Optimizing cationic and neutral lipids for efficient gene delivery at high serum content

Abstract

Background Cationic liposome (CL)-DNA complexes are promising gene delivery vectors with potential applications in gene therapy. A key challenge in creating CL-DNA complexes for applications is that their transfection efficiency (TE) is adversely affected by serum. In particular, little is known about the effects of high serum contents on TE even though this may provide design guidelines for applications in vivo. Methods We prepared CL-DNA complexes in which we varied the neutral lipid (DOPC, glycerol-monooleate (GMO), cholesterol), the headgroup charge and chemical structure of the cationic lipid, and the ratio of neutral to cationic lipid; we then measured the TE of these complexes as a function of serum content and assessed their cytotoxicity. We tested selected formulations in two human cancer cell lines (M21/melanoma and PC-3/prostate cancer). Results In the absence of serum, all CL-DNA complexes of custom-synthesized multivalent lipids show high TE. Certain combinations of multivalent lipids and neutral lipids, such as MVL5(5+)/GMO-DNA complexes or complexes based on the dendritic-headgroup lipid TMVLG3(8+) exhibited high TE both in the absence and presence of serum. Although their TE still dropped to a small extent in the presence of serum, it reached or surpassed that of benchmark commercial transfection reagents, in particular at high serum content. Conclusions Two-component vectors (one multivalent cationic lipid and one neutral lipid) can rival or surpass benchmark reagents at low and high serum contents (up to 50%, v/v). We suggest guidelines for optimizing the serum resistance of CL-DNA complexes based on a given cationic lipid.

Cationic liposome–nucleic acid complexes for gene delivery and gene silencing

“…29-33,58-62 Fig. 3a shows transfection efficiency (TE; a measure of expression of an exogenous gene that is transferred into the cell by the lipid carrier) as a function of mol% cationic lipid for complexes transfecting mouse fibroblast cells at various MVL/DOPC ratios with the headgroup charge of the MVLs varied between +2 e and +5 e .…”

trans-2-Aminocyclohexanol-based amphiphiles as highly efficient helper lipids for gene delivery by lipoplexes

“…As commonly reported for lipoplexes, serum, which is a substantial barrier for gene delivery in vivo [57,58] decreased the overall level of transgene expression in our studies as well. However, compared to DOPE-and cholesterol-based lipoplexes under the same experimental condition (either with or without serum), the TACH lipoplexes consistently mediated higher gene transfection, suggesting that TACH lipoplexes would serve as an improved gene delivery system in both cultured cells and in animals/humans.…”

Recent progress in gene therapy to deliver nucleic acids with multivalent cationic vectors

“…(ii) multivalent cationic lipids [67,78,139,178,181], derivated oligoamines [182] and tripeptide multivalent lipids [122]; (iii) cationic polymers derivatives from PEI [124,127,183,184], PAMAM [132,140], PDMAEMA [123,133,185], PAA [103,131,186,187], chitosan [188], polyphosphoramidates [189], polyhydroxyalkanoate [92], polyamines [107], polyaminoacids [127,190] or diblock copolymers [191]; (iv) polycations from calixarene [40,136,165,192] or cyclodextrin [134,135,142,164,193] derivatives; (v) lipopolymers from lysine derivatives [170]; (vi) pendant polymercationic cyclodextrins [129,130,163]; and (vii) cationic polymer-cyclodextrin polyrotaxanes [89]. The picture that results from these transfection studies is that many of the polyplexes show efficacies comparable to that reported by the Lipo2000 positive control and also by most of the commercial or synthezised univalent CLs, but its efficacy as transfecting agents of DNA is still below than that reported by most of t...…”

“…The results confirm that all these optimized formulations did not report any toxicity to the cell lines studied, the cell viability after transfection being considerably better than the commercial control Lipo2000. The cell viability/cytotoxicity of several complexes between nucleic acids and a wide variety of recent synthesized MVCVs has been analyzed: (i) GCLs as cholesterol-based with alkyl or oligo-oxyethylene spacers [118,119,121,206,207], aromatic-based with alkyl or oligo-oxyethylene spacers [46], ammonium derivatives [54,71,93] imidazolium derivatives [45,75,99] and pyridinium derivatives [57] with alkyl type spacers, aminoacid-based [64,208], SS14 linkers [66], gemini-like amphiphilic peptides [150] or cyclen-based CLs [120,180]; (ii) several MVCLs [67,72,122,181,182]; (iii) cationic polymer-derivatives from PEI [124,127,183,209], PAMAM [140], PDMAEMA [123,133], chitosan [188], polyphosphoramidates [189], polyhydroxyalkanoates [92], polyamines [107,187] or polyaminoacids [127,190]; (iv)…”