A dimerizable cationic lipid with potential for gene delivery.
BACKGROUND
Despite the use of currently optimized lipofection conditions, including transfection in serum-depleted media, the efficiency of gene transfer is low and high transfection rates often induce cytotoxicity. A lipid formulation with transfection efficiency not inhibited by serum would provide an advance towards in vivo applications.


METHODS
We explored the ability of the cationic lipid SH-14 to dimerize upon DNA and form lipoplexes, and potentially release nucleic acids in the intracellular reducing milieu. We investigated the critical micelle-forming concentration of SH-14 and its intrinsic toxicity, size and Zeta potential measurements, the in vitro cytotoxicity of SH-14/plasmid DNA lipoplexes and their ability to transfect cells.


RESULTS
Among all the charge ratios (CR, + /-) tested, lipoplexes at CR 10 with a mean diameter of 295 nm and a surface charge of + 20 mV, exhibited the best compromise between transfection efficiency and tolerability. SH-14 presented the same cytotoxicity level whether alone or complexed in lipoplexes. Lipofections carried out in serum-free medium shared a transfection efficiency, on average, of 40% and a cytotoxicity of 38%. An increase of 73% in transfection efficiency and 24% in cell viability were obtained, extending lipofection over 48 h in complete-medium. Moreover, when serum concentration was increased from 10% to 50%, a three-fold increase in plasmid dose led to more than 72% of cells being transfected with almost no sign of cytotoxicity.


CONCLUSIONS
Overall, SH-14 presents good potential as a novel transfection reagent to be used in the presence of serum.
Candiani
Gabriele
G
CNR, Istituto di Chimica del Riconoscimento Molecolare, Milan, Italy. gabriele.candiani@polimi.it
Pezzoli
Daniele
D
Cabras
Mariasara
M
Ristori
Sandra
S
Pellegrini
Cinzia
C
Kajaste-Rudnitski
Anna
A
Vicenzi
Elisa
E
Sala
Carlo
C
Zanda
Matteo
M
D000704:Analysis of Variance; D000818:Animals; D019556:COS Cells; D002412:Cations / Q000737:chemistry* / Q000633:toxicity; D045744:Cell Line, Tumor; D002522:Chlorocebus aethiops; D004247:DNA / Q000737:chemistry / Q000378:metabolism*; D019281:Dimerization; D005470:Fluorometry; D018014:Gene Transfer Techniques; D006801:Humans; D008055:Lipids / Q000737:chemistry* / Q000633:toxicity; D008823:Micelles; D015394:Molecular Structure; D051381:Rats; D014227:Triazines / Q000737:chemistry* / Q000633:toxicity
D002412:Cations; D008055:Lipids; D008823:Micelles; C532026:SH-14 compound; D014227:Triazines; D004247:DNA