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

doi:10.1021/js980132e

Journal of Pharmaceutical Sciences

Volume 88, Issue 3, March 1999, Pages 347-350

https://doi.org/10.1021/js980132e Get rights and content

Abstract

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. V_max in CHO/hPEPT1 cells was approximately 3-fold higher than those in Caco-2 cells and CHO–K1 cells, while K_m 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.

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The ability to isolate, clone and transfect the cDNAs for peptide transporters has provided a new dimension in developing cell culture models as screening tools. Studies conducted in either hPEPT1 adenovirally transfected Caco-2 cells or Chinese hamster ovary/hPEPT1 cells have demonstrated the utility of transfected cell lines for investigating the uptake of peptide transporter substrates [4,5]. In the present study, we constructed stably transfected HeLa-hPEPT1/HeLa-hPEPT2 clonal cell lines using the liposome transfection method.
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^†: University of Michigan.

^‡: Present address: NIH-NIGMS/FDA-CBER-DCGT, Bethesda, Maryland 20892.

^§: Parke-Davis Pharmaceutical Research.

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

Abstract

Adv. Drug Del. Rev.

Gastroenterology

Biochem. Biophys. Res. Commun.

Biochim. Biophys. Acta.

J. Biol. Chem.

J. Biol. Chem.

J. Biol. Chem.

J. Pharm. Sci.

Biochim. Biophys. Acta

Biochim. Biophays. Acta

J. Biol. Chem.

J. Biol. Chem.

Gastrointestinal Transport of Peptide and Protein Drugs and Prodrugs

Handbk. Exp. Pharmacol.

The use of cultured epithelial and endothelial cells for drug transport and metabolism studies

Pharm. Res.

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