scholarly journals Oncogenic Ras Downregulates Rac Activity, Which Leads to Increased Rho Activity and Epithelial–Mesenchymal Transition

2000 ◽  
Vol 149 (4) ◽  
pp. 775-782 ◽  
Author(s):  
Gerben C.M. Zondag ◽  
Eva E. Evers ◽  
Jean P. ten Klooster ◽  
Lennert Janssen ◽  
Rob A. van der Kammen ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Epithelial Mesenchymal Transition ◽  
Mdck Cells ◽  
Ras Signaling ◽  
Morphological Transformation ◽  
Mesenchymal Transition ◽  
Oncogenic Ras ◽  
Epithelial Phenotype ◽  
Rho Family ◽  
Cytoskeletal Rearrangements

Proteins of the Rho family regulate cytoskeletal rearrangements in response to receptor stimulation and are involved in the establishment and maintenance of epithelial cell morphology. We recently showed that Rac is able to downregulate Rho activity and that the reciprocal balance between Rac and Rho activity is a major determinant of cellular morphology and motility in NIH3T3 fibroblasts. Using biochemical pull-down assays, we analyzed the effect of transient and sustained oncogenic Ras signaling on the activation state of Rac and Rho in epithelial MDCK cells. In contrast to the activation of Rac by growth factor-induced Ras signaling, we found that sustained signaling by oncogenic RasV12 permanently downregulates Rac activity, which leads to upregulation of Rho activity and epithelial–mesenchymal transition. Oncogenic Ras decreases Rac activity through sustained Raf/MAP kinase signaling, which causes transcriptional downregulation of Tiam1, an activator of Rac in epithelial cells. Reconstitution of Rac activity by expression of Tiam1 or RacV12 leads to downregulation of Rho activity and restores an epithelial phenotype in mesenchymal RasV12- or RafCAAX-transformed cells. The present data reveal a novel mechanism by which oncogenic Ras is able to interfere with the balance between Rac and Rho activity to achieve morphological transformation of epithelial cells.

scholarly journals In Vitro Effect of Estradiol and Progesterone on Ovine Amniotic Epithelial Cells

2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Annunziata Mauro ◽  
Hashimita Sanyal ◽  
Angelo Canciello ◽  
Paolo Berardinelli ◽  
Valentina Russo ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Epithelial Mesenchymal Transition ◽  
Biological Properties ◽  
Mesenchymal Transition ◽  
Amniotic Epithelial Cells ◽  
Epithelial Phenotype ◽  
High Doses ◽  
Vitro Effect ◽  
The Impact

Amniotic epithelial cells (AECs), an emerging source of extrafoetal stem cells, have recently attracted attention for their great regenerative potential. Since AEC amplifications are accompanied by the loss of their native epithelial phenotype and by the progressive reduction of relevant biological properties, the issue to be addressed is the development of effective culture protocols. In this context, recently, it has been demonstrated that progesterone (P4) supplementation during ovine AEC (oAEC) expansion could prevent the undesirable epithelial-mesenchymal transition (EMT). In contrast, there is no information to date on the role of the other pregnancy steroids in culture. With this aim, the present study has been designed to clarify the impact of estradiol (E2), alone or in combination with P4 (12.5 μM and 25 μM), during oAEC amplification. Steroid supplementations were assessed by testing oAEC proliferation, stemness, EMT, and osteogenic or chondrogenic plasticity. The results indicated that EMT can be prevented exclusively in the presence of high doses of P4, while it occurred rapidly in cells exposed to E2 as denoted by protein (cytokeratin-8 and alpha-SMA) and gene expression (vimentin and snail) profiles. Moreover, steroid exposure was able to influence highly oAEC plasticity. Particularly, P4-treated cells displayed a precommitment towards osteogenic lineage, confirmed by the upregulation of OCN, RUNX2, and the greater deposition of calcium nodules. Conversely, P4 exposure inhibited oAEC chondrogenic differentiation, which was induced in E2-treated cells as confirmed by the upregulation of chondrogenesis-related genes (SOX9, ACAN, and COL2A1) and by the accumulation of Alcian blue-positive extracellular matrix. Simultaneously, E2-treated cells remained unresponsive to osteogenic inductive stimuli. In conclusion, media supplementation with high doses of steroids may be adopted to modulate phenotype and plasticity during oAEC amplification. Relevantly, the osteo or chondro steroid-induced precommitment may open unprecedented cell-based therapies to face the unsolved orthopaedic issues related to osteochondral regeneration.

