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Reaction of primary C55-allylic alcohol moraprenol (WT3C7-9-OH, a polyprenol from mulberry leaves) with triethylamine in the presence of phosphorus oxychloride leads to a quaternary ammonium chloride with a good yield (72%) and high cis-stereoselectivity of the terminal isoprene unit. Cationic polyprenyl derivatives may be useful for transfection and immunological studies
The construction of an efficient carrier for genetic material is a major research objective that needs to be achieved before gene therapy can become a viable pharmacological approach. Artificial aggregates containing nucleic acids are one of the options for the systemic delivery of genetic information. The diversity of functions the aggregate is expected to fulfill necessitates its complex architecture. In order to obtain a complex supramolecular aggregate, formed from elements that are themselves complex molecules, appropriate procedures based on the detailed understanding of processes at the molecular level are required. In this study, we investigated how the various properties of cationic compounds affect nucleic acid condensation. The combination of two condensing agents, differing in their affinity towards water, when mixed with plasmids, resulted in aggregates which are resistant to enzymatic digestion and which form particles with well-defined size distributions. Such uniform and well-defined complexes may subsequently be further modified in order to obtain a fully functional genetic material carrier.
O - Alkyl derivatives of dioleoylphosphatidylcholine (DOPC) have been previously described as effective DNA transfection reagents. This communication reports the effects of the neutral helper lipid dioleoylphosphatidylethanolamine (DOPE) on the efficiency of transfection of BHK cells mediated by the O-ethyl-, O-hexyl-, and O-octadecyl- DOPC derivatives, compounds that by themselves are known to exhibit lyotropic phase preferences of lamellar, lamellar or cubic (depending on conditions) and inverse hexagonal, respectively. The effect of DOPE on transfection efficiency was found to be inhibition of the ethyl compound, stimulation or inhibition (depending on amount of DOPE) of the hexyl compound and stimulation in the case of the octadecyl compound, i.e., DOPE had a beneficial effect on the lipids that formed non-lamellar phases. X-ray diffraction was used to determine the lyotropic phase of the lipid-DOPE mixtures and of the lipid-DNA complex. DNA-lipid complexes tended to be lamellar unless the lipids had a very strong tendency toward the hexagonal phase, in which case the DNA complex was also hexagonal. Thus, a mixture of equal amounts of DOPE and hexyl-DOPC formed a lamellar complex with DNA, although the lipids on their own assumed the hexagonal phase. Octadecyl-DOPC formed a hexagonal phase with DOPE and the 1:1 DOPE mixture formed a hexagonal phase DNA complex; however, if smaller amounts of DOPE were included, the complex had a lamellar structure, in contrast to the hexagonal phase of the lipids by themselves. For these cationic phospholipids, there was not necessarily a benefit to transfection of generating a hexagonal phase lipid-DNA complex.
This report describes gene transfer in vitro as well as in vivo using cetylated low-molecular mass (600 Da) polyethylenimine (28% of amine groups substituted with cetyl moieties), termed CT-PEI. This compound is hydrophobic and has to be in­corporated into liposomes in order to be suitable for gene transfer studies. Serum-in­duced plasmid DNA degradation assay demonstrated that CT-PEI-containing lipo­somal carriers could protect complexed DNA (probably via condensation). In vitro lu- ciferase gene expression achieved using medium supplemented with 10% serum was comparable to that achieved in serum-reduced medium and was highest for CT-PEI/cholesterol liposomes, followed by CT-PEI/dioleoylphosphatidylcholine liposomes and PEI 600 Da (uncetylated) carrier. In vivo systemic transfer into mice was most efficient when liposome formulations contained CT-PEI and cholesterol. Higher luciferase expression was then observed in lungs than in liver. In conclusion: liposomes containing cetylated polyethylenimine and cholesterol are a suitable vehicle for investigating systemic plasmid DNA transfer into lungs.
 Murine melanoma B16F0 cells were transfected with SA:DPPC:DOPE (2:1:1 molar ratio) liposomes associated with a plasmid encoding murine IL-12. Stearylamine, a cationic lipid, showed a greater transfection efficiency compared to DOTAP-containing liposomes. The lipid:DNA ratio was 2:1 (w/w). Control groups were mock transfected or transfected with an empty plasmid (pNeo). pNeo or IL-12 transfected cells and controls were inoculated intradermically into the dorsal region of the foot or the lateral flank of C57BL6 mice. Results showed that IL-12 expression had a marked effect on in vivo growth of B16 melanoma tumors developed in both anatomic sites, significantly retarding their growth and prolonging host survival.
Rapid progress in molecular biology and genetic engineering techniques has made the induction of cell behavior modifications by altering genetic material possible. This allows us to think about the medical application of gene therapy as an alternative to classical pharmacology and as a means of introducing a new approach to treating hereditary diseases. The major obstacle that prevents the application of this method in clinical practice is the difficulty of delivering genetic material to its destination. The fragile DNA molecule (very unstable in in vivo) requires the assistance of supramolecular structures in order to ensure its extended lifetime in circulation. A number of DNA delivery methods have been considered. One of them, a viral carrier, has been extensively studied as a potential candidate for this purpose. Unfortunately, a number of serious problems exist associated with this approach. The risk of accidental infection has not been eliminated and virus presentation causes the immune system to activate. Transfection efficiency achieved with viral vectors is superior to that of other methods, but safety concerns and financial considerations have stimulated studies aimed at the development of non-viral DNA carriers. At present, the transfection efficiency of such carriers is very low. This paper discusses problems encountered when developing a stable and efficient lipid-DNA aggregate, capable of delivering genetic material into the targeted cell nucleus. Discussion is limited to aggregate interaction with the cellular plasma membrane and its fate in the cytosol.
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