Abstract：
Transmembrane ion transport modality has received a widespread attention due to its apoptotic activation toward anticancer cell activities. In this study, G-quadruplex-based potassium-specific transmembrane channels have been developed to facilitate the intracellular K+ efflux, which perturbs the cellular ion homeostasis thereby inducing cancer cell apoptosis. Cholesterol-tag, a lipophilic anchor moiety, serves as a rudiment for the G-quadruplex immobilization onto the membrane, while G-quadruplex channel structure as a transport module permits ion binding and migration along the channels. A c-Myc sequence tagged with two-cholesterol is designed as a representative lipophilic G-quadruplex, which forms intramolecular parallel G-quadruplex with three stacks of G-quartets (Ch2-Para3). Fluorescence transport assay demonstrates Ch2-Para3 a high transport activity (EC50 = 10.9 × 10-6 m) and an ion selectivity (K+/Na+ selectivity ratio of 84). Ch2-Para3 mediated K+ efflux in cancer cells is revealed to purge cancer cells through K+ efflux-mediated cell apoptosis, which is confirmed by monitoring the changes in membrane potential of mitochondria, leakage of cytochrome c, reactive oxygen species yield, as well as activation of a family of caspases. The lipophilic G-quadruplex exhibits obvious antitumor activity in vivo without systemic toxicity. This study provides a functional scheme aimed at generating DNA-based selective artificial membrane channels for the purpose of regulating cellular processes and inducing cell apoptosis, which shows a great promising for anticancer therapy in the future.
摘要：
跨膜离子运输模式由于其对抗癌细胞活性的凋亡激活而受到广泛关注。在这项研究中,已经开发了基于G-四链体的钾特异性跨膜通道以促进细胞内K外排，扰乱细胞离子稳态，从而诱导癌细胞凋亡。胆固醇标签，亲脂性锚定部分，作为G-四链体固定在膜上的基础，而作为转运模块的G-四链体通道结构允许离子沿着通道结合和迁移。用二胆固醇标记的c-Myc序列被设计为代表性的亲脂性G-四链体，与三个堆叠的G-四重体（Ch2-Para3）形成分子内平行G-四链体。荧光转运分析显示Ch2-Para3具有高转运活性（EC50=10.9×10-6m）和离子选择性（K/Na选择性比为84）。Ch2-Para3介导的K+外排在癌细胞中揭示了通过K+外排介导的细胞凋亡来清除癌细胞，这可以通过监测线粒体膜电位的变化来证实，细胞色素c的渗漏，活性氧的产量，以及caspases家族的激活。亲脂性G-四链体在体内表现出明显的抗肿瘤活性，无全身毒性。这项研究提供了一个功能方案，旨在产生基于DNA的选择性人工膜通道，以调节细胞过程和诱导细胞凋亡。这显示了未来抗癌治疗的巨大前景。
