scholarly journals Substratum stiffness tunes membrane voltage in mammary epithelial cells

2021 ◽  
Author(s):  
Brian B. Silver ◽  
Sherry X. Zhang ◽  
Emann M. Rabie ◽  
Celeste M. Nelson
Keyword(s):  
Epithelial Cells ◽  
Mammary Epithelial Cells ◽  
Critical Role ◽  
Mammary Epithelial ◽  
Membrane Voltage ◽  
Normal Mammary Gland ◽  
Transmembrane Conductance Regulator ◽  
Chloride Currents ◽  
Microenvironmental Condition ◽  
Cellular Behaviors

Membrane voltage (Vm) plays a critical role in the regulation of several cellular behaviors, including proliferation, apoptosis, and phenotypic plasticity. Many of these same behaviors are affected by the stiffness of the underlying extracellular matrix, but the connections between Vm and the mechanical properties of the microenvironment are unclear. Here, we investigated the relationship between matrix stiffness and Vm by culturing mammary epithelial cells on synthetic substrata, the stiffnesses of which mimicked those of the normal mammary gland and breast tumors. Although proliferation is associated with depolarization, we surprisingly observed that cells are hyperpolarized when cultured on stiff substrata, a microenvironmental condition that enhances proliferation. Accordingly, we found that Vm becomes depolarized as stiffness decreases, in a manner dependent on intracellular calcium. Furthermore, inhibiting calcium-gated chloride currents abolishes the effects of substratum stiffness on Vm. Specifically, we uncovered a role for cystic fibrosis transmembrane conductance regulator (CFTR) in the regulation of Vm by substratum stiffness. Together, these results suggest a novel role for CFTR and membrane voltage in the response of mammary epithelial cells to their mechanical microenvironment.

Molecular Characterization of Epithelial to Mesenchymal Transition in Human Prostatic Epithelial Cells

2010 ◽  
Vol 1 (2) ◽  
Author(s):  
Victor K. Lin ◽  
Shih-Ya Wang ◽  
Lanxiao Wu ◽  
Smitha M. Rao ◽  
J. C. Chiao ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Cancer Metastasis ◽  
Epithelial To Mesenchymal Transition ◽  
Mammary Epithelial Cells ◽  
Critical Role ◽  
Three Dimensional ◽  
Mammary Epithelial ◽  
Mesenchymal Transition ◽  
Enhanced Mobility ◽  
E Cadherin

Epithelial to mesenchymal transition (EMT) has been believed to play a critical role in cancer metastasis. TGFβ has been described as an inducer of EMT in normal mammary epithelial cells by signaling through receptor serine/threonine kinase pathways to regulate epithelial cell plasticity and invasion. In this study, we investigated the EMT cellular responses, including morphologic changes, phenotype switches, invasiveness enhancement, and cellular contraction alteration, in TGFβ stimulated human prostate normal epithelial cells (PZ-HPV-7). Migration of TGFβ treated PZ-HPV-7 cells across matrigel was measured in invasion chambers (8 μm pore size). The cells were treated with or without TGFβ (2 ng/ml) in PrEGM media for 3 days. Immunoblot assay was conducted and it was demonstrated that the induction of vimentin when stimulated by TGFβ was accompanied by a downregulation of E-cadherin, though p-cadherin level was not altered. It was also observed that there was a decrease in cytokaretin 5/6 expression associated with the downregulation of E-cadherin during the induction of EMT. In order to study the cell contraction, three-dimensional collage lattice assay was performed. It was demonstrated that TGFβ-stimulated PZ-HPV-7 cells gained contractility. Our results showed that TGFβ stimulation induced PZ-HPV-7 cells to undergo epithelial to mesenchymal transition. EMT characteristics such as acquisition of mesenchymal markers and loss of epithelial markers were evident in the induction of vimentin and downregulation of E-cadherin and cytokeratins, as well as phenotypic alterations including increased contraction and enhanced mobility were detected.

scholarly journals Integrin Signaling in Mammary Epithelial Cells and Breast Cancer

ISRN Oncology ◽  
2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Arthur W. Lambert ◽  
Sait Ozturk ◽  
Sam Thiagalingam
Keyword(s):  
Breast Cancer ◽  
Epithelial Cells ◽  
Intracellular Signaling ◽  
Mammary Epithelial Cells ◽  
Mammary Epithelial ◽  
Integrin Signaling ◽  
Normal Mammary Gland ◽  
Integrin Receptors ◽  
Sense And Respond

