Abstract
Acquisition of P-gp-mediated multidrug-resistance does not always correlate with observed malignant behavior of NB. To characterize alterations accompanying development of multidrug-resistance in NB we established two neuroblastoma cell sublines resistant to vincristine (UKF-NB-3rVCR10) and doxorubicin (UKF-NB-3rDOX20). UKF-NB-3rVCR10 and UKF-NB-3rDOX20 overexpressed functional P-gp and developed an increased malignant phenotype: presented constitutive phosphorylation of AKT, resistance to gamma-irradiation, and had increased survival in serum-free medium. Inhibition of P-gp restored chemosensitivity but did not affect increased survival in serum-free medium and sensitivity to gamma-irradiation. Inhibition of AKT had no influence on chemoresistance but restored sensitivity to serum starvation. Both resistant cell lines acquired additional chromosomal changes. UKF-NB-3rVCR10 cells acquired a missense P53 mutation in exon 5, an increased MYCN amplification, an enhanced adhesion to endothelium, a decreased NCAM expression, a distinctly higher clonogenicity, and an increased in vivo tumorigenicity. We conclude that acquisition of increased malignant behavior in neuroblastoma occurs concomitantly with multidrug-resistance and is P-gp-independent.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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ATP Binding Cassette Transporter, Subfamily B, Member 1 / metabolism*
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Animals
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Antibiotics, Antineoplastic / pharmacology
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Antineoplastic Agents, Phytogenic / pharmacology
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Blotting, Western
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Cell Adhesion
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Cell Line, Tumor
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Cell Proliferation
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Cell Separation
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Cell Survival
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Cells, Cultured
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Culture Media, Serum-Free / metabolism
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Culture Media, Serum-Free / pharmacology
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DNA Mutational Analysis
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Dose-Response Relationship, Drug
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Dose-Response Relationship, Radiation
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Doxorubicin / pharmacology
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Drug Resistance
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Drug Resistance, Multiple*
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Drug Resistance, Neoplasm*
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Exons
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Female
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Flow Cytometry
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Gamma Rays
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Genes, p53 / genetics
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Humans
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In Situ Hybridization, Fluorescence
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Inhibitory Concentration 50
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Karyotyping
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Mice
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Mice, Nude
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Mutation
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Mutation, Missense
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Neuroblastoma / metabolism
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Neuroblastoma / pathology*
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Phenotype
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Phosphorylation
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Proto-Oncogene Proteins c-akt / metabolism
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Rhodamine 123 / pharmacology
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Time Factors
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Tumor Suppressor Protein p53 / metabolism
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Vincristine / pharmacology
Substances
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ATP Binding Cassette Transporter, Subfamily B, Member 1
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Antibiotics, Antineoplastic
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Antineoplastic Agents, Phytogenic
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Culture Media, Serum-Free
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Tumor Suppressor Protein p53
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Rhodamine 123
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Vincristine
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Doxorubicin
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Proto-Oncogene Proteins c-akt