STAT 5诱杀寡脱氧核苷酸对K 562细胞裸鼠致瘤能力的影响

Effect of STAT 5 decoy oligodeoxynucleotide on tumorigenicity of K 562 cells in nude mice

目的:通过动物实验,研究裸鼠信号转导及转录活化蛋白5(signal transducer and activator of transcription5,STAT5)诱杀寡脱氧核苷酸(decoy oligodeoxynucleotide,Decoy ODN)的抑瘤作用。方法:采用皮下注射的方法建立K562细胞裸鼠移植瘤模型,瘤体内注射脂质体-ODN混合物,观察裸鼠生长状况、瘤体大小等。分别采用反转录-聚合酶链反应(reverse tran-scription-polymerase chain reaction,RT-PCR)和Western印迹法检测瘤组织中bcl-xL、cyclin D1和c-myc的mRNA和蛋白表达水平的改变情况。结果:经Decoy ODN处理抑制了K562细胞对裸鼠的致瘤能力,瘤体积和质量明显小于突变ODN组[MutantODN组瘤重(0.93±0.22)gvsDecoy ODN组瘤重(0.485±0.178)g,P<0.05],肿瘤生长抑制率达47.7%。RT-PCR、Western印迹检测结果显示bcl-xL、cyclin D1和c-myc的mRNA和蛋白表达水平下调。结论:转录因子诱杀策略可以有效地在移植瘤裸鼠模型体内阻断STAT5靶基因的表达。

Objective： As a potential gene therapeutic method, transcription factor decoy strategy has been used to block the transcription function of multi-transcription factors. This study aims to further verify the inhibitory effect of signal transducer and activator of transcription 5 （ STAT 5） decoy oligodeoxynucleotides （ODN） on tumor growth in nude mice. Methods ： The xenografted tumor model was established by subcutaneously injecting leukemia K 562 cells in nude mice. Liposome-ODN complex was directly injected into tumor body once daily every 3 days. The tumor growth and tumor size were measured everyday. Nude mice were sacrificed at the end of the experiment. The tumor was removed and weighed. RT-PCR and Western blotting were performed to detect mRNA and protein expression of bcl-xL, cyclin D1, and c-myc, respectively. Results： The tumorigenicity of K 562 cells was significantly inhibited by decoy ODN. The tumor weight was markedly reduced in decoy ODN group than mutant ODN group [ （0.485 ± 0. 178） g vs （0.928 ± 0.223 ） g, P 〈0.05]. The tumor growth inhibition rate was 47.7%. RT-PCR and Western blotting showed that the mRNA and protein expression level of bcl-xL, cyclinD1, and c-myc were down-regulated. Conclusion： Transcription factor decoy strategy effectively blocks transcription of STAT 5 target genes in xenografted tumor of nude mice.