Efficient purification of plasmid DNA for gene transfer using triple-helix affinity chromatography.

Plasmid DNA used for nonviral therapeutic gene transfer or nucleic acid vaccination has to be highly purified devoid of contaminating components such as bacterial proteins, endotoxins, or bacterial chromosomal DNA. We have developed a new affinity chromatography technique for plasmid DNA purification: triple-helix affinity chromatography (THAC). This technique is based on the sequence-specific interaction of an oligonucleotide forming a triple-helix with plasmid DNA.

Interaction of pristinamycin IA with P-glycoprotein in human intestinal epithelial cells.

Pristinamycin IA is a cyclo-peptidic macrolactone antibiotic belonging to the streptogramin family. In the present work, the interaction of pristinamycin IA with the multidrug transporter P-glycoprotein was investigated in the differentiated human intestinal epithelial cell line Caco-2. Pristinamycin IA specifically inhibited the efflux of the P-glycoprotein substrate [3H]vinblastine, thus increasing the cellular accumulation of the drug.

Differentiated intestinal epithelial cell lines as in vitro models for predicting the intestinal absorption of drugs.

The oral absorption of a compound is a critical factor for the future of the compound as a drug. This absorption is mainly controlled by the passage across the intestinal epithelium. Thus, the prediction of the intestinal absorption by means of an in vitro model may represent a powerful tool for the early selection of molecules during the process of drug development.

Polarized transport of docetaxel and vinblastine mediated by P-glycoprotein in human intestinal epithelial cell monolayers.

The expression of the multidrug transporter P-glycoprotein has been studied in two human intestinal epithelial cell lines. No functional expression of P-glycoprotein was found in the differentiated HT29-18-C1 cell line. The expression of P-glycoprotein in the Caco-2 cell line was very high, as judged by immunoblotting and by active efflux of vinblastine.

High lipophilicity decreases drug transport across intestinal epithelial cells.

It is generally admitted in drug research that the passage of molecules across cellular barriers increases with lipophilicity and that the most lipophilic compounds will have the highest intestinal absorption. Using two in vitro models of intestinal epithelium, we presently demonstrate that this concept is not always valid and that highly lipophilic compounds display a low transepithelial permeability. We used epithelial cell lines grown on permeable filters to measure in vitro the transepithelial permeability of various molecules.