title: MDR1 (ABCB1) G1199A (Ser400Asn) polymorphism alters transepithelial permeability and sensitivity to anticancer agents.
abstract: OBJECTIVE
  P-glycoprotein (P-gp), encoded by MDR1 (or ABCB1), is important in anticancer drug delivery and resistance. We evaluated alterations in P-gp-mediated transport of anticancer agents due to the MDR1 G1199A polymorphism.
  
  
  METHODS
  Using stable recombinant epithelial cells expressing wild-type (MDR1 (wt)) or G1199A (MDR1 (1199A)), anticancer drug sensitivity and transepithelial permeability were evaluated.
  
  
  RESULTS
  The recombinant cells MDR1 (wt) and MDR1 ( 1199A ) displayed comparable doxorubicin resistance. However, MDR1 (1199A) cells displayed greater resistance to vinblastine, vincristine, paclitaxel, and VP-16 (11-, 2.9-, 1.9-, and 2.9-fold, respectively). Alterations in transepithelial permeability paralleled these changes. Efflux of doxorubicin was similar between MDR1 wt - and MDR1 (1199A)-expressing cells, while P-gp-mediated transport was greater for vinblastine and vincristine in MDR1 (1199A) cells (2.9- and 2.0-fold, respectively).
  
  
  CONCLUSIONS
  The occurrence and magnitude of the MDR1 G1199A effect is drug specific. Overall, the MDR1 G1199A polymorphism may impact anticancer efficacy through modulation of drug distribution and delivery to target tumor cells.
authors.affiliation: Department of Pharmaceutics, University of Washington, Seattle, WA 98195, USA.
authors.forename: Erica L
authors.initials: EL
authors.lastname: Woodahl
authors.forename: Matthew H
authors.initials: MH
authors.lastname: Crouthamel
authors.forename: Tot
authors.initials: T
authors.lastname: Bui
authors.forename: Danny D
authors.initials: DD
authors.lastname: Shen
authors.forename: Rodney J Y
authors.initials: RJ
authors.lastname: Ho
mesh_terms: D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000235:genetics*; D000818:Animals; D000970:Antineoplastic Agents / Q000493:pharmacokinetics* / Q000494:pharmacology; D001692:Biological Transport / Q000235:genetics; D002478:Cells, Cultured; D019008:Drug Resistance, Neoplasm; D004847:Epithelial Cells / Q000378:metabolism; D019450:Genes, MDR / Q000235:genetics*; D006801:Humans; D018374:LLC-PK1 Cells; D010539:Permeability; D020641:Polymorphism, Single Nucleotide; D013552:Swine
chemical_list: C513055:ABCB1 protein, human; D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000970:Antineoplastic Agents