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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
57
pubmed:dateCreated
2002-1-8
pubmed:abstractText
Cytokine oncostatin M (OM) exerts growth-inhibitory and differentiative effects on breast cancer cells. Previously we showed that the transcription from the p53 gene in breast cancer cells was down regulated by OM. To elucidate the molecular mechanisms underlying the OM effect on p53 transcription, in this study, we dissected the p53 promoter region and analysed the p53 promoter activity in breast tumor cells. We showed that treatment of MCF-7 cells with OM induced a dose- and time-dependent suppression of p53 promoter activity. The p53 promoter activity was decreased to 35% of control at 24 h and further decreased to 20% at 48 h by OM at concentrations of 5 ng/ml and higher. Deletion of the 5'-flanking region of the p53 promoter from -426 to -97 did not affect the OM effect. However, further deletion to -40 completely abolished the repressive effect of OM. The p53 promoter region -96 to -41 contains NF-kappaB and c-myc binding sites, and a newly identified UV-inducible element PE21. Mutations to disrupt NF-kappaB binding or c-myc binding to the p53 promoter decreased the basal promoter activity without affecting the OM-mediated suppression, whereas mutation at the PE21 motif totally abolished the OM effect. We further demonstrated that insertion of PE21 element upstream of the thymidine kinase minimal promoter generated an OM response analogous to that of the p53 promoter. Finally, we detected the specific binding of a nuclear protein with a molecular mass of 87 kDa to the PE21 motif. Taken together, we demonstrate that OM inhibits the transcription of the p53 gene through the PE21 element. Thus, the PE21 element is functionally involved in p53 transcription regulated by UV-induction and OM suppression.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0950-9232
pubmed:author
pubmed:issnType
Print
pubmed:day
13
pubmed:volume
20
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
8193-202
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed-meshheading:11781835-Binding Sites, pubmed-meshheading:11781835-Breast Neoplasms, pubmed-meshheading:11781835-DNA-Binding Proteins, pubmed-meshheading:11781835-Dose-Response Relationship, Drug, pubmed-meshheading:11781835-Down-Regulation, pubmed-meshheading:11781835-Electrophoretic Mobility Shift Assay, pubmed-meshheading:11781835-Female, pubmed-meshheading:11781835-Genes, Reporter, pubmed-meshheading:11781835-Genes, p53, pubmed-meshheading:11781835-Humans, pubmed-meshheading:11781835-Kinetics, pubmed-meshheading:11781835-Nuclear Proteins, pubmed-meshheading:11781835-Oncostatin M, pubmed-meshheading:11781835-Peptides, pubmed-meshheading:11781835-Promoter Regions, Genetic, pubmed-meshheading:11781835-Response Elements, pubmed-meshheading:11781835-Sequence Deletion, pubmed-meshheading:11781835-Transcription, Genetic, pubmed-meshheading:11781835-Tumor Cells, Cultured
pubmed:year
2001
pubmed:articleTitle
The critical role of the PE21 element in oncostatin M-mediated transcriptional repression of the p53 tumor suppressor gene in breast cancer cells.
pubmed:affiliation
Department of Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S.