Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
Ro 31-8220 is a potent protein kinase C (PKC) inhibitor belonging to the chemical class of bisindolylmaleimides (BIMs). Various PKC-independent effects of Ro 31-8220 have however been demonstrated, including inhibition of the ATP-binding cassette drug transporter breast cancer resistance protein. In the present study, we reported that the BIM also blocks activity of the solute carrier organic cation transporter (OCT) 1, involved in uptake of marketed drugs in the liver, in a PKC-independent manner. Ro 31-8220, in contrast to other pan-PKC inhibitors such as staurosporine and chelerythrine, was thus shown to cis-inhibit uptake of the reference OCT1 substrate tetraethylammonium in OCT1-transfected HEK293 cells in a concentration-dependent manner (IC50 = 0.18 μM) and without altering membrane expression of OCT1. This blockage of OCT1 was also observed in human hepatic HepaRG cells that constitutionally express OCT1. It likely occurred through a mixed mechanism of inhibition. Ro 31-8220 additionally trans-inhibited TEA uptake in OCT1-transfected HEK293 cells, which likely discards a transport of Ro 31-8220 by OCT1. Besides Ro 31-8220, 7 additional BIMs, including the PKC inhibitor LY 333531, inhibited OCT1 activity, whereas 4 other BIMs were without effect. In silico analysis of structure-activity relationships next revealed that various molecular descriptors, especially 3D-WHIM descriptors related to total size, correspond to key physico-chemical parameters for inhibition of OCT1 activity by BIMs. In addition to activity of OCT1, Ro 31-8220 inhibited those of other organic cation transporters such as multidrug and toxin extrusion protein (MATE) 1 and MATE2-K, whereas, by contrast, it stimulated that of OCT2. Taken together, these data extend the nature of cellular off-targets of the BIM Ro 31-8220 to OCT1 and other organic cation transporters, which has likely to be kept in mind when using Ro 31-8220 and other BIMs as PKC inhibitors in experimental or clinical studies
ISSN: 1932-6203

hal-01255837
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01255837
DOI : 10.1371/journal.pone.0144667
PUBMED : 26657401
PUBMEDCENTRAL : PMC4675551

Éditeur(s) : HAL CCSD
Résumé : Scope: TNF-Related Apoptosis-Inducing Ligand (TRAIL) induces apoptosis via the extrinsic death pathway in human colon cancer cells. Short Chain Fatty Acids (SCFA) by contrast induce apoptosis of cancer cells via the intrinsic death pathway. We have previously shown that food-grade dairy propionibacteria induce intrinsic apoptosis of colon cancer cells, via SCFA metabolites (propionate and acetate) acting on mitochondria. We investigate here the possible synergistic pro-apoptotic effect between Propionibacterium freudenreichii and TRAIL. Methods and results: Whole transcriptomic analysis demonstrated that propionibacterial supernatant or propionibacterial SCFA, in combination with TRAIL, increased pro-apoptotic gene expression (TRAIL-R2/DR5) and decreased anti-apoptotic gene expression (FLIPL, XIAP) in HT29 human colon cancer cells. The revealed synergistic pro-apoptotic effect, depending on both death receptors (TRAIL-R1/DR4, TRAIL-R2/DR5) and caspases (caspase-8, -9 and -3) activation, was lethal on cancer cells but not on normal human intestinal epithelial cells (HIEC), and was inhibited by Bcl-2 expression. Finally, milk fermented by P. freudenreichii induced HT29 cells apoptosis and enhanced TRAIL cytotoxic activity, as did P. freudenreichii culture supernatants or its SCFA metabolites.Conclusion: The revealed synergy opens new applications for food-grade P. freudenreichii-containing products as new adjuvants to potentiate TRAIL-based cancer therapy in colorectal cancer.
International Scientific Conference on Probiotics and Prebiotics - IPC2016
Budapest, Hungary

