title: ABCC drug efflux pumps and organic anion uptake transporters in human gliomas and the blood-tumor barrier.
abstract: Delivery of therapeutic agents to the brain and its neoplasms depends on the presence of membrane transport proteins in the blood-brain barrier and in the target cells. The cellular and subcellular localization of these membrane transporters determines the drug accessibility to the brain and its tumors. We therefore analyzed the expression and localization of six members of the multidrug resistance protein family of ATP-dependent efflux pumps (ABCC1-ABCC6, formerly MRP1-MRP6) and of six organic anion uptake transporters (OATP1A2, OATP1B1, OATP1B3, OATP1C1, OATP2B1, and OATP4A1) in 61 human glioma specimens of different histologic subtypes. Real-time PCRs indicated expressions of ABCC1, ABCC3, ABCC4, and ABCC5. In addition, we detected expressions of the OATP uptake transporter genes SLCO1A2, SLCO1C1, SLCO2B1, and SLCO4A1. At the protein level, however, only OATP1A2 and OATP2B1 were detectable by immunofluorescence microscopy in the luminal membrane of endothelial cells forming the blood-brain barrier and the blood-tumor barrier, but not in the glioma cells. ABCC4 and ABCC5 proteins were the major ABCC subfamily members in gliomas, localized both at the luminal side of the endothelial cells and in the glioma cells of astrocytic tumors and in the astrocytic portions of oligoastrocytomas. These results indicate that expression of ABCC4 and ABCC5 is associated with an astrocytic phenotype, in accordance with their expression in astrocytes and with the higher chemoresistance of astrocytic tumors as compared with oligodendrogliomas. Our data provide a basis for the assessment of the role of uptake transporters and efflux pumps in the accessibility of human gliomas for chemotherapeutic agents.
authors.affiliation: Division of Tumor Biochemistry, German Cancer Research Center.
authors.forename: Holger
authors.initials: H
authors.lastname: Bronger
authors.forename: Jörg
authors.initials: J
authors.lastname: König
authors.forename: Kathrin
authors.initials: K
authors.lastname: Kopplow
authors.forename: Hans-Herbert
authors.initials: HH
authors.lastname: Steiner
authors.forename: Rezvan
authors.initials: R
authors.lastname: Ahmadi
authors.forename: Christel
authors.initials: C
authors.lastname: Herold-Mende
authors.forename: Dietrich
authors.initials: D
authors.lastname: Keppler
authors.forename: Anne T
authors.initials: AT
authors.lastname: Nies
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000378:metabolism*; D000328:Adult; D000368:Aged; D001254:Astrocytoma / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D001812:Blood-Brain Barrier; D001932:Brain Neoplasms / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D018432:Drug Resistance, Multiple; D019008:Drug Resistance, Neoplasm; D004730:Endothelium, Vascular / Q000378:metabolism / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D026901:Membrane Transport Proteins / Q000378:metabolism; D008856:Microscopy, Fluorescence; D008875:Middle Aged; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000378:metabolism*; D009837:Oligodendroglioma / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D027361:Organic Anion Transporters / Q000378:metabolism*; D013347:Subcellular Fractions
chemical_list: D018528:ATP-Binding Cassette Transporters; D026901:Membrane Transport Proteins; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D027361:Organic Anion Transporters