Objective To inhibit survivin gene expression by RNA interference technology and investigate the effects on chemosensitiv-ity of esophageal carcinoma cell Eca -109.Methods siRNA eukaryotic expressing vector targeting specific sequence of survivin gene was constructed to transfect Eca -109 cells which were screened to select the survivin interference group Eca -109 /si -survivin with stable transfection.Meanwhile, the Eca -109 cells transfected with non -sense sequence were used as the negative control group and those untransfected were used as the blank control group.The expression level of survivin protein was detected by western blot to ob-serve the interference effect.Then the cells of each group were treated with different concentrations of fluorouracil (5 -Fu) , IC50 of 5-Fu in each group was detected by MTT and cell apoptosis rate was analyzed by flow cytometry.Results The survivin protein level (18.75 ±3.12) of the interference group Eca -109 /si -survivin was effectively lower than that of the negative control group Eca -109 /si -control (44.17 ±3.15)and the blank control group Eca -109 (46.20 ±2.62) (P <0.05); IC50 of 5 -Fu in the interfer-ence group Eca -109 /si -survivin was(18.75 ±1.53) mg・ L -1 , which was markedly lower than that of the blank control group (39.65 ±1.75)mg・ L-1 and the negative control group(38.95 ±1.34) mg・ L-1 with a statistically significant difference (P <0.05).The cell apoptosis rate of 5 -Fu in the interference group Eca -109 /si -survivin was(37.35 ±1.52)%, which was evidently higher than that of the blank control group(11.26 ±1.21)% and the negative control group(12.34 ±1.32)% with a statistically sig-nificant difference (P <0.05).Conclusions siRNA targeting survivin can specifically silence the expression of survivin gene, inhibit cell proliferation, induce cell apoptosis, and thus enhance the chemosensitivity of human esophageal cancer Eca -109 cells to 5 -Fu.%目的：利用 RNAi （RNA interference， RNAi）技术抑制食管癌 Eca －109细胞 survivin 基因表达，观察 survivin 基因沉默后对 Eca －109细胞化疗敏感性的影响。方法构建靶向 survivin 基因特定序列的小干扰 RNA（small interference RNA， siRNA）真核表达载体并转染 Eca －109细胞，筛选得到稳定转染的 survivin 干扰组细胞 Eca －109／si －survivin，同时设转染无关干扰质粒的 Eca －109细胞为阴性对照组，未转染的 Eca －109细胞为空白对照组；通过 Western Blot 法检测干扰前后 survivin 基因沉默抑制效果；随后将各组细胞与不同浓度的氟尿嘧啶（5－Fu）作用，MTT 法检测各组细胞对5－Fu 的半数抑制浓度（IC50），流式细胞仪分析各组细胞的凋亡率。结果干扰组 Eca －109／si －survivin 细胞 survivin 蛋白表达水平（18．75±3．12）较阴性对照组 Eca －109／si －control（44．17±3．15）及空白对照组 Eca －109（46．20±2．62）明显下调（P ＜0．05）；联合应用5－Fu 的Eca －109／si －survivin 干扰组细胞 IC50为（18．75±1．53）mg・ L－1，显著低于空白对照组（39．65±1．75）mg・ L－1和阴性对照组（38．95±1．34）mg・ L－1，差异具有统计学意义（P ＜0．05）；联合应用5－Fu 的 Eca －109／si －survivin 干扰组细胞凋亡率为（37．35±1．52）％，明显高于空白对照组（11．26±1．21）％和阴性对照组（12．34±1．32）％，差异具有显著性（P ＜0．05）。结论靶向 survivin 的 siRNA 能特异性沉默 survivin 基因表达，抑制细胞增殖，诱导细胞凋亡，并增强人食管癌 Eca －109细胞对5－Fu 的化疗敏感性。
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