hal-01286497
https://hal.archives-ouvertes.fr/hal-01286497
PRODINRA : 349367

Éditeur(s) : HAL CCSD
Résumé : International audience
Smoking is well-known to impair pharmacokinetics, through inducing expression of drug metabolizing enzymes. In the present study, we demonstrated that cigarette smoke condensate (CSC) also alters activity and expression of hepatic drug transporters, which are now recognized as major actors of hepatobiliary elimination of drugs. CSC thus directly inhibited activities of sinusoidal transporters such as OATP1B1, OATP1B3, OCT1 and NTCP as well as those of canalicular transporters like P-glycoprotein, MRP2, BCRP and MATE1, in hepatic transporters-overexpressing cells. CSC similarly counteracted constitutive OATP, NTCP and OCT1 activities in human highly-differentiated hepatic HepaRG cells. In parallel, CSC induced expression of BCRP at both mRNA and protein level in HepaRG cells, whereas it concomitantly repressed mRNA expression of various transporters, including OATP1B1, OATP2B1, OAT2, NTCP, OCT1 and BSEP, and enhanced that of MRP4. Such changes in transporter gene expression were found to be highly correlated to those caused by 2,3,7,8-tetrachlorodibenzo-p-dioxin, a reference activator of the aryl hydrocarbon receptor (AhR) pathway, and were counteracted, for some of them, by siRNA-mediated AhR silencing. This suggests that CSC alters hepatic drug transporter levels via activation of the AhR cascade. Importantly, drug transporter expression regulations as well as some transporter activity inhibitions occurred for a range of CSC concentrations similar to those required for inducing drug metabolizing enzymes and may therefore be hypothesized to be relevant for smokers. Taken together, these data established human hepatic transporters as targets of cigarette smoke, which could contribute to known alteration of pharmacokinetics and some liver adverse effects caused by smoking. © 2016 Elsevier Ireland Ltd
Toxicology

hal-01367143
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01367143
DOI : 10.1016/j.tox.2016.07.011
PUBMED : 27450509

Éditeur(s) : HAL CCSD Springer
Résumé : International audience
Protocols in In Vitro Hepatocyte Research

hal-01122755
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01122755
DOI : 10.1007/978-1-4939-2074-7_21

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
ISSN: 0887-2333

hal-00866007
https://hal-univ-rennes1.archives-ouvertes.fr/hal-00866007
DOI : 10.1016/j.tiv.2013.07.003
PUBMED : 23850984

Éditeur(s) : HAL CCSD
Résumé : International audience
In vitro evaluation of P-glycoprotein (P-gp) inhibitory potential is now a regulatory issue during drug development, in order to predict clinical inhibition of P-gp and subsequent drug-drug interactions. Assays for this purpose, commonly based on P-gp-expressing cell lines and digoxin as a reference P-gp substrate probe, unfortunately exhibit high variability, raising thus the question of developing alternative or complementary tests for measuring inhibition of P-gp activity. In this context, the present study was designed to investigate the use of the fluorescent dye rhodamine 123 as a reference P-gp substrate probe for characterizing P-gp inhibitory potential of 16 structurally-unrelated drugs known to interact with P-gp. 14/16 of these P-gp inhibitors were found to increase rhodamine 123 accumulation in P-gp-overexpressing MCF7R cells, thus allowing the determination of their P-gp inhibitory potential, i.e., their half maximal inhibitor concentration (IC50) value towards P-gp-mediated transport of the dye. These IC50 values were in the range of variability of previously reported IC50 for P-gp and can be used for the prediction of clinical P-gp inhibition according to Food and Drug Administration (FDA) criteria, with notable sensitivity (80%). Therefore, the data demonstrated the feasibility of the use of rhodamine 123 for evaluating the P-gp inhibitory potential of drugs
Pharmaceutics

hal-01305488
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01305488
DOI : 10.3390/pharmaceutics8020012
PUBMED : 27077878

