RESUMO
Antisense oligonucleotides (ASOs) are a promising therapeutic modality. However, failure to predict acute kidney injury induced by SPC5001 ASO observed in a clinical trial suggests the need for additional preclinical models to complement the preceding animal toxicity studies. To explore the utility of in vitro systems in this space, we evaluated the induction of nephrotoxicity and kidney injury biomarkers by SPC5001 in human renal proximal tubule epithelial cells (HRPTEC), cultured in 2D, and in a recently developed kidney proximal tubule-on-a-chip. 2D HRPTEC cultures were exposed to the nephrotoxic ASO SPC5001 or the safe control ASO 556089 (0.16-40 µM) for up to 72 h, targeting PCSK9 and MALAT1, respectively. Both ASOs induced a concentration-dependent downregulation of their respective mRNA targets but cytotoxicity (determined by LDH activity) was not observed at any concentration. Next, chip-cultured HRPTEC were exposed to SPC5001 (0.5 and 5 µM) and 556089 (1 and 10 µM) for 48 h to confirm downregulation of their respective target transcripts, with 74.1 ± 5.2% for SPC5001 (5 µM) and 79.4 ± 0.8% for 556089 (10 µM). During extended exposure for up to 20 consecutive days, only SPC5001 induced cytotoxicity (at the higher concentration; 5 µM), as evaluated by LDH in the perfusate medium. Moreover, perfusate levels of biomarkers KIM-1, NGAL, clusterin, osteopontin and VEGF increased 2.5 ± 0.2-fold, 3.9 ± 0.9-fold, 2.3 ± 0.6-fold, 3.9 ± 1.7-fold and 1.9 ± 0.4-fold respectively, in response to SPC5001, generating distinct time-dependent profiles. In conclusion, target downregulation, cytotoxicity and kidney injury biomarkers were induced by the clinically nephrotoxic ASO SPC5001, demonstrating the translational potential of this kidney on-a-chip.
Assuntos
Injúria Renal Aguda/induzido quimicamente , Túbulos Renais Proximais/efeitos dos fármacos , Oligonucleotídeos Antissenso/toxicidade , Oligonucleotídeos/toxicidade , Injúria Renal Aguda/patologia , Biomarcadores/metabolismo , Células Cultivadas , Relação Dose-Resposta a Droga , Humanos , Túbulos Renais Proximais/patologia , L-Lactato Desidrogenase/metabolismo , Dispositivos Lab-On-A-Chip , Oligonucleotídeos/administração & dosagem , Oligonucleotídeos Antissenso/administração & dosagem , RNA Mensageiro/metabolismo , Fatores de TempoRESUMO
Drug-induced kidney injury is a major clinical problem and causes drug attrition in the pharmaceutical industry. To better predict drug-induced kidney injury, kidney in vitro cultures with enhanced physiologic relevance are developed. To mimic the proximal tubule, the main site of adverse drug reactions in the kidney, human-derived renal proximal tubule epithelial cells (HRPTECs) were injected in one of the channels of dual-channel Nortis chips and perfused for 7 days. Tubes of HRPTECs demonstrated expression of tight junction protein 1 (zona occludens-1), lotus lectin, and primary cilia with localization at the apical membrane, indicating an intact proximal tubule brush border. Gene expression of cisplatin efflux transporters multidrug and toxin extrusion transporter (MATE) 1 (SLC47A1) and MATE2-k (SLC47A2) and megalin endocytosis receptor increased 19.9 ± 5.0-, 23.2 ± 8.4-, and 106 ± 33-fold, respectively, in chip cultures compared with 2-dimensional cultures. Moreover, organic cation transporter 2 (OCT2) (SLC22A2) was localized exclusively on the basolateral membrane. When infused from the basolateral compartment, cisplatin (25 µM, 72 hours) induced toxicity, which was evident as reduced cell number and reduced barrier integrity compared with vehicle-treated chip cultures. Coexposure with the OCT2 inhibitor cimetidine (1 mM) abolished cisplatin toxicity. In contrast, infusion of cisplatin from the apical compartment did not induce toxicity, which was in line with polarized localization of cisplatin uptake transport proteins, including OCT2. In conclusion, we developed a dual channel human kidney proximal tubule-on-a-chip with a polarized epithelium, restricting cisplatin sensitivity to the basolateral membrane and suggesting improved physiologic relevance over single-compartment models. Its implementation in drug discovery holds promise to improve future in vitro drug-induced kidney injury studies. SIGNIFICANCE STATEMENT: Human-derived kidney proximal tubule cells retained characteristics of epithelial polarization in vitro when cultured in the kidney-on-a-chip, and the dual-channel construction allowed for drug exposure using the physiologically relevant compartment. Therefore, cell polarization-dependent cisplatin toxicity could be replicated for the first time in a kidney proximal tubule-on-a-chip. The use of this physiologically relevant model in drug discovery has potential to aid identification of safe novel drugs and contribute to reducing attrition rates due to drug-induced kidney injury.
