Regulation of multidrug resistance 1 (MDR1)/P-glycoprotein gene expression and activity by heat-shock transcription factor 1 (HSF1).
Infection of HeLa cells with adenovirus-carrying HSF1(+) cDNA, which encodes a mutated form of HSF1 with constitutive transactivation capacity, increased multidrug resistance 1 (MDR1) mRNA level and P-glycoprotein (P-gp) cell surface content and stimulated rhodamine 123 accumulation and vinblastine efflux activity. On the other hand, infection with adenovirus-carrying HSP70 and HSP27 cDNAs did not increase MDR1/P-gp expression. HSF1 regulates MDR1/P-gp expression at the transcriptional level, since HSF1(+) bound the heat-shock consensus elements (HSEs) in the MDR1 gene promoter and also activated the expression of an MDR1 promoter-driven reporter plasmid (pMDR1(-1202)). In addition, heat-shock increased pMDR1(-1202) promoter activity but not the activity of a similar reporter plasmid with point mutations at specific HSEs, and the heat-induced increase was totally inhibited by co-transfection with an expression plasmid carrying HSF1(-), a dominant negative mutant of HSF1. The stress inducers arsenite, butyrate, and etoposide also increased pMDR1(-1202) promoter activity, but the increase was not inhibited (in the case of butyrate) or was only partially inhibited (in the case of arsenite and etoposide) by HSF1(-). These results demonstrate that HSF1 regulates MDR1 expression, and that the HSEs present in the -315 to -285 region mediate the heat-induced activation of the MDR1 promoter. However, other factors may also participate in MDR1 induction by stressing agents.
Vilaboa
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NE
Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Cientificas, 28006 Madrid, Spain.
Galán
A
A
Troyano
A
A
de Blas
E
E
Aller
P
P
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D001665:Binding Sites; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D018432:Drug Resistance, Multiple / Q000235:genetics*; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D055551:HSP27 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics; D006367:HeLa Cells; D000076249:Heat Shock Transcription Factors; D006360:Heat-Shock Proteins; D006358:Hot Temperature; D006801:Humans; D007700:Kinetics; D018832:Molecular Chaperones; D009363:Neoplasm Proteins / Q000235:genetics; D011401:Promoter Regions, Genetic; D011994:Recombinant Proteins / Q000378:metabolism; D013997:Time Factors; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic; D014162:Transfection; D014747:Vinblastine / Q000493:pharmacokinetics
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D004268:DNA-Binding Proteins; C000619706:HSF1 protein, human; D055551:HSP27 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins; C057725:HSPB1 protein, human; D000076249:Heat Shock Transcription Factors; D006360:Heat-Shock Proteins; D018832:Molecular Chaperones; D009363:Neoplasm Proteins; D011994:Recombinant Proteins; D014157:Transcription Factors; D014747:Vinblastine