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Sample records for cell adhesion motility

  1. Mutant p53 in cell adhesion and motility.

    PubMed

    Yeudall, W Andrew; Wrighton, Katharine H; Deb, Sumitra

    2013-01-01

    Pro-oncogenic properties of mutant p53 were investigated with the aid of migration assays, adhesion assays, and soft agar growth assays using cells stably expressing gain-of-function p53 mutants. To determine cell migration, "wound-healing" (scratch) assays and haptotactic (chamber) assays were used. H1299 cells expressing mutant p53 were found to migrate more rapidly than cells transfected with empty vector alone. Results from both types of migration assay were broadly similar. Migratory ability differed for different p53 mutants, suggesting allele-specific effects. Cells expressing p53 mutants also showed enhanced adhesion to extracellular matrix compare to controls. Furthermore, stable transfection of mutant p53-H179L into NIH3T3 fibroblasts was sufficient to allow anchorage-independent growth in soft agar. PMID:23150443

  2. Effects of Adhesion Dynamics and Substrate Compliance on the Shape and Motility of Crawling Cells

    PubMed Central

    Ziebert, Falko; Aranson, Igor S.

    2013-01-01

    Computational modeling of eukaryotic cells moving on substrates is an extraordinarily complex task: many physical processes, such as actin polymerization, action of motors, formation of adhesive contacts concomitant with both substrate deformation and recruitment of actin etc., as well as regulatory pathways are intertwined. Moreover, highly nontrivial cell responses emerge when the substrate becomes deformable and/or heterogeneous. Here we extended a computational model for motile cell fragments, based on an earlier developed phase field approach, to account for explicit dynamics of adhesion site formation, as well as for substrate compliance via an effective elastic spring. Our model displays steady motion vs. stick-slip transitions with concomitant shape oscillations as a function of the actin protrusion rate, the substrate stiffness, and the rates of adhesion. Implementing a step in the substrate’s elastic modulus, as well as periodic patterned surfaces exemplified by alternating stripes of high and low adhesiveness, we were able to reproduce the correct motility modes and shape phenomenology found experimentally. We also predict the following nontrivial behavior: the direction of motion of cells can switch from parallel to perpendicular to the stripes as a function of both the adhesion strength and the width ratio of adhesive to non-adhesive stripes. PMID:23741334

  3. Autocrine netrin function inhibits glioma cell motility and promotes focal adhesion formation.

    PubMed

    Jarjour, Andrew A; Durko, Margaret; Luk, Tamarah L; Marçal, Nathalie; Shekarabi, Masoud; Kennedy, Timothy E

    2011-01-01

    Deregulation of mechanisms that control cell motility plays a key role in tumor progression by promoting tumor cell dissemination. Secreted netrins and their receptors, Deleted in Colorectal Cancer (DCC), neogenin, and the UNC5 homologues, regulate cell and axon migration, cell adhesion, and tissue morphogenesis. Netrin and netrin receptor expression have previously been shown to be disrupted in invasive tumors, including glioblastoma. We determined that the human glioblastoma cell lines U87, U343, and U373 all express neogenin, UNC5 homologues, and netrin-1 or netrin-3, but only U87 cells express DCC. Using transfilter migration assays, we demonstrate DCC-dependent chemoattractant migration of U87 cells up a gradient of netrin-1. In contrast, U343 and U373 cells, which do not express DCC, were neither attracted nor repelled. Ectopic expression of DCC by U343 and U373 cells resulted in these cells becoming competent to respond to a gradient of netrin-1 as a chemoattractant, and also slowed their rate of spontaneous migration. Here, in addition to netrins' well-characterized chemotropic activity, we demonstrate an autocrine function for netrin-1 and netrin-3 in U87 and U373 cells that slows migration. We provide evidence that netrins promote the maturation of focal complexes, structures associated with cell movement, into focal adhesions. Consistent with this, netrin, DCC, and UNC5 homologues were associated with focal adhesions, but not focal complexes. Disrupting netrin or DCC function did not alter cell proliferation or survival. Our findings provide evidence that DCC can slow cell migration, and that neogenin and UNC5 homologues are not sufficient to substitute for DCC function in these cells. Furthermore, we identify a role for netrins as autocrine inhibitors of cell motility that promote focal adhesion formation. These findings suggest that disruption of netrin signalling may disable a mechanism that normally restrains inappropriate cell migration. PMID

  4. Tumor suppressor KAI1 affects integrin {alpha}v{beta}3-mediated ovarian cancer cell adhesion, motility, and proliferation

