替莫唑胺对人胶质瘤细胞系U251细胞的增殖影响

目的探讨替莫唑胺（TMZ）对人胶质瘤细胞系U251细胞的杀伤作用及其作用机理。方法将人胶质瘤细胞系U251细胞分成空白对照组、TMZ组和常用化疗药物组，TMZ组下设10、25、50、100、200、400μmol／L组，常用化疗药物组（ADM、MTX、VCR、DDP）各药物浓度均为其IC50值。各组分别于作用后24、48、72h观察细胞形态学改变，用MTT比色法检测细胞活力，流式细胞仪检测细胞周期和凋亡率。结果①TMZ组各浓度对U251细胞的抑制率分别为4．23％、7．43％、31．63％、64．53％、82．18％、86．15％，呈良好的时间—剂量效应关系，其1％为81μmol，初始抑制浓度为50μmol；②ADM、MTX、VCR、DDP对U251细胞的抑制率分别为39．27％．44．59％、54．56％、55．28％，VCR、DDP两药的抑制作用明显优于ADM、MTX（P均〈0．01），与TMZ的杀伤作用相当（P〉0．05）；③流式细胞仪检测显示，U251细胞经TMZ作用后出现G2／M期阻滞，但促凋亡作用不强。结论TMZ对胶质瘤细胞有明显的杀伤作用，并呈时间和剂量依赖性；TMZ可使胶质瘤细胞阻滞于G2／M期，但其促凋亡作用不强；替奠唑胺对U251细胞的杀伤作用优于其他4种常用化疗药物。

Proliferating changes of human neuroblastoma cell line U251 cells treated with temozolomide

Objective To investigate the proliferation and the cell cycle effect of temozolomide(TMZ) on human neuroblastoma cell line U251 cells. Methods U251 cells were treated with 6 different concentrations of TMZ (10, 25, 50, 100, 200, 400 μmol/L) 24, 48, 72 h and with 5 antineoplastic agents(CTX, ADM, MTX, VCR, DDP)72 h respectively. The morphological changes of the cells were observed under light microscopes. Cell viability was accessed by using colorimetric MTT assay. U251 cells were treated with 50 and 100 μmol/L TMZ 72 h. Cell cycle progression and apoptosis ratio were measured by using flow cytometry. Results Inhibition ratio of 6 different concentrations of TMZ were 4.23%,7.43%,31.63%,64.53%,82.18% and 86.15% respectively. The IC50 of TMZ was 81 μmol/L. There were significant difference between the control group and the groups over 50 μmol/L (P＜0.01). Inhibition ratio of different concentrations TMZ increased gradually as time went by. Inhibition ratio of ADM, MTX, VCR and DDP were 26.22%, 39.27%, 44.59%, 54.56% and 55.28% respectively. There were significant difference between the TMZ group and the ADM, the MTX group respectively (P＜0.01). There were no significant difference between the TMZ group and the VCR, the DDP group respectively (P＞0.05). The flow cytometry showed that U251 cells responded to TMZ by undergoing G2/M arrest and very few cells underwent apoptosis. Conclusions TMZ inhibits the viability of malignant glioma cells in a time- and dose-dependent manner, and induces G2/M arrest but not apoptosis in vitro. The function of TMZ killing U251 cells in vitro is better than that of the other four drugs