Assuntos
Injúria Renal Aguda/induzido quimicamente , Cisplatino/toxicidade , Túbulos Renais Proximais/efeitos dos fármacos , Dispositivos Lab-On-A-Chip , Injúria Renal Aguda/patologia , Injúria Renal Aguda/prevenção & controle , Técnicas de Cultura de Células/instrumentação , Células Cultivadas , Cimetidina/farmacologia , Cimetidina/uso terapêutico , Cisplatino/farmacocinética , Avaliação Pré-Clínica de Medicamentos/instrumentação , Estudos de Viabilidade , Perfilação da Expressão Gênica , Humanos , Túbulos Renais Proximais/citologia , Túbulos Renais Proximais/metabolismo , Proteínas de Transporte de Cátions Orgânicos/metabolismo , Transportador 2 de Cátion Orgânico/antagonistas & inibidores , Transportador 2 de Cátion Orgânico/metabolismoRESUMO
Cisplatin is a cytostatic drug used for treatment of solid organ tumors. The main adverse effect is organic cation transporter 2 (OCT2)-mediated nephrotoxicity, observed in 30% of patients. The contribution of other renal drug transporters is elusive. Here, cisplatin-induced toxicity was evaluated in human-derived conditionally immortalized proximal tubule epithelial cells (ciPTEC) expressing renal drug transporters, including OCT2 and organic anion transporters 1 (OAT1) or 3 (OAT3). Parent ciPTEC demonstrated OCT2-dependent cisplatin toxicity (TC50 34 ± 1 µM after 24-hour exposure), as determined by cell viability. Overexpression of OAT1 and OAT3 resulted in reduced sensitivity to cisplatin (TC50 45 ± 6 and 64 ± 11 µM after 24-hour exposure, respectively). This effect was independent of OAT-mediated transport, as the OAT substrates probenecid and diclofenac did not influence cytotoxicity. Decreased cisplatin sensitivity in OAT-expressing cells was associated directly with a trend toward reduced intracellular cisplatin accumulation, explained by reduced OCT2 gene expression and activity. This was evaluated by Vmax of the OCT2-model substrate ASP+ (23.5 ± 0.1, 13.1 ± 0.3, and 21.6 ± 0.6 minutes-1 in ciPTEC-parent, ciPTEC-OAT1, and ciPTEC-OAT3, respectively). Although gene expression of cisplatin efflux transporter multidrug and toxin extrusion 1 (MATE1) was 16.2 ± 0.3-fold upregulated in ciPTEC-OAT1 and 6.1 ± 0.7-fold in ciPTEC-OAT3, toxicity was unaffected by the MATE substrate pyrimethamine, suggesting that MATE1 does not play a role in the current experimental set-up. In conclusion, OAT expression results in reduced cisplatin sensitivity in renal proximal tubule cells, explained by reduced OCT2-mediated uptake capacity. In vitro drug-induced toxicity studies should consider models that express both OCT and OAT drug transporters.
