Li Qing, Sai Yoshimichi, Kato Yukio, Tamai Ikumi, Tsuji Akira
Department of Pharmaceutical Biology, Faculty of Pharmaceutical Sciences, Kanazawa University, 13-1 Takara-machi, Kanazawa, Ishikawa 920-0934, Japan.
Pharm Res. 2003 Aug;20(8):1119-24. doi: 10.1023/a:1025076326061.
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.
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.
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.
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.
本研究旨在探讨多种药物和营养物质对肠道药物转运体PEPT1、MDR1、MRP2和MRP3以及药物代谢酶CYP3A4表达水平的影响。
采用定量逆转录聚合酶链反应对转运体和CYP3A4 mRNA进行定量分析。利用蛋白质印迹法测定P-糖蛋白的蛋白水平。使用培养的Caco-2细胞单层进行P-糖蛋白的转运研究。
全反式维甲酸和葡萄糖缺乏培养基可使MDR1 mRNA表达增加，而在Caco-2细胞中MRP2和MRP3 mRNA变化不大。P-糖蛋白或CYP3A4的底物和诱导剂往往会使LS180细胞中MDR1和CYP3A4 mRNA的表达产生平行变化，而在Caco-2细胞中未观察到这种协同反应，这可能是由于该细胞系中缺乏类固醇外源性物质受体（SXR）的表达。
发现多种药物和营养物质可影响两种人肠上皮细胞系中转运体基因的表达水平。由于SXR参与了一些表达调控过程，且Caco-2细胞缺乏SXR，因此在研究肠道转运体的调控时应同时使用LS180细胞和Caco-2细胞。
