Graduate School of Pharmaceutical Sciences, Kyushu University, Maidashi, Higashi-ku, Fukuoka, Japan.
Org Biomol Chem. 2012 Oct 3;10(41):8336-41. doi: 10.1039/c2ob26431e.
Triplex forming oligonucleotides (TFOs) are some of the most promising tools in the antigene strategy for the development of gene targeting therapeutics. However, the stable triplex formation is restricted to the homopurine sequences consisting of purine nucleosides, dG and dA. Therefore, the T or dC nucleoside in the homopurine strand inhibits the stable triplex formation. We have developed W-shaped nucleoside analogues (WNAs) for the formation of the unnatural type triplex DNA, with sequences containing the interrupting site in an antiparallel triplex formation. In the present study, we tested the antigene effect of TFOs having WNA-βT, which increased the stability of the triplex formation with a target sequence including the TA interrupting site. We designed the GU TFO (WNA) and GU TFO (natural) for targeting sequences of the Bcl-2 or survivin oncogene. The gel shift assay showed that the TFO (WNA) formed more stable triplexes than the natural TFO. Remarkably, the Bcl-2- or survivin-targeted TFO (WNA) inhibited the cell proliferation and induced a caspase-dependent apoptosis. It was confirmed that the survivin-targeted TFO (WNA) more effectively decreased the number of survivin products in the A549 cell than the natural TFOs.
三链体形成寡核苷酸（TFOs）是反基因策略中用于开发基因靶向治疗的最有前途的工具之一。然而，稳定的三链体形成仅限于由嘌呤核苷、dG 和 dA 组成的同嘌呤序列。因此，同嘌呤链中的 T 或 dC 核苷会抑制稳定的三链体形成。我们已经开发出 W 型核苷类似物（WNAs），用于形成具有中断位点的非天然类型三链体 DNA，这些序列在反平行三链体形成中包含中断位点。在本研究中，我们测试了具有 WNA-βT 的 TFO 的反基因效应，该 TFO 增加了与包含 TA 中断位点的靶序列形成的三链体的稳定性。我们设计了针对 Bcl-2 或 survivin 癌基因的 GU TFO（WNA）和 GU TFO（天然）。凝胶迁移分析表明，TFO（WNA）比天然 TFO 形成更稳定的三链体。值得注意的是，针对 Bcl-2 或 survivin 的 TFO（WNA）抑制了细胞增殖并诱导了 caspase 依赖性细胞凋亡。证实了针对 survivin 的 TFO（WNA）比天然 TFOs 更有效地减少了 A549 细胞中 survivin 产物的数量。
