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Cationic liposomes improve stability and intracellular delivery of antisense oligonucleotides into CaSki cells
K Lappalainen1, A Urtti, E Söderling
1MediCity Research Laboratory, Faculty of Medicine, University of Turku, Finland.
Abstract:
Antisense oligonucleotides (ODNs) are promising novel therapeutic agents against viral infections and cancer. However, problems with their inefficient delivery and inadequate stability have to be solved before they can be used in therapy. To circumvent these obstacles, a wide variety of improvements, including phosphorothioate ODNs and liposomes as a carrier system, have been developed. This study was designed to compare the effects of two cationic liposomes on the intracellular delivery and stability of ODNs in CaSki cell cultures. Also the stability of 3'-end phosphorothioate ODNs were investigated. The 3'-modification neither had any effect on the delivery, nor protected the ODNs against degradation. The cellular delivery and stability of ODNs was improved with both cationic liposomes, but a cationic liposomal preparations containing dimethyldioctadecylammonium bromide and dioleoylphosphatidylethanolamine (DDAB/DOPE) was more efficient than commercially available N-(1-(2,3-dioleoyloxy)propyl)-N,N,N-trimethylammoniummethylsulf ate (DOTAP). The improved cellular delivery was largely due to the stabilization of ODNs by cationic liposomes. The improved stability in the culture medium indicates that the cationic liposomes per se protect the ODNs from enzymatic degradation. Indeed, intact ODNs were found in the cytoplasm and nucleus only when delivered by cationic liposomes.
Insights
Cationic liposomes enhance the delivery and stability of antisense oligonucleotides (ODNs), showing promise for therapeutic applications. The DDAB/DOPE liposome formulation proved more effective than DOTAP for intracellular delivery.
Area of Science:
- Biotechnology
- Molecular Biology
- Drug Delivery Systems
Background:
- Antisense oligonucleotides (ODNs) show therapeutic potential for viral infections and cancer.
- Inefficient delivery and poor stability hinder the clinical application of ODNs.
- Phosphorothioate modifications and liposome carriers are strategies to improve ODN therapy.
Purpose of the Study:
- To compare the efficacy of two cationic liposomes in delivering and stabilizing ODNs in CaSki cells.
- To evaluate the impact of 3'-end phosphorothioate modification on ODN stability and delivery.
- To assess the protective effect of liposomes against ODN degradation in culture medium.
Main Methods:
- Cell culture experiments using CaSki cells.
- Intracellular delivery assessment of ODNs complexed with cationic liposomes (DDAB/DOPE and DOTAP).
- Stability studies of ODNs in culture medium and analysis of 3'-end phosphorothioate modified ODNs.
Main Results:
- Both cationic liposomes improved ODN cellular delivery and stability compared to unmodified ODNs.
- The DDAB/DOPE liposome formulation demonstrated superior efficiency in ODN delivery compared to DOTAP.
- 3'-end phosphorothioate modification did not significantly affect ODN delivery or stability.
- Cationic liposomes protected ODNs from enzymatic degradation in culture medium, enabling their presence in cytoplasm and nucleus.
Conclusions:
- Cationic liposomes, particularly DDAB/DOPE, significantly enhance the intracellular delivery and stability of antisense oligonucleotides.
- Liposome-mediated delivery protects ODNs from degradation, facilitating their access to cellular compartments.
- These findings support the use of cationic liposomes as effective carriers for ODN-based therapeutics.