title: Multidrug resistance protein (MRP) 4 attenuates benzo[a]pyrene-mediated DNA-adduct formation in human bronchoalveolar H358 cells.
abstract: Multi-drug resistance protein (MRP) 4, an ATP-binding cassette (ABC) transporter, has broad substrate specificity. It facilitates the transport of bile salt conjugates, conjugated steroids, nucleoside analogs, eicosanoids, and cardiovascular drugs. Recent studies in liver carcinoma cells and hepatocytes showed that MRP4 expression is regulated by the aryl hydrocarbon receptor (AhR) and nuclear factor E2-related factor 2 (Nrf2). The AhR has particular importance in the lung and is most commonly associated with the up-regulation of cytochrome P-450 (CYP)-mediated metabolism of benzo[a]pyrene (B[a]P) to reactive intermediates. Treatment of H358, human bronchoalveolar, cells with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) or (-)-benzo[a]pyrene-7,8-dihydro-7,8-diol (B[a]P-7,8-dihydrodiol), the proximate carcinogen of B[a]P, revealed that MRP4 expression was increased compared to control. This suggested that MRP4 expression might contribute to the paradoxical decrease in (+)-7,8-dihydroxy-9,10-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene-2'-deoxyguanosine ((+)-anti-trans-B[a]PDE-dGuo) DNA-adducts observed in TCDD-treated H358 cells. We have now found that decreased MRP4 expression induced by a short hairpin RNA (shRNA), or chemical inhibition with probenecid, increased (+)-anti-trans-B[a]PDE-dGuo formation in cells treated with (-)-B[a]P-7,8-dihydrodiol, but not the ultimate carcinogen (+)-anti-trans-B[a]PDE. Thus, up-regulation of MRP4 increased cellular efflux of (-)-B[a]P-7,8-dihydrodiol, which attenuated DNA-adduct formation. This is the first report identifying a specific MRP efflux transporter that decreases DNA damage arising from an environmental carcinogen.
authors.affiliation: Center for Cancer Pharmacology, 421 Curie Boulevard, BRB II/III Room 841, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA. gstacy@mail.med.upenn.edu
authors.forename: Stacy L
authors.initials: SL
authors.lastname: Gelhaus
authors.forename: Oren
authors.initials: O
authors.lastname: Gilad
authors.forename: Wei-Ting
authors.initials: WT
authors.lastname: Hwang
authors.forename: Trevor M
authors.initials: TM
authors.lastname: Penning
authors.forename: Ian A
authors.initials: IA
authors.lastname: Blair
mesh_terms: D001564:Benzo(a)pyrene / Q000037:antagonists & inhibitors* / Q000633:toxicity*; D001980:Bronchi / Q000166:cytology* / Q000187:drug effects; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology; D002273:Carcinogens / Q000037:antagonists & inhibitors* / Q000633:toxicity*; D002460:Cell Line; D004247:DNA / Q000235:genetics / Q000302:isolation & purification; D018736:DNA Adducts / Q000187:drug effects*; D015232:Dinoprostone / Q000096:biosynthesis; D006801:Humans; D007150:Immunohistochemistry; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000494:pharmacology*; D051267:NF-E2-Related Factor 2 / Q000378:metabolism; D000072317:Polychlorinated Dibenzodioxins / Q000633:toxicity; D011339:Probenecid / Q000494:pharmacology; D011650:Pulmonary Alveoli / Q000166:cytology* / Q000187:drug effects; D034741:RNA, Small Interfering / Q000096:biosynthesis / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D020239:Receptor Cross-Talk / Q000187:drug effects; D018336:Receptors, Aryl Hydrocarbon / Q000187:drug effects; D012076:Renal Agents / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects
chemical_list: D001564:Benzo(a)pyrene; D002273:Carcinogens; D004247:DNA; D018736:DNA Adducts; D015232:Dinoprostone; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D051267:NF-E2-Related Factor 2; D000072317:Polychlorinated Dibenzodioxins; D011339:Probenecid; D034741:RNA, Small Interfering; D018336:Receptors, Aryl Hydrocarbon; D012076:Renal Agents; C073492:ABCC4 protein, human; C495635:NFE2L2 protein, human