中文摘要：

目的 利用RNA干扰（RNAi）技术封闭胃癌细胞系SGC7901肝素酶表达，观察其对肿瘤细胞侵袭能力的影响。方法 体外转录合成小干扰RNA（siRNA），经脂质体转染胃癌细胞系；结合逆转录（RT）-PCR，Western印迹检测类肝素酶mRNA及蛋白质表达；通过体外侵袭实验评价肝素酶RNAi后胃癌细胞系的侵袭能力变化。结果 肝素酶siRNA分子可以特异性地抑制SGC7901细胞肝素酶mRNA，抑制率达（70±6）％；肝素酶RNAi后SGC7901细胞的侵袭抑制率达（61±36）％。结论 靶向肝素酶基因的siRNA分子能特异性抑制其蛋白表达水平，降低肿瘤细胞的侵袭能力。肝素酶是促进胃癌细胞侵袭转移的关键分子，并可为抑制胃癌侵袭转移提供新策略。

英文摘要：

Objective To investigate the inhibitory effect of siRNA on heparanase expression and invasion ability gastric cancer cells. Methods A heparanase mRNA-targeting double-stranded siRNA was designed with the bioinformatics technology. Human gastric cancer cells of the line SGC7901 were cultured and transfected with the siRNA of the concentrations of 5,10,20, and 40 nmol/L respectively. Forty-eight hours later RT-PCR and Western blotting were applied to detect the mRNA and protein expression of heparanase. Millicell chamber assay was performed to detect the invasion ability of the SGC7901 cells. Blank control group and negative control group were set. Results The mRNA expression level of the cells transfected with the siRNA of the concentrations 20 nmol/L and 40 nmol/L were 0. 207 ± 0. 095 and 0.200 ± 0.085 respectively, both significantly lower than that of the control group （0.60 ± 0.09, both P 〈 0. 05）. Western blotting showed that the protein expression of heparanase of the different siRN.A subgroups were all decreased dose-dependently; and no heparanase band was seen in the 40 nmol/L subgroup. The invasion rate of the siRNA group was significantly lower than that of the control group with a mean inhibition rate of （61 ±36）%. Conclusion RNAi inhibits the expression of heparanase and the invasion ability of human gastric cancer cells. Heparanase may be a new target in treatment of gastric cancer＇s metastasis.