Next generation macrocyclic and acyclic cationic lipids for gene transfer: Synthesis and in vitro evaluation.
Previously we reported the synthesis and in vitro evaluation of four novel, short-chain cationic lipid gene delivery vectors, characterized by acyclic or macrocyclic hydrophobic regions composed of, or derived from, two 7-carbon chains. Herein we describe a revised synthesis of an expanded library of related cationic lipids to include extended chain analogues, their formulation with plasmid DNA (pDNA) and in vitro delivery into Chinese hamster ovarian (CHO-K1) cells. The formulations were evaluated against each other based on structural differences in the hydrophobic domain and headgroup. Structurally the library is divided into four sets based on lipids derived from two 7- or two 11-carbon hydrophobic chains, C7 and C11 respectively, which possess either a dimethylamine or a trimethylamine derived headgroup. Each set includes four cationic lipids based on an acyclic or macrocyclic, saturated or unsaturated hydrophobic domain. All lipids were co-formulated with the commercial cationic lipid 1,2-dimyristoyl-sn-glycero-3-ethylphosphocholine (EPC) in a 1:1 molar ratio, along with one of two distinct neutral co-lipids, cholesterol or 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) in an overall cationic-to-neutral lipid molar ratio of 3:2. Binding of lipid formulations with DNA, and packing morphology associated with the individual lipid-DNA complexes were characterized by gel electrophoresis and small angle X-ray diffraction (SAXD), respectively. As a general trend, lipoplex formulations based on mismatched binary cationic lipids, composed of a shorter C7 lipid and the longer lipid EPC (C14), were generally associated with higher transfection efficiency and lower cytotoxicity than their more closely matched C11/EPC binary lipid formulation counterparts. Furthermore, the cyclic lipids gave transfection levels as high as or greater than their acyclic counterparts, and formulations with cholesterol exhibited higher transfection and lower cytotoxicity than those formulated with DOPE. A number of the lipid formulations with cholesterol as co-lipid performed as well as, or better than Lipofectamine 2000™ and EPC, the two positive controls employed in these studies. These results suggest that our novel cyclic and acyclic cationic lipid vectors are effective nonviral gene transfer agents that warrant further investigation.
Université Paris-Sud, EA 401, IFR 141, Faculté de pharmacie, F-92296 Châtenay Malabry, France.
Emile
E
Jubeli
School of Chemistry and Chemical Engineering, Queen's University Belfast, David Keir Building, Stranmillis Road, Belfast, Northern Ireland BT9 5AG, United Kingdom.
Amanda B
AB
Maginty
Research Division, Weill Cornell Medical College in Qatar, Education City, PO Box 24144, Doha, Qatar.
Nada
N
Abdul Khalique
Research Division, Weill Cornell Medical College in Qatar, Education City, PO Box 24144, Doha, Qatar.
Liji
L
Raju
Premedical Unit, Weill Cornell Medical College in Qatar, Education City, PO Box 24144, Doha, Qatar.
Mohamad
M
Abdulhai
Department of Chemistry, Norwegian University of Science and Technology (NTNU), 7491 Trondheim, Norway.
David G
DG
Nicholson
Department of Physics, University of Stavanger, 4036 Stavanger, Norway.
Helge
H
Larsen
Premedical Unit, Weill Cornell Medical College in Qatar, Education City, PO Box 24144, Doha, Qatar. Electronic address: mdp2001@qatar-med.cornell.edu.
Michael D
MD
Pungente
School of Chemistry and Chemical Engineering, Queen's University Belfast, David Keir Building, Stranmillis Road, Belfast, Northern Ireland BT9 5AG, United Kingdom. Electronic address: w.goldring@qub.ac.uk.
William P D
WP
Goldring
D000818:Animals; D016466:CHO Cells; D002412:Cations / Q000737:chemistry; D006224:Cricetinae; D003412:Cricetulus; D004134:Dimyristoylphosphatidylcholine / Q000031:analogs & derivatives / Q000737:chemistry; D008055:Lipids / Q000138:chemical synthesis / Q000737:chemistry*; D008081:Liposomes / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism; D010714:Phosphatidylethanolamines / Q000737:chemistry; D010957:Plasmids / Q000235:genetics / Q000378:metabolism; D053838:Scattering, Small Angle; D014162:Transfection; D014961:X-Ray Diffraction
C108836:1,2-dimyristoyl-sn-glycero-3-ethylphosphocholine; D002412:Cations; D008055:Lipids; D008081:Liposomes; D010714:Phosphatidylethanolamines; C020888:1,2-dielaidoylphosphatidylethanolamine; D004134:Dimyristoylphosphatidylcholine
Cationic; In vitro DNA transfer; Lipid structure; Lipoplex formulation; Macrocyclic lipids