scholarly journals Quantitative Imaging of Epithelial Cell Scattering Identifies Specific Inhibitors of Cell Motility and Cell-Cell Dissociation

2012 ◽  
Vol 5 (231) ◽  
pp. rs5-rs5 ◽  
Author(s):  
D. Loerke ◽  
Q. le Duc ◽  
I. Blonk ◽  
A. Kerstens ◽  
E. Spanjaard ◽  
...  
Keyword(s):  
Epithelial Cell ◽  
Cell Motility ◽  
Quantitative Imaging ◽  
Cell Dissociation ◽  
Cell Scattering ◽  
Specific Inhibitors ◽  
Cell Cell

Ras induces NBT-II epithelial cell scattering through the coordinate activities of Rac and MAPK pathways

2002 ◽  
Vol 115 (12) ◽  
pp. 2591-2601 ◽  
Author(s):  
Natacha Edme ◽  
Julian Downward ◽  
Jean-Paul Thiery ◽  
Brigitte Boyer
Keyword(s):  
Cell Migration ◽  
Cell Motility ◽  
Mapk Pathway ◽  
Small Gtpase ◽  
Dominant Negative Mutant ◽  
Cell Periphery ◽  
Cell Dissociation ◽  
Downstream Targets ◽  
Cell Dispersion ◽  
Cell Scattering

Cell dissociation and cell migration are the two main components of epithelium-mesenchyme transitions (EMT). We previously demonstrated that Ras is required for the accomplishment of both of these processes during the EGF-induced EMT of the NBT-II rat carcinoma cell line in vitro. In this study,we examined the downstream targets of Ras that are responsible for the dissociation and motility of NBT-II cells. Overexpression of activated forms of c-Raf and MEK1 (a component of the mitogen-activated protein kinase pathway, MAPK) led to cell dissociation, as inferred by the loss of desmosomes from the cell periphery. By contrast, active PI3K, RalA and RalB did not induce desmosome breakdown. The MEK1 inhibitor PD098059 inhibited EGF- and Ras-induced cell dispersion, whereas the PI3K inhibitor LY294002 had no effect. Accordingly, among the partial loss-of-function mutants of Ras(RasV12) that were used to distinguish between downstream targets of Ras, we found that the Raf-specific Ras mutants RasV12S35 and RasV12E38 induced cell dissociation. The PI3K- and RalGDS-activating Ras mutants had, in contrast, no effect on cell dispersion. However, MEK1 was unable to promote cell motility,whereas RasV12S35 and RasV12E38 induced cell migration, suggesting that another Ras effector was responsible for cell motility. We found that the small GTPase Rac is necessary for EGF-mediated cell dispersion since overexpression of a dominant-negative mutant of Rac1 (Rac1N17) inhibited EGF-induced NBT-II cell migration. All stimuli that promoted cell migration also induced Rac activation. Finally, coexpression of active Rac1 and active MEK1 induced the motility of NBT-II cells, suggesting that Ras mediates NBT-II cell scattering through the coordinate activation of Rac and the Raf/MAPK pathway.

scholarly journals Protrusive Activity Guides Changes in Cell-Cell Tension during Epithelial Cell Scattering

2014 ◽  
Vol 107 (3) ◽  
pp. 555-563 ◽  
Author(s):  
Venkat Maruthamuthu ◽  
Margaret L. Gardel
Keyword(s):  
Epithelial Cell ◽  
Cell Scattering ◽  
Cell Cell

scholarly journals PTP-PEST controls motility, adherens junction assembly, and Rho GTPase activity in colon cancer cells

2010 ◽  
Vol 299 (2) ◽  
pp. C454-C463 ◽  
Author(s):  
Rosario Espejo ◽  
William Rengifo-Cam ◽  
Michael D. Schaller ◽  
B. Mark Evers ◽  
Sarita K. Sastry
Keyword(s):  
Epithelial Cell ◽  
Cell Motility ◽  
Colon Carcinoma ◽  
Rho Gtpase ◽  
Adherens Junctions ◽  
Adherens Junction ◽  
Carcinoma Cells ◽  
Gtpase Activity ◽  
Colon Carcinoma Cells ◽  
Cell Cell

