title: Impact of the cyclooxygenase system on doxorubicin-induced functional multidrug resistance 1 overexpression and doxorubicin sensitivity in acute myeloid leukemic HL-60 cells.
abstract: Multidrug resistance (MDR), a challenge in treating childhood acute myeloid leukemia (AML), is frequently associated with decreased drug accumulation caused by multidrug transporter MDR1. Doxorubicin, an important anti-AML drug, is a known MDR1 substrate and inducer. Its cytostatic efficacy is thus limited by MDR1 overexpression. A recent study demonstrated cyclooxygenase-2-dependent, prostaglandin E(2) (PGE(2))-mediated regulation of mdr1b expression in primary rat hepatocyte cultures. Cyclooxygenase-2 expression is increased in several malignancies and considered a negative prognostic factor. Our study focused on cyclooxygenase system's impact on drug-induced MDR1 overexpression in AML cells. As a prerequisite, coexpression of MDR1 and cyclooxygenase-2 mRNA in HL-60 cells and primary AML blasts was demonstrated by Northern blot. Interestingly, incubation of AML cells with doxorubicin not only induced functionally active MDR1 overexpression but also mediated increased cyclooxygenase-2 mRNA and protein expressions with subsequent PGE(2) release (determined by flow cytometry, rhodamine123 efflux assay, reverse transcription-polymerase chain reaction, and enzyme-linked immunosorbent assay). After preincubation and subsequent parallel treatment with the cyclooxygenase-2-preferential inhibitor meloxicam, doxorubicin-induced MDR1 overexpression and function were reduced (maximally at 0.1-0.5 microM meloxicam), whereas cytostatic efficacy of doxorubicin in 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide assays was significantly increased by up to 78 (HL-60) and 30% (AML blasts) after 72 h of doxorubicin treatment. In HL-60 cells, meloxicam-dependent effect on doxorubicin cytotoxicity was neutralized by PGE(2) preincubation. In conclusion, the cyclooxygenase system, especially the cyclooxygenase-2 isoform, might be involved in regulating doxorubicin-induced MDR1 overexpression in AML cells, with PGE(2) seeming to be a mediating factor. Cyclooxygenase inhibitors thus bear promise to overcome MDR in AML and improve therapy.
authors.affiliation: AML-BFM Study, Department of Pediatric Hematology and Oncology, University Children's Hospital Muenster, Albert-Schweitzer-Str. 33, 48129 Muenster, Germany. ulrike@puhlmann.de
authors.forename: Ulrike
authors.initials: U
authors.lastname: Puhlmann
authors.forename: Christina
authors.initials: C
authors.lastname: Ziemann
authors.forename: Gudrun
authors.initials: G
authors.lastname: Ruedell
authors.forename: Hagen
authors.initials: H
authors.lastname: Vorwerk
authors.forename: Dirk
authors.initials: D
authors.lastname: Schaefer
authors.forename: Claudia
authors.initials: C
authors.lastname: Langebrake
authors.forename: Peter
authors.initials: P
authors.lastname: Schuermann
authors.forename: Ursula
authors.initials: U
authors.lastname: Creutzig
authors.forename: Dirk
authors.initials: D
authors.lastname: Reinhardt
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism*; D017209:Apoptosis; D001692:Biological Transport; D051546:Cyclooxygenase 2; D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D015232:Dinoprostone / Q000378:metabolism; D004317:Doxorubicin / Q000009:adverse effects*; D004347:Drug Interactions; D018432:Drug Resistance, Multiple; D019008:Drug Resistance, Neoplasm / Q000502:physiology*; D004354:Drug Screening Assays, Antitumor; D015870:Gene Expression / Q000187:drug effects; D018922:HL-60 Cells; D006801:Humans; D015470:Leukemia, Myeloid, Acute; D000077239:Meloxicam; D008565:Membrane Proteins; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism*; D020112:Rhodamine 123 / Q000494:pharmacology; D013843:Thiazines / Q000494:pharmacology; D013844:Thiazoles / Q000494:pharmacology
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors; D008565:Membrane Proteins; D013843:Thiazines; D013844:Thiazoles; D020112:Rhodamine 123; D004317:Doxorubicin; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; D015232:Dinoprostone; D000077239:Meloxicam