中文摘要：

目的：研究核转录因子STAT3的诱骗寡核苷酸（decoy ODNs）对人膀胱癌细胞系增殖的抑制作用，并探讨其作用机制。方法：采用阳离子聚合物Sofast为转染试剂将STAT3decoyODNs转染入膀胱癌T24及5637细胞；用MTY法检测细胞增殖情况；流式细胞术检测ODNs的转染效率；荧光显微镜检测ODNs人核情况；RT-PCR及Western blot检测转染ODNs前后bcl-xl、cyclinD1和c-myc表达水平的变化。结果：ODNs可有效地转染至细胞内，部分可进入核内，转染效率呈剂量依赖关系；STAT3 decoy ODNs可抑制膀胱癌细胞的增殖，100nmoL／L组抑制率最明显，达40％-48％；100nmoL／L decoy ODNs明显抑制bcl-xl、cyclinD1和c—myc mRNA及蛋白的表达水平。结论：STAT3 decoy ODNs可显著抑制膀胱癌细胞的增殖，其作用机制可能是通过下调癌基因c-myc、细胞周期基因cyclinD1及凋亡相关基因bcl-xl的基因转录及蛋白表达而实现的。

英文摘要：

Objective： To investigate the inhibitory effects of STAT3 decoy ODNs on the growth of human bladder cancer cell lines in vitro. Methods： STAT3 decoy and scramble ODNs were transfected into the bladder cell lines （T24 cells and 5637 cells） with Sofast, a positive compound transfection agent. MTT assay was used to detect cell growth rate; the transfection efficiency was detected by flow cytometry assay ;the locations of FITC labeled decoy ODNs were observed by reflected light fluorescence microscope ; and the expression of STAT3 downstream genes, such as bcl-xl, cyclinD1 and dc-myc mRNA and proteins, were examined by RT-PCR and Western bloting. Results： STAT3 decoy ODNs were effectively incorporated into the bladder cancer cells in a dose-dependent manner, and they inhibited the proliferation of cancer cells. The most obvious inhibition rate （40 % to 48% ） was found when the concentration of STAT3 decoy ODNs was at 100 nmol/L. The expression levels of Bcl-xl, c-myc and CylinD1 mRNA and protein were also significantly inhibited by 100 nmol/L STAT3 decoy ODNs. Conclusion： STAT3 decoy ODNs can obviously inhibit the proliferation of the bladder cancer cell lines T24 and 5637 , which may be associated with the inhibition of STAT3-mediated gene expression, such as bcl-xl,c-myc, and cylinD1.