An important step in carcinoma progression is loss of cell-cell adhesion leading to increased invasion and metastasis. We show here that the protein tyrosine phosphatase, PTP-PEST, is a critical regulator of cell-cell junction integrity and epithelial cell motility. Using colon carcinoma cells, we show that the expression level of PTP-PEST regulates cell motility. Either transient small interfering RNA or stable short hairpin RNA knockdown of PTP-PEST enhances haptotactic and chemotactic migration of KM12C colon carcinoma cells. Furthermore, KM12C cells with stably knocked down PTP-PEST exhibit a mesenchymal-like phenotype with prominent membrane ruffles and lamellae. In contrast, ectopic expression of PTP-PEST in KM20 or DLD-1 cells, which lack detectable endogenous PTP-PEST expression, suppresses haptotactic migration. Importantly, we find that PTP-PEST localizes in adherens junctions. Concomitant with enhanced motility, stable knockdown of PTP-PEST causes a disruption of cell-cell junctions. These effects are due to a defect in junctional assembly and not to a loss of E-cadherin expression. Adherens junction assembly is impaired following calcium switch in KM12C cells with stably knocked down PTP-PEST and is accompanied by an increase in the activity of Rac1 and a suppression of RhoA activity in response to cadherin engagement. Taken together, these results suggest that PTP-PEST functions as a suppressor of epithelial cell motility by controlling Rho GTPase activity and the assembly of adherens junctions.

scholarly journals Helicobacter pylori CagA Induces Cortactin Y-470 Phosphorylation-Dependent Gastric Epithelial Cell Scattering via Abl, Vav2 and Rac1 Activation

Cancers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 4241
Author(s):  
Nicole Tegtmeyer ◽  
Aileen Harrer ◽  
Klemens Rottner ◽  
Steffen Backert
Keyword(s):  
Helicobacter Pylori ◽  
Epithelial Cell ◽  
Cell Motility ◽  
Sh2 Domain ◽  
Small Gtpase ◽  
Gastric Epithelial Cell ◽  
Gastric Epithelium ◽  
Actin Binding ◽  
Cell Scattering ◽  
H Pylori

The pathogen Helicobacter pylori is the first reported bacterial type-1 carcinogen playing a role in the development of human malignancies, including gastric adenocarcinoma. Cancer cell motility is an important process in this scenario, however, the molecular mechanisms are still not fully understood. Here, we demonstrate that H. pylori subverts the actin-binding protein cortactin through its type-IV secretion system and injected oncoprotein CagA, e.g., by inducing tyrosine phosphorylation of cortactin at Y-470, which triggers gastric epithelial cell scattering and motility. During infection of AGS cells, cortactin was discovered to undergo tyrosine dephosphorylation at residues Y-421 and Y-486, which is mediated through inactivation of Src kinase. However, H. pylori also profoundly activates tyrosine kinase Abl, which simultaneously phosphorylates cortactin at Y-470. Phosphorylated cortactin interacts with the SH2-domain of Vav2, a guanine nucleotide exchange factor for the Rho-family of GTPases. The cortactin/Vav2 complex then stimulates a previously unrecognized activation cascade including the small GTPase Rac1, to effect actin rearrangements and cell scattering. We hypothesize that injected CagA targets cortactin to locally open the gastric epithelium in order to get access to certain nutrients. This may disturb the cellular barrier functions, likely contributing to the induction of cell motility, which is important in gastric cancer development.

scholarly journals Integrin-dependent actomyosin contraction regulates epithelial cell scattering

2005 ◽  
Vol 171 (1) ◽  
pp. 153-164 ◽  
Author(s):  
Johan de Rooij ◽  
Andre Kerstens ◽  
Gaudenz Danuser ◽  
Martin A. Schwartz ◽  
Clare M. Waterman-Storer
Keyword(s):  
Cell Adhesion ◽  
Epithelial Cell ◽  
Traction Force ◽  
Time Lapse ◽  
Cell Junctions ◽  
Traction Forces ◽  
Compliant Substrates ◽  
Cell Scattering ◽  
Cell Cell

The scattering of Madin-Darby canine kidney cells in vitro mimics key aspects of epithelial–mesenchymal transitions during development, carcinoma cell invasion, and metastasis. Scattering is induced by hepatocyte growth factor (HGF) and is thought to involve disruption of cadherin-dependent cell–cell junctions. Scattering is enhanced on collagen and fibronectin, as compared with laminin1, suggesting possible cross talk between integrins and cell–cell junctions. We show that HGF does not trigger any detectable decrease in E-cadherin function, but increases integrin-mediated adhesion. Time-lapse imaging suggests that tension on cell–cell junctions may disrupt cell–cell adhesion. Varying the density and type of extracellular matrix proteins shows that scattering correlates with stronger integrin adhesion and increased phosphorylation of the myosin regulatory light chain. To directly test the role of integrin-dependent traction forces, substrate compliance was varied. Rigid substrates that produce high traction forces promoted scattering, in comparison to more compliant substrates. We conclude that integrin-dependent actomyosin traction force mediates the disruption of cell–cell adhesion during epithelial cell scattering.

