摘要
目的研究拓扑替康(TPT)对宫颈癌HeLa细胞的抑制和放疗增敏作用。方法噻唑蓝法(MTT)和流式细胞仪法(FCM)检测不同浓度TPT在不同作用时间下对HeLa细胞的抑制作用;细胞克隆形成法进一步检测TPT作用24h和48h后对HeLa细胞抑制及放疗增敏作用,应用单击多靶模型拟合细胞存活曲线并计算放疗增敏比。结果TPT对宫颈癌HeLa细胞的抑制作用呈时间剂量依赖性,作用浓度越大、作用时间越长,对肿瘤细胞的抑制程度越大(P<0.05)。TPT作用24h时的半数致死浓度(IC50)为8μg/mL,显著低于作用48h和72h时IC50(P<0.05)。FCM检测TPT联合放射线辐射对HeLa细胞的抑制率为68.2%,明显高于单化疗组(45.7%)和单放射线辐射组(14.4%)(P<0.05)。细胞克隆形成法表明TPT作用24h和48h后联合不同剂量放射线,对HeLa细胞的杀伤作用明显增强,提示TPT具有放疗增敏作用。应用单击多靶模型拟合生存曲线得到24h和48h放疗增敏比为1.167和1.344。结论TPT对宫颈癌HeLa细胞具有抑制和放疗增敏作用,呈时间剂量依赖性,其机制可能与细胞放射线损伤修复功能抑制有关。
Objective The aim was to investigate the inhibition and radiosensitization effect of topotecan （TPT） on cervical cancer cell line HeLa. Methods The inhibition of TPT on HeLa was evaluated by MTT assay and the 24- hour 50 % inhibitory concentration （IC50） was applied in further experiments. Its radiosensitization was investigated by flow cytometry （FCM） and clone formation assay. Results The inhibition of TPT on HeLa cell was time-dependent and dose-dependent. The IC40 at 24 hours of TPT was 8 μg/mL, significantly lower than that at 48 hours （2.6 pg/mL） and 72 hours （0.8 μg/mL） （P〈 0.05）. The apoptosis rate at 24 hours of the chemotherapy-only group, radiation-only group and the combination group by FCM were 14.4%, 45.7% and 68.2%, respectively, and the difference among them was significant （P〈 0.05）. Further clone formation assay showed that TPT could significantly enhance the inhibition of radiation on HeLa, which showed the radiosensitization of TPT on the tumor cell. After fitting the curve of HeLa cell surviving by single hit multi target model, the sensitization enhancement ratio of TPT at 24 hours and 48 hours were 1.167 and 1. 344 respectively. Conclusion Topotecan has the effect of inhibition and radiosensitization on HeLa cell, which was both time-dependent and dose-dependent. These may be related with the inhibition of post-injury repair ability of TPT.
