干扰小RNA序列非依赖性地影响胰腺癌细胞的基因表达

干扰小RNA(small interference RNA, siRNA)是基因敲减的常用工具，广泛用于基因沉默技术和基因功能研究，在临床疾病治疗等方面也有潜在的应用。一般认为，达到一定长度（比如大于27 bp）的双链RNA可以诱导干扰素反应，降低相关基因的表达。目前，siRNA对基因表达的非特异性作用尚不完全清楚。为研究siRNA干扰的非特异基因表达，本研究以胰腺癌细胞HPAC 和BxPC3 为模型，采用高通量测序技术对6种不同干扰小RNA处理及未作处理的HPAC和BxPC3细胞进行转录组测序分析，筛选出干扰小RNA处理后表达量共同下调的基因进行研究。通过生物信息学方法对表达下调基因的功能进行研究，并利用实时荧光定量PCR(qRT-PCR)技术对部分下调基因进行验证。结果表明，短片段双链小RNA能够显著改变细胞的基因表达，而这些基因表达谱的变化是有规律的，特定功能的基因优先发生变化。在表达下调的基因中，某些特定类型的基因变化非常显著，包括氨基酸代谢相关基因、Hedgehog信号途径基因和多巴胺受体D5基因等。这些结果表明，在使用siRNA时需要考虑其序列非依赖性地基因表达调控作用。

Sequence-independent Effects of Small Interfering RNAs on the Gene Expression of Pancreatic Cancer Cells

Small interfering RNA (siRNA), known as short interfering RNA or silencing RNA, is widely used in biological research. Double-stranded RNAs, longer than 27 bp, have been found to induce the interferon response. But the non-specific effects of siRNAs were not fully understood. In the current study, we used pancreatic cancer cell lines HPAC and BxPC3 as a model to study the sequence-independent effects of siRNA. We treated the cells with six different siRNAs and used RNA-seq to identify down-regulated genes, part of which were verified by real-time fluorescence quantitative PCR (qRT-PCR). The function of down-regulated genes was studied by bioinformatics. The results showed that short double-stranded RNA affects gene expression significantly. The change of gene expression profile is rather specific, as genes with specific function changes preferentially. We found that genes involved in biosynthesis and activation of amino acids, and genes from the hedgehog pathway, were down-regulated significantly. The results indicate that significant sequence-independent effects should be taken into account when using siRNAs as a tool for research and therapeutic purposes.