Éditeur(s) : HAL CCSD Taylor & Francis
Résumé : International audience
Introduction: Drug transporters are now recognized as major players involved in pharmacokinetics and toxicology. Methods for assessing their activity are important to consider, particularly owing to regulatory requirements with respect to inhibition of drug transporter activity and prediction of drug–drug interactions. In this context, the use of fluorescent-dye-based transport assays is likely to deserve attention.Areas covered: This review provides an overview of the nature of fluorescent dye substrates for ATP-binding cassette and solute carrier drug transporters. Their use for investigating drug transporter activity in cultured cells and clinical hematological samples, drug transporter inhibition, drug transporter imaging and drug transport at the organ level are summarized.Expert opinion: A wide range of fluorescent dyes is now available for use in various aspects of drug transporter studies. The use of these dyes for transporter analyses may, however, be hampered by classic pitfalls of fluorescence technology, such as quenching. Transporter-independent processes such as passive diffusion of dyes through plasma membrane or dye sequestration into subcellular compartments must also be considered, as well as the redundant handling by various distinct transporters of some fluorescent probes. Finally, standardization of dye-based transport assays remains an important on-going issue
ISSN: 1742-5255

hal-01162381
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01162381
DOI : 10.1517/17425255.2015.1053462
PUBMED : 26050735

Éditeur(s) : HAL CCSD Wiley-Blackwell Wiley
Résumé : International audience
Rhodamine 123 is a fluorescent cationic dye commonly used as a mitochondrial probe and known or suspected to be transported by certain drug membrane transporters. The present study was designed to characterize the putative interactions of rhodamine 123 with human organic cation transporter (OCT) 1 and OCT2. Intracellular uptake of the dye was demonstrated to be enhanced in both hOCT1- and hOCT2-overexpressing HEK293 cells when compared with control HEK293 cells. This increase of rhodamine 123 influxes was found to be a saturable carrier-mediated process, with low K(m) values (K(m) = 0.54 μm and K(m ) = 0.61 μm for transport of the dye in hOCT1- and hOCT2-positive HEK293 cells, respectively). Known inhibitors of hOCT1 and hOCT2 activities such as verapamil, amitriptyline, prazosin, and quinine were next demonstrated to decrease rhodamine 123 accumulation in hOCT1- and hOCT2-overexpressing HEK293 cells. In addition, the dye was found to inhibit hOCT1- and hOCT2-mediated uptake of tetraethylammonium (TEA), a model substrate for both hOCT1 and hOCT2; rhodamine 123 appeared nevertheless to be a more potent inhibitor of hOCT1-mediated TEA transport (IC(50) = 0.37 μm) than of that mediated by hOCT2 (IC(50 ) = 61.5 μm). Taken together, these data demonstrate that rhodamine 123 is a high-affinity substrate for both hOCT1 and hOCT2. This dye may be therefore useful for fluorimetrically investigating cellular hOCT1 or hOCT2 activity, knowing, however, that other factors potentially contributing to cellular accumulation of rhodamine 123, including mitochondrial membrane potential or expression of the efflux transporter P-glycoprotein, have also to be considered.
ISSN: 0767-3981

inserm-00872840
http://www.hal.inserm.fr/inserm-00872840
DOI : 10.1111/j.1472-8206.2012.01071.x
PUBMED : 22913740

