Nonviral vectors with a biosurfactant MEL-A promote gene transfection into solid tumors in the mouse abdominal cavity.

Recently, we showed that a biosurfactatnt 4-O-[(4',6'-di-O-acethyl-2',3'-di-O-alkanoyl)-beta-D-mannopyranosyl] meso-erythritol A (MEL-A) greatly increased the efficiency of gene transfection mediated by cationic liposomes in vitro. We then studied whether the high transfection efficiency of these liposomes is maintained in vivo for tumor cells in the mouse abdominal cavity. When a complex of the liposomes and plasmid DNA was injected intraperitoneally into C57BL/6J mice bearing B16/BL6 tumors, we found that the biosurfactant significantly increased liposome-mediated gene transfection to the mouse tumor cells. The transfection efficiency of the plasmids into the solid tumors by the cationic liposomes of cholesteryl-3beta-carboxyamidoethylene-N-hydroxyethylamine (OH-Chol) with MEL-A increased by about 100-fold compared with that by the cationic liposomes of DC-Chol (commercially available) without MEL-A. The results suggest that nonviral vectors with MEL-A are very useful for gene transfection in vivo.