    SciTech Connect

    Ruseva, Zlatna; Geiger, Pamina Xenia Charlotte; Hutzler, Peter; Kotzsch, Matthias; Luber, Birgit; Schmitt, Manfred; Gross, Eva; Reuning, Ute

    2009-06-10

    The tetraspanin KAI1 had been described as a metastasis suppressor in many different cancer types, a function for which associations of KAI1 with adhesion and signaling receptors of the integrin superfamily likely play a role. In ovarian cancer, integrin {alpha}v{beta}3 correlates with tumor progression and its elevation in vitro provoked enhanced cell adhesion accompanied by significant increases in cell motility and proliferation in the presence of its major ligand vitronectin. In the present study, we characterized integrin {alpha}v{beta}3-mediated tumor biological effects as a function of cellular KAI1 restoration and proved for the first time that KAI1, besides its already known physical crosstalk with {beta}1-integrins, also colocalizes with integrin {alpha}v{beta}3. Functionally, elevated KAI1 levels drastically increased integrin {alpha}v{beta}3/vitronectin-dependent ovarian cancer cell adhesion. Since an intermediate level of cell adhesive strength is required for optimal cell migration, we next studied ovarian cancer cell motility as a function of KAI1 restoration. By time lapse video microscopy, we found impaired integrin {alpha}v{beta}3/vitronectin-mediated cell migration most probably due to strongly enhanced cellular immobilization onto the adhesion-supporting matrix. Moreover, KAI1 reexpression significantly diminished cell proliferation. These data strongly indicate that KAI1 may suppress ovarian cancer progression by inhibiting integrin {alpha}v{beta}3/vitronectin-provoked tumor cell motility and proliferation as important hallmarks of the oncogenic process.

  5. Cadherin-mediated cell adhesion and cell motility in Drosophila trachea regulated by the transcription factor Escargot.

    PubMed

    Tanaka-Matakatsu, M; Uemura, T; Oda, H; Takeichi, M; Hayashi, S

    1996-12-01

    Coordination of cell motility and adhesion is essential for concerted movement of tissues during animal morphogenesis. The Drosophila tracheal network is formed by branching, migration and fusion of tubular ectodermal epithelia. Tracheal tip cells, located at the end of each branch that is going to fuse, extend filopodia to search for targets and later change their cell shape to a seamless ring to allow passage of lumen. The cell adhesion molecule DE-cadherin accumulates at the site of contact to form a ring that marks the site of lumen entry and is essential for the fusion. DE-cadherin expression in tip cells of a subset of branches is dependent on escargot, a zinc finger gene expressed in all tip cells. Such escargot mutant tip cells failed to adhere to each other and continued to search for alternative targets by extending long filopodia. We present evidence indicating escargot positively regulates transcription of the DE-cadherin gene, shotgun. Overexpression of DE-cadherin rescued the defect in one of the fusion points in escargot mutants, demonstrating an essential role of DE-cadherin in target recognition and identifying escargot as a key regulator of cell adhesion and motility in tracheal morphogenesis. PMID:9012491

  6. An Adhesion-Dependent Switch between Mechanisms That Determine Motile Cell Shape

    PubMed Central

    Barnhart, Erin L.; Lee, Kun-Chun; Keren, Kinneret; Mogilner, Alex; Theriot, Julie A.

    2011-01-01

    Keratocytes are fast-moving cells in which adhesion dynamics are tightly coupled to the actin polymerization motor that drives migration, resulting in highly coordinated cell movement. We have found that modifying the adhesive properties of the underlying substrate has a dramatic effect on keratocyte morphology. Cells crawling at intermediate adhesion strengths resembled stereotypical keratocytes, characterized by a broad, fan-shaped lamellipodium, clearly defined leading and trailing edges, and persistent rates of protrusion and retraction. Cells at low adhesion strength were small and round with highly variable protrusion and retraction rates, and cells at high adhesion strength were large and asymmetrical and, strikingly, exhibited traveling waves of protrusion. To elucidate the mechanisms by which adhesion strength determines cell behavior, we examined the organization of adhesions, myosin II, and the actin network in keratocytes migrating on substrates with different adhesion strengths. On the whole, our results are consistent with a quantitative physical model in which keratocyte shape and migratory behavior emerge from the self-organization of actin, adhesions, and myosin, and quantitative changes in either adhesion strength or myosin contraction can switch keratocytes among qualitatively distinct migration regimes. PMID:21559321