Éditeur(s) : HAL CCSD Impact journals
Résumé : International audience
TNF-Related Apoptosis-Inducing Ligand (TRAIL) is a well-known apoptosis inducer, which activates the extrinsic death pathway. TRAIL is pro-apoptotic on colon cancer cells, while not cytotoxic towards normal healthy cells. However, its clinical use is limited by cell resistance to cell death which occurs in approximately 50% of cancer cells. Short Chain Fatty Acids (SCFA) are also known to specifically induce apoptosis of cancer cells. In accordance, we have shown that food grade dairy propionibacteria induce intrinsic apoptosis of colon cancer cells, via the production and release of SCFA (propionate and acetate) acting on mitochondria. Here, we investigated possible synergistic effect between Propionibacterium freudenreichii and TRAIL. Indeed, we hypothesized that acting on both extrinsic and intrinsic death pathways may exert a synergistic pro-apoptotic effect. Whole transcriptomic analysis demonstrated that propionibacterial supernatant or propionibacterial metabolites (propionate and acetate), in combination with TRAIL, increased pro-apoptotic gene expression (TRAIL-R2/DR5) and decreased anti-apoptotic gene expression (FLIP, XIAP) in HT29 human colon cancer cells. The revealed synergistic pro-apoptotic effect, depending on both death receptors (TRAIL-R1/DR4, TRAIL-R2/DR5) and caspases (caspase-8, -9 and -3) activation, was lethal on cancer cells but not on normal human intestinal epithelial cells (HIEC), and was inhibited by Bcl-2 expression. Finally, milk fermented by P. freudenreichii induced HT29 cells apoptosis and enhanced TRAIL cytotoxic activity, as did P. freudenreichii DMEM culture supernatants or its SCFA metabolites. These results open new perspectives for food grade P. freudenreichii-containing products in order to potentiate TRAIL-based cancer therapy in colorectal cancer
ISSN: 1949-2553

hal-01259215
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01259215
DOI : 10.18632/oncotarget.6881
PUBMED : 26771233

Éditeur(s) : HAL CCSD
Résumé : International audience
Gevokizumab is a potent anti-interleukin (IL)-1 beta neutralizing monoclonal antibody (mAb), which may be used for treating inflammatory or autoimmune diseases. The present study was designed to characterize the potential effects of this mAb towards well-established IL-1 beta-mediated repression of hepatic drug detoxifying proteins, like cytochrome P450 (CYP) 3A4 and drug transporters. Primary cultured human hepatocytes were exposed to various concentrations of IL-1 beta in the absence or presence of gevokizumab (5 A mu g/mL); mRNA expression and activity of CYP3A4 and transporters were next determined. Gevokizumab was found to down-modulate, but not abolish, the repression of CYP3A4 and drug transporter mRNAs caused by IL-1 beta in human hepatocytes, through shifting up IL-1 beta half maximal inhibitory concentration (IC50) values by factors ranging from 6.8 to 10.4. The mAb concomitantly shifted IL-1 beta IC50 values towards CYP3A4 activity from 22.0 pg/mL (in the absence of gevokizumab) to 796 pg/mL (in the presence of gevokizumab) and counteracted the decrease of organic anion-transporting polypeptide activity occurring in response to 50 pg/mL IL-1 beta, but not that occurring at higher IL-1 beta concentration (1000 pg/mL). Gevokizumab attenuates, but not abolishes, IL-1 beta-mediated functional repression of CYP3A4 and drug transporters in human hepatocytes, which agrees with the fact that the mAb is considered as a modulator and not a blocker of IL-1 beta signaling. This attenuation of IL-1 beta-mediated down-regulation of hepatic detoxifying proteins by gevokizumab may have to be evaluated in terms of potential therapeutic protein drug-drug interactions when considering future development and therapeutic uses of this IL-1 beta neutralizing mAb.
ISSN: 0378-7966

hal-01616062
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01616062
DOI : 10.1007/s13318-017-0406-1

