title: Expression of the multidrug resistance-associated protein (MRP) gene correlates with amplification and overexpression of the N-myc oncogene in childhood neuroblastoma.
abstract: The MRP gene (Cole et al., Science (Washington DC), 258: 1650-1654, 1992) encodes a membrane-bound glycoprotein the expression of which correlates with non-P-glycoprotein-mediated multidrug resistance in a variety of cultured human cell lines. Using an RNA-polymerase chain reaction assay, expression of this gene was examined in the highly chemoresistant pediatric malignancy, neuroblastoma. MRP expression was observed in 5 human neuroblastoma cell lines and in all 25 primary neuroblastoma tumors of stage I through IVS. Tumors with amplification of the N-myc oncogene were found to have significantly higher MRP expression that those with no amplification (P = 0.0016). Expression of the MRP gene in the tumor specimens was highly correlated with expression of the N-myc gene (P = 0.0009), while expression of the MDR1 gene, encoding P-glycoprotein, was not related to expression of either the N-myc or MRP genes. Decreased expression of the N-myc oncogene in neuroblastoma cell lines SH-SY5Y and BE(2)-C, following treatment with retinoic acid, was paralleled by down-regulation of MRP gene expression, contrasting with increased expression of the MDR1 gene. Expression of the MRP gene is thus common in both primary neuroblastoma tumors and cultured cell lines, and correlates with amplification and overexpression of the N-myc oncogene, which is central to the malignant phenotype of this disease.
authors.affiliation: Children's Leukaemia and Cancer Research Centre, Prince of Wales Children's Hospital, Randwick, Sydney, New South Wales, Australia.
authors.forename: S B
authors.initials: SB
authors.lastname: Bordow
authors.forename: M
authors.initials: M
authors.lastname: Haber
authors.forename: J
authors.initials: J
authors.lastname: Madafiglio
authors.forename: B
authors.initials: B
authors.lastname: Cheung
authors.forename: G M
authors.initials: GM
authors.lastname: Marshall
authors.forename: M D
authors.initials: MD
authors.lastname: Norris
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000235:genetics*; D001483:Base Sequence; D002454:Cell Differentiation / Q000187:drug effects; D004351:Drug Resistance / Q000235:genetics*; D005784:Gene Amplification; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D016259:Genes, myc; D006801:Humans; D008969:Molecular Sequence Data; D009447:Neuroblastoma / Q000235:genetics*; D014212:Tretinoin / Q000494:pharmacology; D014407:Tumor Cells, Cultured
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D014212:Tretinoin