Cells sense and respond to the extracellular matrix (ECM) by way of integrin receptors, which facilitate cell adhesion and intracellular signaling. Advances in understanding the mammary epithelial cell hierarchy are converging with new developments that reveal how integrins regulate the normal mammary gland. But in breast cancer, integrin signaling contributes to the development and progression of tumors. This paper highlights recent studies which examine the role of integrin signaling in mammary epithelial cells and their malignant counterparts.

scholarly journals MicroRNA in the ovine mammary gland during early pregnancy: spatial and temporal expression of miR-21, miR-205, and miR-200

2013 ◽  
Vol 45 (4) ◽  
pp. 151-161 ◽  
Author(s):  
Laurent Galio ◽  
Stéphanie Droineau ◽  
Patrick Yeboah ◽  
Hania Boudiaf ◽  
Stephan Bouet ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Mammary Gland ◽  
Epithelial Cells ◽  
Early Pregnancy ◽  
Mammary Epithelial Cells ◽  
Mammary Epithelial ◽  
Normal Mammary Gland ◽  
Basal Cells ◽  
Pregnancy And Lactation ◽  
Luminal Cells

The mammary gland undergoes extensive remodeling between the beginning of pregnancy and lactation; this involves cellular processes including cell proliferation, differentiation, and apoptosis, all of which are under the control of numerous regulators. To unravel the role played by miRNA, we describe here 47 new ovine miRNA cloned from mammary gland in early pregnancy displaying strong similarities with those already identified in the cow, human, or mouse. A microarray study of miRNA variations in the adult ovine mammary gland during pregnancy and lactation showed that 100 miRNA are regulated according to three principal patterns of expression: a decrease in early pregnancy, a peak at midpregnancy, or an increase throughout late pregnancy and lactation. One miRNA displaying each pattern (miR-21, miR-205, and miR-200b) was analyzed by qRT-PCR. Variations in expression were confirmed for all three miRNA. Using in situ hybridization, we detected both miR-21 and miR-200 in luminal mammary epithelial cells when expressed, whereas miR-205 was expressed in basal cells during the first half of pregnancy and then in luminal cells during the second half. We therefore conclude that miR-21 is strongly expressed in the luminal cells of the normal mammary gland during early pregnancy when extensive cell proliferation occurs. In addition, we show that miR-205 and miR-200 are coexpressed in luminal cells, but only during the second half of pregnancy. These two miRNA may cooperate to maintain epithelial status by repressing an EMT-like program, to achieve and preserve the secretory phenotype of mammary epithelial cells.

scholarly journals C-terminal domain small phosphatase-like 2 promotes epithelial-to-mesenchymal transition via Snail dephosphorylation and stabilization

Open Biology ◽  
2018 ◽  
Vol 8 (4) ◽  
pp. 170274 ◽  
Author(s):  
Yulan Zhao ◽  
Jinquan Liu ◽  
Fenfang Chen ◽  
Xin-Hua Feng
Keyword(s):  
Gene Expression ◽  
Epithelial Cells ◽  
Epithelial To Mesenchymal Transition ◽  
Mammary Epithelial Cells ◽  
Critical Role ◽  
Mesenchymal Cell ◽  
Cellular Reprogramming ◽  
Mammary Epithelial ◽  
Mesenchymal Transition ◽  
Proteasome Degradation

The epithelial-to-mesenchymal transition (EMT) is a cellular reprogramming process converting epithelial cells into mesenchymal cell morphology. Snail is a critical regulator of EMT by both suppressing epithelial gene expression and promoting mesenchymal gene expression. Expression and activity of Snail are tightly controlled at transcriptional and post-translational levels. It has previously been reported that Snail undergoes phosphorylation and ubiquitin-dependent proteasome degradation. Here, we report nuclear phosphatase SCP4/CTDSPL2 acts as a novel Snail phosphatase. SCP4 physically interacts with and directly dephosphorylates Snail. SCP4-mediated dephosphorylation of Snail suppresses the ubiquitin-dependent proteasome degradation of Snail and consequently enhances TGFβ-induced EMT. The knockdown of SCP4 in MCF10A mammary epithelial cells leads to attenuated cell migration. Collectively, our finding demonstrates that SCP4 plays a critical role in EMT through Snail dephosphorylation and stabilization.