scholarly journals Semaphorin-7a reverses the ERF-induced inhibition of EMT in Ras-dependent mouse mammary epithelial cells

2012 ◽  
Vol 23 (19) ◽  
pp. 3873-3881 ◽  
Author(s):  
Maryline Allegra ◽  
Andreas Zaragkoulias ◽  
Elena Vorgia ◽  
Marina Ioannou ◽  
Gabriele Litos ◽  
...  
Keyword(s):  
Growth Factor ◽  
Epithelial Cells ◽  
Molecular Mechanisms ◽  
Transforming Growth Factor ◽  
Mammary Epithelial Cells ◽  
Mammary Epithelial ◽  
Ras Signaling ◽  
Collagen Gels ◽  
Mesenchymal Transition ◽  
Oncogenic Ras

Epithelial-to-mesenchymal transition (EMT) is a key process in cancer progression and metastasis, requiring cooperation of the epidermal growth factor/Ras with the transforming growth factor-β (TGF-β) signaling pathway in a multistep process. The molecular mechanisms by which Ras signaling contributes to EMT, however, remain elusive to a large extent. We therefore examined the transcriptional repressor Ets2-repressor factor (ERF)—a bona fide Ras–extracellular signal-regulated kinase/mitogen-activated protein kinase effector—for its ability to interfere with TGF-β–induced EMT in mammary epithelial cells (EpH4) expressing oncogenic Ras (EpRas). ERF-overexpressing EpRas cells failed to undergo TGF-β–induced EMT, formed three-dimensional tubular structures in collagen gels, and retained expression of epithelial markers. Transcriptome analysis indicated that TGF-β signaling through Smads was mostly unaffected, and ERF suppressed the TGF-β–induced EMT via Semaphorin-7a repression. Forced expression of Semaphorin-7a in ERF-overexpressing EpRas cells reestablished their ability to undergo EMT. In contrast, inhibition of Semaphorin-7a in the parental EpRas cells inhibited their ability to undergo TGF-β–induced EMT. Our data suggest that oncogenic Ras may play an additional role in EMT via the ERF, regulating Semaphorin-7a and providing a new interconnection between the Ras- and the TGF-β–signaling pathways.

scholarly journals NF-κB–Dependent Snail Expression Promotes Epithelial–Mesenchymal Transition in Mastitis

Animals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3422
Author(s):  
Haokun Liu ◽  
Ying Zhao ◽  
Yanfang Wu ◽  
Yutong Yan ◽  
Xiaoe Zhao ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Signaling Pathway ◽  
Epithelial Mesenchymal Transition ◽  
Mammary Epithelial Cells ◽  
Mesenchymal Cell ◽  
Vital Role ◽  
Morphological Transformation ◽  
Snail Expression ◽  
Mesenchymal Transition

Mastitis is a common and important clinical disease in ruminants. This may be associated with inflammatory fibrosis if not treated promptly. Inflammation-derived fibrosis is usually accompanied by epithelial–mesenchymal transition (EMT) in epithelial cells. However, the precise molecular mechanism underlying mastitis-induced fibrosis remains unclear. Nuclear factor kappa-B (NF-κB) and Snail are key regulators of EMT. In this study, primary goat mammary epithelial cells (GMECs) were treated with 10 μg/mL lipopolysaccharide (LPS) for 14 d to mimic the in vivo mastitis environment. After LPS treatment, the GMECs underwent mesenchymal morphological transformation and expressed mesenchymal cell markers. Snail expression was induced by LPS and was inhibited by suppression of the TLR4/NF-κB signaling pathway. Snail knockdown alleviated LPS-induced EMT and altered the expression of inflammatory cytokines. Finally, we found that the expression of key molecules of the TLR4/NF-κB/Snail signaling pathway was increased in mastitis tissues. These results suggest that Snail plays a vital role in LPS-induced EMT in GMECs and that the mechanism is dependent on the activation of the TLR4/NF-κB signaling pathway.

scholarly journals Galectin-8 induces partial epithelial–mesenchymal transition with invasive tumorigenic capabilities involving a FAK/EGFR/proteasome pathway in Madin–Darby canine kidney cells

