title: Functional characterization of common protein variants in the efflux transporter ABCC11 and identification of T546M as functionally damaging variant.
abstract: Multidrug resistance protein 8 (ABCC11) is an efflux transporter for anionic lipophilic compounds, conferring resistance to antiviral and anticancer agents like 5-fluorouracil (5-FU). ABCC11 missense variants may contribute to variability in drug response but functional consequences, except for the 'earwax variant' c.538G>A, are unknown. Using the 'Screen and Insert' technology, we generated human embryonic kidney 293 cells stably expressing ABCC11 missense variants frequently occurring in different ethnic populations: c.57G>A, c.538G>A, c.950C>A, c.1637C>T, c.1942G>A, c.4032A>G. A series of in silico prediction analyses and in vitro plasma membrane vesicle uptake, immunoblotting and immunolocalization experiments were undertaken to investigate functional consequences. We identified c.1637C>T (T546M), previously associated with 5-FU-related toxicity, as a novel functionally damaging ABCC11 variant exhibiting markedly reduced transport function of 5-FdUMP, the active cytotoxic metabolite of 5-FU. Detailed analysis of 14 subpopulations revealed highest allele frequencies of c.1637C>T in Europeans and Americans (up to 11%) compared with Africans and Asians (up to 3%).
authors.affiliation: Dr Margarete Fischer-Bosch Institute of Clinical Pharmacology, Stuttgart and University of Tübingen, Stuttgart, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Arlanov
authors.affiliation: Dr Margarete Fischer-Bosch Institute of Clinical Pharmacology, Stuttgart and University of Tübingen, Stuttgart, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Lang
authors.affiliation: Department of Pharmacology, Center of Drug Absorption and Transport (C_DAT), University Medicine of Greifswald, Greifswald, Germany.
authors.forename: G
authors.initials: G
authors.lastname: Jedlitschky
authors.affiliation: Dr Margarete Fischer-Bosch Institute of Clinical Pharmacology, Stuttgart and University of Tübingen, Stuttgart, Germany.
authors.forename: E
authors.initials: E
authors.lastname: Schaeffeler
authors.affiliation: RIKEN Center for Life Science Technologies, Yokohama, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Ishikawa
authors.affiliation: Dr Margarete Fischer-Bosch Institute of Clinical Pharmacology, Stuttgart and University of Tübingen, Stuttgart, Germany.|Department of Clinical Pharmacology, Institute of Experimental and Clinical Pharmacology and Toxicology, University Hospital of Tübingen, Tübingen, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Schwab
authors.affiliation: Dr Margarete Fischer-Bosch Institute of Clinical Pharmacology, Stuttgart and University of Tübingen, Stuttgart, Germany.
authors.forename: A T
authors.initials: AT
authors.lastname: Nies
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D000251:Adenosine Triphosphatases / Q000378:metabolism; D000970:Antineoplastic Agents / Q000378:metabolism; D044466:Asian People; D001692:Biological Transport; D044383:Black People; D002460:Cell Line; D003198:Computer Simulation; D019314:Dehydroepiandrosterone Sulfate / Q000378:metabolism; D004970:Estrone / Q000031:analogs & derivatives / Q000378:metabolism; D005468:Fluorodeoxyuridylate / Q000378:metabolism; D005787:Gene Frequency; D006801:Humans; D015810:Linkage Disequilibrium; D020125:Mutation, Missense; D044465:White People
chemical_list: C435500:ABCC11 protein, human; D018528:ATP-Binding Cassette Transporters; D000970:Antineoplastic Agents; D005468:Fluorodeoxyuridylate; D004970:Estrone; D019314:Dehydroepiandrosterone Sulfate; D000251:Adenosine Triphosphatases; C017296:estrone sulfate