title: The human organic cation transporter OCT1 mediates high affinity uptake of the anticancer drug daunorubicin.
abstract: Anthracyclines such as daunorubicin are anticancer agents that are transported into cells, and exert cytotoxicity by blocking DNA metabolism. Although there is evidence for active uptake of anthracyclines into cells, the specific transporter involved in this process has not been identified. Using the high-grade serous ovarian cancer cell line TOV2223G, we show that OCT1 mediated the high affinity (Km ~ 5 μM) uptake of daunorubicin into the cells, and that micromolar amounts of choline completely abolished the drug entry. OCT1 downregulation by shRNA impaired daunorubicin uptake into the TOV2223G cells, and these cells were significantly more resistant to the drug in comparison to the control shRNA. Transfection of HEK293T cells, which accommodated the ectopic expression of OCT1, with a plasmid expressing OCT1-EYFP showed that the transporter was predominantly localized to the plasma membrane. These transfected cells exhibited an increase in the uptake of daunorubicin in comparison to control cells transfected with an empty EYFP vector. Furthermore, a variant of OCT1, OCT1-D474C-EYFP, failed to enhance daunorubicin uptake. This is the first report demonstrating that human OCT1 is involved in the high affinity transport of anthracyclines. We postulate that OCT1 defects may contribute to the resistance of cancer cells treated with anthracyclines.
authors: Maisonneuve-Rosemont Hospital, Research Center, Université de Montréal, Department of Medicine, 5415 Boul. de l' Assomption, Montréal, Québec, Canada, H1T 2M4.
authors: Emil
authors: E
authors: Andreev
authors: Maisonneuve-Rosemont Hospital, Research Center, Université de Montréal, Department of Medicine, 5415 Boul. de l' Assomption, Montréal, Québec, Canada, H1T 2M4.
authors: Nicolas
authors: N
authors: Brosseau
authors: Institut du cancer de Montréal/Centre de recherche du Centre hospitalier de l'Université de Montréal (CRCHUM), 900 rue Saint-Denis, Montréal, Québec, Canada, H2X 0A9.
authors: Euridice
authors: E
authors: Carmona
authors: Institut du cancer de Montréal/Centre de recherche du Centre hospitalier de l'Université de Montréal (CRCHUM), 900 rue Saint-Denis, Montréal, Québec, Canada, H2X 0A9.|Department of Medicine, Université de Montréal, 2900 Boulevard Edouard-Montpetit, Montréal, Québec, Canada, H3T 1J4.
authors: Anne-Marie
authors: AM
authors: Mes-Masson
authors: Maisonneuve-Rosemont Hospital, Research Center, Université de Montréal, Department of Medicine, 5415 Boul. de l' Assomption, Montréal, Québec, Canada, H1T 2M4.
authors: Dindial
authors: D
authors: Ramotar
mesh_terms: D000970:Antineoplastic Agents / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D001692:Biological Transport / Q000187:drug effects; D015153:Blotting, Western; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D002794:Choline / Q000494:pharmacology; D003630:Daunorubicin / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D004880:Ergothioneine / Q000494:pharmacology; D057809:HEK293 Cells; D006801:Humans; D008856:Microscopy, Fluorescence; D027702:Organic Cation Transporter 1 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D010957:Plasmids / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism; D014162:Transfection
chemical_list: D000970:Antineoplastic Agents; D027702:Organic Cation Transporter 1; D034741:RNA, Small Interfering; D004880:Ergothioneine; D002794:Choline; D003630:Daunorubicin