  7. Platelet endothelial cell adhesion molecule-1 modulates endothelial cell motility through the small G-protein Rho.

    PubMed

    Gratzinger, Dita; Canosa, Sandra; Engelhardt, Britta; Madri, Joseph A

    2003-08-01

    Platelet endothelial cell adhesion molecule-1 (PECAM-1), an immunoglobulin family vascular adhesion molecule, is involved in endothelial cell migration and angiogenesis (1, 2). We found that endothelial cells lacking PECAM-1 exhibit increased single cell motility and extension formation but poor wound healing migration, reminiscent of cells in which Rho activity has been suppressed by overexpressing a GTPase-activating protein (3). The ability of PECAM-1 to restore wound healing migration to PECAM-1-deficient cells was independent of its extracellular domain or signaling via its immunoreceptor tyrosine-based inhibitory motif. PECAM-1-deficient endothelial cells had a selective defect in RhoGTP loading, and inhibition of Rho activity mimicked the PECAM-1-deficient phenotype of increased chemokinetic single cell motility at the expense of coordinated wound healing migration. The wound healing advantage of PECAM-1-positive endothelial cells was not only Rho mediated but pertussis toxin inhibitable, characteristic of migration mediated by heterotrimeric G-protein-linked seven-transmembrane receptor signaling such as signaling in response to the serum sphingolipid sphingosine-1-phosphate (S1P) (4, 5). Indeed, we found that the wound healing defect of PECAM-1 null endothelial cells is minimized in sphingolipid-depleted media; moreover, PECAM-1 null endothelial cells fail to increase their migration in response to S1P. We have also found that PECAM-1 localizes to rafts and that in its absence heterotrimeric G-protein components are differentially recruited to rafts, providing a potential mechanism for PECAM-1-mediated coordination of S1P signaling. PECAM-1 may thus support the effective S1P/RhoGTP signaling required for wound healing endothelial migration by allowing for the spatially directed, coordinated activation of Galpha signaling pathways. PMID:12890700

  8. Triterpene glycoside cucumarioside A(2)-2 from sea cucumber stimulates mouse immune cell adhesion, spreading, and motility.

    PubMed

    Aminin, Dmitry L; Gorpenchenko, Tatyana Y; Bulgakov, Viktor P; Andryjashchenko, Polina V; Avilov, Sergey A; Kalinin, Vladimir I

    2011-06-01

    Holothurian triterpene glycosides are known to possess multiple biological activities. Here we show that cucumarioside A(2)-2 from the Far-Eastern edible holothurian Cucumaria japonica possesses potent immunomodulatory properties. The present studies were done to determine if cucumarioside A(2)-2 would affect macrophage adhesion, spreading, and motility. Resident peritoneal macrophages, collected from BALB/c mice, were exposed in vitro to low concentrations of cucumarioside A(2)-2 and compared with appropriate controls. Results indicate that 0.02 μg/mL cucumarioside A(2)-2 significantly enhanced macrophage morphology parameters and behavior. The glycoside stimulated these parameters by increasing the number of cells with increased adhesion properties as well as the spreading reaction and motility velocity by at least almost twofold. The data are discussed in terms of possible mechanisms underlying the immunomodulatory properties of cucumarioside A(2)-2. PMID:21554137

  9. Stonin1 mediates endocytosis of the proteoglycan NG2 and regulates focal adhesion dynamics and cell motility

    PubMed Central

    Feutlinske, Fabian; Browarski, Marietta; Ku, Min-Chi; Trnka, Philipp; Waiczies, Sonia; Niendorf, Thoralf; Stallcup, William B.; Glass, Rainer; Krause, Eberhard; Maritzen, Tanja

    2015-01-01

    Cellular functions, ranging from focal adhesion (FA) dynamics and cell motility to tumour growth, are orchestrated by signals cells receive from outside via cell surface receptors. Signalling is fine-tuned by the exo–endocytic cycling of these receptors to control cellular responses such as FA dynamics, which determine cell motility. How precisely endocytosis regulates turnover of the various cell surface receptors remains unclear. Here we identify Stonin1, an endocytic adaptor of unknown function, as a regulator of FA dynamics and cell motility, and demonstrate that it facilitates the internalization of the oncogenic proteoglycan NG2, a co-receptor of integrins and platelet-derived growth factor receptor. Embryonic fibroblasts obtained from Stonin1-deficient mice display a marked surface accumulation of NG2, increased cellular signalling and defective FA disassembly as well as altered cellular motility. These data establish Stonin1 as a specific adaptor for the endocytosis of NG2 and as an important factor for FA dynamics and cell migration. PMID:26437238

