• Korean Journal of Radiology
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• v.21 no.6
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• pp.726-735
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• 2020

Objective: Recent innovations in biology are boosting gene and cell therapy, but monitoring the response to these treatments is difficult. The purpose of this study was to find an MRI-reporter gene that can be used to monitor gene or cell therapy and that can be delivered without a viral vector, as viral vector delivery methods can result in long-term complications. Materials and Methods: CMV promoter-human organic anion transporting polypeptide 1B3 (CMV-hOATP1B3) cDNA or CMV-blank DNA (control) was transfected into HEK293 cells using Lipofectamine. OATP1B3 expression was confirmed by western blotting and confocal microscopy. In vitro cell phantoms were made using transfected HEK293 cells cultured in various concentrations of gadoxetic acid for 24 hours, and images of the phantoms were made with a 9.4T micro-MRI. In vivo xenograft tumors were made by implanting HEK293 cells transfected with CMV-hOATP1B3 (n = 4) or CMV-blank (n = 4) in 8-week-old male nude mice, and MRI was performed before and after intravenous injection of gadoxetic acid (1.2 µL/g). Results: Western blot and confocal microscopy after immunofluorescence staining revealed that only CMV-hOATP1B3-transfected HEK293 cells produced abundant OATP1B3, which localized at the cell membrane. OATP1B3 expression levels remained high through the 25th subculture cycle, but decreased substantially by the 50th subculture cycle. MRI of cell phantoms showed that only the CMV-hOATP1B3-transfected cells produced a significant contrast enhancement effect. In vivo MRI of xenograft tumors revealed that only CMV-hOATP1B3-transfected HEK293 tumors demonstrated a T1 contrast effect, which lasted for at least 5 hours. Conclusion: The human endogenous OATP1B3 gene can be non-virally delivered into cells to induce transient OATP1B3 expression, leading to gadoxetic acid-mediated enhancement on MRI. These results indicate that hOATP1B3 can serve as an MRI-reporter gene while minimizing the risk of long-term complications.

• Archives of Pharmacal Research
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• v.25 no.4
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• pp.397-415
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• 2002

This paper deals with a crucial mechanism for interaction of basic drugs and cardiac glycosides at the hepatic uptake level. Available literature data is provided and new material is presented to picture the differential transport inhibition of bulky (type2) cationic drugs by a number of cardiac glycosides in rat liver. It is shown that the so called organic anion transporting peptide 2 (oatp2) is the likely interaction site: differential inhibition patterns as observed in oocytes expressing oatp2, could be clearly identified also in isolated rat hepatocytes, isolated perfused rat liver and the rat in vivo. The anticipation of transport interactions at the hepatic clearance level should be based on data on the relative affinities of interacting substrates for the transport systems involved along with knowledge on the pharmacokinetics of these agents as well as the chosen dose regimen in the studied species. This review highlights the importance of multispecific tranporter systems such as OATP, accommodating a broad spectrum of organic compounds of various charge, implying potential transport interactions that can affect body distribution and organ clearance.

• Biomolecules & Therapeutics
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• v.23 no.5
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• pp.400-406
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• 2015

MicroRNAs (miRNAs) are a family of non-coding RNA that are able to adjust the expression of many proteins, including ATP-binding cassette transporter and organic cation transporter. We sought to evaluate the effect of miR-511 on the regulation of OATP1B1 expression by free fatty acids. When using free fatty acids to stimulate Chang liver cells, we found that the expression of miR-511 increased significantly while the expression of OATP1B1 decreased. We also proved that SLCO1B1 is the target gene of miR-511 with a bioinformatics analysis and using the dual luciferase reporter assay. Furthermore, the expressions of SLCO1B1 and OATP1B1 decreased if transfecting Chang liver cells with miR-511, but did not increase when transfecting the inhibitors of miR-511 into steatosis cells. Our study indicates that miR-511 may play an important role in the regulation of OATP1B1 expression by free fatty acids.

