Open AccessCCAAT/Enhancer Binding Protein Beta Regulates Stem Cell Activity and Specifies Luminal Cell Fate in the Mammary Gland
Author(s) -
LaMarca Heather L.,
Visbal Adriana P.,
Creighton Chad J.,
Liu Hao,
Zhang Yiqun,
Behbod Fariba,
Rosen Jeffrey M.
Publication year - 2010
Publication title -
stem cells
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.159
H-Index - 229
eISSN - 1549-4918
pISSN - 1066-5099
DOI - 10.1002/stem.297
Subject(s) - biology , stem cell , progenitor cell , ccaat enhancer binding proteins , transplantation , transcription factor , microbiology and biotechnology , cell fate determination , cellular differentiation , null cell , foxo3 , mammary gland , cancer research , medicine , cell culture , gene , genetics , cancer , nuclear protein , breast cancer
The bZIP transcription factor C/EBPβ is important for mammary gland development and its expression is deregulated in human breast cancer. To determine whether C/EBPβ regulates mammary stem cells (MaSCs), we employed two different knockout strategies. Using both a germline and a conditional knockout strategy, we demonstrate that mammosphere formation was significantly decreased in C/EBPβ‐deficient mammary epithelial cells (MECs). Functional limiting dilution transplantation assays indicated that the repopulating ability of C/EBPβ‐deleted MECs was severely impaired. Serial transplantation experiments demonstrated that C/EBPβ deletion resulted in decreased outgrowth potential and premature MaSC senescence. In accord, fluorescence‐activated cell sorting analysis demonstrated that C/EBPβ‐null MECs contained fewer MaSCs, the loss of luminal progenitors and an increase in differentiated luminal cells as compared with wild‐type. Gene profiling of C/EBPβ‐null stem cells revealed an alteration in cell fate specification, exemplified by the expression of basal markers in the luminal compartment. Thus, C/EBPβ is a critical regulator of both MaSC repopulation activity and luminal cell lineage commitment. These findings have critical implications for understanding both stem cell biology and the etiology of different breast cancer subtypes. S TEM C ELLS 2010;28:535–544