title: Molecular cytogenetic characterization of doxorubicin-resistant neuroblastoma cell lines: evidence that acquired multidrug resistance results from a unique large amplification of the 7q21 region.
abstract: Neuroblastoma is a heterogeneous neural crest-derived embryonic childhood neoplasm that is the second most common solid tumor found in children. Despite recent advances in combined therapy, the overall survival of patients with high-stage disease has not improved in the last decades. Treatment failure is in part attributed to multidrug resistance. To address the mechanisms involved in the development of multidrug resistance, we have generated two doxorubicin-resistant neuroblastoma cell lines (IGRN-91R and LAN-1R). These cells were shown to overexpress the MDR1 gene coding for the P-glycoprotein and were resistant to other MDR1- and non-MDR1-substrate drugs. Indeed, the MDR1 inhibitor verapamil only partially restored sensitivity to drugs, confirming that P-glycoprotein-mediated drug efflux was not responsible for 100% resistance. High-resolution and array-based comparative genomic hybridization analyses revealed the presence of an amplicon in the 7q21 region as the unique genomic alteration common to both doxorubicin-resistant cell lines. In addition to the MDR1 locus, this large amplified region is likely to harbor additional genes potentially involved in the development of drug resistance. This study represents the first molecular cytogenetic and genomic approach to identifying genomic regions involved in the multidrug-resistant phenotype of neuroblastoma. These results could lead to the identification of relevant target genes for the development of new therapeutic modalities.
authors.affiliation: Paediatric Oncology Research, Paediatric Department, University Hospital CHUV, Lausanne, Switzerland.
authors.forename: Marjorie
authors.initials: M
authors.lastname: Flahaut
authors.forename: Annick
authors.initials: A
authors.lastname: Mühlethaler-Mottet
authors.forename: Danielle
authors.initials: D
authors.lastname: Martinet
authors.forename: Sarah
authors.initials: S
authors.lastname: Fattet
authors.forename: Katia Balmas
authors.initials: KB
authors.lastname: Bourloud
authors.forename: Katya
authors.initials: K
authors.lastname: Auderset
authors.forename: Roland
authors.initials: R
authors.lastname: Meier
authors.forename: Nathalie Besuchet
authors.initials: NB
authors.lastname: Schmutz
authors.forename: Olivier
authors.initials: O
authors.lastname: Delattre
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Joseph
authors.forename: Nicole
authors.initials: N
authors.lastname: Gross
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D001483:Base Sequence; D015153:Blotting, Western; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D045744:Cell Line, Tumor; D002897:Chromosomes, Human, Pair 7; D017931:DNA Primers; D004317:Doxorubicin / Q000494:pharmacology*; D018432:Drug Resistance, Multiple / Q000235:genetics*; D019008:Drug Resistance, Neoplasm / Q000235:genetics*; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D009447:Neuroblastoma / Q000201:enzymology / Q000235:genetics* / Q000473:pathology; D016133:Polymerase Chain Reaction
chemical_list: D000970:Antineoplastic Agents; D017931:DNA Primers; D004317:Doxorubicin; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases