| Abstract | Hepatocyte growth factor (HGF) plays a major role in the pathogenesis of a variety of human epithelial tumors including papillary carcinoma of the thyroid. Previous reports demonstrated that HGF, acting through the Met receptor, repressed thrombospondin-1 (TSP-1) expression. To study the mechanisms by which HGF down-regulated TSP-1 expression, we transiently transfected a panel of deleted human TSP-1 promoter reporter plasmids into papillary thyroid carcinoma cells. We identified a region between -1210 and -1123 bp relative to the transcription start site that is responsive to HGF treatment and harbors a cAMP-responsive element (CRE) at position -1199 (TGACGTCC). Overexpression of various members of the CRE-binding protein family identified activating transcription factor-1 (ATF-1) as the transcription factor responsible for HGF-induced repression of TSP-1 promoter activity. This inhibition was associated with a concomitant increase in the abundance of nuclear ATF-1 protein. Gel shift and antibody supershift studies indicated that ATF-1 was involved in DNA binding to the TSP-1-CRE site. Finally, we utilized small hairpin RNA to target ATF-1 and showed that these small interfering RNA constructs significantly inhibited ATF-1 expression at both the RNA and the protein level. ATF-1 knockdown prevented HGF-induced down-regulation of TSP-1 promoter activity and protein expression and also reduced HGF-dependent tumor cell invasion. Taken together, our results indicate that HGF-induced down-regulation of TSP-1 expression is mediated by the interaction of ATF-1 with the CRE binding site in the TSP-1 promoter and that this transcription factor plays a crucial role for tumor invasiveness in papillary carcinoma of the thyroid triggered by HGF. |
| Authors | Christelle Ghoneim, Mahdhia Soula-Rothhut, Charlotte Blanchevoye, Laurent Martiny, Frank Antonicelli, Bernard Rothhut
(Affiliation: Unité Matrice Extracellulaire et Régulations Cellulaires, Laboratory of Biochemistry, Université de Reims Champagne Ardenne (URCA), CNRS, 51687 Reims, France.)
|
| Journal | The Journal of biological chemistry
(J Biol Chem)
Vol. 282
Issue 21
Pg. 15490-7
(May 25 2007)
ISSN: 0021-9258 United States |
| PMID | 17409099
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
|
| Chemical References |
- DNA-Binding Proteins
- Neoplasm Proteins
- Nuclear Proteins
- RNA, Messenger
- RNA, Small Interfering
- TRE-binding protein
- Thrombospondin 1
- Hepatocyte Growth Factor
|
| Topics |
- Carcinoma, Papillary
(genetics, metabolism, pathology)
- Cell Line, Tumor
- DNA-Binding Proteins
(genetics, metabolism)
- Down-Regulation
(drug effects)
- Gene Expression Regulation, Neoplastic
(drug effects)
- Hepatocyte Growth Factor
(metabolism, pharmacology)
- Humans
- Neoplasm Invasiveness
- Neoplasm Proteins
(biosynthesis, genetics, metabolism)
- Nuclear Proteins
(genetics, metabolism)
- Protein Binding
(genetics)
- RNA, Messenger
(biosynthesis, genetics)
- RNA, Small Interfering
(genetics)
- Response Elements
- Thrombospondin 1
(biosynthesis, genetics)
- Thyroid Neoplasms
(genetics, metabolism, pathology)
|
