Abstract
The overexpression of the multidrug resistance (mdr1) gene and its product, P-glycoprotein (P-gp), is thought to limit the successful chemotherapy of human tumours. The mechanism by which mdr1 gene and P-gp are overexpressed in human tumours, however, is not yet clear. In this report, we show that the mdm2 (murine double minute 2) gene induced the expression of the mdr1 gene and P-gp in human glioblastoma U87-MG cells, which did not express the MDM2 protein or P-gp. The mdm2 gene, in addition, conferred the resistance of U87-MG cells to the apoptotic cell death induced by etoposide (VP-16) or doxorubicin. Furthermore, treatment with mdm2 antisense oligonucleotides inhibited the expression of P-gp in MDM2-expressing U87-MG cells. These findings suggest that the mdm2 gene may play an important role in the development of MDR phenotype in human tumours.
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 / biosynthesis*
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ATP Binding Cassette Transporter, Subfamily B, Member 1 / genetics*
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Antibiotics, Antineoplastic / pharmacology
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Antineoplastic Agents, Phytogenic / pharmacology
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Apoptosis / physiology
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Doxorubicin / pharmacology
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Drug Resistance, Multiple / genetics*
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Etoposide / pharmacology
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Gene Expression Regulation, Neoplastic
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Glioblastoma / genetics*
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Glioblastoma / metabolism*
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Humans
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Nuclear Proteins*
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Proto-Oncogene Proteins / genetics*
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Proto-Oncogene Proteins / physiology
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Proto-Oncogene Proteins c-mdm2
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Tumor Cells, Cultured
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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Nuclear Proteins
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Proto-Oncogene Proteins
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Etoposide
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Doxorubicin
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MDM2 protein, human
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Proto-Oncogene Proteins c-mdm2