Id4 regulates mammary epithelial cell growth and differentiation and is overexpressed in rat mammary gland carcinomas.
Am J Pathol
; 163(6): 2495-502, 2003 Dec.
Article
em En
| MEDLINE
| ID: mdl-14633621
ABSTRACT
Id4 belongs to a family of helix-loop-helix (HLH) proteins that impact cellular growth and differentiation via regulation of basic HLH transcription factors. Herein the rat Id4 gene was cloned (GenBank Accession No. AF468681). The expression of rat Id4 was examined in rat mammary gland tumors induced by 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), a carcinogen found in the human diet. By real-time polymerase chain reaction analysis, relative expression of Id4 mRNA in carcinomas, adenomas, and normal tissue was 27, 6, and 1, respectively. Immunohistochemical analysis indicated statistically elevated nuclear expression for Id4 protein in carcinomas in comparison to adenomas and normal mammary gland. In carcinomas, Id4 nuclear expression was positively correlated with proliferation, invasiveness, and tumor weight (Fisher Exact Test or Spearman Correlation, P < 0.05). The consequence of enforced expression of Id4 on mammary epithelial cell proliferation, differentiation, and growth in soft agar was examined in HC11 cells, a well-characterized model for studying various aspects of mammary epithelial cell biology. After transient and stable transfection of HC11 cells, Id4 overexpression increased cell proliferation and inhibited lactogenic hormone-mediated differentiation as revealed by inhibition of beta-casein promoter activity and beta-casein expression. In addition, enforced expression of Id4 in HC11 cells induced a statistically significant increase in colony growth in soft agar. The results implicate Id4 in rat mammary gland carcinogenesis and suggest that Id4 may contribute to carcinogenesis by inhibiting mammary epithelial cell differentiation and stimulating mammary epithelial cell growth.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Fatores de Transcrição
/
Carcinoma
/
Adenoma
/
Proteínas de Ligação a DNA
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Glândulas Mamárias Animais
/
Neoplasias Mamárias Experimentais
Tipo de estudo:
Prognostic_studies
Limite:
Animals
Idioma:
En
Revista:
Am J Pathol
Ano de publicação:
2003
Tipo de documento:
Article
País de afiliação:
Estados Unidos