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Lactogenic hormones and Tenascin‐C regulate C/EBPα and β in mammary epithelial cells
Author(s) -
Cella Nathalie,
ChiquetEhrismann Ruth,
Hynes Nancy E.
Publication year - 2000
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/(sici)1097-4644(20000301)76:3<394::aid-jcb7>3.0.co;2-b
Subject(s) - ccaat enhancer binding proteins , biology , cell growth , transcription factor , prolactin , extracellular matrix , fibronectin , tenascin c , microbiology and biotechnology , medicine , hormone , endocrinology , nuclear protein , gene , biochemistry
Mammary epithelial cell differentiation depends on lactogenic hormones, growth factors, and cell‐cell and cell‐substrate interactions, all of which modulate transcription factors essential for milk protein gene expression. The CCAAT/enhancer binding protein (C/EBP) family and the signal transducer and activator of transcription 5 (Stat5) have been implicated in mammary epithelial cell growth and differentiation. We have investigated the effects of extracellular matrix components and lactogenic hormones on C/EBP and Stat5 activity. In the mammary gland, tenascin is expressed mainly during embryogenesis and carcinogenesis and in cell culture tenascin downregulates β‐casein gene expression. In HC11 mammary cells, we found that tenascin, but not laminin or fibronectin, specifically downregulated C/EBPα levels but had no effect on Stat5 amount or DNA binding activity. Furthermore, we found that the lactogenic hormones, glucocorticoids, prolactin, and insulin, had no effect on C/EBPα and C/EBPβ protein levels but downregulated the DNA binding activity of the transcriptional repressor C/EBPβLIP. Thus, C/EBPα and β are regulated by tenascin and lactogenic hormones in mammary epithelial cells. J. Cell. Biochem. 76:394–403, 2000. © 2000 Wiley‐Liss, Inc.