Cells of the Caco-2 line as a model for studying the absorption of medicinal substances

Abstract

Cells of the Caco-2 line have the basic properties of enterocytes of the small intestine, and therefore can be used to study the absorption of medicinal substances. Aim. To characterize the properties of the Caco-2 cell line from the Institute of Cytology of the Russian Academy of Sciences and to evaluate with its help the mechanism of absorption of the original domestic drug - ethylmethylhydroxypyridine succinate (EMGPS). Materials and methods. The study was performed on Caco2 cells that were cultured for 21 days, since at this time their spontaneous differentiation into polarized cells similar to enterocytes of the small intestine occurs. The density of the cell monolayer was estimated by the value of transepithelial resistance. The number of major efflux proteins of glycoprotein-P transporters (Pgp) and breast cancer resistance protein (BCRP) in Caco-2 cells was analyzed using enzyme immunoassay. In specialized transwell systems, the transport of the Pgp substrate fexofenadine (40, 150 and 300 microns), the BCRP substrate methotrexate (5, 10, 50 microns) and EMGPS (10, 100 and 250 microns) through the cell monolayer was studied. The results of the study. By day 21 of cultivation, cells of the Caco2 line formed a merging monolayer with pronounced dense contacts. The amount of Pgp and BCRP was 110.8±14.1 ng/mg and 4.39±0.12 ng/mg, respectively, which correlates with the amount of these proteins in the human small intestine. Transport of fexofenadine (40, 150 and 300 microns) and methotrexate (5 microns) from the basolateral chamber to the apical chamber (corresponding to transport from enterocytes to the intestinal lumen) prevailed over transport in the opposite direction, which is associated with the work of Pgp and BCRP. The transport of EMGPS significantly exceeded the transport of fexofenadine and methotrexate and was symmetrical with respect to the cellular monolayer. Conclusion. Thus, the cells of the Caco-2 line, commercially available in the Russian Federation, have the basic properties of enterocytes of the small intestine, and can be used to study the absorption of medicinal substances in vitro. EMGPS quickly passes through the cellular monolayer, and the mechanism of its absorption is passive diffusion, without the participation of specific transporters.