Assuntos
Cisplatino/farmacologia , Expressão Gênica/fisiologia , Túbulos Renais Proximais/efeitos dos fármacos , Túbulos Renais Proximais/metabolismo , Proteínas de Transporte de Cátions Orgânicos/metabolismo , Transporte Biológico/efeitos dos fármacos , Transporte Biológico/fisiologia , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/metabolismo , Humanos , Probenecid/farmacologiaRESUMO
Accurate prediction of pharmacokinetic parameters, such as renal clearance, is fundamental to the development of effective and safe new treatments for patients. However, conventional renal models have a limited ability to predict renal drug secretion, a process that is dependent on transporters in the proximal tubule. Improvements in microphysiological systems (MPS) have extended our in vitro capabilities to predict pharmacokinetic parameters. In this study a kidney-MPS model was developed that successfully recreated renal drug secretion. Human proximal tubule cells grown in the kidney-MPS, resembling an in vivo phenotype, actively secreted the organic cation drug metformin and organic anion drug cidofovir, in contrast to cells cultured in conventional culture formats. Metformin and cidofovir renal secretory clearance were predicted from kidney-MPS data within 3.3- and 1.3-fold, respectively, of clinically reported values by employing a semi-mechanistic drug distribution model using kidney-MPS drug transport parameters together with in vitro to in vivo extrapolation. This approach introduces an effective application of a kidney-MPS model coupled with pharmacokinetic modelling tools to evaluate and predict renal drug clearance in humans. Kidney-MPS renal clearance predictions can potentially complement pharma-cokinetic animal studies and contribute to the reduction of pre-clinical species use during drug development.
Assuntos
Metformina , Sistemas Microfisiológicos , Animais , Humanos , Cidofovir/farmacologia , Rim/metabolismo , Metformina/metabolismo , Metformina/farmacologia , Vias de Eliminação de FármacosRESUMO
Proximal tubule epithelial cells (PTEC) are susceptible to drug-induced kidney injury (DIKI). Cell-based, two-dimensional (2D) in vitro PTEC models are often poor predictors of DIKI, probably due to the lack of physiological architecture and flow. Here, we assessed a high throughput, 3D microfluidic platform (Nephroscreen) for the detection of DIKI in pharmaceutical development. This system was established with four model nephrotoxic drugs (cisplatin, tenofovir, tobramycin and cyclosporin A) and tested with eight pharmaceutical compounds. Measured parameters included cell viability, release of lactate dehydrogenase (LDH) and N-acetyl-ß-d-glucosaminidase (NAG), barrier integrity, release of specific miRNAs, and gene expression of toxicity markers. Drug-transporter interactions for P-gp and MRP2/4 were also determined. The most predictive read outs for DIKI were a combination of cell viability, LDH and miRNA release. In conclusion, Nephroscreen detected DIKI in a robust manner, is compatible with automated pipetting, proved to be amenable to long-term experiments, and was easily transferred between laboratories. This proof-of-concept-study demonstrated the usability and reproducibility of Nephroscreen for the detection of DIKI and drug-transporter interactions. Nephroscreen it represents a valuable tool towards replacing animal testing and supporting the 3Rs (Reduce, Refine and Replace animal experimentation).
Assuntos
Túbulos Renais Proximais , Dispositivos Lab-On-A-Chip , Animais , Interações Medicamentosas , Humanos , Rim , Reprodutibilidade dos TestesRESUMO
BACKGROUND: Kidney disease modeling and assessment of drug-induced kidney injury can be advanced using three-dimensional (3D) microfluidic models that recapitulate in vivo characteristics. Fluid shear stress (FSS) has been depicted as main modulator improving in vitro physiology in proximal tubule epithelial cells (PTECs). We aimed to elucidate the role of FSS and primary cilia on transport activity and morphology in PTECs. METHODS: Human conditionally immortalized PTEC (ciPTEC-parent) was cultured in a microfluidic 3D device, the OrganoPlate, under a physiological peak FSS of 2.0 dyne/cm2 or low peak FSS of 0.5 dyne/cm2. Upon a 9-day exposure to FSS, albumin-FITC uptake, activity of P-glycoprotein (P-gp) and multidrug resistance-associated proteins 2/4 (MRP2/4), cytotoxicity and cell morphology were determined. RESULTS: A primary cilium knock-out cell model, ciPTEC-KIF3α-/-, was successfully established via CRISPR-Cas9 genome editing. Under physiological peak FSS, albumin-FITC uptake (pâ¯=â¯.04) and P-gp efflux (pâ¯=â¯.002) were increased as compared to low FSS. Remarkably, a higher albumin-FITC uptake (pâ¯=â¯.03) and similar trends in activity of P-gp and MRP2/4 were observed in ciPTEC-KIF3α-/-. FSS induced cell elongation corresponding with the direction of flow in both cell models, but had no effect on cyclosporine A-induced cytotoxicity. CONCLUSIONS: FSS increased albumin uptake, P-gp efflux and cell elongation, but this was not attributed to a mechanosensitive mechanism related to primary cilia in PTECs, but likely to microvilli present at the apical membrane. GENERAL SIGNIFICANCE: FSS-induced improvements in biological characteristics and activity in PTECs was not mediated through a primary cilium-related mechanism.
