RNAi-Mediated Targeting of Noncoding and Coding Sequences in DNA Repair Gene Messages Efficiently Radiosensitizes Human Tumor Cells
RNAi-Mediated Targeting of Noncoding and Coding Sequences in DNA Repair Gene Messages Efficiently Radiosensitizes Human Tumor Cells
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DOI：
10.1158/0008-5472.can-11-2785
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发表时间：
2012-03-01
期刊：
影响因子：
11.2
通讯作者：
Wang, Ya
中科院分区：
文献类型：
--
作者：
Zheng, Zhiming;Ng, Wooi Loon;Wang, Ya
放射治疗期间的人类肿瘤细胞死亡主要是由电离辐射（IR）诱导的DNA双链断裂（DSB）引起的，其通过同源重组修复（HRR）或非同源末端连接（NHEJ）修复。虽然siRNA介导的DNA DSB修复基因敲低可以使肿瘤细胞对IR敏感，但这种方法受到基因沉默效率低下的限制。在这项研究中，我们表明，结合人工miRNA（amiR）工程靶向XRCC 2（HRR因子）或XRCC 4（NHEJ因子）的3 '-非翻译区与siRNA靶向基因编码区沿着可以提高沉默效率，实现更强大的放射增敏比单独的单一方法。从机制上讲，组合敲低通过降低mRNA稳定性和阻断mRNA翻译来降低靶基因表达。总之，我们的研究结果建立了一种更有效的基因沉默的一般方法，特别适合于抑制难以单独通过基于amiR或siRNA的方法下调的基因。Cancer Res; 72（5）; 1221-8. (C)2012年AACR。
Human tumor cell death during radiotherapy is caused mainly by ionizing radiation (IR)-induced DNA double-strand breaks (DSB), which are repaired by either homologous recombination repair (HRR) or nonhomologous end-joining (NHEJ). Although siRNA-mediated knockdown of DNA DSB repair genes can sensitize tumor cells to IR, this approach is limited by inefficiencies of gene silencing. In this study, we show that combining an artificial miRNA (amiR) engineered to target 3'-untranslated regions of XRCC2 (an HRR factor) or XRCC4 (an NHEJ factor) along with an siRNA to target the gene coding region can improve silencing efficiencies to achieve more robust radiosensitization than a single approach alone. Mechanistically, the combinatorial knockdown decreased targeted gene expression through both a reduction in mRNA stability and a blockade to mRNA translation. Together, our findings establish a general method of gene silencing that is more efficient and particularly suited for suppressing genes that are difficult to downregulate by amiR- or siRNA-based methods alone. Cancer Res; 72(5); 1221-8. (C) 2012 AACR.