title: Interaction of human organic anion transporter 2 (OAT2) and sodium taurocholate cotransporting polypeptide (NTCP) with antineoplastic drugs.
abstract: The ability of an antineoplastic drug to exert its cytostatic effect depends largely on the balance between its uptake into and extrusion from the cancer cells. ATP driven efflux transporter proteins drive the export of antineoplastic drugs and play a pivotal role in the development of chemoresistance. As regards uptake transporters, comparably less is known on their impact in drug action. In the current study, we characterized the interactions of two uptake transporter proteins, expressed mainly in the liver; the organic anion transporter 2 (OAT2, encoded by the SLC22A7 gene) and the sodium taurocholate cotransporting polypeptide (NTCP, encoded by the SLC10A1 gene), stably transfected in human embryonic kidney cells, with some antineoplastic agents that are routinely being used in cancer chemotherapy. Whereas NTCP did not show any strong interactions with the cytostatics tested, we observed a very strong inhibition of OAT2 mediated [(3)H] cGMP uptake in the presence of bendamustine, irinotecan and paclitaxel. The Ki values of OAT2 for bendamustine, irinotecan and paclitaxel were determined to be 43.3±4.33μM, 26.4±2.34μM and 10.4±0.45μM, respectively. Incubation of bendamustine with OAT2 expressing cells increased the caspase-3 activity, and this increase was inhibited by simultaneous incubation with bendamustine and probenecid, a well-known inhibitor of OATs, suggesting that bendamustine is a substrate of OAT2. A higher accumulation of irinotecan was observed in OAT2 expressing cells compared to control pcDNA cells by HPLC analysis of cell lysates. The accumulation was diminished in the presence of cGMP, the substrate we used to functionally characterize OAT2, suggesting specificity of this uptake and the fact that OAT2 mediates uptake of irinotecan.
authors.affiliation: Institut für Vegetative Physiologie und Pathophysiologie, Universitätmedizin Göttingen, Humboldtallee 23, 37073 Göttingen, Germany. Electronic address: venkata.marada@med.uni-goettingen.de.
authors.forename: Venkata V V R
authors.initials: VV
authors.lastname: Marada
authors.affiliation: PortaCellTec biosciences GmbH, Humboldtallee 23, 37073 Goettingen, Germany. Electronic address: floerl@portacelltec.de.
authors.forename: Saskia
authors.initials: S
authors.lastname: Flörl
authors.affiliation: PortaCellTec biosciences GmbH, Humboldtallee 23, 37073 Goettingen, Germany. Electronic address: kuehne@portacelltec.de.
authors.forename: Annett
authors.initials: A
authors.lastname: Kühne
authors.affiliation: Institut für Vegetative Physiologie und Pathophysiologie, Universitätmedizin Göttingen, Humboldtallee 23, 37073 Göttingen, Germany. Electronic address: judith.mueller@med.uni-goettingen.de.
authors.forename: Judith
authors.initials: J
authors.lastname: Müller
authors.affiliation: Institut für Vegetative Physiologie und Pathophysiologie, Universitätmedizin Göttingen, Humboldtallee 23, 37073 Göttingen, Germany. Electronic address: gerhard.burckhardt@med.uni-goettingen.de.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Burckhardt
authors.affiliation: Institut für Vegetative Physiologie und Pathophysiologie, Universitätmedizin Göttingen, Humboldtallee 23, 37073 Göttingen, Germany; PortaCellTec biosciences GmbH, Humboldtallee 23, 37073 Goettingen, Germany. Electronic address: hagos@physiol.med.uni-goettingen.de.
authors.forename: Yohannes
authors.initials: Y
authors.lastname: Hagos
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D000069461:Bendamustine Hydrochloride; D001692:Biological Transport; D002166:Camptothecin / Q000031:analogs & derivatives / Q000494:pharmacology; D006152:Cyclic GMP / Q000378:metabolism; D004970:Estrone / Q000031:analogs & derivatives / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D000077146:Irinotecan; D009588:Nitrogen Mustard Compounds / Q000494:pharmacology; D029363:Organic Anion Transporters, Sodium-Dependent / Q000378:metabolism*; D029362:Organic Anion Transporters, Sodium-Independent / Q000378:metabolism*; D017239:Paclitaxel / Q000494:pharmacology; D027981:Symporters / Q000378:metabolism*
chemical_list: D000970:Antineoplastic Agents; D009588:Nitrogen Mustard Compounds; D029363:Organic Anion Transporters, Sodium-Dependent; D029362:Organic Anion Transporters, Sodium-Independent; C490280:SLC22A7 protein, human; D027981:Symporters; C071908:sodium-bile acid cotransporter; D004970:Estrone; D000077146:Irinotecan; D000069461:Bendamustine Hydrochloride; D006152:Cyclic GMP; D017239:Paclitaxel; C017296:estrone sulfate; D002166:Camptothecin
keywords: 5 fluorouracil (PubChem CID: 3385); Antineoplastic compounds; Bendamustine (PubChem CID: 65628); Cancer chemotherapy; Chlorambucil (PubChem CID: 2708); Cyclic GMP (PubChem CID: 24316); Drug transporter interactions; Estrone 3-sulfate (PubChem CID: 3001028); Etoposide (PubChem CID: 3310); Gemcitabine (PubChem CID: 60750); Irinotecan (PubChem CID: 60838); Organic anion transporter 2 (OAT2); Paclitaxel (PubChem CID: 36314); Sodium taurocholate cotransporting polypeptide (NTCP); Uptake transporter proteins; Vincristine (PubChem CID: 5978)