Tp53-Associated Growth Arrest and DNA Damage Repair Gene Expression Is Attenuated in Mammary Epithelial Cells of Rats Fed Whey Proteins

Abstract Recent studies in breast cancer cell lines have shown that oncostatin M (OSM) not only inhibits proliferation but also promotes cell detachment and enhances cell motility. In this study, we have looked at the role of OSM signaling in nontransformed mouse mammary epithelial cells in vitro using the KIM-2 mammary epithelial cell line and in vivo using OSM receptor (OSMR)-deficient mice. OSM and its receptor were up-regulated approximately 2 d after the onset of postlactational mammary regression, in response to leukemia inhibitory factor (LIF)-induced signal transducer and activator of transcription-3 (STAT3). This resulted in sustained STAT3 activity, increased epithelial apoptosis, and enhanced clearance of epithelial structures during the remodeling phase of mammary involution. Concurrently, OSM signaling precipitated the dephosphorylation of STAT5 and repressed expression of the milk protein genes β-casein and whey acidic protein (WAP). Similarly, during pregnancy, OSM signaling suppressed β-casein and WAP gene expression. In vitro, OSM but not LIF persistently down-regulated phosphorylated (p)-STAT5, even in the continued presence of prolactin. OSM also promoted the expression of metalloproteinases MMP3, MMP12, and MMP14, which, in vitro, were responsible for OSM-specific apoptosis. Thus, the sequential activation of IL-6-related cytokines during mammary involution culminates in an OSM-dependent repression of epithelial-specific gene expression and the potentiation of epithelial cell extinction mediated, at least in part, by the reciprocal regulation of p-STAT5 and p-STAT3.

Download Full-text

Influence of a reconstituted basement membrane and its components on casein gene expression and secretion in mouse mammary epithelial cells.

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.84.1.136 ◽

1987 ◽

Vol 84 (1) ◽

pp. 136-140 ◽

Cited By ~ 312

Author(s):

M. L. Li ◽

J. Aggeler ◽

D. A. Farson ◽

C. Hatier ◽

J. Hassell ◽

...

Keyword(s):

Gene Expression ◽

Epithelial Cells ◽

Basement Membrane ◽

Mammary Epithelial Cells ◽

Mammary Epithelial ◽

Casein Gene

Download Full-text

Cyclooxygenase-2 Gene Expression is Upregulated in Transformed Mammary Epithelial Cells

Annals of the New York Academy of Sciences ◽

10.1111/j.1749-6632.1997.tb48606.x ◽

1997 ◽

Vol 833 (1 Cancer) ◽

pp. 179-185 ◽

Cited By ~ 9

Author(s):

KOTHA SUBBARAMAIAH ◽

NITIN TELANG ◽

MEENA B. BANSAL ◽

BABETTE B. WEKSLER ◽

ANDREW J. DANNENBERG

Keyword(s):

Gene Expression ◽

Epithelial Cells ◽

Mammary Epithelial Cells ◽

Cyclooxygenase 2 ◽

Mammary Epithelial

Download Full-text

FISH-based analysis of 10- and 25-kV soft X-ray–induced DNA damage in 184A1 human mammary epithelial cells

Radiation and Environmental Biophysics ◽

10.1007/s00411-011-0396-3 ◽

2011 ◽

Vol 51 (1) ◽

pp. 33-42 ◽

Cited By ~ 1

Author(s):

E. Beyreuther ◽

W. Dörr ◽

A. Lehnert ◽

E. Leßmann ◽

J. Pawelke

Keyword(s):

Dna Damage ◽

Epithelial Cells ◽

Mammary Epithelial Cells ◽

Mammary Epithelial ◽

X Ray ◽

Human Mammary Epithelial Cells ◽

Human Mammary Epithelial

Download Full-text

Tenascin-C inhibits extracellular matrix-dependent gene expression in mammary epithelial cells. Localization of active regions using recombinant tenascin fragments

Journal of Cell Science ◽

10.1242/jcs.108.2.519 ◽

1995 ◽

Vol 108 (2) ◽

pp. 519-527 ◽

Cited By ~ 6

Author(s):

P.L. Jones ◽

N. Boudreau ◽

C.A. Myers ◽

H.P. Erickson ◽

M.J. Bissell

Keyword(s):

