Cationic amphiphilic macromolecule (CAM)–lipid complexes for efficient siRNA gene silencing

Abstract

The accumulated evidence has shown that lipids and polymers each have distinct advantages as carriers for siRNA delivery. Composite materials comprising both lipids and polymers may present improved properties that combine the advantage of each. Cationic amphiphilic macromolecules (CAMs) containing a hydrophobic alkylated mucic acid segment and a hydrophilic poly(ethylene glycol) (PEG) tail were non-covalently complexed with two lipids.1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) and 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP), to serve as a siRNA delivery vehicle. By varying the weight ratio of CAM to lipid, cationic complexes with varying compositions were obtained in aqueous media and their properties evaluated. CAM-lipid complex sizes were relatively independent of composition, ranging from 100 to 200 nm, and zeta potentials varied from 10 to 30 mV. Transmission electron microscopy confirmed the spherical morphology of the complexes. The optimal N/P ratio was 50 as determined by electrophoretic mobility shift assay. The ability to achieve gene silencing was evaluated by anti-luciferase siRNA delivery to a U87-luciferase cell line. Several weight ratios of CAM-lipid complexes were found to have similar delivery efficiency compared to the gold standard, Lipofectamine. Isothermal titration calorimetry revealed that siRNA binds more tightly at pH = 7.4 than pH = 5 to CAM-lipid (1:10 w/w). Further intracellular trafficking studies monitored the siRNA escape from the endosomes at 24 h following transfection of cells. The findings in the paper indicate that CAM-lipid complexes can serve as a novel and efficient siRNA delivery vehicle.

Folate-decorated hydrophilic three-arm star-block terpolymer as a novel nanovehicle for targeted co-delivery of doxorubicin and Bcl-2 siRNA in breast cancer therapy

“…The changes not only weakened electrostatic interactions between PDMAPMA blocks and siRNA molecules, but also loosened nanomicellar structure via the electrostatic repulsion between PDMAPMA blocks, which significantly accelerated the releasing rate of siRNA molecules. This was demonstrated by the fact that about 42% of siRNA was released after 140 h. In a recent study, a similar pH-responsive interaction between siRNA and cationic amphiphilic macromolecule-lipid complexes was also observed [50]. Such property might be employed to mediate gene silencing.…”

Multicomponent mannose-containing liposomes efficiently deliver RNA in murine immature dendritic cells and provide productive anti-tumour response in murine melanoma model

“…Our data show that transfection efficiency of Lipofectamine 2000 which approved oneself in NA delivery in different cell lines [54][55][56][57] was low in the case of murine bone-marrow derived DC progenitors and their immature offsets. Nevertheless, the efficiency of Lipofectamine 2000 was demonstrated for RNA delivery into monocyte-derived human CD14 + DCs [58].…”

Para amino benzoic acid-derived self-assembled biocompatible nanoparticles for efficient delivery of siRNA

“…Moreover, synthetic vectors show less efficiency for in vivo delivery compared with viral vectors. 9 Cationic lipid-based 10,11 and cationic polymer-based 12,13 delivery vehicles bind electrostatically with the negatively charged phosphate groups of nucleic acids in a reversible and non-reversible manner, which condense the nucleic acid and form virus-like structures protecting them from degradation by nucleases. 14 …”