title: Human dipeptide transporter, hPEPT1, stably transfected into Chinese hamster ovary cells.
abstract: OBJECTIVE
  A cDNA encoding the H(+)-coupled peptide transporter, hPEPT1, has previously been cloned from human ileum (8). The objective of this study was to establish a stably transfected cell line expressing hPEPT1 in mammalian cell culture.
  
  
  METHODS
  The hPEPT1 cDNA was subcloned into an expression vector carrying the CMV promoter and a neomycin resistance gene. This vector, pCDNA3-PEPT1, was transiently transfected into several cell lines to identify those capable of expressing PEPT1 transport function. CHO cells were selected and stably transfected with PEPT1 (CHO-PEPT1). Dipeptide transport activity was measured with 3H-Gly-Sar, in the presence and absence of inhibitors.
  
  
  RESULTS
  The clonal cell line, CHO-PEPT1, displayed high transport activity. Dipeptide transport was sensitive to pH and specific for dipeptides and other small peptides. Peptidomimetic antibiotics, such as cephalexin, were competitors for peptide transport.
  
  
  CONCLUSIONS
  The stably transfected cell line, CHO-PEPT1 exhibits enhanced transport over that of cell lines with native expression of PEPT1, and therefore, represents a useful tool for rapid screening of drugs that utilize the peptide transporter in the human intestine for absorption.
authors.affiliation: Department of Biopharmaceutical Sciences, University of California, San Francisco 94143-0446, USA.
authors.forename: K M
authors.initials: KM
authors.lastname: Covitz
authors.forename: G L
authors.initials: GL
authors.lastname: Amidon
authors.forename: W
authors.initials: W
authors.lastname: Sadée
mesh_terms: D000667:Ampicillin / Q000494:pharmacology; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D016466:CHO Cells / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D019556:COS Cells; D002352:Carrier Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism*; D002506:Cephalexin / Q000494:pharmacology; D002511:Cephalosporins / Q000494:pharmacology; D002999:Clone Cells; D006224:Cricetinae; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D004285:Dogs; D006367:HeLa Cells; D006801:Humans; D006863:Hydrogen-Ion Concentration; D009842:Oligopeptides / Q000493:pharmacokinetics; D010406:Penicillins / Q000494:pharmacology; D000074011:Peptide Transporter 1; D012680:Sensitivity and Specificity; D027981:Symporters; D014162:Transfection
chemical_list: D002352:Carrier Proteins; D002511:Cephalosporins; D018076:DNA, Complementary; D009842:Oligopeptides; D010406:Penicillins; D000074011:Peptide Transporter 1; C082186:SLC15A1 protein, human; D027981:Symporters; D000667:Ampicillin; D002506:Cephalexin