scholarly journals Conversion of Helicobacter pylori CagA from senescence inducer to oncogenic driver through polarity-dependent regulation of p21

2010 ◽  
Vol 207 (10) ◽  
pp. 2157-2174 ◽  
Author(s):  
Yasuhiro Saito ◽  
Naoko Murata-Kamiya ◽  
Toshiya Hirayama ◽  
Yusuke Ohba ◽  
Masanori Hatakeyama
Keyword(s):  
Helicobacter Pylori ◽  
Epithelial Cells ◽  
Kinase Inhibitor ◽  
Epithelial Mesenchymal Transition ◽  
Critical Role ◽  
Nucleotide Exchange ◽  
Mesenchymal Transition ◽  
Erk Activation ◽  
Cyclin Dependent Kinase Inhibitor ◽  
Polarized Epithelial Cells

The Helicobacter pylori CagA bacterial oncoprotein plays a critical role in gastric carcinogenesis. Upon delivery into epithelial cells, CagA causes loss of polarity and activates aberrant Erk signaling. We show that CagA-induced Erk activation results in senescence and mitogenesis in nonpolarized and polarized epithelial cells, respectively. In nonpolarized epithelial cells, Erk activation results in oncogenic stress, up-regulation of the p21Waf1/Cip1 cyclin-dependent kinase inhibitor, and induction of senescence. In polarized epithelial cells, CagA-driven Erk signals prevent p21Waf1/Cip1 expression by activating a guanine nucleotide exchange factor–H1–RhoA–RhoA-associated kinase–c-Myc pathway. The microRNAs miR-17 and miR-20a, induced by c-Myc, are needed to suppress p21Waf1/Cip1 expression. CagA also drives an epithelial-mesenchymal transition in polarized epithelial cells. These findings suggest that CagA exploits a polarity-signaling pathway to induce oncogenesis.

TGF-β-induced EMT: mechanisms and implications for fibrotic lung disease

2007 ◽  
Vol 293 (3) ◽  
pp. L525-L534 ◽  
Author(s):  
Brigham C. Willis ◽  
Zea Borok
Keyword(s):  
Epithelial Cells ◽  
Lung Disease ◽  
Transforming Growth Factor ◽  
Epithelial Mesenchymal Transition ◽  
Critical Role ◽  
Alveolar Epithelial Cells ◽  
Mesenchymal Transition ◽  
Fibrotic Lung Disease

Epithelial-mesenchymal transition (EMT), a process whereby fully differentiated epithelial cells undergo transition to a mesenchymal phenotype giving rise to fibroblasts and myofibroblasts, is increasingly recognized as playing an important role in repair and scar formation following epithelial injury. The extent to which this process contributes to fibrosis following injury in the lung is a subject of active investigation. Recently, it was demonstrated that transforming growth factor (TGF)-β induces EMT in alveolar epithelial cells (AEC) in vitro and in vivo, and epithelial and mesenchymal markers have been colocalized to hyperplastic type II (AT2) cells in lung tissue from patients with idiopathic pulmonary fibrosis (IPF), suggesting that AEC may exhibit extreme plasticity and serve as a source of fibroblasts and/or myofibroblasts in lung fibrosis. In this review, we describe the characteristic features of EMT and its mechanistic underpinnings. We further describe the contribution of EMT to fibrosis in adult tissues following injury, focusing especially on the critical role of TGF-β and its downstream mediators in this process. Finally, we highlight recent descriptions of EMT in the lung and the potential implications of this process for the treatment of fibrotic lung disease. Treatment for fibrosis of the lung in diseases such as IPF has heretofore focused largely on amelioration of potential inciting processes such as inflammation. It is hoped that this review will stimulate further consideration of the cellular mechanisms of fibrogenesis in the lung and especially the role of the epithelium in this process, potentially leading to innovative avenues of investigation and treatment.

scholarly journals EGF-Mediated Overexpression of Myc Attenuates miR-26b by Recruiting HDAC3 to Induce Epithelial-Mesenchymal Transition of Lens Epithelial Cells

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Ning Dong ◽  
Bing Xu ◽  
Jingmei Xu
Keyword(s):  
Epithelial Cells ◽  
Egf Receptor ◽  
Epithelial Mesenchymal Transition ◽  
Critical Role ◽  
Luciferase Reporter ◽  
Human Lens ◽  
Lens Epithelial Cells ◽  
Egfr Signaling ◽  
Mesenchymal Transition ◽  
And Migration