Éditeur(s) : HAL CCSD Impact journals
Résumé : International audience
TNF-Related Apoptosis-Inducing Ligand (TRAIL) is a well-known apoptosis inducer, which activates the extrinsic death pathway. TRAIL is pro-apoptotic on colon cancer cells, while not cytotoxic towards normal healthy cells. However, its clinical use is limited by cell resistance to cell death which occurs in approximately 50% of cancer cells. Short Chain Fatty Acids (SCFA) are also known to specifically induce apoptosis of cancer cells. In accordance, we have shown that food grade dairy propionibacteria induce intrinsic apoptosis of colon cancer cells, via the production and release of SCFA (propionate and acetate) acting on mitochondria. Here, we investigated possible synergistic effect between Propionibacterium freudenreichii and TRAIL. Indeed, we hypothesized that acting on both extrinsic and intrinsic death pathways may exert a synergistic pro-apoptotic effect. Whole transcriptomic analysis demonstrated that propionibacterial supernatant or propionibacterial metabolites (propionate and acetate), in combination with TRAIL, increased pro-apoptotic gene expression (TRAIL-R2/DR5) and decreased anti-apoptotic gene expression (FLIP, XIAP) in HT29 human colon cancer cells. The revealed synergistic pro-apoptotic effect, depending on both death receptors (TRAIL-R1/DR4, TRAIL-R2/DR5) and caspases (caspase-8,-9 and-3) activation, was lethal on cancer cells but not on normal human intestinal epithelial cells (HIEC), and was inhibited by Bcl-2 expression. Finally, milk fermented by P. freudenreichii induced HT29 cells apoptosis and enhanced TRAIL cytotoxic activity, as did P. freudenreichii DMEM culture supernatants or its SCFA metabolites. These results open new perspectives for food grade P. freudenreichii-containing products in order to potentiate TRAIL-based cancer therapy in colorectal cancer.
ISSN: 1949-2553

hal-01404971
https://hal.inria.fr/hal-01404971
https://hal.inria.fr/hal-01404971/document
https://hal.inria.fr/hal-01404971/file/2016%20Oncotarget_The%20probiotic%20Propionibacterium%20freudenreichii%20as%20a%20new%20adjuvant%20for%20TRAIL-based%20therapy%20in%20colorectal%20cancer..pdf
DOI : 10.18632/oncotarget.6881

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Hepatic drug transporters are now recognized as major actors of hepatobiliary elimination of drugs. Characterization of their regulatory pathways is therefore an important issue. In this context, the present study was designed to analyze the potential regulation of human hepatic transporter expression by protein kinase C (PKC) activation. Treatment by the reference PKC activator phorbol 12-myristate 13-acetate (PMA) for 48 h was shown to decrease mRNA expression of various sinusoidal transporters, including OATP1B1, OATP2B1, NTCP, OCT1 and MRP3, but to increase that of OATP1B3, whereas mRNA expression of canalicular transporters was transiently enhanced (MDR1), decreased (BSEP and MRP2) or unchanged (BCRP) in human hepatoma HepaRG cells. The profile of hepatic transporter mRNA expression changes in PMA-treated HepaRG cells was correlated to that found in PMA-exposed primary human hepatocytes and was similarly observed in response to the PKC-activating marketed drug ingenol mebutate. It was associated with concomitant repression of OATP1B1 and OATP2B1 protein expression and reduction of OATP, OCT1, NTCP and MRP2 activity. The use of chemical PKC inhibitors further suggested a contribution of novel PKCs isoforms to PMA-mediated regulations of transporter mRNA expression. PMA was finally shown to cause epithelial-mesenchymal transition (EMT) in HepaRG cells and exposure to various additional EMT inducers, i.e., hepatocyte growth factor, tumor growth factor-β1 or the HNF4α inhibitor ≡I6015, led to transporter expression alterations highly correlated to those triggered by PMA. Taken together, these data highlight PKC-dependent regulation of human hepatic drug transporter expression, which may be closely linked to EMT triggered by PKC activation
ISSN: 0006-2952

hal-01216205
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01216205
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01216205/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01216205/file/Protein%20kinase%20C-dependent%20regulation.pdf
DOI : 10.1016/j.bcp.2015.10.007

