Biosurfactants of MEL-A increase gene transfection mediated by cationic liposomes

Many microorganisms growing on water-insoluble substrates have been known to produce surface-active compounds called biosurfactants. Although biosurfactants have received increasing attention due to their special properties, there has been no information available until now of a role for them with regard to gene transfection. Thus, we studied here the effects of biosurfactants on gene transfection by cationic liposomes with a cationic cholesterol derivative. Our results showed clearly that a biosurfactant of mannosylerythritol lipid A (MEL-A) increased dramatically the efficiency of gene transfection mediated by cationic liposomes with a cationic cholesterol derivative. Among them, the liposomes with a cationic cholesterol derivative, cholesteryl-3 beta -carboxyamindoethylene-N-hydroxyethylamine (I), were much more effective for gene transfection than the liposomes with DC-Chol (cholesteryl-3 beta -oxycarboxyamidoethylenedimethyl-amine) or liposomes without MEL-A in various cultured cells. This demonstrates that this new finding has great potential in the experiment of gene transfection and gene therapy mediated by nonviral vectors such as cationic liposomes. (C) 2001 Academic Press.