In vitro transfection efficiencies of T-shaped spermine-based cationic lipids with identical and nonidentical tails under high serum conditions

T-shaped spermine-based cationic lipids with identical and nonidentical hydrophobic tails having variable carbon lengths (from C10 to C18) were designed and synthesized. These lipids were characterized, and their structure-activity relationships were determined for DNA binding and transfection ability of these compounds when formulated as cationic liposomes. These liposomes were then applied as non-viral vectors to transfect HEK293T, HeLa, PC3, H460, HepG2, and Calu'3 cell lines with plasmid DNA encoding the green fluorescent protein. ST9, ST12 and ST13 with nonidentical tails could deliver DNA into HEK293T cells up to 60% under serum-free conditions. The lipid ST15 bearing nonidentical tails was found to be a potent gene transfer agent under 40% serum conditions in HEK293T and HeLa cells. Besides their low cytotoxicity, these lipoplexes also exhibited greater transfection efficiency than the commercially available transfection agent, Lipofectamine 3000.

Serum Compatible Spermine-based Cationic Lipids with Non-identical Hydrocarbon Tails Mediate High Transfection Efficiency

Cationic lipids are widely used as non-viral synthetic vectors for gene delivery as a safer alternative to viral vectors. In this work, a library of L-shaped spermine-based cationic lipids with identical and non-identical hydrophobic chains having variable carbon length (from C10 to C18) was designed and synthesized. These lipids were characterized and the structure-activity relationships of these compounds were determined for DNA binding and transfection ability when formulated as cationic liposomes. The liposomes were then used successfully for the transfection of HEK293T, HeLa, PC3, H460, HepG2, SH-SY5Y and Calu'3 cell lines. The transfection efficiency of lipids with non-identical hydrocarbon chains was greater than the identical analog. These reagents exhibited superior efficiency to the commercial reagent, Lipofectamine3000, under both serum-free and 10-40% serum conditions in HEK293T, HeLa and H460 cell lines. The lipids were also not toxic to the tested cells. The results suggested that L-shaped spermine-based cationic lipids with non-identical hydrocarbon tails could serve as an efficient and safe non-viral vector gene carrier for further in vivo studies.

Novel carbamate-linked quaternary ammonium lipids containing unsaturated hydrophobic chains for gene delivery

In this paper, two novel carbamate-linked quaternary ammonium lipids (MU18: a lipid with a mono-ammonium head; GU18: a lipid with a Gemini-ammonium head) containing unsaturated hydrophobic chains were designed and synthesized. The chemical structures of the synthetic lipids were characterized by infrared spectrum, ESI-MS, ¹H NMR, ¹³C NMR, and HPLC. For investigating the effect of unsaturation on gene delivery, the previous reported saturated cationic liposomes (MS18 and GS18) were used as comparison. Cationic liposomes were prepared by using these cationic lipids and neutral lipid DOPE at the molar ratio of 1:1. Particle sizes and zeta potentials of the cationic liposomes were studied to show that they were suitable for gene transfection. The binding abilities of the cationic liposomes were investigated by gel electrophoresis at various N/P ratios from 0.5/1 to 8/1. The results indicated that the binding ability of GU18 was much better than MU18 and the saturated cationic liposomes (MS18 and GS18). DNA transfection of these liposomes comparable to commercially available reagent (DOTAP) was achieved in vitro against Hela, HepG-2 and NCI-H460 cell lines. GU18 showed higher transfection at the N/P ratio of 3/1 than other cationic liposomes and the positive control, DOTAP. All of the liposomes presented a relatively low cytotoxicity, which was measured by MTT. Therefore, the synthetic lipids bearing unsaturated hydrophobic chains and Gemini-head could be promising candidates for gene delivery.

A review on cationic lipids with different linkers for gene delivery

Cationic lipids have become known as one of the most versatile tools for the delivery of DNA, RNA and many other therapeutic molecules, and are especially attractive because they can be easily designed, synthesized and characterized. Most of cationic lipids share the common structure of cationic head groups and hydrophobic portions with linker bonds between both domains. The linker bond is an important determinant of the chemical stability and biodegradability of cationic lipid, and further governs its transfection efficiency and cytotoxicity. Based on the structures of linker bonds, they can be grouped into many types, such as ether, ester, amide, carbamate, disulfide, urea, acylhydrazone, phosphate, and other unusual types (carnitine, vinyl ether, ketal, glutamic acid, aspartic acid, malonic acid diamide and dihydroxybenzene). This review summarizes some research results concerning the nature (such as the structure and orientation of linker groups) and density (such as the spacing and the number of linker groups) of linker bond for improving the chemical stability, biodegradability, transfection efficiency and cytotoxicity of cationic lipid to overcome the critical barriers of in vitro and in vivo transfection.

