Yota Sakurai, Takao Yamaguchi, Tokuyuki Yoshida, Masahiko Horiba, Takao Inoue, Satoshi Obika
The Journal of organic chemistry 2023 Jan 06Naturally occurring 5-hydroxycytosine (5-OHCyt), which is associated with DNA damage, was recently found to reduce the hepatotoxicity of antisense oligonucleotides (ASOs) without compromising its antisense activity when used as a replacement for cytosine (Cyt). Additionally, sugar-modified nucleic acids, such as 2'-O-methylribonucleic acid (2'-OMe-RNA) and 2'-O,4'-C-spirocyclopropylene-bridged nucleic acid (scpBNA), have emerged as useful antisense materials. Herein, we aimed to combine these two advantages by designing dual modified nucleic acids 2'-OMe-RNA-5-OHCyt and scpBNA-5-OHCyt bearing the 5-OHCyt nucleobase to develop efficient and safe ASOs. We describe the synthesis of 2'-OMe-RNA-5-OHCyt and scpBNA-5-OHCyt phosphoramidites and their incorporation into oligonucleotides (ONs). The duplex-forming ability and base discrimination properties of 2'-OMe-RNA-5-OHCyt- and scpBNA-5-OHCyt-modified ONs were similar to those of 2'-OMe-RNA-Cyt- and scpBNA-mCyt-modified ONs, respectively. We also synthesized two 2'-OMe-RNA-5-OHCyt-modified ASOs, and one of the two was found to exhibit reduced hepatotoxicity while retaining target mRNA knockdown activity in in vivo experiments.
Yota Sakurai, Takao Yamaguchi, Tokuyuki Yoshida, Masahiko Horiba, Takao Inoue, Satoshi Obika. Synthesis and Properties of Nucleobase-Sugar Dual Modified Nucleic Acids: 2'-OMe-RNA and scpBNA Bearing a 5-Hydroxycytosine Nucleobase. The Journal of organic chemistry. 2023 Jan 06;88(1):154-162
PMID: 36520114
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