Background:
One of the main drawbacks of synthetic, non-viral gene vectors is their relatively low in vivo efficiency when compared with viral vectors. the present paper describes the use of a partially fluorinated glycerophosphoethanolamine (f-pe), a close analog of dope, which, as a helper lipid with the cationic lipopolyamine pctg90, increases its in vitro and in vivo gene transfer capability to a larger extent than dope.
Methods:
To evaluate the contribution of f-pe to lipoplex-mediated gene transfer, the effect of including f-pe in lipoplexes formulated with the lipopolyamine pctg90 for various pctg90/dope/f-pe molar ratios [1:(1-x): x; 1:(2-y):y] was examined. for the in vitro analyses on human lung carcinoma epithelial a549 cells, the lipoplexes were formulated with the luciferase reporter plasmid ptg11033 using various n/p ratios (from 10 to 0.8, n = number of pctg90 amines, p = number of dna phosphates). the in vivo analyses were performed (1) with the luciferase reporter plasmid pcmv-luc, which gives higher luciferase expression in the lung than pctg11033; (2) with pctg90/co-lipid(s) (1:2) lipoplexes which yield higher expression than the (1:1) formulations; and (3) by intravenous (iv) injection into the tail vein of mice.
Results:
The efficiency of the f-pe lipoplexes to transfect in vitro a549 cells was significantly higher (5-90-fold) than that of dope lipoplexes, when formulated in hepes. however, when formulated in 5% glucose, both co-lipids display a comparable transfection helper potential. most remarkably, an up to eight-fold increase of luciferase expression could be measured in the lung after iv injection of pctg90/f-pe (1:2) n/p 5 lipoplexes as compared with the pctg90/dope lipoplexes. it led also to higher luciferase expression than pei(exgen500)/pcmv-luc n/p 10 polyplexes. besides expression in lung, low levels of luciferase expression were also observed in heart, spleen and liver.
Conclusion:
The present work, showing a higher in vitro and in vivo transfection potential for lipoplexes formulated with a partially fluorinated co-lipid as compared with its analogous dope lipoplexes or pei polyplexes, indicates that 'fluorinated' lipoplexes are attractive candidates for in vivo applications.