Novel cationic amphiphilic 1,4-dihydropyridine derivatives for DNA delivery

In order to find new efficient and safe agents for gene delivery, we have d esigned and synthesized nine novel single- and double-charged amphiphiles o n the base of 1,4-dihydropyridine (1,4-DHP) ring. Some biophysical properti es of the amphiphilic dihydropyridines and their complexes with DNA were ex amined. We investigated the transfer of beta -galactosidase gene into fibro blasts (CV1-P) and retinal pigment epithelial (D 4O7) cell lines in vitro. The structure-property relationships of the compounds were investigated in various ways. The net surface charges of 1,4-DHP liposomes were highly posi tive (25-49 mV). The double-charged compounds condensed DNA more efficientl y than single-charged and the condensation increases with the increasing +/ - charge ratio between the carrier and DNA. Double-charged compounds showed also buffering properties at endosomal pH and these compounds were more ef ficient in transfecting the cells, but transfection efficiency of amphiphil es was cell type-dependent. The length of alkyl chains in double-charged co mpounds affected the transfection efficacy. The most active amphiphile (com pound VI) was double-charged and had two C-12 alkyl chains. At optimal char ge ratio (+/- 4), it was 2.5 times more effective than PEI 25 and 10 times better than DOTAP, known efficient polymeric and liposomal transfection age nts. Formulation of amphiphiles with DOPE did not change their activities. Our data demonstrate some important effects of amphiphile structure on biop hysics and activity. The data also suggest that cationic amphiphilic 1,4-DH P derivatives may find use as DNA delivery system. (C) 2000 Elsevier Scienc e B.V. All rights reserved.