Qing Li1, Yoshimichi Sai, Yukio Kato, Ikumi Tamai, Akira Tsuji. 1. Department of Pharmaceutical Biology, Faculty of Pharmaceutical Sciences, Kanazawa University, 13-1 Takara-machi, Kanazawa, Ishikawa 920-0934, Japan.
Abstract
PURPOSE: The aim of this study was to investigate the influences of various drugs and nutrients on the expression levels of intestinal drug transporters PEPT1, MDR1, MRP2 and MRP3, and drug-metabolizing enzyme CYP3A4. METHODS: Quantitative reverse transcriptase polymerase chain reaction was used to quantitate transporter and CYP3A4 mRNAs. Western blotting was used to determine protein levels of P-gp. Transport studies of P-gp were performed using cultured Caco-2 cell monolayers. RESULTS: The expression of MDR1 mRNA was increased by all-trans retinoic acid and in glucose-depleted medium, whereas little change of MRP2 and MRP3 mRNA was observed in Caco-2 cells. Substrates and inducers of P-gp or CYP3A4 tended to produce parallel changes in the expression of MDR1 and CYP3A4 mRNA in LS180 cells, whereas in Caco-2 cells no such coordinate response was observed, possibly due to the absence of the expression of steroid xenobiotic receptor (SXR) in this cell line. CONCLUSION: Several drugs and nutrients were found to affect transporter gene expression level in two human intestinal epithelial cell lines. Since SXR is involved in some expression-regulatory processes, and Caco-2 cells lack SXR, LS180 cells as well as Caco-2 cells should be used for the study of the regulation of intestinal transporters.
PURPOSE: The aim of this study was to investigate the influences of various drugs and nutrients on the expression levels of intestinal drug transporters PEPT1, MDR1, MRP2 and MRP3, and drug-metabolizing enzyme CYP3A4. METHODS: Quantitative reverse transcriptase polymerase chain reaction was used to quantitate transporter and CYP3A4 mRNAs. Western blotting was used to determine protein levels of P-gp. Transport studies of P-gp were performed using cultured Caco-2 cell monolayers. RESULTS: The expression of MDR1 mRNA was increased by all-trans retinoic acid and in glucose-depleted medium, whereas little change of MRP2 and MRP3 mRNA was observed in Caco-2 cells. Substrates and inducers of P-gp or CYP3A4 tended to produce parallel changes in the expression of MDR1 and CYP3A4 mRNA in LS180 cells, whereas in Caco-2 cells no such coordinate response was observed, possibly due to the absence of the expression of steroid xenobiotic receptor (SXR) in this cell line. CONCLUSION: Several drugs and nutrients were found to affect transporter gene expression level in two human intestinal epithelial cell lines. Since SXR is involved in some expression-regulatory processes, and Caco-2 cells lack SXR, LS180 cells as well as Caco-2 cells should be used for the study of the regulation of intestinal transporters.
Authors: S A Jones; L B Moore; J L Shenk; G B Wisely; G A Hamilton; D D McKee; N C Tomkinson; E L LeCluyse; M H Lambert; T M Willson; S A Kliewer; J T Moore Journal: Mol Endocrinol Date: 2000-01
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