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Cellular penetration and antisense activity by a phenoxazine-substituted heptanucleotide
W M Flanagan1, R W Wagner, D Grant
1Gilead Sciences, Inc., Foster City, CA 94404, USA. michael_flanagan@gilead.com
Nature Biotechnology
|January 27, 1999
Summary
A novel phenoxazine modification enhances oligonucleotide delivery, improving antisense therapeutics. These modified oligonucleotides show self-permeable properties and potent gene-specific activity, overcoming bioavailability barriers.
Area of Science:
- Oligonucleotide chemistry
- Antisense therapeutics
- Molecular biology
Background:
- Poor bioavailability limits antisense therapeutic development.
- Existing oligonucleotide modifications show limited success in enhancing cellular permeation.
- Phenoxazine analogs were designed to improve oligonucleotide properties.
Purpose of the Study:
- To evaluate the bioactivity and cellular permeation of phenoxazine-modified oligonucleotides.
- To assess the potential of phenoxazine modifications for enhancing antisense therapeutics.
- To investigate the mechanism of cellular uptake and antisense activity.
Main Methods:
- Synthesis of phenoxazine-modified oligonucleotides.
- In vitro binding affinity and RNAse H cleavage assays.
- In vitro antisense activity assays following microinjection and cell incubation.
Main Results:
- Phenoxazine incorporation enhanced in vitro binding affinity and redirected RNAse H cleavage.
- Phenoxazine-modified oligonucleotides demonstrated dose-dependent, sequence-specific, and target-selective antisense activity.
- Unaided cellular penetration, nuclear accumulation, and antisense activity were observed without cationic lipids.
Conclusions:
- Phenoxazine modification significantly improves oligonucleotide properties for antisense therapeutics.
- The modified oligonucleotides exhibit potent, self-permeable, and gene-specific antisense activity.
- This approach offers a promising strategy for developing effective and cost-efficient antisense drugs.