摘要目的 探讨针对血管内皮生长因子(VEGF)、端粒酶逆转录酶(TERT)、Bcl-xl的3个短发夹状双链RNA(shRNA)的串联表达质粒对人喉鳞癌裸鼠移植瘤生长抑制作用及其机制.方法 构建串联表达3个shRNA的质粒pEGFP-shVEGF-shTERT-shBcl-xl.建立人喉鳞癌Hep-2细胞系荷瘤裸鼠模型.将该质粒转染入荷瘤裸鼠瘤体内,观察肿瘤生长情况.荧光定量即时PCR检测三种目的 基因的mRNA在肿瘤组织中的表达情况,Western blot法检测三种蛋白的表达,原位末端标记法(TUNEL法)检测肿瘤细胞凋亡,免疫组织化学sP法检测肿瘤组织微血管密度.结果 与治疗前比较,质粒pEGFP-shVEGF-shTERT-shBcl-xl注射裸鼠皮下移植瘤后,肿瘤生长明显受抑制,治疗后14 d抑瘤率达91.2%.三个目的 基因的mRNA及蛋白表达水平比治疗前均有显著下降.移植瘤组织内检测到大量凋亡细胞,凋亡指数为(60.34±5.32)%.治疗组微血管密度明显低于生理盐水对照组及阴性质粒处理组.结论 pEGFP-shVEGF-shTERT-shBcl-xl能高效特异性地同时抑制3个靶基因在人喉鳞癌Hep-2细胞中的表达,增强基因沉默的多样性,并显著的抑制移植瘤的生长,提示未来应用多基因共沉默治疗喉鳞癌可能具有广阔的前景.

abstractsObjective To investigate the biological impact of pEGFP-shVEGF-shTERT-shBcl-xl expression in human laryngeal squamous carcinomas xenografted in nude mice and the related antitumor mechanism.Methods A recombinant plasmid vector containing 3 different short hairpin RNA (shRNA) segments including pEGFP-shVEGF-shTERT-shBcl-xl was constructed and directly injected into the grafted tumors of human laryngeal squamous carcinoma in nude mice.The mRNA and protein expressions were determined by real-time RT-PCR and Western blot respectively.Apoptosis was determined by TUNEL assay using a commercial kit.Intratumoral microvessel density (MVD) was assessed by immunhistochemistry.Results On the 14th days after the final treatment,mRNA and protein expression of VEGF,TERT,and Bcl-xl were markedly suppressed.The tumor sizes were significantly smaller than those in the other two group,with an overall tumor inhibition ratio of 91.2%.MVD counts in the pEGFP-shVEGF-shTERT-shBcl-xl treated group were significantly lower than those of the other two groups,along with increased apeptotic cells.Conclusions The data showed that inhibition of VEGF,TERT,Bcl-xl expression by RNAi technique induces cellular apeptosis and suppresses the growth of laryngeal squamous carcinoma in vivo.VEGF,TERT and Bcl-xl may be involved in the development of laryngeal cancers.The findings suggest a synergistic tumor therapeutic effect through simultaneous inhibition of the three genes.Multi-target RNA interference may provide a powerful strategy against human laryngeal cancers.