多西紫杉醇对大肠癌细胞放射增敏的作用研究

目的观察多西紫杉醇对大肠癌细胞株SW480的放射增敏作用及其机制。方法采用MTr法检测多西紫杉醇对SW480增殖的影响；克隆形成实验检测多西紫杉醇对SW480细胞的放射敏感性，并绘制存活曲线；流式细胞仪测定多西紫杉醇对SW480细胞周期的影响和细胞凋亡的变化。结果多西紫杉醇对SW480细胞株具有抑制增殖作用，随剂量增加和时间的延长而增强。多西紫杉醇＋放疗组的SF2、D0、Dq较单纯放疗组均有所下降，多西紫杉醇的放射增益比（SER）为1．73。多西紫杉醇使SW480细胞发生GeM期阻滞，并抑制S期的比例；与放疗联合时SW480细胞GJM期阻滞更明显。多西紫杉醇增加放疗引起的细胞凋亡。结论多西紫杉醇能诱导肠癌细胞SW480凋亡增加，同时细胞周期再分布，从而增加其放射敏感性。

Study on radiosensitization of Docetaxel for colorectal SW480 cells

Objective To observe the radiosensitization of Docetaxel on colorectal SW480 cells in vitro and try to discuss its possible radiosensitizing mechanism. Methods Proliferation inhibition of Docetaxel on SW480 ceils was detected by MTI＂ method. Radiosensitization of Docetaxel was measured by clone formation assay, and survival curve was described. Alterations in cell cycle and apoptosis were tested by flow cytometry （FCM）. Results Inhibition of cell proliferation seemed more dependent on the time and the concentration. The value of SF2, D0, Dq in the group of radiation combined with Docetaxel was obviously lower than those in radiation group. The SER of Docetaxel was 1.73. Cell cycle analysis showed that cells blocked in G2/M phase by Docetaxel treatment, which showed more obvious when combined treatment with radiation, and inhibited the S phase ratio. Docetaxel could enhance radiation-induced apoptosis. Conclusion Docetaxel can enhance the radiotherapy of SW480 cells by promotion of apoptosis and promotion of cell cycle＇ redistribution.