bcl-2 over-expression enhances NF-kappaB activity and induces mmp-9 transcription in human MCF7(ADR) breast-cancer cells.
Int J Cancer
; 86(2): 188-96, 2000 Apr 15.
Article
em En
| MEDLINE
| ID: mdl-10738245
ABSTRACT
bcl-2 expression is often associated with poor prognosis in several types of tumors; however, the role of this molecule in breast cancer is still controversial. We found earlier that over-expression of bcl-2 in a human breast-cancer cell line (MCF7(ADR)) enhances its tumorigenicity and metastatic potential by inducing metastasis-associated properties such as increased secretion of the matrix metalloproteinase-9 (mmp-9). In the present study, we investigated the effect of bcl-2 over-expression on the activity of the transcription factor NF-kappaB, an important regulator of genes involved in tumor progression and invasion. Transient transfection experiments indicate that over-expression of bcl-2 in the MCF7(ADR) cell line, enhances NF-kappaB-dependent transcriptional activity. Mobility-shift analysis revealed an increase of NF-kappaB DNA-binding in bcl-2-over-expressing clones that correlated with lower levels of the NF-kappaB cytoplasmic inhibitor IkappaBalpha. Moreover, point mutations of 2 highly conserved residues within the BH1 and BH2 domains that abrogate the interaction of bcl-2 with bax, or deletion of the N-terminal BH4 domain, completely eliminate the ability of this molecule to up-regulate NF-kappaB-dependent transactivation. Since mmp-9 is a NF-kappaB-regulated gene, we also investigated whether bcl-2 over-expression up-regulated mmp-9 transcription. We found that induction of mmp-9 mRNA correlates with the activation of an mmp-9-promoter-reporter-gene construct in transient transfection assay, and a mutation of the (-600)mmp-9-NF-kappaB binding element abolishes this effect. The overall data indicate that bcl-2-mediated regulation of NF-kappaB-transcription-factor activity may represent an important mechanism for the promotion of malignant behavior in MCF-7(ADR) cells.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Transcrição Gênica
/
Neoplasias da Mama
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Expressão Gênica
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NF-kappa B
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Genes bcl-2
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Metaloproteinase 9 da Matriz
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Proteínas I-kappa B
Tipo de estudo:
Prognostic_studies
Limite:
Humans
Idioma:
En
Revista:
Int J Cancer
Ano de publicação:
2000
Tipo de documento:
Article
País de afiliação:
Itália
País de publicação:
EEUU
/
ESTADOS UNIDOS
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ESTADOS UNIDOS DA AMERICA
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EUA
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UNITED STATES
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UNITED STATES OF AMERICA
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US
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USA