Nuclear factor-kappaB (NF-kappaB) is involved in several pathological processes, such as inflammation. Pro-inflammatory genes expression can be down-regulated by using an oligonucleotide (ODN) decoy to NF-kappaB. Cationic liposomes are largely used to improve ODN uptake into cells, although a higher transfection efficiency and a lower toxicity are required to use them in therapy. In this work, we investigated the potential of a novel liposome formulation, based on the recently synthesised cationic lipid (2,3-didodecyloxypropyl) (2-hydroxyethyl) dimethylammonium bromide (DE), as the delivery system for a double stranded ODN decoy to NF-kappaB. Liposomes composed of DE or DE mixed with 1,2-dioleyl-sn-glycero-3-phosphoethanolamine or cholesterol as helper lipids were complexed with ODN at different +/- charge ratios. In vitro uptake and the effect of ODN, naked or complexed with DE-containing liposomes, were evaluated in lipopolysaccharide-stimulated RAW 264.7 macrophages. The use of helper lipids increased liposome physical stability up to 1 year at 4 degrees C. ODN complexed with DE/cholesterol liposomes, at the +/- charge ratio of 8, showed a limited cytotoxicity and the highest inhibition of nitrite production, inducible nitric oxide synthase protein expression and NF-kappaB/DNA binding activity. Confocal microscopy confirmed a high ODN cell uptake obtained with DE/cholesterol liposomes at the highest +/- charge ratio.
"On the other hand, among different cationic lipids some lipids that are widely used in preparation of cationic liposomes like the DOTAP (11, 12), are permanently positively charged, regardless of the pH (13). This investigation aimed to prepare DOTAP cationic liposomes containing AP1261 as an ODN against protein kinase C-alpha (PKC-α). "
[Show abstract][Hide abstract] ABSTRACT: The current methods for treatment of cancers are inadequate and more specific methods such as gene therapy are in progress. Among different vehicles, cationic liposomes are frequently used for delivery of genetic material. This investigation aims to prepare and optimize DOTAP cationic liposomes containing an antisense oligonuclotide (AsODN) against protein kinase C alpha in non-small cells lung cancer (NSCLC).
To perform this investigation, two different methods of ethanol injection and thin film hydration were used to prepare AsODN-loaded DOTAP liposomes.
The formulated liposomes were then evaluated for their morphology, particle size, zeta potential and encapsulation efficiency, and the best formulation was chosen. In-vitro growth inhibitory effect of encapsulated ODN on A549 cells were evaluated by MTT and colonogenic assay. The physical and serum stability of liposomal ODN were also evaluated.
Thin film hydration method resulted in large liposomes that required downsizing by extrusion with an encapsulation efficiency of 13%. Ethanol injection, in a single step gave liposomes with a small size of 115 nm and an encapsulation efficiency of around 90% which were physically stable for 6 months. The optimized liposome could protect oligonucleotides from degradation by nuclease. Cell studies showed a 20% sequence-specific inhibition of cell growth in MTT assay and revealed an LC50 of 103 nM in colonogenic studies.
In conclusion, ethanol injection was able to provide suitable liposomes from the permanently charged DOTAP. Also the resulted liposomes were able to inhibit the growth of lung cancer cells.
Iranian journal of pharmaceutical research (IJPR) 02/2013; 12(Suppl):3-10. · 1.07 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Oligonucleotides (ONs) are synthetic fragments of nucleic acid designed to modulate the expression of target proteins. DNA-based ONs (antisense, antigene, aptamer or decoy) and more recently a new class of RNA-based ONs, the small interfering RNAs (siRNAs), have gained great attention for the treatment of different disease states, such as viral infections, inflammation, diabetes, and cancer. However, the development of therapeutic strategies based on ONs is hampered by their low bioavailability, poor intracellular uptake and rapid degradation in biological fluids. The use of a non-viral carrier can be a powerful tool to overcome these drawbacks. Lipid or polymer-based nanotechnologies can improve biological stability and cellular uptake of ONs, with possibility of tissue and/or cellular targeting. The use of polymeric devices can also produce a prolonged release of the ON, thus reducing the need of frequent administrations. This review summarizes advantages and issues related to the main non-viral vectors used for ON delivery.
[Show abstract][Hide abstract] ABSTRACT: RNAi technology has brought a new category of treatments for various diseases including genetic diseases, viral diseases, and cancer. Despite the great versatility of RNAi that can down regulate almost any protein in the cells, the delicate and precise machinery used for silencing is the same. The major challenge indeed for RNAi-based therapy is the delivery system. In this review, we start with the uniqueness and mechanism of RNAi machinery and the utility of RNAi in therapeutics. Then we discuss the challenges in systemic siRNA delivery by dividing them into two categories-kinetic and physical barriers. At the end, we discuss different strategies to overcome these barriers, especially focusing on the step of endosome escape. Toxicity issues and current successful examples for lipid-based delivery are also included in the review.
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