Synthesis and properties of oligonucleotides containing triazole backbone linkages and 2′-modifications for therapeutic applications

Thesis

Antisense oligonucleotides are short strands of DNA, which bind to their complementary mRNA target to prevent protein translation. Although conceptually appealing, for their practical use as drugs, these oligonucleotides must have better cellular uptake, resistance to enzymatic degradation, and target selectivity. In this work, new synthetic chemistry is established to prepare a novel group of chemically modified oligonucleotides. The anionic phosphodiester backbone is partially replaced with a neutral triazole and, at the same time, the 2′-position of the ribose sugar is functionalised with pyrene, anthraquinone, or guanidine moieties. Being unnatural, the triazole backbone is inherently resistant to enzymatic degradation, while the reduced negative charge potentially improves cell penetration. The limitation of introduction of a triazole backbone into the antisense strand is its destabilising effect on the duplex formation with their complementary target. In this study, the 2′-modifications are used to restore the lost duplex stability and they have been found to be very efficient stabilising moieties. To evaluate the viability of this strategy, reporter gene assays based on spliceswitching model are used. Promisingly, these modified oligonucleotides have successfully shown antisense splice-switching activity, suggesting there is further scope for their improvement.

Authors: Dysko, A

• DOI: 10.5287/ora-ko6pzxdk6
• Type of award: DPhil
• Level of award: Doctoral
• Awarding institution: University of Oxford
• Keywords: Antisense nucleic acids
• Subjects: Antisense nucleic acids