  10. Regulation of T-lymphocyte motility, adhesion and de-adhesion by a cell surface mechanism directed by low density lipoprotein receptor-related protein 1 and endogenous thrombospondin-1

    PubMed Central

    Talme, Toomas; Bergdahl, Eva; Sundqvist, Karl-Gösta

    2014-01-01

    T lymphocytes are highly motile and constantly reposition themselves between a free-floating vascular state, transient adhesion and migration in tissues. The regulation behind this unique dynamic behaviour remains unclear. Here we show that T cells have a cell surface mechanism for integrated regulation of motility and adhesion and that integrin ligands and CXCL12/SDF-1 influence motility and adhesion through this mechanism. Targeting cell surface-expressed low-density lipoprotein receptor-related protein 1 (LRP1) with an antibody, or blocking transport of LRP1 to the cell surface, perturbed the cell surface distribution of endogenous thrombospondin-1 (TSP-1) while inhibiting motility and potentiating cytoplasmic spreading on intercellular adhesion molecule 1 (ICAM-1) and fibronectin. Integrin ligands and CXCL12 stimulated motility and enhanced cell surface expression of LRP1, intact TSP-1 and a 130 000 MW TSP-1 fragment while preventing formation of a de-adhesion-coupled 110 000 MW TSP-1 fragment. The appearance of the 130 000 MW TSP-1 fragment was inhibited by the antibody that targeted LRP1 expression, inhibited motility and enhanced spreading. The TSP-1 binding site in the LRP1-associated protein, calreticulin, stimulated adhesion to ICAM-1 through intact TSP-1 and CD47. Shear flow enhanced cell surface expression of intact TSP-1. Hence, chemokines and integrin ligands up-regulate a dominant motogenic pathway through LRP1 and TSP-1 cleavage and activate an associated adhesion pathway through the LRP1–calreticulin complex, intact TSP-1 and CD47. This regulation of T-cell motility and adhesion makes pro-adhesive stimuli favour motile responses, which may explain why T cells prioritize movement before permanent adhesion. PMID:24877199

  11. Human epididymis protein 4 (HE4) plays a key role in ovarian cancer cell adhesion and motility

    SciTech Connect

    Lu, Renquan; Sun, Xinghui; Xiao, Ran; Zhou, Lei; Gao, Xiang; Guo, Lin

    2012-03-09

    Highlights: Black-Right-Pointing-Pointer We generated stable transduced HE4 overexpression and knockdown cells. Black-Right-Pointing-Pointer HE4 was associated with EOC cell adhesion and motility. Black-Right-Pointing-Pointer HE4 might have some effects on activation of EGFR-MAPK signaling pathway. Black-Right-Pointing-Pointer HE4 play an important role in EOC tumorigenicity. -- Abstract: Human epididymis protein 4 (HE4) is a novel and specific biomarker for epithelial ovarian cancer (EOC). We previously demonstrated that serum HE4 levels were significantly elevated in the majority of EOC patients but not in subjects with benign disease or healthy controls. However, the precise mechanism of HE4 protein function is unknown. In this study, we generated HE4-overexpressing SKOV3 cells and found that stably transduced cells promoted cell adhesion and migration. Knockdown of HE4 expression was achieved by stable transfection of SKOV3 cells with a construct encoding a short hairpin DNA directed against the HE4 gene. Correspondingly, the proliferation and spreading ability of HE4-expressed cells were inhibited by HE4 suppression. Mechanistically, impaired EGFR and Erk1/2 phosphorylation were observed in cells with HE4 knockdown. The phosphorylation was restored when the knockdown cells were cultured in conditioned medium containing HE4. Moreover, in vivo tumorigenicity showed that HE4 suppression markedly inhibited the growth of tumors. This suggests that expression of HE4 is associated with cancer cell adhesion, migration and tumor growth, which can be related to its effects on the EGFR-MAPK signaling pathway. Our results provide evidence of the cellular and molecular mechanisms that may underlie the motility-promoting role of HE4 in EOC progression. The role of HE4 as a target for gene-based therapy might be considered in future studies.