The previous study has demonstrated that epidermal growth factor (EGF) and EGF receptor (EGFR) signaling plays a critical role in the development of posterior capsule opacification (PCO) through regulating lens epithelial cells (LECs) proliferation. Recent studies have suggested that the residual LECs undergo proliferation and migration, and epithelial-mesenchymal transition (EMT) is the important cause of PCO formation after cataract surgery. EMT of LECs is considered to be playing a central role in the pathogenesis of PCO. In the present study, we investigated whether and how EGF may regulate EMT of LECs. First, we demonstrated that EGF and EGFR signaling induces Myc overexpression in primary human lens epithelial cells (HLECs). In turn, Myc overexpression could inhibit miR-26b by recruitment of HDAC3. Consequently, the downregulated expression of miR-26b increased the expression of EZH2 in primary HLECs. Mechanistically, miR-26b directly controls EZH2 expression by targeting its 3′-UTR in HLECs by luciferase reporter assays. Finally, we demonstrated that EGF induces the expression of EMT markers in primary HLECs via a miR-26b-dependent mechanism. In summary, EGF activated Myc and Myc overexpression inhibited miR-26b by recruitment of HDAC3, which in turn induced the expression of EZH2 and promoted the progression of EMT in HLECs.

Expression of the cyclin-dependent kinase inhibitor p27kip1 is reduced in gastric epithelial cells of patients with helicobacter pylori-induced gastritis

2000 ◽  
Vol 118 (4) ◽  
pp. A763
Author(s):  
Haim Shirin ◽  
Yuichi Kawabata ◽  
Hanina Hibshoosh ◽  
Dorin Andrescu ◽  
I. Bernard Weinstein ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Epithelial Cells ◽  
Kinase Inhibitor ◽  
Gastric Epithelial Cells ◽  
Cyclin Dependent Kinase ◽  
Cyclin Dependent Kinase Inhibitor

scholarly journals Crk Adapter Proteins Promote an Epithelial–Mesenchymal-like Transition and Are Required for HGF-mediated Cell Spreading and Breakdown of Epithelial Adherens Junctions

2002 ◽  
Vol 13 (5) ◽  
pp. 1449-1461 ◽  
Author(s):  
Louie Lamorte ◽  
Isabelle Royal ◽  
Monica Naujokas ◽  
Morag Park
Keyword(s):  
Epithelial Cells ◽  
Epithelial Mesenchymal Transition ◽  
Adherens Junctions ◽  
Critical Role ◽  
Cell Spreading ◽  
Dominant Negative ◽  
Dominant Negative Mutant ◽  
Adapter Proteins ◽  
Mesenchymal Transition ◽  
Hepatocyte Growth

Activation of the Met receptor tyrosine kinase through its ligand, hepatocyte growth factor (HGF), promotes an epithelial–mesenchymal transition and cell dispersal. However, little is known about the HGF-dependent signals that regulate these events. HGF stimulation of epithelial cell colonies leads to the enhanced recruitment of the CrkII and CrkL adapter proteins to Met-dependent signaling complexes. We provide evidence that signals involving CrkII and CrkL are required for the breakdown of adherens junctions, the spreading of epithelial colonies, and the formation of lamellipodia in response to HGF. The overexpression of a CrkI SH3 domain mutant blocks these HGF-dependent events. In addition, the overexpression of CrkII or CrkL promotes lamellipodia formation, loss of adherens junctions, cell spreading, and dispersal of colonies of breast cancer epithelial cells in the absence of HGF. Stable lines of epithelial cells overexpressing CrkII show enhanced activation of Rac1 and Rap1. The Crk-dependent breakdown of adherens junctions and cell spreading is inhibited by the expression of a dominant negative mutant of Rac1 but not Rap1. These findings provide evidence that Crk adapter proteins play a critical role in the breakdown of adherens junctions and the spreading of sheets of epithelial cells.

Epithelial-mesenchymal transition of biliary epithelial cells during cholestatic fibrosis

2007 ◽  
Vol 45 (01) ◽  
Author(s):  
F Schulze ◽  
E Konze ◽  
K Petmecky ◽  
K Schardt ◽  
O Dirsch ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Epithelial Mesenchymal Transition ◽  
Mesenchymal Transition ◽  
Biliary Epithelial Cells

Roles of Helicobacter pylori in the Epithelial-Mesenchymal Transition of Gastric Cancer

2020 ◽  
Vol 04 (04) ◽  
Author(s):  
Shuai Ruan ◽  
Wenjie Huang ◽  
Fang Wen ◽  
Xiaona Lu ◽  
Su Ping Gu ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Helicobacter Pylori ◽  
Epithelial Mesenchymal Transition ◽  
Mesenchymal Transition
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