siRNA-mediated knockdown of Pdcd4 expression causes upregulation of p21(Waf1/Cip1) expression.
Oncogene
; 27(35): 4820-9, 2008 Aug 14.
Article
in En
| MEDLINE
| ID: mdl-18427550
ABSTRACT
The transformation suppressor gene, programmed cell death gene 4 (Pdcd4), inhibits tumor-promoter-mediated transformation of mouse keratinocytes and has been implicated as a tumor suppressor gene in the development of human cancer. The Pdcd4 protein interacts with translation initiation factors eIF4A and eIF4G and binds to RNA, suggesting that it might be involved in regulating protein translation or other aspects of RNA metabolism. To study the function of Pdcd4 in more detail, we have downregulated Pdcd4 expression in HeLa cells by stable expression of shRNA. We have found that diminished Pdcd4 expression leads to increased expression of p21(Waf1/Cip1) and several other p53-regulated genes. Reporter gene studies demonstrate that Pdcd4 interferes with the activation of p53-responsive promoters genes by p53. Pdcd4 knockdown cells show decreased apoptosis and increased survival after UV irradiation. Taken together, our observations suggest a model in which low Pdcd4 expression after DNA damage favors the survival of cells, which would be eliminated by apoptosis under normal levels of Pdcd4 expression. Our results provide the first evidence that Pdcd4 is important role in the DNA-damage response and suggest that low levels of Pdcd4 expression observed in certain tumor cells contribute to tumorigenesis by affecting the fate of DNA-damaged cells.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Up-Regulation
/
RNA-Binding Proteins
/
RNA, Small Interfering
/
Apoptosis Regulatory Proteins
/
Cyclin-Dependent Kinase Inhibitor p21
Type of study:
Etiology_studies
/
Prognostic_studies
Limits:
Humans
Language:
En
Journal:
Oncogene
Journal subject:
BIOLOGIA MOLECULAR
/
NEOPLASIAS
Year:
2008
Document type:
Article
Affiliation country:
Germany