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Polycyclic aromatic hydrocarbons (PAHs) such as benzo(a)pyrene (BaP) are widely-distributed environmental contaminants known to exert toxic effects in various tissues, including placenta. PAHs have notably been shown to inhibit proliferation of trophoblastic cells. The present study was designed to determine whether PAHs can concomitantly affect differentiated functions of trophoblastic cells. BaP was found to induce expression and secretion of β-human chorionic gonadotropin (β-hCG) in human trophoblastic BeWo cells. The PAH also increased mRNA expressions of other trophoblastic differentiation markers, including those of the steroid metabolism enzymes CYP19A1 and HSD11B2 and of the fusogenic protein syncytin-2; in parallel, it triggered syncytialisation of BeWo cells. BaP-mediated β-hCG and syncytin-2 up-regulation was prevented by co-treatment by the aryl hydrocarbon receptor (AhR) antagonist CH-223191 or by knocking-down AhR expression through siRNA transfection. However, the potent AhR agonist 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) failed to induce expression of β-hCG and syncytin-2, indicating that activation of the AhR pathway, known to be implicated in most, if not all, effects of PAHs, was required, but not sufficient. Interestingly, the p53 signaling pathway was activated by BaP, but not by TCDD, in BeWo cells and co-treatment by the p53 inhibitor pifithrin-α or siRNAs-mediated silencing of p53 prevented up-regulation of β-hCG and syncytin-2 induced by BaP. Taken together, these data demonstrate that BaP induces differentiation of placental trophoblastic BeWo cells in an AhR- and p53-dependent manner.
ISSN: 0009-2797

hal-00982355
https://hal-univ-rennes1.archives-ouvertes.fr/hal-00982355
DOI : 10.1016/j.cbi.2013.12.004
PUBMED : 24361490

Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
Organochlorine (OC) pesticides constitute a major class of persistent and toxic organic pollutants, known to modulate drug-detoxifying enzymes. In the present study, OCs were demonstrated to also alter the activity and expression of human hepatic drug transporters. Activity of the sinusoidal influx transporter OCT1 (organic cation transporter 1) was thus inhibited by endosulfan, chlordane, heptachlor, lindane, and dieldrine, but not by dichlorodiphenyltrichloroethane isomers, whereas those of the canalicular efflux pumps MRP2 (multidrug resistance-associated protein 2) and BCRP (breast cancer resistance protein) were blocked by endosulfan, chlordane, heptachlor, and chlordecone; this latter OC additionally inhibited the multidrug resistance gene 1 (MDR1)/P-glycoprotein (P-gp) activity. OCs, except endosulfan, were next found to induce MDR1/P-gp and MRP2 mRNA expressions in hepatoma HepaRG cells; some of them also upregulated BCRP. By contrast, expression of sinusoidal transporters was not impaired (organic anion-transporting polypeptide (OATP) 1B1 and OATP2B1) or was downregulated (sodium taurocholate co-transporting polypeptide (NTCP) and OCT1). Such regulations of drug transporter activity and expression, depending on the respective nature of OCs and transporters, may contribute to the toxicity of OC pesticides.
ISSN: 1095-6670

hal-01063656
https://hal.archives-ouvertes.fr/hal-01063656
DOI : 10.1002/jbt.21543
PUBMED : 24464585

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Human hepatocytes cultured in a monolayer configuration represent a well-established in vitro model in liver toxicology, notably used in drug transporter studies. Polarized status of drug transporters, i.e., their coordinated location at sinusoidal or canalicular membranes, remains however incompletely documented in these cultured hepatocytes. The present study was therefore designed to analyze transporter expression and location in such cells. Most of drug transporters were first shown to be present at notable mRNA levels in monolayer-cultured human hepatocytes. Cultured human hepatocytes, which morphologically exhibited bile canaliculi-like structures, were next demonstrated, through immunofluorescence staining, to express the influx transporters organic anion transporting polypeptide (OATP) 1B1, OATP2B1 and organic cation transporter (OCT) 1 and the efflux transporter multidrug resistance-associated protein (MRP) 3 at their sinusoidal pole. In addition, the efflux transporters P-glycoprotein and MRP2 were detected at the canalicular pole of monolayer-cultured human hepatocytes. Moreover, canalicular secretion of reference substrates for the efflux transporters bile salt export pump, MRP2 and P-glycoprotein as well as sinusoidal drug transporter activities were observed. This polarized and functional expression of drug transporters in monolayer-cultured human hepatocytes highlights the interest of using this human in vitro cell model in xenobiotic transport studies.
ISSN: 0887-2333

hal-01141725
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01141725
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01141725/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01141725/file/Polarized%20location%20of%20SLC.pdf
DOI : 10.1016/j.tiv.2015.03.019

