ABSTRACT
Objective To establish double-transfected Madin-Darby canine kidney (MDCK) [Ⅱ cells expressing human organic anion transporting polypeptide 1B1 (hOATP1B1) and multidrug resistanceassociated protein 2 (hMRP2)and to testify their functions,moreover,to study the transcellur transport of indoleamine 2,3-dioxygenase (IDO) inhibitor 1-methyltryptophan (1-MT) in the transfectants.Methods hOATP1B1/hMRP2 eukaryotic vectors pVITRO2-SLCO1B1-ABCC2 was obtained by genetic engineering method and then transfected into MDCK cells.Stably expressed MDCK cells were screened by using the geneticin G418.Real-time PCR,Western blot analysis and immuno fluorescent confocal microscopy were used to verify the proteins expression.Transport of the representative substrate pravastatin in different pH values and substrate concentrations and 1-MT were evaluated using the double transfectants.Results MDCK-OATP1B1/MRP2 was successfully established.Pravastatin displayed the optimal transcellular transport when pH value was 6.5.Transport of pravastatin demonstrated the concentration-dependent in the concertation range of 0) to 500 μmol/L.Transport of 1-MT showed no significant difference in MDCK cells and transfectants.Conclusions MDCK-OATP1B1/MRP2 was successful established;1-MT was not the substrate of OATP1B1 or MRP2 protein;and the eatablished double transfectant cell lines can be used to evaluate OATP1B1/MRP2-medicated transport of xenobiotics (e.g.new drug candidates) and endogenous compounds (e.g.bilirubin).
ABSTRACT
This study was designed to explore the effect and mechanism of miR-206/miR-613 on the expression of OATP1B1 gene. Bioinformatic analysis was used to predict the potential miRNAs target sites in 3'-untranslated region (3'-UTR) of OATP1B1 mRNA. The expression level of miR-206/miR-613 and OATP1B1 mRNA and protein was determined with RT-qPCR and Western blot, respectively. Luciferase assay was used to explore the exact mechanism of the effect of miR-206/miR-613 on the expression of OATP1B1 mRNA and protein. The results showed that the seed sequences of miR-206/miR-613 has perfect complementary with 3'-UTR of OATP1B1 mRNA in terms of sequence specificity. The secondary structure between miR-206/miR-613 and 3'-UTR of OATP1B1 mRNA was rather stable. The OATP1B1 protein level was down-regulated by 24.7%, 38.8% by overexpression of miR-206/miR-613. The expression was up-regulated by 25%, 38.2% by inhibition of miR-206/miR-613. However, overexpression or inhibition of miR-206/miR-613 had no effect on the expression of OATP1B1 mRNA. The luciferase activity of pMIR/OATP1B1-WT luciferase reporter gene was decreased by 35% and 30% through overexpression of miR-206/miR-613. The expression was increased by 33.1% and 32.5% through inhibition of miR-206/miR-613. When the binding sites in the 3'-UTR of OATP1B1 mRNA complementary with miR-206/miR-613 was mutated, overexpression or inhibition of miR-206/miR-613 had no effect on the luciferase activity. Collectively, miR-206/miR-613 post-transcriptionally regulates the expression of OATP1B1 protein by directly targeting the 3'-UTR of OATP1B1 mRNA.
ABSTRACT
Objective To investigate influences of paeonol on mRNA expression and function of drug transporters BCRP and SLCO1B1 in HepG2 cell.Methods Cell counting Kit-8 assay was used to detect the viability of HepG2 cells;Real-time fluorescent quantitative PCR (qPCR) was performed to measure the expressions of BCRP and SLCO1B1 mRNAs; flow cytometry was applied to determine the transport functions of BCRP and SLCO1B1. Results Paeonol (2-8μg/mL) did not decrease HepG2 cell survival rate, but 16 μg/mL paeonol significantly reduced cell survival rate (P<0.05). Paeonol(2-8μg/mL)significantly induced the mRNA expression and function of drug transporters BCRP and SLCO1B1(P <0.05).Compared with control group, transcription level of paeonol group’s BCRP and SLCO1B1 drug transporters obviously up-regulated, the of translocation efficiency of substrate specificity increased significantly (P <0.05).Conclusion Paeonol can induce drug hepatocellular transporters BCRP and SLCO1B1 gene expression, thereby promote the substrate transport the transmembrane.It is indicated that the drug combination of paeonol and BCRP and SLCO1B1 transporters, there may be a risk of drug interactions.