Mnt represses epithelial identity to promote Epithelial to Mesenchymal Transition

2021 ◽  
Author(s):  
Deborah P. Lavin ◽  
Leila Abassi ◽  
Mohammed Inayatullah ◽  
Vijay K. Tiwari
Keyword(s):  
Epithelial Cells ◽  
Cell Fate ◽  
Cancer Metastasis ◽  
Epithelial To Mesenchymal Transition ◽  
Mammary Epithelial Cells ◽  
Morphological Changes ◽  
Critical Role ◽  
Chromatin Accessibility ◽  
Mammary Epithelial ◽  
Mesenchymal Transition

The multi-step process of epithelial to mesenchymal transition (EMT), whereby static epithelial cells become migratory mesenchymal cells, plays a critical role during various developmental contexts, wound healing, and pathological conditions such as cancer metastasis. Despite the established function of basic helix-loop-helix (bHLH) transcription factors (TFs) in cell-fate determination, only a few have been examined for their role in EMT. Here, using transcriptome analysis of distinct stages during stepwise progression of TGFβ-induced EMT in mammary epithelial cells, we revealed distinct categories of bHLH TFs that show differential expression kinetics during EMT. Using a siRNA-mediated functional screen for bHLH TFs during EMT, we found Max network transcription repressor (MNT) to be essential for EMT in mammary epithelial cells. We show that the depletion of MNT blocks TGFβ-induced morphological changes during EMT, and this is accompanied by de-repression of a large number of epithelial genes. We show that MNT mediates the repression of epithelial identity genes during EMT by recruiting HDAC1 and mediating the loss of H3K27ac and chromatin accessibility. Lastly, we show that MNT is expressed at higher levels in EMT-High breast cancer cells and is required for their migration. Taken together, these findings establish MNT as a critical regulator of cell-fate changes during mammary EMT.

scholarly journals mTORC2 Regulates Lipogenic Gene Expression through PPARγ to Control Lipid Synthesis in Bovine Mammary Epithelial Cells

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Zhixin Guo ◽  
Keyu Zhao ◽  
Xue Feng ◽  
Dandan Yan ◽  
Ruiyuan Yao ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Proliferation ◽  
Epithelial Cells ◽  
Mammary Epithelial Cells ◽  
Critical Role ◽  
Lipid Synthesis ◽  
Mammary Epithelial ◽  
Lipogenic Gene ◽  
Bovine Mammary Epithelial Cells ◽  
Lipogenic Gene Expression

The mechanistic target of rapamycin complex 2 (mTORC2) primarily functions as an effector of insulin/PI3K signaling to regulate cell proliferation and is associated with cell metabolism. However, the function of mTORC2 in lipid metabolism is not well understood. In the present study, mTORC2 was inactivated by the ATP-competitive mTOR inhibitor AZD8055 or shRNA targeting RICTOR in primary bovine mammary epithelial cells (pBMECs). MTT assay was performed to examine the effect of AZD8055 on cell proliferation. ELISA assay and GC-MS analysis were used to determine the content of lipid. The mRNA and protein expression levels were investigated by RT/real-time PCR and western blot analysis, respectively. We found that cell proliferation, mTORC2 activation, and lipid secretion were inhibited by AZD8055. RICTOR was knocked down and mTORC2 activation was specifically attenuated by the shRNA. Compared to control cells, the expression of the transcription factor gene PPARG and the lipogenic genes LPIN1, DGAT1, ACACA, and FASN was downregulated in RICTOR silencing cells. As a result, the content of intracellular triacylglycerol (TAG), palmitic acid (PA), docosahexaenoic acid (DHA), and other 16 types of fatty acid was decreased in the treated cells; the accumulation of TAG, PA, and DHA in cell culture medium was also reduced. Overall, mTORC2 plays a critical role in regulating lipogenic gene expression, lipid synthesis, and secretion in pBMECs, and this process probably is through PPARγ. This finding provides a model by which lipogenesis is regulated in pBMECs.

scholarly journals Laminin alpha 5 regulates mammary gland remodeling through luminal cell differentiation and Wnt4-mediated epithelial crosstalk

Development ◽  
2021 ◽  
Vol 148 (12) ◽  
Author(s):  
Johanna I. Englund ◽  
Alexandra Ritchie ◽  
Leander Blaas ◽  
Hanne Cojoc ◽  
Nalle Pentinmikko ◽  
...  
Keyword(s):  
Mammary Gland ◽  
Epithelial Cells ◽  
Mammary Epithelial Cells ◽  
Branching Morphogenesis ◽  
Mammary Epithelial ◽  
Normal Mammary Gland ◽  
Reduced Frequency ◽  
Luminal Cells ◽  
Vitro Model

