塞来昔布对宫颈癌HeLa细胞放射增敏效应的观察

目的探讨环氧合酶2(COX-2)抑制剂塞来昔布对人宫颈癌HeLa细胞株的放射增敏作用及其机制。方法MTT实验测定塞来昔布对宫颈癌HeLa细胞的毒性,筛选出塞来昔布的半数抑制浓度(IC50),实验分为不同浓度药物组(10、20、40、80μmol/L)、对照组和空白组。克隆形成实验检测20%IC50浓度的塞来昔布对He-La细胞的放射增敏作用,实验分为空白对照组、单纯放射组(2、4、68、Gy)、单纯加药组(药物浓度为20%IC50)、放射加药组(20%IC50药物浓度+2、4、68、Gy放射剂量),根据各组的克隆形成率,计算放射敏感性相关参数;流式细胞仪(FCM)分析细胞周期的分布情况,实验分为对照组和药物组(药物浓度为20%IC50)。结果MTT实验显示塞来昔布对HeLa细胞毒性呈现出浓度和时间依赖性,72 h的IC50是44μmol/L;克隆形成实验显示,放射加药组与单纯放射组相比,反映放射敏感性的指标平均致死剂量(D0)、准域剂量(Dq)、2 Gy照射的存活分数(SF2)均下降,放射增敏比(SER)升高。流式细胞术检测细胞周期S期细胞明显减少,G0~G1期细胞增多,细胞阻滞于G1期。结论塞来昔布能增强宫颈癌HeLa细胞的放射敏感性,其机制可能与促进细胞凋亡、抑制肿瘤细胞亚致死性损伤修复和促进肿瘤细胞周期再分布有关。

THE EFFECT OF CELECOXIB ON RADIOSENSITIVITY ENHANCEMENT OF CERVICAL CANCER He La CELLS

Objective To investigate the effect of celecoxib,an inhibitor of cyclooxygenase-2(COX-2),on radiosensitivity enhancement of human cervical cancer HeLa cells and its mechanism. Methods MTT assay was used to measure the proliferation inhibition of celecoxib on HeLa cells and determine the concentration IC50 of celecoxib.The cells were randomized to three groups: drug group(10,20,40,80 μmol/L),control group and blank group.The cells were treated in vitro with different doses of radiation alone(0,2,4,6,8 Gy),celecoxib(20% IC50) alone and radiation combined with celecoxib administrated.The clonogenic assay was performed to determine the radiosensitivity effect of celecoxib on HeLa cells with the concentration of 20% IC50.The cell cycle distribution was analyzed by flow cytometry(FCM) to compare control group with drug group. Results Inhibition of celecoxib on HeLa cell proliferation was dose and time dependent.Values of SF2,D0,Dq,SER displayed the group of radiation combined with celecoxib were significantly lower than those of radiation alone group.Cell population in G0/G1 phase increased and in S phase decreased. Conclusion Celecoxib can increase the radiosensitivity of HeLa cells in cancer of the cervix,which is probably associated with promotion of apoptosis,inhibition of sublethal damage of tumor cells and facilitation of redistribution of tumor cell cycle.