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
Diesel exhaust particles (DEPs) are common environmental air pollutants primarily affecting the lung. DEPs or chemicals adsorbed on DEPs also exert extra-pulmonary effects, including alteration of hepatic drug detoxifying enzyme expression. The present study was designed to determine whether organic DEP extract (DEPe) may target hepatic drug transporters that contribute in a major way to drug detoxification. Using primary human hepatocytes and transporter-overexpressing cells, DEPe was first shown to strongly inhibit activities of the sinusoidal solute carrier (SLC) uptake transporters organic anion-transporting polypeptides (OATP) 1B1, 1B3 and 2B1 and of the canalicular ATP-binding cassette (ABC) efflux pump multidrug resistance-associated protein 2, with IC50 values ranging from approximately 1 to 20 μg/mL and relevant to environmental exposure situations. By contrast, 25 μg/mL DEPe failed to alter activities of the SLC transporter organic cation transporter (OCT) 1 and of the ABC efflux pumps P-glycoprotein and bile salt export pump (BSEP), whereas it only moderately inhibited those of sodium taurocholate co-transporting polypeptide and of breast cancer resistance protein (BCRP). Treatment by 25 μg/mL DEPe was next demonstrated to induce expression of BCRP at both mRNA and protein level in cultured human hepatic cells, whereas it concomitantly repressed mRNA expression of various transporters, including OATP1B3, OATP2B1, OCT1 and BSEP. Such changes in transporter expression were found to be highly correlated to those caused by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a reference activator of the aryl hydrocarbon receptor (AhR) pathway. This suggests that DEPe, which is enriched in known ligands of AhR like polycyclic aromatic hydrocarbons, alters drug transporter expression via activation of the AhR cascade. Taken together, these data established human hepatic transporters as targets of organic chemicals containing in DEPs, which may contribute to their systemic effects through impairing hepatic transport of endogenous compound or drug substrates of these transporters.
ISSN: 1932-6203

Droits : http://creativecommons.org/licenses/by/
hal-01138535
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01138535
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01138535/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01138535/file/Regulation%20of%20human%20hepatic%20drug.pdf
DOI : 10.1371/journal.pone.0121232

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
All-trans retinoic acid (atRA) is the active form of vitamin A, known to activate retinoid receptors, especially the heterodimer retinoid X receptor (RXR):retinoic acid receptor (RAR) that otherwise may play a role in regulation of some drug transporters. The present study was designed to characterize the nature of human hepatic transporters that may be targeted by atRA and the heterodimer RXR:RAR. Exposure of human hepatoma HepaRG cells and primary human hepatocytes to 5μM atRA down-regulated mRNA levels of various sinusoidal solute carrier (SLC) influx transporters, including organic anion transporting polypeptide (OATP) 2B1, OATP1B1, organic cation transporter (OCT) 1 and organic anion transporter (OAT) 2, and induced those of the canalicular breast cancer resistance protein (BCRP). The retinoid concomitantly reduced protein expression of OATP2B1 and OATP1B1 and activity of OATPs and OCT1 and induced BCRP protein expression in HepaRG cells. Some transporters such as OATP1B3 and the bile salt export pump (BSEP) were however down-regulated by atRA in primary human hepatocytes, but induced in HepaRG cells, thus pointing out discrepancies between these two liver cell models in terms of detoxifying protein regulation. atRA-mediated repressions of OATP2B1, OATP1B1, OAT2 and OCT1 mRNA expression were finally shown to be counteracted by knocking-down expression of RARα and RXRα through siRNA transfection in HepaRG cells. atRA thus differentially regulated human hepatic drug transporters, mainly in a RXR:RAR-dependent manner, therefore establishing retinoids and retinoid receptors as modulators of liver drug transporter expression.
ISSN: 0928-0987

inserm-00804935
http://www.hal.inserm.fr/inserm-00804935
DOI : 10.1016/j.ejps.2013.01.005
PUBMED : 23352986