• Biomolecules & Therapeutics
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• v.25 no.3
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• pp.288-295
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• 2017

The incidence of polypharmacy-which can result in drug-drug interactions-has increased in recent years. Drug-metabolizing enzymes and drug transporters are important polypharmacy modulators. In this study, the effects of bosentan and rifampin on the expression and activities of organic anion-transporting peptide (OATP) and cytochrome P450 (CYP450) 2C9 and CYP3A4 were investigated in vitro. HEK293 cells and primary human hepatocytes overexpressing the target genes were treated with bosentan and various concentrations of rifampin, which decreased the uptake activities of OATP transporters in a dose-dependent manner. In primary human hepatocytes, CYP2C9 and CYP3A4 gene expression and activities decreased upon treatment with $20{\mu}M$ $bosentan+200{\mu}M$ rifampin. Rifampin also reduced gene expression of OATP1B1, OATP1B3, and OATP2B1 transporter, and inhibited bosentan influx in human hepatocytes at increasing concentrations. These results confirm rifampin- and bosentan-induced interactions between OATP transporters and CYP450.

• Korean Journal of Clinical Pharmacy
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• v.24 no.4
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• pp.231-239
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• 2014

Background and objective: Pravastatin has been shown to have favorable risk-benefit profile when it is administered to hypercholesterolemic subjects to prevent cardiovascular events. However, subjects with impaired OATP1B1 activity may be more susceptible to pravastatin-induced muscle toxicity than subjects with normal OATP1B1 activity. A systematic review was conducted to evaluate the effect of SLCO1B1 genetic polymorphism on pharmacokinetics of pravastatin. Method: Medline$^{(R)}$ and Embase$^{(R)}$ were searched for relevant studies until July 2013. The search terms used were pravastatin AND (SLCO1B1 OR OATP1B1 OR LST1 OR SLC21A6) AND (gene OR $genetic^*$ OR $genomic^*$ OR $pharmacogenet^*$ OR $pharmacogenom^*$ OR $polymorph^*$). Results: A meta-analysis of the area under the concentration-time curve (AUC) of pravastatin in $SLCO1B1^*15$ and $SLCO1B1^*1a/^*1a$ was conducted. Five studies met all the inclusion criteria and methodological requirements. There was no statistically significant difference in the AUC value between $SLCO1B1^*15$ and $SLCO1B1^*1a/^*1a$ (p=0.728). However, $SLCO1B1^*15$ participants exhibited significantly higher AUC values than $SLCO1B1^*1b/^*1b$ carriers (p<0.001). In case of $SLCO1B1^*15^*15$ carriers, they had significantly higher AUC value than $SLCO1B1^*1a/^*1a$ subjects (p=0.002). Lastly, compared with to the subjects of $SLCO1B1^*1a/^*1a$, the carriers of heterozygous $SLCO1B1^*15$ increased the AUC value of pravastatin statistically significantly in Asian population (p=0.014). Conclusion: The present meta-analysis suggests that subjects with $SLCO1B1^*15$ are associated with increased AUC of pravastatin.

• Korean Journal of Clinical Pharmacy
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• v.23 no.4
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• pp.316-321
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• 2013

Purpose: Atorvastatin, a HMG-CoA reductase inhibitor is widely prescribed in hyperlipidemic patients and telmisartan, an angiotensin receptor blocker is frequently used in the treatment of hypertension. Both drugs are substrates of organic anion transporting polypeptide (OATP) expressed in basolateral membrane in the liver, and undergo high first pass metabolism. Therefore, OATP-mediated hepatic uptake is important for disposition and metabolism of these drugs. The present study was designed to investigate the pharmacokinetic interactions between atorvastatin and telmisartan in rats. Method: Young adult SD rats were divided into three groups (n=6, each) and atorvastatin (10 mg/kg) and telmisartan (4 mg/kg) were orally given alone and together. Heparinized blood was serially taken and plasma concentrations of both drugs were measured using HPLC-MS/MS. Pharmacokinetic parameters of two drugs were calculated. Results: No significant pharmacokinetic change was found except a delay of time to peak of telmisartan when administered with atorvastatin. Each drug at the present dosage seemed to be insufficient to alter the pharmacokinetic parameters of its counterpart drug. Conclusion: Conclusively, co-administration of atorvastatin and telmisartan may lead to negligible clinical consequences.

