scholarly journals JunB contributes to Id2 repression and the epithelial–mesenchymal transition in response to transforming growth factor–β

2012 ◽  
Vol 196 (5) ◽  
pp. 589-603 ◽  
Author(s):  
Megan Gervasi ◽  
Anna Bianchi-Smiraglia ◽  
Michael Cummings ◽  
Qiao Zheng ◽  
Dan Wang ◽  
...  

The process of epithelial–mesenchymal transition (EMT) in response to transforming growth factor–β (TGF-β) contributes to tissue fibrosis, wound healing, and cancer via a mechanism that is not fully understood. This study identifies a critical role of JunB in the EMT and profibrotic responses to TGF-β. Depletion of JunB by small interfering ribonucleic acid abrogates TGF-β–induced disruption of cell–cell junctions, formation of actin fibers, focal adhesions, and expression of fibrotic proteins. JunB contributes to Smad-mediated repression of inhibitor of differentiation 2 through interaction with transcription repressor activating transcription factor 3. Importantly, JunB mediates the TGF-β induction of profibrotic response factors, fibronectin, fibulin-2, tropomyosin (Tpm1), and integrin-β3, which play critical roles in matrix deposition, cell–matrix adhesion, and actin stress fibers. In summary, JunB provides important input in setting the transcriptional program of the EMT and profibrotic responses to TGF-β. Thus, JunB represents an important target in diseases associated with EMT, including cancer and fibrosis.

2021 ◽  
Vol 19 (4) ◽  
pp. 501-507
Author(s):  
Yunhe Gu ◽  
Peiyao Guo ◽  
Guangbiao Xu

Transforming growth factor-β1 promotes excessive extracellular matrix deposition and epithelial-mesenchymal transition of tubular epithelial cells, thus stimulating the progression of renal fibrosis. Carvacrol has been shown to alleviate cardiac and liver fibrosis and attenuate renal injury. However, the role of carvacrol on renal fibrosis has not been examined. First, measurements using Cell Counting Kit-8 showed that carvacrol reduced cell viability of tubular epithelial cell line HK-2 in a dose-dependent fashion. Second, transforming growth factor-β1 induced excessive extracellular matrix deposition in HK-2 cells with enhanced collagen I, collagen IV, and fibronectin expression. However, carvacrol decreased the expression of collagen I, collagen IV in a dose-dependent manner and fibronectin to attenuate the extracellular matrix deposition in HK-2. Third, carvacrol attenuated TGF-β1-induced decrease of E-cadherin and increase of snail, vimentin, and alpha-smooth muscle actin in HK-2 cells. Transforming growth factor-β1-induced increase in PI3K and AKT phosphorylation in HK-2 were also reversed by carvacrol. Collectively, carvacrol ameliorates renal fibrosis through inhibition of transforming growth factor-β1-induced extracellular matrix deposition and epithelial-mesenchymal transition of HK-2 cells, providing potential therapy for the treatment of renal fibrosis.


2018 ◽  
Vol 19 (11) ◽  
pp. 3672 ◽  
Author(s):  
Yutaro Tsubakihara ◽  
Aristidis Moustakas

Metastasis of tumor cells from primary sites of malignancy to neighboring stromal tissue or distant localities entails in several instances, but not in every case, the epithelial-mesenchymal transition (EMT). EMT weakens the strong adhesion forces between differentiated epithelial cells so that carcinoma cells can achieve solitary or collective motility, which makes the EMT an intuitive mechanism for the initiation of tumor metastasis. EMT initiates after primary oncogenic events lead to secondary secretion of cytokines. The interaction between tumor-secreted cytokines and oncogenic stimuli facilitates EMT progression. A classic case of this mechanism is the cooperation between oncogenic Ras and the transforming growth factor β (TGFβ). The power of TGFβ to mediate EMT during metastasis depends on versatile signaling crosstalk and on the regulation of successive waves of expression of many other cytokines and the progressive remodeling of the extracellular matrix that facilitates motility through basement membranes. Since metastasis involves many organs in the body, whereas EMT affects carcinoma cell differentiation locally, it has frequently been debated whether EMT truly contributes to metastasis. Despite controversies, studies of circulating tumor cells, studies of acquired chemoresistance by metastatic cells, and several (but not all) metastatic animal models, support a link between EMT and metastasis, with TGFβ, often being a common denominator in this link. This article aims at discussing mechanistic cases where TGFβ signaling and EMT facilitate tumor cell dissemination.


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