Characterization of mammary epithelial cell line HC11 using the NIA 15k gene array reveals potential regulators of the undifferentiated and differentiated phenotypes.
Differentiation of undifferentiated mammary epithelial stem and/or progenitor cells results in the production of luminal-ductal and myoepithelial cells in the young animal and upon pregnancy, the production of luminal alveolar cells. A few key regulators of differentiation have been identified, though it is not known yet how these proteins function together to achieve their well-orchestrated products. In an effort to identify regulators of early differentiation, we screened the NIA 15k gene array of 15,247 developmentally expressed genes using mouse mammary epithelial HC11 cells as a model of differentiation. We have confirmed a number of genes preferentially expressed in the undifferentiated cells (Lgals1, Ran, Jam-A and Bmpr1a) and in those induced to undergo differentiation (Id1, Nfkbiz, Trib1, Rps21, Ier3). Using antibodies to the proteins encoded by Lgals1, and Jam-A, we confirmed that their proteins levels were higher in the undifferentiated cells. Although the amounts of bone morphogenetic protein receptor-1A (BMPR1A) protein were present at all stages, we found the activity of its downstream signal transduction pathway, as measured by the presence of phosphorylated-SMAD1, -SMAD5, and -SMAD8, is elevated in undifferentiated cells and decreases in fully differentiated cells. This evidence supports that the BMPR1A pathway functions primarily in undifferentiated mammary epithelial cells. We have identified a number of genes, of known and unknown function, that are candidates for the maintenance of the undifferentiated phenotype and for early regulators of mammary alveolar cell differentiation.
Perotti
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Department of Biological Sciences, University of Calgary, 2500 University Drive, N.W. Calgary, AB, Canada T2N 1N4.
Wiedl
T
T
Florin
L
L
Reuter
H
H
Moffat
S
S
Silbermann
M
M
Hahn
M
M
Angel
P
P
Shemanko
C S
CS
D000818:Animals; D052005:Bone Morphogenetic Protein Receptors, Type I / Q000378:metabolism; D002454:Cell Differentiation; D002460:Cell Line; D015870:Gene Expression; D008321:Mammary Glands, Animal / Q000166:cytology* / Q000378:metabolism*; D051379:Mice; D054561:National Institute on Aging (U.S.); D020411:Oligonucleotide Array Sequence Analysis; D015398:Signal Transduction; D014481:United States
C498212:Bmpr1a protein, mouse; D052005:Bone Morphogenetic Protein Receptors, Type I