Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of Russian Academy of Science, Novosibirsk, Russia.
Nucleic Acid Ther. 2012 Jun;22(3):196-204. doi: 10.1089/nat.2011.0328. Epub 2012 Apr 17.
Small interfering RNAs (siRNA) are able to activate the mammalian innate immune system depending on their structure, sequence, and method of delivery. The immunostimulatory activity of double-stranded RNA can be applied to antiviral and antitumor therapy. Here we identified a set of 19-bp RNA duplexes with 3-nucleotid overhangs in the 3' ends that display immunostimulating activity (here and after immunostimulating RNA, or isRNA) and studied their sequence/activity relationships. It was found that the introduction of substitutions in the middle part of the isRNA sequence (10-16 positions counting from the 5' end of strand 1) does not alter the antiproliferative activity, while substitutions in the 3' end region of isRNA substantially reduce it. isRNAs efficiently inhibit the proliferation of human oral epidermoid carcinoma cells [half-maximal inhibitory concentration (IC(50)) values varied from 10 to 100 nM]. Our research demonstrated that antiproliferative effects of isRNAs are related to cell growth arrest, rather than the induction of apoptosis. These isRNAs strongly stimulate the synthesis of interferon-α (IFN-α), and to a lesser extent the synthesis of tumor necrosis factor (TNF-α) and interleukin-6 (IL-6), in adherent peripheral blood mononuclear cells. An intravenous injection of isRNA/Lipofectamine complexes into C57BL mice increases IFN-α and IL-6 levels in the blood serum up to 15-fold and 3-fold, respectively, compared to the control mice. The results obtained clearly demonstrate the pronounced immunostimulatory and antiproliferative properties of the isRNAs under study. Hence, these short double-stranded RNAs can be considered as potential agents for the therapy of oncological and viral diseases.
小干扰 RNA（siRNA）能够根据其结构、序列和递送方式激活哺乳动物固有免疫系统。双链 RNA 的免疫刺激性活性可应用于抗病毒和抗肿瘤治疗。在这里，我们鉴定了一组带有 3' 端 3 个核苷酸突出的 19 个碱基 RNA 双链体，它们具有免疫刺激活性（以下简称免疫刺激 RNA 或 isRNA），并研究了它们的序列/活性关系。结果发现，在 isRNA 序列的中间部分（从第 1 条链的 5' 端开始计数 10-16 位）引入取代不会改变其抗增殖活性，而 isRNA 的 3' 端区域的取代则会大大降低其活性。isRNA 能有效抑制人口腔表皮样癌细胞的增殖（半最大抑制浓度（IC50）值在 10-100 nM 之间变化）。我们的研究表明，isRNA 的抗增殖作用与细胞生长停滞有关，而不是诱导细胞凋亡。这些 isRNA 强烈刺激贴壁外周血单核细胞中干扰素-α（IFN-α）的合成，以及在较小程度上刺激肿瘤坏死因子（TNF-α）和白细胞介素-6（IL-6）的合成。将 isRNA/Lipofectamine 复合物静脉注射到 C57BL 小鼠中，与对照组小鼠相比，血清中 IFN-α 和 IL-6 的水平分别增加了 15 倍和 3 倍。这些结果清楚地表明，所研究的 isRNA 具有明显的免疫刺激和抗增殖特性。因此，这些短的双链 RNA 可以被认为是治疗肿瘤和病毒性疾病的潜在药物。
