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A lipid-based delivery system for antisense oligonucleotides derived from a hydrophobic complex
F M P Wong1, S A MacAdam, A Kim
1Department of Advanced Therapeutics, British Columbia Cancer Agency, 601 West 10th Avenue, Vancouver, B.C, Canada VSZ L3.
Journal of Drug Targeting
|April 10, 2003
Summary
This study explored lipid-based delivery for antisense oligodeoxynucleotides (ASOs). While certain cationic lipids facilitated ASO recovery, stabilized PEG-conjugated lipids in lipid-ASO particles (LAPs) hindered effective ASO delivery and protein downregulation.
Area of Science:
- Biochemistry
- Molecular Biology
- Drug Delivery Systems
Background:
- Antisense oligodeoxynucleotides (ASOs) are therapeutic molecules that inhibit protein expression by targeting mRNA.
- Efficient delivery of ASOs into cells remains a challenge for their therapeutic application.
- Lipid-based systems are being investigated as potential carriers for nucleic acid therapeutics like ASOs.
Purpose of the Study:
- To investigate the efficacy of a novel lipid-based delivery system for antisense oligodeoxynucleotides (ASOs).
- To characterize the formation and properties of hydrophobic complexes between ASOs and cationic lipids.
- To evaluate the impact of lipid composition, particularly PEG-conjugated lipids, on ASO delivery and therapeutic effect.
Main Methods:
- Formation and recovery of hydrophobic complexes between ASOs and various cationic lipids in a Bligh and Dyer monophase.
- Characterization of lipid-ASO particles (LAPs) using specific lipid formulations.
- In vitro assessment of ASO delivery into B-cell lymphoma cells (DoHH2) and protein downregulation (Bcl-2) via Western Blot analysis.
Main Results:
- Monovalent cationic lipids enabled >95% ASO recovery when neutralizing phosphate charge, with cholesteryldimethylaminoethylcarbamate being particularly effective.
- Polyvalent lipids and dioleoylphosphatidylethanolamine (DOPE) showed limited or destabilizing effects on hydrophobic complex formation.
- Increased incorporation of PEG-conjugated phosphatidylethanolamine in LAPs reduced cell-associated ASO and failed to downregulate Bcl-2 protein.
Conclusions:
- Certain cationic lipids can facilitate the formation of hydrophobic complexes with ASOs, aiding in their recovery.
- The presence of stabilized PEG-conjugated lipids in lipid-ASO particles (LAPs) may impede efficient ASO delivery and subsequent protein silencing.
- Careful selection of lipid components is crucial for optimizing cationic lipid-based ASO delivery systems.