Application of 2′-O-(2-N-Methylcarbamoylethyl) Nucleotides in RNase H-Dependent Antisense Oligonucleotides

Abstract

An RNase H-dependent antisense oligonucleotide (ASO), having the 2′-O-(2-N-methylcarbamoylethyl) (MCE) modification, was evaluated in vitro and in vivo. The antisense activities of an ASO having the MCE modification were comparable with those of an ASO having the 2′-O-methoxyethyl (MOE) modification in both in vitro and in vivo experiments. In contrast, the hepatotoxic potential of the ASO having the MCE modification was lower than that of the ASO having the MOE modification. Thus, these findings suggested that the MCE modification could be used as an alternative to the MOE modification.

Nucleic acid degradation as barrier to gene delivery: a guide to understand and overcome nuclease activity

“…300,301 Volanesorsen, approved for treatment with familial chylomicronemia syndrome, is also modified with 2 0 -MOE and PS, with a human plasma t 1/2 over 2 weeks after single SC administration. [302][303][304] Third generation ASOs contain different modifications, such as PMOs, PNAs and LNAs. One example are SSOs that bind specific RNA-target sequences and modulate pre-mRNA splicing by sterically blocking the binding of splicing factors to the pre-mRNA.…”

“…Both preventing off-target effects and gathering more insights into mechanism of toxicity will remain of importance for developing chemically modified ASOs. 304,[313][314][315][316] 4.2.2 siRNA therapeutics. Over 20 years after RNAi discovery, siRNA therapeutics finally found their way into the clinic for gene silencing in biomedical research and disease treatment.…”

“…Both preventing off-target effects and gathering more insights into mechanism of toxicity will remain of importance for developing chemically modified ASOs. 304,313–316…”

Synthesis of 4′‐C‐(Aminoethyl)thymidine and 4′‐C‐[(N‐Methyl)aminoethyl] Thymidine Nucleosides to Enhance DNA Stability

“…the stability as well as biological activity of ASOs are of utmost need. Sugar modification and phosphorothioate linkages have displayed notable improvement in the stability of DNAs but loss of biological function and cytotoxicity have also been observed (Masaki et al, 2018;Miroshnichenko et al, 2019;Shen et al, 2018Shen et al, , 2019, whereas 4ʹmodifications have been reported to considerably increase the resistance against nucleases and exhibit the RNase Hdependent degradation of mRNA (Kanazaki et al, 2000;Kano, Katsuragi, Maeda, & Ueno, 2018;Koizumi et al, 2018;Morita et al, 2003). Based on this information, we have synthesized a novel nucleoside analog 4 -MAE-T and compared its properties to known 4ʹ-AE-T. Also, we designed a new facile synthetic route for synthesizing corresponding nucleoside phosphoramidites with high total yield.…”

Potential and Challenges of Aptamers as Specific Carriers of Therapeutic Oligonucleotides for Precision Medicine in Cancer

“…ASOs affect protein levels via several mechanisms. Among them, RNAse H triggering represents the most relevant knockdown system, and via Watson-Crick hybridization, ASOs can form RNA-DNA hybrids that become RNAse H substrates [63,64]. Furthermore, they can modulate pre-mRNA splicing, reducing or restoring protein expression [65].…”