scholarly journals Proteasome-mediated Degradation of Rac1-GTP during Epithelial Cell Scattering

2006 ◽  
Vol 17 (5) ◽  
pp. 2236-2242 ◽  
Author(s):  
Emma A. Lynch ◽  
Jennifer Stall ◽  
Gudila Schmidt ◽  
Philippe Chavrier ◽  
Crislyn D'Souza-Schorey
Keyword(s):  
Epithelial Cell ◽  
Actin Polymerization ◽  
Actin Dynamics ◽  
Cell Contacts ◽  
Rho Family Gtpases ◽  
Cell Scattering ◽  
Rho Family ◽  
Powerful Mechanism ◽  
Sustained Activation ◽  
Cell Cell

Epithelial cells disassemble their adherens junctions and “scatter” during processes such as tumor cell invasion as well as some stages of embryonic development. Control of actin polymerization is a powerful mechanism for regulating the strength of cell–cell adhesion. In this regard, studies have shown that sustained activation of Rac1, a well-known regulator of actin dynamics, results in the accumulation of polymerized actin at cell–cell contacts in epithelia and an increase in E-cadherin–mediated adhesion. Here we show that active Rac1 is ubiquitinated and subject to proteasome-mediated degradation during the early stages of epithelial cell scattering. These findings delineate a mechanism for the down-regulation of Rac1 in the disassembly of epithelial cell–cell contacts and support the emerging theme that UPS-mediated degradation of the Rho family GTPases may serve as an efficient mechanism for GTPase deactivation in the sustained presence of Dbl-exchange factors.

scholarly journals Involvement of IQGAP1, an Effector of Rac1 and Cdc42 GTPases, in Cell-Cell Dissociation during Cell Scattering

2001 ◽  
Vol 21 (6) ◽  
pp. 2165-2183 ◽  
Author(s):  
Masaki Fukata ◽  
Masato Nakagawa ◽  
Naohiro Itoh ◽  
Aie Kawajiri ◽  
Masaki Yamaga ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Fluorescent Protein ◽  
Dominant Negative ◽  
Dominant Negative Mutant ◽  
Cell Contact ◽  
Cell Dissociation ◽  
Physiological Processes ◽  
Cell Scattering ◽  
Green Fluorescent ◽  
Cell Cell

ABSTRACT We have previously proposed that IQGAP1, an effector of Rac1 and Cdc42, negatively regulates cadherin-mediated cell-cell adhesion by interacting with β-catenin and by causing the dissociation of α-catenin from cadherin–β-catenin–α-catenin complexes and that activated Rac1 and Cdc42 positively regulate cadherin-mediated cell-cell adhesion by inhibiting the interaction of IQGAP1 with β-catenin. However, it remains to be clarified in which physiological processes the Rac1-Cdc42-IQGAP1 system is involved. We here examined whether the Rac1-IQGAP1 system is involved in the cell-cell dissociation of Madin-Darby canine kidney II cells during 12-O-tetradecanoylphorbol-13-acetate (TPA)- or hepatocyte growth factor (HGF)-induced cell scattering. By using enhanced green fluorescent protein (EGFP)-tagged α-catenin, we found that EGFP–α-catenin decreased prior to cell-cell dissociation during cell scattering. We also found that the Rac1-GTP level decreased after stimulation with TPA and that the Rac1-IQGAP1 complexes decreased, while the IQGAP1–β-catenin complexes increased during action of TPA. Constitutively active Rac1 and IQGAP1 carboxyl terminus, a putative dominant-negative mutant of IQGAP1, inhibited the disappearance of α-catenin from sites of cell-cell contact induced by TPA. Taken together, these results indicate that α-catenin is delocalized from cell-cell contact sites prior to cell-cell dissociation induced by TPA or HGF and suggest that the Rac1-IQGAP1 system is involved in cell-cell dissociation through α-catenin relocalization.

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