Transferrin-Associated Lipoplexes as Gene Delivery Systems: Relevance of Mode of Preparation and Biophysical Properties

Abstract

The successful application of gene therapy depends highly on understanding the properties of gene carriers and their correlation with the ability to mediate transfection. An important parameter that has been described to improve transfection mediated by cationic liposomes involves association of ligands to cationic liposome-DNA complexes (lipoplexes). In this study, ternary complexes composed of 1,2-dioleoyl-3-(trimethylammonium) propane:cholesterol, plasmid DNA and transferrin (Tf, selected as a paradigm of a ligand) were prepared under various conditions, namely, in medium with different ionic strengths (HEPES-buffered saline [HBS] or dextrose), at different lipid/DNA (+/-) charge ratios and using different modes for component addition. We investigated the effect of these formulation parameters on transfection (in the absence and presence of serum), size of the complexes, degree of DNA protection and extent of their association with cells (in terms of both lipid and DNA). Our results show that all the tested parameters influenced to some extent the size of the complexes and their capacity to protect the carried genetic material, as well as the levels of cell association and transfection. The best transfection profile was observed for ternary complexes (Tf-complexes) prepared in high ionic strength solution (HBS), at charge ratios close to neutrality and according to the following order of component addition: cationic liposomes-Tf-DNA. Interestingly, in contrast to what was found for dextrose-Tfcomplexes, transfection mediated by HBS-Tf-complexes in the presence of serum was highly enhanced.

The transferrin receptor and the targeted delivery of therapeutic agents against cancer

“…Gene therapy is seen as a promising strategy for cancer treatment and requires two main entities, the therapeutic gene and the vector responsible for its transportation and arrival at the target cell in an intact form [198]. Cationic liposomes can complex with DNA and form lipoplexes through a combination of electrostatic interactions.…”

Development of glycyrrhetinic acid-modified stealth cationic liposomes for gene delivery

“…The published ligands used to modify cationic liposomes included folate (Yan and Qi, 2008), galactosyl (Fumoto et al, 2003), integrins (Hood et al, 2002), sigma ligands (Mukherjee et al, 2005), estradiol (Reddy and Banerjee, 2005), transferrin (Penacho et al, 2008), TAT (MacKay et al, 2008), and so on. In this study, glycyrrhetinic acid (GA) was selected as the specific ligand of cationic liposomes.…”

Addressing the Challenge: Current and Future Directions in Ovarian Cancer Therapy

“…In vitro studies demonstrated that the addition of the ligand significantly increased the transfection efficiency of tumor cells in culture compared to the liposome alone even in the presence of high levels of serum [140]. For example, presence of transferrin, enhanced transfection activity by more than 750-fold in HeLa cells at the lipid/DNA charge ratio [141,142]. P53 ligand targeted non-viral delivery approaches used in ovarian and other cancers are tabulated in Table 4.…”