Gene Expression ◽

Extracellular Matrix ◽

Protein Synthesis ◽

Epithelial Cells ◽

Mammary Epithelial Cells ◽

Active Regions ◽

Mammary Epithelial ◽

Dependent Manner ◽

Beta Casein ◽

Casein Protein

The physiological role of tenascin in vivo has remained obscure. Although tenascin is regulated in a stage and tissue-dependent manner, knock-out mice appear normal. When tenascin expression was examined in the normal adult mouse mammary gland, little or none was present during lactation, when epithelial cells actively synthesize and secrete milk proteins in an extracellular matrix/lactogenic hormone-dependent manner. In contrast, tenascin was prominently expressed during involution, a stage characterized by the degradation of the extracellular matrix and the subsequent loss of milk production. Studies with mammary cell lines indicated that tenascin expression was high on plastic, but was suppressed in the presence of the laminin-rich, Engelbreth-Holm-Swarm (EHS) tumour biomatrix. When exogenous tenascin was added together with EHS to mammary epithelial cells, beta-casein protein synthesis and steady-state mRNA levels were inhibited in a concentration-dependent manner. Moreover, this inhibition by tenascin could be segregated from its effects on cell morphology. Using two beta-casein promoter constructs attached to the chloramphenicol acetyltransferase reporter gene we showed that tenascin selectively suppressed extracellular matrix/prolactin-dependent transcription of the beta-casein gene in three-dimensional cultures. Finally, we mapped the active regions within the fibronectin type III repeat region of the tenascin molecule that are capable of inhibiting beta-casein protein synthesis. Our data are consistent with a model where both the loss of a laminin-rich basement membrane by extracellular matrix-degrading enzymes and the induction of tenascin contribute to the loss of tissue-specific gene expression and thus the involuting process.

Download Full-text

Gene expression of six major milk proteins in primary bovine mammary epithelial cells isolated from milk during the first twenty weeks of lactation

Czech Journal of Animal Science ◽

10.17221/6347-cjas ◽

2012 ◽

Vol 57 (No. 10) ◽

pp. 469-480 ◽

Cited By ~ 15

Author(s):

T. Sigl ◽

H.H.D. Meyer ◽

S. Wiedemann

Keyword(s):

Gene Expression ◽

Epithelial Cells ◽

Milk Protein ◽

Protein Gene ◽

Mammary Epithelial Cells ◽

Mammary Epithelial ◽

Milk Protein Gene ◽

Bovine Mammary Epithelial Cells ◽

Milk Protein Genes ◽

Milk Protein Gene Expression

The objective of the present study was to refine a previously developed method to isolate primary bovine mammary epithelial cells (pBMEC) from fresh milk. Using this method, it was tested whether the number of pBMEC and the relation of recovered pBMEC to total somatic cell count vary within the individual lactation stages. Furthermore, the expression levels of the milk protein genes during the first twenty weeks of lactation were determined by quantitative PCR method. A total number of 152 morning milk samples were obtained from twenty-four Holstein-Friesian cows during the first 20 weeks of lactation (day 8, 15, 26, 43, 57, 113, and 141 postpartum). Numbers of extracted pBMEC were consistent at all time-points (1.1 ± 0.06 to 1.4 ± 0.03 ×103/ml) and an average value of RNA integrity number (RIN) was 6.3 ± 0.3. Percentage of pBMEC in relation to total milk cells (2.0 ± 0.2 to 6.7 ± 1.0%) correlated with milk yield. Expression patterns of the casein genes alpha (α)S1, (α)S2, beta (β), and kappa (κ) (CSN1S1, CSN1S2, CSN2, CSN3, respectively) and the whey protein genes α-lactalbumin (LALBA) and progestagen-associated endometrial protein (PAEP; known as β-lactoglobulin) were shown to be comparable, i.e. transcripts of all six milk protein genes were found to peak during the first two weeks of lactation and to decline continuously towards mid lactation. However, mRNA levels were different among genes with CSN3 showing the highest and LALBA the lowest abundance. We hypothesized that milk protein gene expression has a pivotal effect on milk protein composition with no influence on milk protein concentration. This paper is the first to describe milk protein gene expression during lactation in pBMEC collected in milk. Future studies will be needed to understand molecular mechanisms in pBMEC including regulation of expression and translation throughout lactation.

Download Full-text