Dong Ai-Qiang, Kong Min-Jian, Ma Zhi-Yuan, Qian Jian-Fang, Xu Xiao-Hong
Department of Cardiothoracic Surgery, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310009, P.R. China.
Cell Biol Int. 2007 May;31(5):500-7. doi: 10.1016/j.cellbi.2006.11.017. Epub 2006 Nov 28.
Type I insulin-like growth factor receptor (IGF-IR), which is frequently overexpressed in a variety of human cancers including lung cancer, mediates cancer cell proliferation and tumor growth. In this study, we used a human U6 promoter-driven DNA-template approach to induce hairpin RNA (hpRNA)-triggered RNAi to silence IGF-IR gene expression in the human lung cancer cell line A549, and then evaluate its effects on apoptosis, apoptosis-related gene expression, and the growth of tumor cells in vitro and in nude mice. IGF-IR expression levels were found to markedly decrease in cells transfected with a plasmid expressing hairpin siRNA for IGF-IR (by more than 78.9%). Down-regulation of IGR-IR concomitantly accompanied reduction of bcl-2 as well as pERK and pAkt levels, activation of caspase-3, apoptosis and growth inhibition of A549 cells in vitro. Direct intratumoral injections of plasmid DNA expressing hpRNA for IGF-IR significantly regressed pre-established tumors in nude mice. Our results support the therapeutic potential of RNAi as a method for gene therapy in treating lung cancer.
I型胰岛素样生长因子受体（IGF-IR）在包括肺癌在内的多种人类癌症中经常过度表达，介导癌细胞增殖和肿瘤生长。在本研究中，我们使用人类U6启动子驱动的DNA模板方法来诱导发夹RNA（hpRNA）触发的RNA干扰，以沉默人类肺癌细胞系A549中的IGF-IR基因表达，然后评估其对细胞凋亡、凋亡相关基因表达以及体外和裸鼠体内肿瘤细胞生长的影响。发现用表达针对IGF-IR的发夹小干扰RNA的质粒转染的细胞中IGF-IR表达水平显著降低（超过78.9%）。IGR-IR的下调同时伴随着bcl-2以及pERK和pAkt水平的降低、caspase-3的激活、A549细胞在体外的凋亡和生长抑制。直接瘤内注射表达针对IGF-IR的hpRNA的质粒DNA可使裸鼠中预先建立的肿瘤显著消退。我们的结果支持RNA干扰作为一种基因治疗方法在治疗肺癌方面的治疗潜力。
