Document Detail


Characterization of ΔNp73 expression and regulation in gastric and esophageal tumors.
MedLine Citation:
PMID:  20676143     Owner:  NLM     Status:  In-Process    
Abstract/OtherAbstract:
p73 is a member of the p53 protein family. Although the tumor suppressor function of p53 is clearly defined, the role of p73 in tumorigenesis is still a matter of debate. A complex pattern of expression of p73 isoforms makes it difficult to unambiguously interpret the experimental results. Previously, we along with others have found that the N-terminally truncated isoform of p73, ΔNp73, has potent anti-apoptotic and oncogenic properties in vitro and in vivo. In this study, we analyzed, for the first time, the regulation of ΔNp73 in a large number of gastric, gastroesophageal junction and esophageal tumors. We found that expression of ΔNp73 mRNA and protein is increased in these neoplasms. Furthermore, the upregulation of the ΔNp73 protein is significantly associated with poor patient survival. Oncogenic properties of ΔNp73 were further confirmed by finding that ΔNp73 facilitates anchorage-independent growth of gastric epithelial cells in soft agar. As little is currently known about the regulation of ΔNp73 transcription, we investigated the alternative p73 gene promoter that mediates the ΔNp73 expression. Analyzing the ΔNp73 promoter in silico as well as by using chromatin immunoprecipitation, site-directed mutagenesis and deletion analyses, we identified the evolutionary conserved region within the ΔNp73 promoter that contains binding sites for HIC1 (hypermethylated in cancer) protein. We found that HIC1 negatively regulates ΔNp73 transcription in mucosal epithelial cells. This leads to a decrease in ΔNp73 protein levels and may normally control the oncogenic potential of the ΔNp73 isoform.
Authors:
A E Vilgelm; S-M Hong; M K Washington; J Wei; H Chen; W El-Rifai; A Zaika
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural     Date:  2010-08-02
Journal Detail:
Title:  Oncogene     Volume:  29     ISSN:  1476-5594     ISO Abbreviation:  Oncogene     Publication Date:  2010 Oct 
Date Detail:
Created Date:  2010-10-28     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8711562     Medline TA:  Oncogene     Country:  England    
Other Details:
Languages:  eng     Pagination:  5861-8     Citation Subset:  IM    
Affiliation:
Department of Surgery, Vanderbilt University Medical Center and Vanderbilt-Ingram Cancer Center, Nashville, TN 37232, USA.
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MeSH Terms
Descriptor/Qualifier:
Grant Support
ID/Acronym/Agency:
CA108956/CA/NCI NIH HHS; UL1RR024975/RR/NCRR NIH HHS

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