Department of Cellular and Molecular Medicine, University of California San Diego, School of Medicine, La Jolla, CA 92093, USA.
Sorrento Therapeutics, San Diego, CA 92121, USA.
Molecules. 2019 Sep 10;24(18):3287. doi: 10.3390/molecules24183287.
Nucleic Acid Therapeutics (NATs), including siRNAs and AntiSense Oligonucleotides (ASOs), have great potential to drug the undruggable genome. Targeting siRNAs and ASOs to specific cell types of interest has driven dramatic improvement in efficacy and reduction in toxicity. Indeed, conjugation of tris-GalNAc to siRNAs and ASOs has shown clinical efficacy in targeting diseases driven by liver hepatocytes. However, targeting non-hepatic diseases with oligonucleotide therapeutics has remained problematic for several reasons, including targeting specific cell types and endosomal escape. Monoclonal antibody (mAb) targeting of siRNAs and ASOs has the potential to deliver these drugs to a variety of specific cell and tissue types. However, most conjugation strategies rely on random chemical conjugation through lysine or cysteine residues resulting in conjugate heterogeneity and a distribution of Drug:Antibody Ratios (DAR). To produce homogeneous DAR-2 conjugates with two siRNAs per mAb, we developed a novel two-step conjugation procedure involving microbial transglutaminase (MTGase) tagging of the antibody C-terminus with an azide-functionalized linker peptide that can be subsequently conjugated to dibenzylcyclooctyne (DBCO) bearing oligonucleotides through azide-alkyne cycloaddition. Antibody-siRNA (and ASO) conjugates (ARCs) produced using this strategy are soluble, chemically defined targeted oligonucleotide therapeutics that have the potential to greatly increase the number of targetable cell types.
核酸治疗药物（NATs），包括 siRNA 和反义寡核苷酸（ASO），具有很大的潜力来治疗不可成药的基因组。将 siRNA 和 ASO 靶向特定感兴趣的细胞类型，显著提高了疗效并降低了毒性。事实上，将三-GalNAc 与 siRNA 和 ASO 缀合已显示出在靶向由肝实质细胞驱动的疾病方面的临床疗效。然而，由于多种原因，寡核苷酸治疗药物靶向非肝脏疾病仍然存在问题，包括靶向特定细胞类型和内体逃逸。单克隆抗体（mAb）靶向 siRNA 和 ASO 有可能将这些药物递送到各种特定的细胞和组织类型。然而，大多数缀合策略依赖于通过赖氨酸或半胱氨酸残基的随机化学缀合，导致缀合物的异质性和药物：抗体比（DAR）的分布。为了生产具有每个 mAb 两个 siRNA 的均一 DAR-2 缀合物，我们开发了一种新的两步缀合程序，涉及微生物转谷氨酰胺酶（MTGase）对抗体 C 末端进行叠氮化物功能化接头肽的标记，该接头肽随后可以通过叠氮化物-炔烃环加成与带有寡核苷酸的二苄基环辛炔（DBCO）缀合。使用这种策略产生的抗体-siRNA（和 ASO）缀合物（ARCs）是可溶性的、化学定义的靶向寡核苷酸治疗药物，具有极大地增加可靶向细胞类型数量的潜力。