Éditeur(s) : HAL CCSD
Résumé : International audience
Human hepatoma cells may represent a valuable alternative to the use of human hepatocytes for studying hepatic drug transporters, which is now a regulatory issue during drug development. In the present work, we have characterized hepatic drug transporter expression, activity and regulation in human hepatoma HuH-7 cells, in order to determine the potential relevance of these cells for drug transport assays. HuH-7 cells displayed notable multidrug resistance-associated protein (MRP) activity, presumed to reflect expression of various hepatic MRPs, including MRP2. By contrast, they failed to display functional activities of the uptake transporters sodium taurocholate co-transporting polypeptide (NTCP), organic anion-transporting polypeptides (OATPs) and organic cation transporter 1 (OCT1), and of the canalicular transporters P-glycoprotein and breast cancer resistance protein (BCRP). Concomitantly, mRNA expressions of various sinusoidal and canalicular hepatic drug transporters were not detected (NTCP, OATP1B1, organic anion transporter 2 (OAT2), OCT1 and bile salt export pump) or were found to be lower (OATP1B3, OATP2B1, multidrug and toxin extrusion protein 1, BCRP and MRP3) in hepatoma HuH-7 cells than those found in human hepatocytes, whereas other transporters such as OAT7, MRP4 and MRP5 were up-regulated. HuH-7 cells additionally exhibited farnesoid X receptor (FXR)- and nuclear factor erythroid
Pharmaceutics

hal-01477210
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01477210
DOI : 10.3390/pharmaceutics9010003
PUBMED : 28036031

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The heterodimeric L-type amino acid transporter (LAT) 1/ CD98hc is overexpressed in lung cancers with a poor prognosis factor. Factors that contribute to LAT1/CD98hc overexpression in lung cells remain however to be determined, but the implication of atmospheric pollution can be suspected. The present study was therefore designed to analyze the effects of diesel exhaust particle (DEP) extract (DEPe) on LAT1/CD98hc expression in bronchial epithelial BEAS-2B cells. Exposure to DEPe up-regulated LAT1 and CD98hc mRNA levels in a concentration-dependent manner, with DEPe EC50 values (around 0.2 μg/mL) relevant to environmental situations. DEPe concomitantly induced LAT1/CD98hc protein expression and LAT1-mediated leucine accumulation in BEAS-2B cells. Inhibition of the aryl hydrocarbon receptor (AhR) pathway through the use of a chemical AhR antagonist or the siRNA-mediated silencing of AhR expression was next found to prevent DEPe-mediated induction of LAT1/CD98hc, indicating that this regulation depends on AhR, known to be activated by major chemical DEP components like polycyclic aromatic hydrocarbons. DEPe exposure was finally shown to induce mRNA expression and activity of matrix metalloproteinase (MMP)-2 in BEAS-2B cells, in a CD98hc/focal adhesion kinase (FAK)/extracellular regulated kinase (ERK) manner, thus suggesting that DEPe-mediated induction of CD98hc triggers activation of the integrin/FAK/ERK signaling pathway known to be involved in MMP-2 regulation. Taken together, these data demonstrate that exposure to DEPe induces functional overexpression of the amino acid transporter LAT1/CD98h in lung cells. Such a regulation may participate to pulmonary carcinogenic effects of DEPs, owing to the well-documented contribution of LAT1 and CD98hc to cancer development.
ISSN: 0041-008X

hal-01237095
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01237095
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01237095/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01237095/file/Aryl%20hydrocarbon%20receptor-dependent%20up-regulation_accepted.pdf
DOI : 10.1016/j.taap.2015.11.014