Research ArticlePharmacokinetics, Pharmacodynamics and Drug Transport and MetabolismChloroquine and Hydroxychloroquine Are Novel Inhibitors of Human Organic Anion Transporting Polypeptide 1A2
Introduction
Chloroquine (CQ) and hydroxychloroquine (HCQ) are 4-aminoquinolone derivatives that have long been used in the prevention and treatment of malaria.1, 2 These two agents also have clinical applications in many inflammatory diseases such as systemic lupus erythematosus, rheumatoid arthritis, dermatomyositis, and Sjogren syndrome.3, 4, 5 The chemical structure of HCQ differs from CQ with a hydroxyl group at the end of N-ethyl side chain (Fig. 1). Clinically, HCQ is used more frequently than CQ as it has similar activity to but is less toxic than CQ.2 CQ and HCQ are often administered orally but can also be given by intravenous injection. The common adverse effects of CQ and HCQ include gastrointestinal upset, mild nausea, and occasional stomach cramps with mild diarrhea.6 However, since the 1960s, long-term usage of CQ or HCQ has also been reported to lead to severe retinopathy and loss of retinal function.7, 8, 9, 10, 11 Lack of treatment for CQ- or HCQ-induced retinopathy results in permanent visual loss for patients and as such has significantly restricted the clinical applications of these otherwise cost-effective and widely available drugs.12
Influx transporters, primarily the solute carrier transporters (SLCs), are the membrane proteins responsible for the cellular uptake of various substrates including endogenous and exogenous substances. SLCs are known to transport a wide range of drugs, many of which are clinically important.13 SLCs are broadly expressed in key human organs, such as the kidney, liver, and brain, where they facilitate drug access to these tissues.13 The transport activities of these transporters thus largely determine the absorption, distribution, and elimination of drugs, influencing drug efficacy and toxicity.14 Furthermore, competition between therapeutic drugs and endogenous substances for a specific SLC transporter may often lead to disappointing clinical outcomes and unexpected toxicities.
The organic anion transporting polypeptides (OATPs) encoded by SLCO genes and the organic anion/cation transporters (OATs/OCTs/OCTNs) encoded by SLC22A genes represent the most important SLC members involved with drug transport.13, 15 These SLC transporters interact with a remarkably broad range of substances ranging from endogenous molecules, from hormones to various xenobiotics, particularly pharmaceutical agents such as anticancer drugs (e.g., imatinib, methotrexate) and antibiotics (e.g., penicillin).13, 15, 16, 17 SLC transporters are widely expressed in human tissues. More specifically, OATP2B1, OCT1, OCT2, OCTN1, and OCTN2 are expressed by enterocytes, whereas organic anion transporting polypeptide 1A2 (OATP1A2), OAT1, OAT2, OAT3, OAT4, OCT2, OCT3, OCTN1, and OCTN2 have been identified in the renal tubule epithelium.13, 15 OATP1B1, OATP1B3, OATP2B1, OAT2, OCT1, and OCT3 are expressed by hepatocytes, thus facilitating drug access to the liver for biotransformation, whereas OATP1A2, OATP2B1, OAT1, OAT2, OAT3, OCT1, OCT2, and OCT3 have been found in the brain, contributing to central nervous system drug transport.13, 15 Recently, we reported that OATP1A2 is expressed in the retinal pigment epithelium (RPE) within the eye and is capable of transporting all-trans-retinol (atROL), a retinoid essential for the classic visual cycle.18 Overall, these transporters mediate the cellular influx of structurally diverse compounds and greatly impact on the pharmacokinetics of drugs in body. Drugs and endogenous substances competing for SLC transporters have also been widely reported,19, 20, 21 and can significantly impact on therapeutic outcomes and toxicities.
To date, the interactions between SLC transporters and CQ or HCQ remain unclear. This study is the first to comprehensively investigate the inhibitory effect of CQ and HCQ on the substrate uptake mediated through a range of essential SLC transporters and contributes to our understanding of the observed therapeutic toxicity of these agents.
Section snippets
Materials
[3H]-4-aminohippuric acid (PAH; 60 Ci/mmol), [3H]-L-ergothioneine (1.7 Ci/mmol), and [14C]-L-carnitine (56 mCi/mmol) were obtained from BioScientific Pty. Ltd. (Gymea, New South Wales, Australia). [3H]-estrone-3-sulfate (E3S; 57.3 Ci/mmol), [3H]-cholecystokinin octapeptide (CCK-8; 97.5 Ci/mmol), [3H]-atROL (12.5 Ci/mmol), and [3H]-methyl-4-phenylpyridinium acetate (MPP+; 82.1 Ci/mmol) were purchased from PerkinElmer (Melbourne, Victoria, Australia). Human embryonic kidney (HEK293) cell line was
Inhibitory Effects of CQ and HCQ on OATs, OATPs, OCTs, and OCTNs
As shown in our previous studies,28 significantly increased accumulation of [3H]- or [14C]-labeled prototypical substrates was observed in HEK293 cells overexpressing individual SLC transporters compared with the vector-transfected controls.