Evaluation of Maltose-Based Cationic Liposomes with Different Hydrophobic Tails for Plasmid DNA Delivery

In this paper, three cationic glycolipids with different hydrophobic chains Malt-DiC12MA (IX a), Malt-DiC14MA (IX b) and Malt-DiC16MA (IX c) were constructed by using maltose as starting material via peracetylation, selective 1-O-deacetylation, trichloroacetimidation, glycosylation, azidation, deacetylation, Staudinger reaction, tertiary amination and quaternization. Target compounds and some intermediates were characterized by ¹H-NMR, ¹³C-NMR, ¹H-¹H COSY and ¹H-¹³C HSQC. The results of gel electrophoresis assay, atomic force microscopy images (AFM) and dynamic light scattering (DLS) demonstrate that all the liposomes could efficiently bind and compact DNA (N/P ratio less than 2) into nanoparticles with proper size (88 nm–146 nm, PDI < 0.4) and zeta potential (+15 mV–+26 mV). The transfection efficiency and cellular uptake of glycolipids in HEK293 cell were evaluated through the enhanced green fluorescent protein (EGFP) expression and Cy3-labeled pEGFP-C1 (Enhanced Green Fluorescent Protein plasmid) images, respectively. Importantly, it indicated that Malt-DiC14MA exhibited high gene transfer efficiency and better uptake capability at N/P ratios of 8:1. Additionally, the result of cell viability showed glycolipids exhibited low biotoxicity and good biocompatibility by thiazolyl blue tetrazolium bromide (MTT) assay.

Prenyl Ammonium Salts--New Carriers for Gene Delivery: A B16-F10 Mouse Melanoma Model

PURPOSE

Prenyl ammonium iodides (Amino-Prenols, APs), semi-synthetic polyprenol derivatives were studied as prospective novel gene transfer agents.

METHODS

AP-7, -8, -11 and -15 (aminoprenols composed of 7, 8, 11 or 15 isoprene units, respectively) were examined for their capacity to form complexes with pDNA, for cytotoxicity and ability to transfect genes to cells.

RESULTS

All the carriers were able to complex DNA. The highest, comparable to commercial reagents, transfection efficiency was observed for AP-15. Simultaneously, AP-15 exhibited the lowest negative impact on cell viability and proliferation--considerably lower than that of commercial agents. AP-15/DOPE complexes were also efficient to introduce pDNA to cells, without much effect on cell viability. Transfection with AP-15/DOPE complexes influenced the expression of a very few among 44 tested genes involved in cellular lipid metabolism. Furthermore, complexes containing AP-15 and therapeutic plasmid, encoding the TIMP metallopeptidase inhibitor 2 (TIMP2), introduced the TIMP2 gene with high efficiency to B16-F10 melanoma cells but not to B16-F10 melanoma tumors in C57BL/6 mice, as confirmed by TIMP2 protein level determination.

CONCLUSION

Obtained results indicate that APs have a potential as non-viral vectors for cell transfection.

Complex Behavior of Series of Cationic Carbamate Surfactants with SDBS, SDS, SAS Anionic Surfactants

The spontaneous formation of vesicles in aqueous catanionic mixtures, composed of six double-chain cationic surfactants 2,3-bis (alkyl carbamoyloxy)-N, N-dimethyl-N-(2-hydroxy alkyl) propyl chloride (CnPAC, n = 12, 14) and the three conventional anionic surfactants sodium dodecylbenzene sulfonate (SDBS), sodium dodecyl sulfate (SDS), sodium dodecyl sulfonate (SAS), was investigated. The aggregation behavior of a catanionic system is proved by visual observation, electrical conductivity, dynamic light scattering (DLS), zeta (ζ) potential, and transmission electronic microscopy (TEM). By variation of the mixing ratios of cationic and anionic surfactants, we find that the formed vesicles are stable, and the complex system with hydrophobic C14 tail shows larger turbidity than that of hydrophobic C12 tail. The positive and negative electrostatic interactions are regarded as the main driving forces for vesicles formation.

Anionic nanoparticles based on Span 80 as low-cost, simple and efficient non-viral gene-transfection systems

The existing strategies in the design of non-viral vectors for gene therapy are primarily conceived for cationic systems. However, the safety concerns associated with the use of positively charged systems for nucleic acid delivery and several reports regarding the efficacy of negatively charged systems highlights the need for improved gene-delivery vectors. With these premises in mind, we investigated the development of new negatively charged nanoparticles based on Sorbitan esters (Span(®)) – extremely cheap excipients broadly used in the pharmaceutical industry – on the basis of a simple, one-step and easily scalable procedure. For their specific use in gene therapy, we have incorporated oleylamine (OA) or poly-L-arginine (PA) into these nanosystems. Thus, we used Sorbitan monooleate (Span(®) 80) to design Span(®) 80-oleylamine and Span(®) 80-poly-L-arginine nanosystems (SP-OA and SP-PA, respectively). These systems can associate with the model plasmid pEGFP-C3 and show mean particle sizes of 304 nm and 247 nm and surface charges of -13 mV and -17 mV, respectively. The nanoparticles developed were evaluated in terms of in vitro cell viability and transfection ability. Both systems exhibited an appropriate cell-toxicity profile and are able to transfect the plasmid effectively. Specifically, the nanosystems including OA among their components provided higher transfection levels than the SP-PA nanoparticles. In conclusion, anionic nanoparticles based on Span(®) 80 can be considered low-cost, simple and efficient non-viral anionic gene-transfection systems.