗拒细胞对比模型中高迁移率簇蛋白B1（HMGB1）和mRNA诱导表达的差异性，分析HMGB1对宫颈癌放射敏感性调控的可能性。方法人宫颈癌细胞系HeLa重复照射12次后，传代培养调整细胞状态至细胞增殖稳定，筛选得抗拒细胞系HeLaR。以2、5、10 Gy X射线分别照射亲代HeLa和HeLaR细胞，于照射后0、0.5、2、4、6、12、18、24、36、48 h收集细胞，提取蛋白质和RNA，采用Western blot和实时荧光定量PCR法分别检测样本中HMGB1蛋白和mRNA的表达情况。结果 在蛋白水平，2、5、10 Gy X射线照射后，HeLaR细胞在48 h内均表现为HMGB1表达量下降，在48 h达到未照射水平，后有增加趋势，与照射后0 h比较，2、5、10 Gy照射后6~36 h各时间点，差异具有统计学意义（t=3.574~9.754，P < 0.05）；相反，HeLa细胞在照射后6 h，其HMGB1表达逐渐增多，尤其在5和10 Gy表现明显，与照射后0 h比较，2 Gy照射后6、12、48 h（t=3.945~4.864，P < 0.05）、5 Gy照射后6、36、48 h（t=-2.875~3.295，P < 0.05）及10 Gy照射后36、48 h（t=-4.480、-4.517，P < 0.05），差异具有统计学意义。在mRNA水平其趋势与蛋白水平基本一致。结论 不同剂量X射线照射后可诱导人宫颈癌细胞中HMGB1的表达变化，且其变化在人宫颈癌放射敏感细胞及放射抗拒细胞中不同。HMGB1可能参与人宫颈癌放射抗拒机制。

Radiation induced expression of HMGB1 in the cells with different radiosensitivity

Objective To investigate the effect of ionizing radiation (IR) on the expressions of HMGB1 in the radiation-sensitive and radiation-resistant human cervical cancer cells and to analysis the role of HMGB1 in the regulation of radiosensitivity. Methods Human cervical cancer cells HeLa and its radioresistant strain HeLaR cells were irradiated with different doses of X-rays. The cells were collected at different time points after irradiation. The expressions of protein and mRNA of HMGB1 were detected by Western blot and real-time quantitative PCR. Results At the protein level, the expression of HMGB1 in HeLaR cells was significantly reduced at 6-36 h after 2, 5 and 10 Gy X-ray irradiation (t=3.574-9.754, P < 0.05), and then it was recovered to the control level at 48 h after IR. On the contrary, the expression of HMGB1 in HeLa cells was significantly increased at 6, 12, 48 h after 2 Gy IR (t=3.945-4.864, P < 0.05), at 6, 36, 48 h after 5 Gy IR (t=-2.875-3.295, P < 0.05), and at 36, 48 h after 10 Gy IR (t=-4.480, -4.517, P < 0.05). At mRNA level, the trend of HMGB1 expression alteration was consistent with that of protein expression. Conclusions The changes of HMGB1 expression can be differently induced by X-rays in the human cervical cancer radiation-sensitivity cells and radiation-resistant cells. HMGB1 may be involved in the radioresistance of human cervical cancer.