β-榄香烯联合X线照射对肺腺癌A549细胞DNA损伤及修复影响

The effect of β-elemene combined with irradiation on DNA damage and repair in A549 cells

目的探讨β-榄香烯联合放射对肺腺癌A549细胞DNA损伤及修复影响。方法10、20μg／m1β-榄香烯作用于肺腺癌A549细胞24h后进行X线照射。通过克隆形成实验观察β-榄香烯对A549细胞放射敏感性影响，采用彗星分析法探讨损伤修复的机制。结果克隆形成实验结果显示β-榄香烯能增加A549细胞放射敏感性，10μg／ml和20μg／mlβ-榄香烯联合照射组的放射增敏比分别为1．55和1．64（D0值比）及1．43和1．75（Dq值比）。20μg／mlβ-榄香烯联合X线照射组与单独照射组和单独药物组0．2、6、24h的彗星尾力矩相比有所增加，分别为7．16±2．61与0．95±0．65和1．81±1．23（F=231．24，P〈0．01）、3．65±2．06与0．11±0．07和1．58±1．40（F=90．22，P〈0．01）、2．09±0．83与0．1±0．05和0．45±0．25（F=238．44，P〈0．01）、1．45±1．37与0．11±0．08和0．60±0．40（F=38．94，P〈0．01），表明β-榄香烯与放射线联合对A549细胞DNA损伤增加和修复的抑制作用。结论β-榄香烯对A549细胞放射敏感性的影响可能与其对DNA放射损伤及修复作用有关。

Objective To study if β-elemene can increase radiation-induced deoxyribonucleic acid （DNA） damage and decrease the damage repair. Methods Exponentially growing human lung adenocarcinoma cells （A549） were exposed to 10 or 20 μg/ml β-elemene for 24 h before irradiation. The effect of β-elemene on the in vitro radiosensitivity of A549 ceils was evaluated using clonogenic assay. DNA damage and repair were evaluated using comet assay. Results Exposure to β-elemene before irradiation increased the radiosensitivity of A549 cells. The SERo0 for 10 μg/ml and 20 μg/ml 13-elemene was 1.55 and 1.64, respectively. The SERDq for 10 μg/ml and 20 μg/ml β-elemene was 1.43 and 1.75, respectively. Combined treatment, comparing to irradiation or β-elemene treatment alone, induced higher levels of DNA damage and slower rate of damage repair. A549 cells exposed to 20 μg/ml β-elemene followed by irradiation showed a higher levels of tail moment （TM） than those exposed to irradiation or β-elemene alone at 0 h,2 h,6 h and 24 h after irradiation. The TM of the three groups at 0 h,2 h,6 h and 24 h after irradiation was 7.16 ± 2. 61,0.95 ± 0. 65 and 1.81 ± 1.23 （ F = 231.24, P 〈 0.01 ）, 3.65 s 2.06,0.11 ± 0. 07 and 1.58±1.40（F =90. 22,P 〈0.01 ）, 2.09 ±0. 83,0.1±0.05 and 0.45 ±0. 25（F =238.44,P 〈 0.01）, 1.45＋1.37,0.11±0.08 and0.60±0.40（F=38.94,P〈0.01）, respectively. Conclusions β-elemene can enhance the radiosensitivity of A549 cells through the enhancement of DNA damage and the inhibition of DNA damage repair.