  12. Coupling actin flow, adhesion, and morphology in a computational cell motility model

    NASA Astrophysics Data System (ADS)

    Levine, Herbert

    2014-03-01

    Eukaryotic cells crawl by means of the coordinated spatiotemporal dynamics of an active polymer gel, consisting of actin, myosin and regulators thereof. Motility is necessarily coupled to shape, as the force generating mechanisms such as polymerization-based protrusions interact with the elasticity of the cell membrane and thereby determine the cell morphology. We have introduced a ``phase-field'' model of crawling cells, utilizing a mathematical approach originally developed for morphology problems arising in the field of liquid-solid phase transitions. Our model can be used to explain the pattern of traction forces applied to the substrate as well as some recent observations concerning oscillatory instabilities of cells moving on one-dimensional fiber tracks.

  13. Neutrophils lacking platelet-endothelial cell adhesion molecule-1 exhibit loss of directionality and motility in CXCR2-mediated chemotaxis.

    PubMed

    Wu, Yue; Stabach, Paul; Michaud, Michael; Madri, Joseph A

    2005-09-15

    Time-lapsed videomicroscopy was used to study the migration of platelet-endothelial cell adhesion molecule-1-deficient (PECAM-1(-/-)) murine neutrophils undergoing chemotaxis in Zigmond chambers containing IL-8, KC, or fMLP gradients. PECAM-1(-/-) neutrophils failed to translocate up the IL-8, KC, and fMLP gradients. Significant reductions in cell motility and cell spreading were also observed in IL-8 or KC gradients. In wild-type neutrophils, PECAM-1 and F-actin were colocalized at the leading fronts of polarized cells toward the gradient. In contrast, in PECAM-1(-/-) neutrophils, although F-actin also localized to the leading front of migrating cells, F-actin polymerization was unstable, and cycling was remarkably increased compared with that of wild-type neutrophils. This may be due to the decreased cytokine-induced mobilization of the actin-binding protein, moesin, into the cytoskeleton of PECAM-1(-/-) neutrophils. PECAM-1(-/-) neutrophils also exhibited intracellularly dislocalized Src homology 2 domain containing phosphatase 1 (SHP-1) and had less IL-8-induced SHP-1 phosphatase activity. These results suggest that PECAM-1 regulates neutrophil chemotaxis by modulating cell motility and directionality, in part through its effects on SHP-1 localization and activation. PMID:16148090

  14. Mechanics of motility initiation and motility arrest in crawling cells

    NASA Astrophysics Data System (ADS)

    Recho, Pierre; Putelat, Thibaut; Truskinovsky, Lev

    2015-11-01

    Motility initiation in crawling cells requires transformation of a symmetric state into a polarized state. In contrast, motility arrest is associated with re-symmetrization of the internal configuration of a cell. Experiments on keratocytes suggest that polarization is triggered by the increased contractility of motor proteins but the conditions of re-symmetrization remain unknown. In this paper we show that if adhesion with the extra-cellular substrate is sufficiently low, the progressive intensification of motor-induced contraction may be responsible for both transitions: from static (symmetric) to motile (polarized) at a lower contractility threshold and from motile (polarized) back to static (symmetric) at a higher contractility threshold. Our model of lamellipodial cell motility is based on a 1D projection of the complex intra-cellular dynamics on the direction of locomotion. In the interest of analytical transparency we also neglect active protrusion and view adhesion as passive. Despite the unavoidable oversimplifications associated with these assumptions, the model reproduces quantitatively the motility initiation pattern in fish keratocytes and reveals a crucial role played in cell motility by the nonlocal feedback between the mechanics and the transport of active agents. A prediction of the model that a crawling cell can stop and re-symmetrize when contractility increases sufficiently far beyond the motility initiation threshold still awaits experimental verification.

  15. The Shape of Motile Cells

    PubMed Central

    Mogilner, Alex; Keren, Kinneret

    2010-01-01

    Motile cells — fan-like keratocytes, hand-shaped nerve growth cones, polygonal fibroblasts, to name but a few — come in different shapes and sizes. We discuss the origins of this diversity as well as what shape tells us about the physics and biochemistry underlying cell movement. We start with geometric rules describing cell-edge kinetics that govern cell shape, followed by a discussion of the underlying biophysics; we consider actin treadmilling, actin–myosin contraction, cell-membrane deformations, adhesion, and the complex interactions between these modules, as well as their regulation by microtubules and Rho GTPases. Focusing on several different cell types, including keratocytes and fibroblasts, we discuss how dynamic cell morphology emerges from the interplay between the different motility modules and the environment. PMID:19906578

  16. Autophagy Promotes Focal Adhesion Disassembly and Cell Motility of Metastatic Tumor Cells through the Direct Interaction of Paxillin with LC3.