Assuntos
Injúria Renal Aguda/metabolismo , Cílios/metabolismo , Túbulos Renais Proximais/efeitos dos fármacos , Dispositivos Lab-On-A-Chip , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/genética , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/metabolismo , Injúria Renal Aguda/induzido quimicamente , Injúria Renal Aguda/genética , Transporte Biológico/efeitos dos fármacos , Cílios/efeitos dos fármacos , Ciclosporina/toxicidade , Células Epiteliais/efeitos dos fármacos , Humanos , Túbulos Renais Proximais/metabolismo , Mecanotransdução Celular/genética , Proteína 2 Associada à Farmacorresistência Múltipla , Proteínas Associadas à Resistência a Múltiplos Medicamentos/genética , Resistência ao Cisalhamento , Estresse MecânicoRESUMO
Drug attrition related to kidney toxicity remains a challenge in drug discovery and development. In vitro models established over the past 2 decades to supplement in vivo studies have improved the throughput capacity of toxicity evaluation, but usually suffer from low predictive value. To achieve a paradigm shift in the prediction of drug-induced kidney toxicity, two aspects are fundamental: increased physiological relevance of the kidney model, and use of appropriate toxicity end points. Recent studies have suggested that increasing the physiological relevance of kidney models can improve their sensitivity to drug-induced damage. Here, we discuss how advanced culture models, including modified cell lines, induced pluripotent stem cells, kidney organoid cultures, and microfluidic devices enhance in vivo similarity. To this end, culture models aim to increase the proximal tubule epithelial phenotype, reconstitute multiple tissue compartments and extracellular matrix, allow exposure to fluid shear stress, and enable interaction between multiple cell types. Applying computation-aided end points and novel biomarkers to advanced culture models will further improve sensitivity and clinical relevance of in vitro drug-induced toxicity prediction. Implemented at the right stage of drug discovery and development and coupled to high-content evaluation techniques, these models have the potential to reduce attrition and aid the selection of candidate drugs with an appropriate safety profile.
Assuntos
Injúria Renal Aguda/induzido quimicamente , Técnicas In Vitro , Túbulos Renais/citologia , Animais , Linhagem Celular , Humanos , Células-Tronco Pluripotentes Induzidas , Dispositivos Lab-On-A-Chip , Organoides , Medição de RiscoRESUMO
Antisense oligonucleotide therapy has been reported to be associated with renal injury. Here, the mechanism of reversible proteinuria was investigated by combining clinical, pre-clinical, and in vitro data. Urine samples were obtained from Duchenne muscular dystrophy (DMD) patients treated with drisapersen, a modified 2'O-methyl phosphorothioate antisense oligonucleotide (6 mg/kg). Urine and kidney tissue samples were collected from cynomolgus monkeys (Macaca fascicularis) dosed with drisapersen (39 weeks). Cell viability and protein uptake were evaluated in vitro using human conditionally immortalized proximal tubule epithelial cells (ciPTECs). Oligonucleotide treatment in DMD patients was associated with an increase in urinary alpha-1-microglobulin (A1M), which returned to baseline following treatment interruptions. In monkeys, increased urinary A1M correlated with dose-dependent accumulation of oligonucleotide in kidney tissue without evidence of tubular damage. Furthermore, oligonucleotides accumulated in the lysosomes of ciPTECs and reduced the absorption of A1M, albumin, and receptor-associated protein, but did not affect cell viability when incubated for up to 7 days. In conclusion, phosphorothioate oligonucleotides appear to directly compete for receptor-mediated endocytosis in proximal tubules. We postulate that oligonucleotide-induced low molecular weight proteinuria in patients is therefore a transient functional change and not indicative of tubular damage.
