title: Effects of benzo(e)pyrene and benzo(a)pyrene on P-glycoprotein-mediated transport in Caco-2 cell monolayer: a comparative approach.
abstract: The previous studies from our laboratory reported that benzo(a)pyrene (Bap) influenced efflux transport of rhodamine 123 (Rho-123) by induction of P-glycoprotein (P-gp) in Caco-2 cells. The present study investigated whether induction of P-gp and the enhanced efflux transport of Rho-123 were caused by benzo(e)pyrene (Bep), which has a structure similar to Bap, but is not a carcinogenic compound. In Caco-2 monolayer exposed to 50 microM Bep for 72 h, the ratio of the apparent permeability coefficient (P(app)) of Rho-123 efflux increased significantly compared to that of the control monolayer. Similarly, a significant increase in expression of MDR1 mRNA and of P-gp at the protein level were detected by RT-PCR and by Western blot analysis, respectively, in Caco-2 cells exposed to Bep, compared to that of the control. Caco-2 cells exposed to Bep showed oxidative stress that was detected by fluorescence microscopy using aminophenyl fluorescein. However, the oxidative stress was weaker compared with that of Bap. The cellular GSH content was decreased to 80% or 59% of control cells, respectively, in Caco-2 cells exposed to either Bep or Bap. Our results further show that Bep or Bap-induced P-gp in Caco-2 cells might have been the result of oxidative stress rather than DNA damage.
authors.affiliation: Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama University, Sanzou, Fukuyama, Hiroshima 729-0292, Japan. sugihara@fupharm-fukuyama-u.ac.jp
authors.forename: Narumi
authors.initials: N
authors.lastname: Sugihara
authors.forename: Kumiko
authors.initials: K
authors.lastname: Toyama
authors.forename: Tastuaki
authors.initials: T
authors.lastname: Okamoto
authors.forename: Masaaki
authors.initials: M
authors.lastname: Kadowaki
authors.forename: Kazumi
authors.initials: K
authors.lastname: Terao
authors.forename: Koji
authors.initials: K
authors.lastname: Furuno
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000502:physiology*; D001564:Benzo(a)pyrene / Q000633:toxicity*; D001580:Benzopyrenes / Q000633:toxicity*; D001693:Biological Transport, Active / Q000187:drug effects; D015153:Blotting, Western; D018938:Caco-2 Cells; D002273:Carcinogens / Q000633:toxicity*; D002470:Cell Survival / Q000187:drug effects; D004249:DNA Damage / Q000187:drug effects; D005978:Glutathione / Q000378:metabolism; D006801:Humans; D008856:Microscopy, Fluorescence; D018384:Oxidative Stress / Q000187:drug effects; D011084:Polycyclic Aromatic Hydrocarbons / Q000633:toxicity; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D020112:Rhodamine 123
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D001580:Benzopyrenes; D002273:Carcinogens; D011084:Polycyclic Aromatic Hydrocarbons; D012333:RNA, Messenger; D020112:Rhodamine 123; D001564:Benzo(a)pyrene; C026487:benzo(e)pyrene; D005978:Glutathione