ABSTRACT Epithelial attachment to the basement membrane (BM) is essential for mammary gland development, yet the exact roles of specific BM components remain unclear. Here, we show that Laminin α5 (Lama5) expression specifically in the luminal epithelial cells is necessary for normal mammary gland growth during puberty, and for alveologenesis during pregnancy. Lama5 loss in the keratin 8-expressing cells results in reduced frequency and differentiation of hormone receptor expressing (HR+) luminal cells. Consequently, Wnt4-mediated crosstalk between HR+ luminal cells and basal epithelial cells is compromised during gland remodeling, and results in defective epithelial growth. The effects of Lama5 deletion on gland growth and branching can be rescued by Wnt4 supplementation in the in vitro model of branching morphogenesis. Our results reveal a surprising role for BM-protein expression in the luminal mammary epithelial cells, and highlight the function of Lama5 in mammary gland remodeling and luminal differentiation.

scholarly journals Co-expression of transcription factor AP-2beta (TFAP2B) and GATA3 in human mammary epithelial cells with intense, apicobasal immunoreactivity for CK8/18

2021 ◽  
Author(s):  
M. Raap ◽  
L. Gierendt ◽  
C. Werlein ◽  
E. Kuehnle ◽  
H. H. Kreipe ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Hormone Receptors ◽  
Mammary Epithelial Cells ◽  
Lobular Carcinoma ◽  
Epithelial Differentiation ◽  
Mammary Epithelial ◽  
Normal Mammary Gland ◽  
Stem Cell Markers ◽  
Normal Breast Epithelium ◽  
Differentiation Marker

AbstractAP-2β is a new mammary epithelial differentiation marker and its expression is preferentially retained and enhanced in lobular carcinoma in situ and invasive lobular breast cancer. In normal breast epithelium AP-2β is expressed in a scattered subpopulation of luminal cells. So far, these cells have not been further characterized. Co-expression of AP-2β protein and luminal epithelium markers (GATA3, CK8/18), hormone receptors [estrogen receptor (ER), androgen receptor (AR)] and candidate stem cells markers (CK5/14, CD44) were assessed by double-immunofluorescence staining in normal mammary gland epithelium. The subpopulation of AP-2β-positive mammary epithelial cells showed an almost complete, superimposable co-expression with GATA3 and a peculiar intense, ring-like appearing immunoreactivity for CK8/18. Confocal immunofluorescence microscopy revealed an apicobasal staining for CK8/18 in AP-2β-positive cells, which was not seen in in AP-2β-negative cells. Furthermore, AP-2β-positive displayed a partial co-expression with ER and AR, but lacked expression of candidate stem cell markers CK5/14 and CD44. In summary, AP-2β is a new luminal mammary epithelial differentiation marker, which is expressed in the GATA3-positive subpopulation of luminal epithelial cells. These AP-2β-positive/GATA3-positive cells also show a peculiar CK8/18-expression which may indicate a previously unknown functionally specialized mammary epithelial cell population.

scholarly journals Laminin alpha 5 is Necessary for Mammary Epithelial Growth and Function by Maintaining Luminal Epithelial Cell Identity

2019 ◽  
Author(s):  
Johanna I Englund ◽  
Hanne Cojoc ◽  
Leander Blaas ◽  
Alexandra Ritchie ◽  
Nalle Pentinmikko ◽  
...  
Keyword(s):  
Mammary Gland ◽  
Epithelial Cells ◽  
Mammary Epithelial Cells ◽  
Mammary Epithelial ◽  
Normal Mammary Gland ◽  
Hormone Receptor Positive ◽  
And Function ◽  
Gland Development ◽  
Luminal Epithelial Cells ◽  
Basal Epithelial Cells

ABSTRACTEpithelial attachment to the basement membrane (BM) is essential for mammary gland development, yet the exact roles of specific BM components remain unclear. Here, we demonstrate that expression of distinct laminin α-isoforms by luminal and basal mammary epithelial cells enforces lineage identity that is necessary for normal mammary gland growth and function. Laminin α5 (LMα5) is mainly expressed by the luminal epithelial cells, and it is necessary for pubertal mammary gland growth, pregnancy induced gland remodeling, and for alveolar function. Adhesion to LMα5 containing laminin promotes luminal traits in both luminal and basal epithelial cells, and reduces progenitor activity of basal epithelial cells. Mechanistically, we show that Lama5 loss interferes with differentiation of hormone receptor positive luminal cells, which results in reduced Wnt4 expression and defective crosstalk between luminal and basal epithelial cells during gland remodeling. Our results reveal a novel BM-mediated mechanism, which regulates mammary gland remodeling and function via specification of luminal epithelial cells.

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