title: Reactive oxygen species-linked regulation of the multidrug resistance transporter P-glycoprotein in Nox-1 overexpressing prostate tumor spheroids.
abstract: Expression of the multidrug resistance (MDR) transporter P-glycoprotein (P-gp) has been demonstrated to be regulated by hypoxia-inducible factor-1alpha (HIF-1alpha) and inhibited by intracellular reactive oxygen species (ROS). Herein, P-gp and HIF-1alpha expression were investigated in multicellular prostate tumor spheroids overexpressing the ROS-generating enzyme Nox-1 in comparison to the mother cell line DU-145. In Nox-1-overexpressing tumor spheroids (DU-145Nox1) generation of ROS as well as expression of Nox-1 was significantly increased as compared to DU-145 tumor spheroids. ROS generation was significantly inhibited in the presence of the NADPH-oxidase antagonists diphenylen-iodonium chloride (DPI) and 4-(2-aminoethyl)benzenesulfonyl fluoride (AEBSF). Albeit growth kinetic of DU-145Nox1 tumor spheroids was decreased as compared to DU-145 spheroids, elevated expression of Ki-67 was observed indicating increased cell cycle activity. In DU-145Nox1 tumor spheroids, expression of HIF-1alpha as well as P-gp was significantly decreased as compared to DU-145 spheroids, which resulted in an increased retention of the anticancer agent doxorubicin. Pretreatment with the free radical scavengers vitamin E and vitamin C increased the expression of P-gp as well as HIF-1alpha in Nox-1-overexpressing cells, whereas no effect of free radical scavengers was observed on mdr-1 mRNA expression. In summary, the data of the present study demonstrate that the development of P-gp-mediated MDR is abolished under conditions of elevated ROS levels, suggesting that the MDR phenotype can be circumvented by modest increase of intracellular ROS generation.
authors.affiliation: Department of Cell Biology, GKSS Research Center, Teltow, Germany.
authors.forename: Maria
authors.initials: M
authors.lastname: Wartenberg
authors.forename: Edda
authors.initials: E
authors.lastname: Hoffmann
authors.forename: Heinrich
authors.initials: H
authors.lastname: Schwindt
authors.forename: Frank
authors.initials: F
authors.lastname: Grünheck
authors.forename: John
authors.initials: J
authors.lastname: Petros
authors.forename: J Rebecca S
authors.initials: JR
authors.lastname: Arnold
authors.forename: Jürgen
authors.initials: J
authors.lastname: Hescheler
authors.forename: Heinrich
authors.initials: H
authors.lastname: Sauer
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism*; D001205:Ascorbic Acid / Q000494:pharmacology; D001713:Biphenyl Compounds / Q000494:pharmacology; D045744:Cell Line, Tumor; D018432:Drug Resistance, Multiple / Q000187:drug effects; D016166:Free Radical Scavengers / Q000494:pharmacology; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D008297:Male; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000235:genetics / Q000378:metabolism; D000074624:NADPH Oxidase 1; D019255:NADPH Oxidases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D009861:Onium Compounds / Q000494:pharmacology; D011471:Prostatic Neoplasms / Q000235:genetics / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism* / Q000494:pharmacology; D018874:Spheroids, Cellular; D013450:Sulfones / Q000494:pharmacology; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014810:Vitamin E / Q000494:pharmacology
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D001205:Ascorbic Acid; D001713:Biphenyl Compounds; D016166:Free Radical Scavengers; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D000074624:NADPH Oxidase 1; D019255:NADPH Oxidases; D009861:Onium Compounds; D017382:Reactive Oxygen Species; D013450:Sulfones; D014157:Transcription Factors; D014810:Vitamin E; C497442:HIF1A protein, human; C031291:diphenyliodonium; C002010:4-(2-aminoethyl)benzenesulfonylfluoride; C402799:NOX1 protein, human