CHO/hPEPT1 cells overexpressing the human peptide transporter (hPEPT1) as an alternative in vitro model for peptidomimetic drugs

• Published in: Journal of pharmaceutical sciences Vol. 88; no. 3; pp. 347 - 350
• Main Authors: Han, Hyo-kyung, Rhie, Julie K., Oh, Doo-man, Saito, Go, Hsu, Cheng-pang, Stewart, Barbra H., Amidon, Gordon L.
• Format: Journal Article
• Language: English
• Published: New York Elsevier Inc 01.03.1999; John Wiley & Sons, Inc; Wiley; American Pharmaceutical Association
• Subjects: Analytical, structural and metabolic biochemistry; Animals; Binding and carrier proteins; Biological and medical sciences; Biological Transport; Caco-2 Cells - metabolism; Carrier Proteins - biosynthesis; Carrier Proteins - genetics; CHO Cells - metabolism; Cricetinae; Dipeptides - antagonists & inhibitors; Dipeptides - pharmacokinetics; Fundamental and applied biological sciences. Psychology; Gene expression; Humans; Kinetics; Molecular and cellular biology; Molecular genetics; Peptide Transporter 1; Proteins; Reproducibility of Results; Symporters; Transfection; Human; Cell culture; Peptides; Digestive system; Peptidomimetic compound; Rodentia; Gut; Gene overexpression; In vitro; Ovary; Vertebrata; Biological fixation; Mammalia; Transfection; Animal; Female genital system; Established cell line; Hamster; Carrier protein
• ISSN: 0022-3549; 1520-6017
• DOI: 10.1021/js980132e

The present study characterized Chinese hamster ovary cells overexpressing a human intestinal peptide transporter, CHO/hPEPT1 cells, as an in vitro model for peptidomimetic drugs. The kinetic parameters of Gly-Sar uptake were determined in three different cell culture systems such as untransfected CHO cells (CHO–K1), transfected CHO cells (CHO/hPEPT1) and Caco-2 cells. Vmax in CHO/hPEPT1 cells was approximately 3-fold higher than those in Caco-2 cells and CHO–K1 cells, while Km values were similar in all cases. The uptake of β-lactam antibiotics in CHO/hPEPT1 cells was three to twelve fold higher than that in CHO–K1 cells, indicating that CHO/hPEPT1 cells significantly enhanced the peptide transport activity. However, amino acid drugs also exhibited high cellular uptake in both CHO–K1 and CHO/hPEPT1 cells due to the high background level of amino acid transporters. Thus, cellular uptake study in CHO/hPEPT1 cells is not sensitive enough to distinguish the peptidyl drugs from amino acid drugs. The potential of CHO/hPEPT1 cells as an in vitro model for peptidomimetic drugs was also examined through the inhibition study on Gly-Sar uptake. Peptidomimetic drugs such as β-lactam antibiotics and enalapril significantly inhibited Gly-Sar uptake whereas the nonpeptidyl compounds, l-dopa and α-methyldopa, did not compete with Gly-Sar for cellular uptake within the therapeutic concentrations. In conclusion, the present study demonstrates the further characterization of CHO/hPEPT1 cells as an uptake model as well as inhibition study and suggests their utility as an alternative in vitro model for drug candidates targeting the hPEPT1 transporter.