title: Reversal of P-glycoprotein-mediated multidrug resistance by the murine double minute 2 antagonist nutlin-3.
abstract: Murine double minute 2 (MDM2) negatively regulates the activity of the tumor suppressor protein p53. Nutlin-3 is a MDM2 inhibitor under preclinical investigation as nongenotoxic activator of the p53 pathway for cancer therapy. Here, nutlin-3 was evaluated for its activity alone or in combination with established chemotherapeutic drugs for antitumor action in chemosensitive and chemoresistant neuroblastoma and rhabdomyosarcoma cell lines. Effects of nutlin-3 single treatment were much more pronounced in p53 wild-type cell lines (IC(50)s <3 micromol/L) than in p53-mutated cell lines (IC(50)s >17 micromol/L). In sharp contrast to the expectations, nutlin-3 concentrations that did not affect viability of p53-mutated cell lines strongly increased the efficacy of vincristine in p53-mutated, P-glycoprotein (P-gp)-overexpressing cell lines (decrease in IC(50)s 92- to 3,434-fold). Similar results were obtained for other P-gp substrates. Moreover, nutlin-3 reduced efflux of rhodamine 123 and other fluorescence dyes that are effluxed by P-gp. Investigation of Madin-Darby canine kidney (MDCK) II cells stably transfected with plasmids encoding for P-gp (MDCKII MDR1) or multidrug resistance protein 1 (MRP-1, MDCKII MRP1) revealed that nutlin-3 not only interferes with P-gp but also affects MRP-1-mediated efflux. Kinetic studies and investigation of P-gp-ATPase activity showed that nutlin-3 is likely to act as a P-gp transport substrate. Examination of the nutlin-3 enantiomers nutlin-3a and nutlin-3b revealed that, in contrast to MDM2-inhibitory activity that is limited to nutlin-3a, both enantiomers similarly interfere with P-gp-mediated drug efflux. In conclusion, nutlin-3-induced inhibition of P-gp and MRP-1 was discovered as a novel anticancer mechanism of the substance in this report.
authors.affiliation: Institut für Medizinische Virologie, Klinikum der JW Goethe-Universität, Klinikum der Johann Wolfgang Goethe-Universität, Frankfurt am Main, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Michaelis
authors.forename: Florian
authors.initials: F
authors.lastname: Rothweiler
authors.forename: Denise
authors.initials: D
authors.lastname: Klassert
authors.forename: Andreas
authors.initials: A
authors.lastname: von Deimling
authors.forename: Kristoffer
authors.initials: K
authors.lastname: Weber
authors.forename: Boris
authors.initials: B
authors.lastname: Fehse
authors.forename: Bernd
authors.initials: B
authors.lastname: Kammerer
authors.forename: Hans Wilhelm
authors.initials: HW
authors.lastname: Doerr
authors.forename: Jindrich
authors.initials: J
authors.lastname: Cinatl
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000037:antagonists & inhibitors* / Q000096:biosynthesis / Q000378:metabolism; D000818:Animals; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000494:pharmacology*; D045744:Cell Line, Tumor; D019008:Drug Resistance, Neoplasm; D004357:Drug Synergism; D006801:Humans; D007093:Imidazoles / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000494:pharmacology*; D051379:Mice; D009154:Mutation; D009447:Neuroblastoma / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism; D010879:Piperazines / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000494:pharmacology*; D051736:Proto-Oncogene Proteins c-mdm2 / Q000037:antagonists & inhibitors; D018232:Rhabdomyosarcoma, Alveolar / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism; D020112:Rhodamine 123 / Q000493:pharmacokinetics; D013237:Stereoisomerism; D016159:Tumor Suppressor Protein p53 / Q000096:biosynthesis / Q000235:genetics; D014750:Vincristine / Q000008:administration & dosage
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D007093:Imidazoles; D010879:Piperazines; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; D020112:Rhodamine 123; C482205:nutlin 3; D014750:Vincristine; C497207:Mdm2 protein, mouse; D051736:Proto-Oncogene Proteins c-mdm2