RESUMO
Drug-transporter interactions could impact renal drug clearance and should ideally be detected in early stages of drug development to avoid toxicity-related withdrawals in later stages. This requires reliable and robust assays for which current high-throughput screenings have, however, poor predictability. Kidney-on-a-chip platforms have the potential to improve predictability, but often lack compatibility with high-content detection platforms. Here, we combined conditionally immortalized proximal tubule epithelial cells overexpressing organic anion transporter 1 (ciPTEC-OAT1) with the microfluidic titer plate OrganoPlate to develop a screenings assay for renal drug-transporter interactions. In this platform, apical localization of F-actin and intracellular tight-junction protein zonula occludens-1 (ZO-1) indicated appropriate cell polarization. Gene expression levels of the drug transporters organic anion transporter 1 (OAT1; SLC22A6), organic cation transporter 2 (OCT2; SLC22A2), P-glycoprotein (P-gp; ABCB1), and multidrug resistance-associated protein 2 and 4 (MRP2/4; ABCC2/4) were similar levels to 2D static cultures. Functionality of the efflux transporters P-gp and MRP2/4 was studied as proof-of-concept for 3D assays using calcein-AM and 5-chloromethylfluorescein-diacetate (CMFDA), respectively. Confocal imaging demonstrated a 4.4 ± 0.2-fold increase in calcein accumulation upon P-gp inhibition using PSC833. For MRP2/4, a 3.0 ± 0.2-fold increased accumulation of glutathione-methylfluorescein (GS-MF) was observed upon inhibition with a combination of PSC833, MK571, and KO143. Semi-quantitative image processing methods for P-gp and MRP2/4 was demonstrated with corresponding Z'-factors of 0.1 ± 0.3 and 0.4 ± 0.1, respectively. In conclusion, we demonstrate a 3D microfluidic PTEC model valuable for screening of drug-transporter interactions that further allows multiplexing of endpoint read-outs for drug-transporter interactions and toxicity.
Assuntos
Avaliação Pré-Clínica de Medicamentos/métodos , Células Epiteliais/efeitos dos fármacos , Túbulos Renais Proximais/efeitos dos fármacos , Dispositivos Lab-On-A-Chip , Moduladores de Transporte de Membrana/toxicidade , Proteínas de Membrana Transportadoras/efeitos dos fármacos , Técnicas Analíticas Microfluídicas/instrumentação , Actinas/metabolismo , Transporte Biológico , Linhagem Celular Transformada , Polaridade Celular , Células Epiteliais/metabolismo , Humanos , Túbulos Renais Proximais/metabolismo , Proteínas de Membrana Transportadoras/genética , Proteínas de Membrana Transportadoras/metabolismo , Microscopia Confocal , Proteína 2 Associada à Farmacorresistência Múltipla , Medição de Risco , Proteína da Zônula de Oclusão-1/metabolismoRESUMO
Proximal tubules in the kidney play a crucial role in reabsorbing and eliminating substrates from the body into the urine, leading to high local concentrations of xenobiotics. This makes the proximal tubule a major target for drug toxicity that needs to be evaluated during the drug development process. Here, we describe an advanced in vitro model consisting of fully polarized renal proximal tubular epithelial cells cultured in a microfluidic system. Up to 40 leak-tight tubules were cultured on this platform that provides access to the basolateral as well as the apical side of the epithelial cells. Exposure to the nephrotoxicant cisplatin caused a dose-dependent disruption of the epithelial barrier, a decrease in viability, an increase in effluent LDH activity, and changes in expression of tight-junction marker zona-occludence 1, actin, and DNA-damage marker H2A.X, as detected by immunostaining. Activity and inhibition of the efflux pumps P-glycoprotein (P-gp) and multidrug resistance protein (MRP) were demonstrated using fluorescence-based transporter assays. In addition, the transepithelial transport function from the basolateral to the apical side of the proximal tubule was studied. The apparent permeability of the fluorescent P-gp substrate rhodamine 123 was decreased by 35% by co-incubation with cyclosporin A. Furthermore, the activity of the glucose transporter SGLT2 was demonstrated using the fluorescent glucose analog 6-NBDG which was sensitive to inhibition by phlorizin. Our results demonstrate that we developed a functional 3D perfused proximal tubule model with advanced renal epithelial characteristics that can be used for drug screening studies.
