DNA alkylation studies of combined treatment with methylnitrosourea and ethylmethanesulfonate in mice

Platzek, Thomas; Bochert, Gerd

doi:10.1002/(sici)1520-6866(2000)20:1<27::aid-tcm3>3.0.co;2-g

Cited by 1 publication

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“…However, the transfection efficiency of EMS-DADP was not reduced compared to the quaternary compound, HE-DADP. Mesylates have been shown to alkylate DNA ( − ) and can react with amine functionalities in aqueous conditions at room temperature (). Furthermore, the steric positioning of the mesylate group is expected to be close to the neighboring phosphates on the surface of double stranded DNA molecule, when the quaternary nitrogen forms electrostatic bonds with the anionic phosphates.…”

Section: Discussionmentioning

confidence: 99%

Cationic Lipids with Increased DNA Binding Affinity for Nonviral Gene Transfer in Dividing and Nondividing Cells

et al. 2004

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Effect of headgroup structure on catonic lipid-mediated transfection was investigated with either a (i) tertiary amine, (ii) quaternary amine with a hydroxyl, or (iii) quaternary amine with mesylate as headgroups. Liposomes were formulated using cholesterol or dioleoyl phosphatidyl ethanolamine (DOPE) as colipids, and transfection efficiencies were determined in rapidly dividing colon carcinoma (CT 26) and rat aortic smooth muscle (RASM) cells as well as in nondividing human pancreatic islets using luciferase and green fluorescent protein expression plasmids, pcDNA3-Luc and pCMS-EGFP, respectively. Liposome/pDNA complexes were evaluated for DNA conformational state by circular dichroism (CD), DNA condensation by electrophoretic mobility shift assay (EMSA), particle size and zeta potential by laser diffraction technique, and surface morphology by transmission electron microscopy (TEM). Encouraging transfection results were obtained with the mesylate headgroup based lipid in liposome formulations with DOPE as a colipid, which were higher than the commercially available Lipofectamine formulation. We hypothesize that the additional hydrogen bonding or covalent interactions of the headgroup with the plasmid DNA, leading to higher binding affinity of the cationic lipids to pDNA, results in higher transfection. This hypothesis is supported by TEM observations where elongated complexes were observed and more lipid was seen associated with the DNA.

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