• 대한임상약리학회:학술대회논문집
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• 2006.11a
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• pp.41-42
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• 2006

• The Korean Journal of Physiology and Pharmacology
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• v.22 no.3
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• pp.321-329
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• 2018

It was recently reported that the $C_{max}$ and AUC of rosuvastatin increases when it is coadministered with telmisartan and cyclosporine. Rosuvastatin is known to be a substrate of OATP1B1, OATP1B3, NTCP, and BCRP transporters. The aim of this study was to explore the mechanism of the interactions between rosuvastatin and two perpetrators, telmisartan and cyclosporine. Published (cyclosporine) or newly developed (telmisartan) PBPK models were used to this end. The rosuvastatin model in Simcyp (version 15)'s drug library was modified to reflect racial differences in rosuvastatin exposure. In the telmisartan-rosuvastatin case, simulated rosuvastatin $C_{maxI}/C_{max}$ and $AUC_I/AUC$ (with/without telmisartan) ratios were 1.92 and 1.14, respectively, and the $T_{max}$ changed from 3.35 h to 1.40 h with coadministration of telmisartan, which were consistent with the aforementioned report ($C_{maxI}/C_{max}$: 2.01, $AUC_I/AUC$:1.18, $T_{max}:5h{\rightarrow}0.75h$). In the next case of cyclosporine-rosuvastatin, the simulated rosuvastatin $C_{maxI}/C_{max}$ and $AUC_I/AUC$ (with/without cyclosporine) ratios were 3.29 and 1.30, respectively. The decrease in the $CL_{int,BCRP,intestine}$ of rosuvastatin by telmisartan and cyclosporine in the PBPK model was pivotal to reproducing this finding in Simcyp. Our PBPK model demonstrated that the major causes of increase in rosuvastatin exposure are mediated by intestinal BCRP (rosuvastatin-telmisartan interaction) or by both of BCRP and OATP1B1/3 (rosuvastatin-cyclosporine interaction).

• The Korean Journal of Physiology and Pharmacology
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• v.5 no.2
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• pp.107-122
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• 2001

A function of the kidney is elimination of a variety of xenobiotics ingested and wasted endogenous compounds from the body. Organic anion and cation transport systems play important roles to protect the body from harmful substances. The renal proximal tubule is the primary site of carrier-mediated transport from blood into urine. During the last decade, molecular cloning has identified several families of multispecific organic anion and cation transporters, such as organic anion transporter (OAT), organic cation transporter (OCT), and organic anion-transporting polypeptide (oatp). Additional findings also suggested ATP-dependent organic ion transporters such as MDR1/P-glycoprotein and the multidrug resistance-associated protein (MRP) as efflux pump. The substrate specificity of these transporters is multispecific. These transporters also play an important role as drug transporters. Studies on their functional properties and localization provide information in renal handling of drugs. This review summarizes the latest knowledge on molecular properties and pharmacological significance of renal organic ion transporters.

• Toxicological Research
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• v.23 no.1
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• pp.1-9
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• 2007

Transporters are membrane proteins that mediate the transfer of substrate across the cellular membrane. In this overview, the characteristics and the toxicological relevance were discussed for various types of transporters. For drug transporters, the overview focused on ATP-binding cassette transporters and solute carrier family 21A/22A member transporters. Except for OCTN transporters and OATP transporters, drug transporters tend to have broad substrate specificity, suggesting drug-drug interaction at the level of transport processes (e.g., interaction between methotrexate and non-steroidal anti-inflammatory agents) is likely. For metal transporters, transporters for zinc, copper and multiple metals were discussed in this overview. These metal transporters have comparatively narrow substrate specificity, except for multiple metal transporters, suggesting that inter-substrate interaction at the level of transport is less likely. In contrast, the expressions of the transporters are often regulated by their substrates, suggesting cellular adaptation mechanism exists for these transporters. The drug-drug interactions in drug transporters and the cellular adaptation mechanisms for metal transporters are likely to lead to alterations in pharmacokinetics and cellular metal homeostasis, which may be linked to the development of toxicity. Therefore, the transporter-mediated alterations may have toxicological relevance.