Assuntos
Técnicas de Cultura de Células , Células Epiteliais/efeitos dos fármacos , Nefropatias/induzido quimicamente , Túbulos Renais Proximais/efeitos dos fármacos , Moduladores de Transporte de Membrana/toxicidade , Proteínas de Membrana Transportadoras/efeitos dos fármacos , Perfusão , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/antagonistas & inibidores , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/metabolismo , Transporte Biológico , Linhagem Celular , Polaridade Celular , Cisplatino/toxicidade , Ciclosporina/toxicidade , Relação Dose-Resposta a Droga , Células Epiteliais/metabolismo , Células Epiteliais/patologia , Humanos , Nefropatias/metabolismo , Nefropatias/patologia , Túbulos Renais Proximais/metabolismo , Túbulos Renais Proximais/patologia , Dispositivos Lab-On-A-Chip , Proteínas de Membrana Transportadoras/metabolismo , Técnicas Analíticas Microfluídicas , Florizina/toxicidade , Transportador 2 de Glucose-Sódio/efeitos dos fármacos , Transportador 2 de Glucose-Sódio/metabolismo , Inibidores do Transportador 2 de Sódio-Glicose/toxicidade , Junções Íntimas/efeitos dos fármacos , Junções Íntimas/metabolismo , Junções Íntimas/patologiaRESUMO
The renal proximal tubule epithelium is responsible for active secretion of endogenous and exogenous waste products from the body and simultaneous reabsorption of vital compounds from the glomerular filtrate. The complexity of this transport machinery makes investigation of processes such as tubular drug secretion a continuous challenge for researchers. Currently available renal cell culture models often lack sufficient physiological relevance and reliability. Introducing complex biological culture systems in a 3D microfluidic design improves the physiological relevance of in vitro renal proximal tubule epithelium models. Organ-on-a-chip technology provides a promising alternative, as it allows the reconstruction of a renal tubule structure. These microfluidic systems mimic the in vivo microenvironment including multi-compartmentalization and exposure to fluid shear stress. Increasing data supports that fluid shear stress impacts the phenotype and functionality of proximal tubule cultures, for which we provide an extensive background. In this review, we discuss recent developments of kidney-on-a-chip platforms with current and future applications. The improved proximal tubule functionality using 3D microfluidic systems is placed in perspective of investigating cellular signalling that can elucidate mechanistic aberrations involved in drug-induced kidney toxicity.
Assuntos
Túbulos Renais Proximais/citologia , Técnicas Analíticas Microfluídicas/métodos , Animais , Biomimética , Técnicas de Cultura de Células , Microambiente Celular , Humanos , Transdução de SinaisRESUMO
Drug-induced nephrotoxicity still hampers drug development, because current translation from in vitro or animal studies to human lacks high predictivity. Often, renal adverse effects are recognized only during clinical stages of drug development. The current study aimed to establish a robust and a more complete human cell model suitable for screening of drug-related interactions and nephrotoxicity. In addition to endogenously expressed renal organic cation transporters and efflux transporters, conditionally immortalized proximal tubule epithelial cells (ciPTEC) were completed by transduction of cells with the organic anion transporter (OAT) 1 or OAT3. Fluorescence-activated cell sorting upon exposure to the OAT substrate fluorescein successfully enriched transduced cells. A panel of organic anions was screened for drug-interactions in ciPTEC-OAT1 and ciPTEC-OAT3. The cytotoxic response to the drug-interactions with antivirals was further examined by cell viability assays. Upon subcloning, concentration-dependent fluorescein uptake was found with a higher affinity for ciPTEC-OAT1 (Km = 0.8 ± 0.1 µM) than ciPTEC-OAT3 (Km = 3.7 ± 0.5 µM). Co-exposure to known OAT1 and/or OAT3 substrates (viz. para-aminohippurate, estrone sulfate, probenecid, furosemide, diclofenac, and cimetidine) in cultures spanning 29 passage numbers revealed relevant inhibitory potencies, confirming the robustness of our model for drug-drug interactions studies. Functional OAT1 was directly responsible for cytotoxicity of adefovir, cidofovir, and tenofovir, while a drug interaction with zidovudine was not associated with decreased cell viability. Our data demonstrate that human-derived ciPTEC-OAT1 and ciPTEC-OAT3 are promising platforms for highly predictive drug screening during early phases of drug development.