The inhibitory effects of CQ and HCQ (10 μM) on the substrate uptake mediated via OAT1, OAT2, OAT3, and OAT4 were assessed. As shown in Figure 2a, our data demonstrated that mild inhibition was observed for CQ on the uptake of E3S through OAT2 and OAT3 for
Discussion
Chloroquine and HCQ have been widely used to treat malaria, rheumatoid arthritis, systemic lupus erythematosus, and other inflammatory and autoimmune diseases.1, 2, 3, 4, 5 Influx SLC transporters, in particular OATPs, OATs, and OCTs/OCTNs, are broadly expressed throughout the epithelia of the body and responsible for drug access to these tissues as well as cellular transport of many endogenous substances. Drugs that compete with endogenous substances for transporters are one of the primary
Conclusions
In summary, the present study evaluated the inhibitory effects of CQ and HCQ on the substrate uptake mediated by a number of important SLC transporters. The most potent inhibition identified was for the OATP1A2. We also found that CQ and HCQ are capable of inhibiting OATP1A2-mediated atROL uptake in primary human RPE. This may lead to malfunction of human classical visual cycle in vivo and contribute to the retinal degeneration observed clinically in patients using CQ and HCQ therapeutically.
Acknowledgments
We thank Mr. R. Devashayam and Dr. M. Zhu, Lions New South Wales Eye Bank for coordinating access to human eye specimens. This work was supported by the University of Sydney DVCR Compact Research Innovation Challenge Research Grant to Fanfan Zhou. Mark C. Gillies is a Sydney Medical Foundation Fellow and is supported by the Australian National Health and Medical Research Council (NH&MRC) Clinical Practitioner Fellowship. Michele C. Madigan is funded by the National Foundation for Medical
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2022, Advances in Ophthalmology and OptometryCitation Excerpt :Despite its therapeutic benefits, retinal toxicity is a clinically significant side effect that must be carefully monitored by physicians [2]. The pathophysiology of HCQ/CQ-induced retinal toxicity remains unclear and is summarized in Fig. 1 [3,4]. Although pathogenesis is thought to begin at the level of retinal pigment epithelium (RPE), animal histopathological studies suggest that early degeneration starts in ganglion and photoreceptor cells followed by secondary RPE atrophy [5].
UV-vis and electrical impedance characterizations of the hydroxychloroquine-zinc complex in the phospholipid-like oleic acid phase
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2021, Biomedicine and PharmacotherapyImpaired Transport Activity of Human Organic Anion Transporters (OATs) and Organic Anion Transporting Polypeptides (OATPs) by Wnt Inhibitors
2021, Journal of Pharmaceutical SciencesCitation Excerpt :Kinetic studies were performed using a range of transporter substrate concentrations (0.01–100 μM) over a 4 min uptake interval. As described previously, initial rates of transporter-mediated substrate uptake in HEK-293T cells were linear under these conditions.46,50–53 In the time-dependence studies, the culture medium was replaced with PBS in all the wells and then replaced with Wnt inhibitors in PBS for varying periods prior to estimation of substrate uptake.
Post-translational regulation of the major drug transporters in the families of organic anion transporters and organic anion-transporting polypeptides
2020, Journal of Biological ChemistryCitation Excerpt :When cells stably expressing the liver-type OATP1B3 were treated with chloroquine (a lysosomal inhibitor) or bortezomib (a proteasome inhibitor), the total OATP1B3 protein (assessed by OATP1B3 immunoblots) was increased only by chloroquine (121). Similar to the case of OATP1B1, the increased level of the total OATP1B3 protein by chloroquine treatment was associated with a decreased transport activity (121, 129). Despite having no impact on the OATP1B3 protein levels in total cell lysates or surface membrane fraction, the bortezomib treatment also led to a modest decrease in the Vmax value but no change in the Km value for OATP1B3-mediated transport of cholecystokinin-8 (121).
Molecular effects and retinopathy induced by hydroxychloroquine during SARS-CoV-2 therapy: Role of CYP450 isoforms and epigenetic modulations
2020, European Journal of PharmacologyCitation Excerpt :Increasing body of evidence illustrated that HCQ potentially prevents tumor growth and inflammatory pathways (e.g RA) via inhibiting PPT1 (Fig. 1B) (Cook et al., 2014; Schrezenmeier and Dörner, 2020). Recently, organic anion transporter family member 1A2 (OATP1A2) was identified as a novel target of HCQ (Xu et al., 2016). OATP1A2, is a solute carrier transporter, expressed in a wide spectrum of tissues such as brain, liver, breast, testis, lung, kidney, and in retinal pigment epithelial (RPE) cells to regulate the transport and uptake of multiple substrates especially drugs and xenobiotics (Lee et al., 2005).
Chenghao Xu and Ling Zhu contributed equally to this article.