    PubMed

    Sharifi, Marina N; Mowers, Erin E; Drake, Lauren E; Collier, Chris; Chen, Hong; Zamora, Marta; Mui, Stephanie; Macleod, Kay F

    2016-05-24

    Autophagy is a conserved catabolic process that plays a housekeeping role in eliminating protein aggregates and organelles and is activated during nutrient deprivation to generate metabolites and energy. Autophagy plays a significant role in tumorigenesis, although opposing context-dependent functions of autophagy in cancer have complicated efforts to target autophagy for therapeutic purposes. We demonstrate that autophagy inhibition reduces tumor cell migration and invasion in vitro and attenuates metastasis in vivo. Numerous abnormally large focal adhesions (FAs) accumulate in autophagy-deficient tumor cells, reflecting a role for autophagy in FA disassembly through targeted degradation of paxillin. We demonstrate that paxillin interacts with processed LC3 through a conserved LIR motif in the amino-terminal end of paxillin and that this interaction is regulated by oncogenic SRC activity. Together, these data establish a function for autophagy in FA turnover, tumor cell motility, and metastasis. PMID:27184837

  17. Flagellar motility is necessary for Aeromonas hydrophila adhesion.

    PubMed

    Qin, Yingxue; Lin, Guifang; Chen, Wenbo; Xu, Xiaojin; Yan, Qingpi

    2016-09-01

    Adhesion to host surface or cells is the initial step in bacterial pathogenesis, and the adhesion mechanisms of the fish pathogenic bacteria Aeromonas hydrophila were investigated in this study. First, a mutagenesis library of A. hydrophila that contained 332 random insertion mutants was constructed via mini-Tn10 Km mutagenesis. Four mutants displayed the most attenuated adhesion. Sequence analysis revealed that the mini-Tn10 insertion sites in the four mutant strains were flgC(GenBank accession numbers KX261880), cytb4(GenBank accession numbers JN133621), rbsR(GenBank accession numbers KX261881) and flgE(GenBank accession numbers JQ974982). To further study the roles of flgC and flgE in the adhesion of A. hydrophila, some biological characteristics of the wild-type strain B11, the mutants M121 and M240, and the complemented strains C121 and C240 were investigated. The results showed that the mutation in flgC or flgE led to the flagellar motility of A. hydrophila significant reduction or abolishment. flgC was not necessary for flagellar biosynthesis but was necessary for the full motility of A. hydrophila, flgE was involved in both flagellar biosynthesis and motility. The flagellar motility is necessary for A. hydrophila to adhere to the host mucus, which suggests flagellar motility plays crucial roles in the early infection process of this bacterium. PMID:27432325

  18. Cell motility on nanotopography

    NASA Astrophysics Data System (ADS)

    Kimura, Masahiro; Tsai, Irene; Green, Angelo; Jacobson, Bruce; Russell, Thomas

    2003-03-01

    Cell motility is strongly influenced by the structure of the substratum. Understanding cells motility on a surface has significant applications both in vivo and in vitro applications, such as biological sensors and hip replacement. A gradient surface is used to study the effect of the lateral nanotopography on cell motility. A gradient surface is generated by block copolymer and homopolymer blends, where the concentration of the components varies uniformly across the surface. The two homopolymers phase separate on the micron scale and this length scale gradually decrease to the nanoscopic, i.e. microphase separation of the diblock, as the copolymer concentration increases. Quantitative analysis of the speed of cell migration is correlated to the lateral length scale of the surface.

  19. Modeling collective cell motility

    NASA Astrophysics Data System (ADS)

    Rappel, Wouter-Jan

    Eukaryotic cells often move in groups, a critical aspect of many biological and medical processes including wound healing, morphogenesis and cancer metastasis. Modeling can provide useful insights into the fundamental mechanisms of collective cell motility. Constructing models that incorporate the physical properties of the cells, however, is challenging. Here, I discuss our efforts to build a comprehensive cell motility model that includes cell membrane properties, cell-substrate interactions, cell polarity, and cell-cell interaction. The model will be applied to a variety of systems, including motion on micropatterned substrates and the migration of border cells in Drosophila. This work was supported by NIH Grant No. P01 GM078586 and NSF Grant No. 1068869.

  20. Protein 4.1R regulates cell adhesion, spreading, migration and motility of mouse keratinocytes by modulating surface expression of β1 integrin

    PubMed Central

    Chen, Lixiang; Hughes, Richard A.; Baines, Anthony J.; Conboy, John; Mohandas, