目的：DNA修复能力与肿瘤细胞对铂类药物的敏感性密切相关。该研究利用一种新型单核苷酸多态性（SNP）的检测方法，探讨DNA修复基因XPA的SNP与非小细胞肺癌（NSCLC）患者对顺铂（ciaplatin）或卡铂（carboplatin）为主的化疗方案敏感性的关系。方法：经病理学确诊的晚期NSCLC患者96例，采用顺铂或卡铂为主的方案化疗，2～3个周期后进行临床疗效评价。根据cDNA芯片原理制作一种目的基因芯片，利用双色荧光探针杂交进行咒蹦的A23G多态的基因分型，比较不同基因型对化疗敏感性的影响。组间比较采用χ^2检验，比值比（OR）及其95％可信区间（CI）由logistic回归模型计算。结果：成功进行基因分型，野生型、杂合型和突变型的叠加荧光分别显示为绿色、黄色和红色。携带咒蹦23A／A、A／G和G／G基因型的患者，化疗有效率（完全缓解＋部分缓解）分别为35．7％、46．9％和16．7％，差异有显著性统计学意义（P〈0．05）；携带G／G基因型患者的化疗失败风险是携带至少1个A等位基因（A／G和A/A基因型）个体的3．57倍；但G等位基因携带者的疗效与A等位基因携带者的相似，差异无统计学意义（30．9％ vs 41．7％，P=0．2045）。结论：该芯片检测方法准确、高通量且价格低廉，适用于大规模样本SNP调查；XPA基因多态与NSCLC患者对铂类药物化疗的敏感性相关。
Objective To assess the ability of tetrandrine （Tet） to enhance the sensitivity to irradiation and its mechanism in cell lines of human breast cancer p53-mutant MCF-7/ADR, p53-wild-type MCF-7 and human colon carcinoma p53-mutant HT-29 as well as in C26 colorectal carcinoma-bearing BALB/c mice. Methods MCF-7/ADR, HT-29 and MCF-7 cells were exposed to irradiation in the absence or presence of tetrandrine. The effect of Tet on the cytotoxicity of X-irradiation in these three cells was determined and the effect of tetrandrine on cell cycle arrest induced by irradiation in its absence or presence was studied by flow cytometry. Moreover, mitotic index measurement determined mitosis of cells to enter mitosis. Western blotting was employed to detect cyclin B1 and Cdc2 proteins in extracts from irradiated or non-irradiated cells of MCF-7/ADR, HT-29 and MCF-7 treated with tetrandrine at various concentrations. Tumor growth delay assay was conducted to determine the radio-sensitization of tetrandrine in vivo. Results Clonogenic assay showed that tetrandrine markedly enhanced the lethal effect of X-rays on p53-mutant MCF-7/ADR and HT-29 cells and the sensitization enhancement ratio （SER） of tetrandrine was 1.51 and 1.63, but its SER was only 1.1 in p53-wt MCF-7 cells. Irradiated p53-mutant MCF-7/ADR and HT-29 cells were only arrested in G2/M phase while MCF-7 cells were arrested in G1 and G2/M phases. Radiation-induced G2 phase arrests were abrogated by tetrandrine in a concentration-dependent manner in MCF-7/ADR and HT-29 cells, whereas redistribution within MCF-7 cell cycle changed slightly. The proportion of cells in M phase increased from 1.3% to 14.7% in MCF-7/ADR cells, and from 1.5% to 13.2% in HT-29 cells, but 2.4% to 7.1% in MCF-7 cells. Furthermore, the levels of cyclin B 1 and Cdc2 expression decreased after X-irradiation in MCF-7/ADR and HT-29 cells, and the mitotic index was also lower. Tet could reverse the decrease and induce the irradiated cells to enter mitosis （M phase）. Endosomatic experiment s
XIN-CHEN SUNHONG-YAN CHENGYu-XIA DENGRONG-GUANG SHAOJUN MA
