Vincristine induction of mutant and wild-type human multidrug-resistance promoters is cell-type-specific and dose-dependent.
To investigate multidrug-resistance gene (MDR1) promoter efficacy and drug inducibility in cells with different multidrug-resistance phenotypes, multidrug-resistant HCT15 and drug-sensitive KM12 human colon carcinoma cell lines were transfected with constructs incorporating the chloramphenicol acetyltransferase (CAT) reporter gene, driven by wild-type and point-mutated MDR1 promoter regions. The basal CAT expression level in HCT15 cells was markedly elevated compared to KM12 cells. CAT induction by vincristine was dose-dependent over a broad concentration range (40-500 ng/ml) in both lines. The induction levels were related to the cells' MDR phenotype, with the multidrug-resistant HCT15 cells showing the greater effect. In both cell types, basal and drug-induced CAT expression were significantly enhanced by the point-mutated promoter regions. The findings support the possible exploitation of the MDR1 promoter for construction of drug-inducible and MDR-cell-targeted expression vectors for use in gene therapy.
Stein
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Division of Cancer Treatment, National Cancer Institute-Frederick Cancer Research and Development Center, Frederick, MD 21702, USA.
Walther
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W
Shoemaker
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RH
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000235:genetics*; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology*; D015500:Chloramphenicol O-Acetyltransferase / Q000235:genetics; D003110:Colonic Neoplasms / Q000188:drug therapy* / Q000473:pathology; D004305:Dose-Response Relationship, Drug; D018432:Drug Resistance, Multiple / Q000235:genetics; D006801:Humans; D009154:Mutation; D011401:Promoter Regions, Genetic; D014407:Tumor Cells, Cultured; D014750:Vincristine / Q000494:pharmacology*
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000972:Antineoplastic Agents, Phytogenic; D014750:Vincristine; D015500:Chloramphenicol O-Acetyltransferase