Ionis制药公司的Stanley T. Crooke等研究人员的研究结果表明，对PS-ASO疗法进行化学修饰可降低其与细胞蛋白的结合，以此减弱毒性，提高治疗指数。 相关论文发表在2019年6月出版的《Nature Biotechnology》杂志上。

研究组报道,目前多种具有毒性的gapmer PS-ASOs（如：限制性乙烷基 (cEt)、锁核酸(LNA)和 2′-O-甲氧乙基 (2′-MOE)）能高亲和性地结合许多细胞蛋白质,并且使其功能、定位和稳定性发生改变。他们还指出,在PS-ASO产生毒性作用过程中，会发生核糖核酸酶H1介导的paraspeckle蛋白向核仁转移的早期事件，接着nucleolar stress、P53抑癌基因激活以及细胞程序性死亡等过程将发生。在PS-ASO的2号位引入单个2'-O-甲基（2'-OMe），将会显著减弱它们与蛋白质的结合能力，因而会大大降低肝毒性，并使治疗指数得到改善，却不会对反义寡核苷酸的活性造成太大影响。他们还进行了超过300条序列实验，对结果的普适性进行了检验，实验结果都表明该方法能降低PS-ASO疗法的毒性。

该成果对反义寡核苷酸疗法具有重要意义，能指导PS-ASO的设计，有助于对该疗法进一步的优化。

附：英文原文

Title: Chemical modification of PS-ASO therapeutics reduces cellular protein-binding and improves the therapeutic index

Author: Wen Shen, Cheryl L. De Hoyos, Michael T. Migawa, Timothy A. Vickers, Hong Sun, Audrey Low, Thomas A. Bell, Meghdad Rahdar, Swagatam Mukhopadhyay, Christopher E. Hart, Melanie Bell, Stan Riney, Susan F. Murray, Sarah Greenlee, Rosanne M. Crooke, Xue-hai Liang, Punit P. Seth, Stanley T. Crooke

Issue&Volume: Volume 37 Issue 6, June 2019

Abstract: The molecular mechanisms of toxicity of chemically modified phosphorothioate antisense oligonucleotides (PS-ASOs) are not fully understood. Here, we report that toxic gapmer PS-ASOs containing modifications such as constrained ethyl (cEt), locked nucleic acid (LNA) and 2-O-methoxyethyl (2-MOE) bind many cellular proteins with high avidity, altering their function, localization and stability. We show that RNase H1dependent delocalization of paraspeckle proteins to nucleoli is an early event in PS-ASO toxicity, followed by nucleolar stress, p53 activation and apoptotic cell death. Introduction of a single 2-O-methyl (2-OMe) modification at gap position 2 reduced protein-binding, substantially decreasing hepatotoxicity and improving the therapeutic index with minimal impairment of antisense activity. We validated the ability of this modification to generally mitigate PS-ASO toxicity with more than 300 sequences. Our findings will guide the design of PS-ASOs with optimal therapeutic profiles.

DOI: 10.1038/s41587-019-0106-2

Source:https://www.nature.com/articles/s41587-019-0106-2