Document Detail


Negative regulation of glucocorticoid-dependent induction of c-fos by ras in intestinal epithelial cells.
MedLine Citation:
PMID:  10395074     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
In order to investigate the regulatory mechanisms involved in the expression of fos and jun family members by glucocorticoids, and the effect of ras transformation in intestinal epithelial cells, we used the rat cell line IEC-6. Dexamethasone treatment induced transiently c-jun mRNAs, in contrast to the sustained expression of c-fos, whereas its effect on junB expression resulted in a later increase. Dexamethasone-dependent stimulation of c-fos and c-jun was modulated predominantly at the level of transcription. Sustained levels of induced c-fos and c-jun proteins were observed after dexamethasone treatment. AP-1 DNA-binding capacity of c-fos, and to a smaller extent c-jun, was increased by glucocorticoids later than after serum treatment. To analyse the effect of ras on the glucocorticoid response of AP-1 components, we studied several IEC-6 cell clones transformed by the Ha-ras oncogene. In comparison to normal cells, these transformants displayed increased AP-1 DNA-binding activity with higher levels of junB and variable levels of c-jun in the AP-1 complex. Ras transformation repressed the growth-inhibitory properties of glucocorticoids. Furthermore, ras inhibited the glucocorticoid-dependent induction of c-fos protein and mRNA, leading to changes in AP-1 composition as compared to normal cells. As assessed by transient transfection luciferase assays, glucocorticoids induced significantly a minimal promoter containing 3 copies of an AP-1 DNA-binding site as well as the murine c-fos -276 to +112 promoter in non-transformed cells. In contrast, glucocorticoid addition did not induce these constructs in two ras transformed cell lines. These results suggest that ras negatively modulates specific responses of intestinal epithelial cells to glucocorticoids.
Authors:
F Boudreau; S Zannoni; N Pelletier; T Bardati; S J Yu; C Asselin
Related Documents :
1516834 - Yeast gcn4 as a probe for oncogenesis by ap-1 transcription factors: transcriptional ac...
7561734 - Ap-1 transcription factor complexes in cns disorders and development.
15192124 - Hmg-i/y is a c-jun/activator protein-1 target gene and is necessary for c-jun-induced a...
1761754 - Specific temporal and spatial distribution of jun, fos, and krox-24 proteins in spinal ...
19900134 - Cox-2 expression in uterine carcinosarcoma.
10051564 - Trnaval-heterodimeric maxizymes with high potential as geneinactivating agents: simulta...
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Molecular and cellular biochemistry     Volume:  195     ISSN:  0300-8177     ISO Abbreviation:  Mol. Cell. Biochem.     Publication Date:  1999 May 
Date Detail:
Created Date:  1999-10-28     Completed Date:  1999-10-28     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0364456     Medline TA:  Mol Cell Biochem     Country:  NETHERLANDS    
Other Details:
Languages:  eng     Pagination:  99-111     Citation Subset:  IM    
Affiliation:
Département d'Anatomie et Biologie Cellulaire, Faculté de Médecine, Université de Sherbrooke, Québec, Canada.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Descriptor/Qualifier:
Animals
Blotting, Northern
Blotting, Western
Cell Fractionation
Cell Line
Cell Transformation, Neoplastic / genetics
Epithelial Cells / drug effects,  metabolism*
Gene Expression Regulation / drug effects*
Glucocorticoids / antagonists & inhibitors,  pharmacology*
Intestinal Mucosa / cytology,  drug effects,  metabolism*
Macromolecular Substances
Nuclear Proteins / analysis
Proto-Oncogene Proteins c-fos / biosynthesis*,  genetics
Proto-Oncogene Proteins p21(ras) / genetics,  physiology*
RNA, Messenger / analysis
Rats
Transcription Factor AP-1 / chemistry,  metabolism
Transfection
Chemical
Reg. No./Substance:
0/Glucocorticoids; 0/Macromolecular Substances; 0/Nuclear Proteins; 0/Proto-Oncogene Proteins c-fos; 0/RNA, Messenger; 0/Transcription Factor AP-1; EC 3.6.5.2/Proto-Oncogene Proteins p21(ras)

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


Previous Document:  Arginine vasopressin increases the rate of protein synthesis in isolated perfused adult rat heart vi...
Next Document:  Transport and metabolism of exogenous fumarate and 3-phosphoglycerate in vascular smooth muscle.