Absorption properties and P-glycoprotein activity of modified Caco-2 cell lines.

Caco-2 cell line is extensively used as an in vitro model in studying small intestinal absorption but it lacks proper expression of efflux pumps and cytochrome P450 enzymes that are involved in absorption and first pass metabolism of drugs. We created two novel Caco-2 cell lines expressing orphan nuclear receptors pregnane X receptor and constitutive androstane receptor that regulate many genes involved in xenobiotic metabolism. We conducted a systematic study on expression of some metabolic genes, P-glycoprotein activity and absorption properties of several drugs with these new cell lines and previously described modified Caco-2 cell lines (MDR1 transfection, vincristine treatment and 1alpha,25-dihydroxyvitamin D3 treatment).

Dioleoyl phosphatidylethanolamine and PEG-lipid conjugates modify DNA delivery mediated by 1,4-dihydropyridine amphiphiles.

Complexes of amphiphilic cationic 1,4-dihydropyridines with DNA (lipoplexes) can be used for nonviral gene delivery. In order to achieve serum-resistant transfection system, DOPE and PEG-lipid conjugates were used to modify 1,4-dihydropyridine amphiphile DHP-12 complexes with DNA. The ability to bind DNA was examined by ethidium bromide displacement assay.