2018 ◽  
Vol 29 (5) ◽  
pp. 557-574 ◽  
Author(s):  
Claudia Oyanadel ◽  
Christopher Holmes ◽  
Evelyn Pardo ◽  
Claudio Retamal ◽  
Ronan Shaughnessy ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Plasminogen Activator ◽  
Epithelial Mesenchymal Transition ◽  
Mdck Cells ◽  
Urokinase Plasminogen Activator ◽  
Madin Darby Canine Kidney ◽  
Mesenchymal Transition ◽  
Β1 Integrins ◽  
Darby Canine Kidney ◽  
Canine Kidney

Epithelial cells can acquire invasive and tumorigenic capabilities through epithelial–mesenchymal-transition (EMT). The glycan-binding protein galectin-8 (Gal-8) activates selective β1-integrins involved in EMT and is overexpressed by certain carcinomas. Here we show that Gal-8 overexpression or exogenous addition promotes proliferation, migration, and invasion in nontumoral Madin–Darby canine kidney (MDCK) cells, involving focal-adhesion kinase (FAK)-mediated transactivation of the epidermal growth factor receptor (EGFR), likely triggered by α5β1integrin binding. Under subconfluent conditions, Gal-8–overexpressing MDCK cells (MDCK-Gal-8H) display hallmarks of EMT, including decreased E-cadherin and up-regulated expression of vimentin, fibronectin, and Snail, as well as increased β-catenin activity. Changes related to migration/invasion included higher expression of α5β1 integrin, extracellular matrix-degrading MMP13 and urokinase plasminogen activator/urokinase plasminogen activator receptor (uPA/uPAR) protease systems. Gal-8–stimulated FAK/EGFR pathway leads to proteasome overactivity characteristic of cancer cells. Yet MDCK-Gal-8Hcells still develop apical/basolateral polarity reverting EMT markers and proteasome activity under confluence. This is due to the opposite segregation of Gal-8 secretion (apical) and β1-integrins distribution (basolateral). Strikingly, MDCK-Gal-8Hcells acquired tumorigenic potential, as reflected in anchorage-independent growth in soft agar and tumor generation in immunodeficient NSG mice. Therefore, Gal-8 can promote oncogenic-like transformation of epithelial cells through partial and reversible EMT, accompanied by higher proliferation, migration/invasion, and tumorigenic properties.

scholarly journals Different macrophages equally induce EMT in endometria of adenomyosis and normal

Reproduction ◽  
2017 ◽  
Vol 154 (1) ◽  
pp. 79-92 ◽  
Author(s):  
Min An ◽  
Dong Li ◽  
Ming Yuan ◽  
Qiuju Li ◽  
Lu Zhang ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Transforming Growth Factor ◽  
Epithelial Mesenchymal Transition ◽  
Quantitative Polymerase Chain Reaction ◽  
Immunohistochemical Analysis ◽  
Secretory Phase ◽  
Normal Endometrium ◽  
Mesenchymal Transition ◽  
Expression Levels ◽  
Endometrial Cells

Endometrial cells and microenvironment are two important factors in the pathogenesis of adenomyosis. Our previous study demonstrated that macrophages can induce eutopic epithelial cells of adenomyosis to suffer from epithelial–mesenchymal transition (EMT). The aim of this study is to detect whether macrophages interacting with epithelial cells equally induce the EMT process in normal and eutopic endometria of healthy and adenomyotic patients; and whether macrophages parallelly polarize to M2. We investigated the expression levels of epithelial cadherin (E-cadherin), neural cadherin (N-cadherin), cytokeratin7 (CK7), vimentin, transforming growth factor-β1 (TGFB1), SMAD3 and pSMAD3 using immunohistochemistry and western blot, and then estimated the genetic levels of CD163, IL10 and MMP12 using real-time quantitative polymerase chain reaction (RT-PCR) in macrophages. Eutopic and normal endometrial tissues were obtained from 20 patients with adenomyosis and 11 control patients without adenomyosis, respectively. The immunohistochemical analysis shows distinct EMT in eutopic endometria in secretory phase; the expression levels of TGFB1, SMAD3 and pSMAD3 that indicate signal pathway of EMT were also higher in secretory phase. Macrophages can induce EMT process in primary endometrial epithelial cells derived from normal and eutopic endometria. After co-culturing, THP-1-derived macrophages polarized to M2. Compared with the eutopic endometrium group, further polarization to M2 was observed in the normal endometrium group. These results indicate that adenomyosis may be promoted by the pathologic EMT of epithelial cells, which is induced by macrophages that incapably polarize to M2.

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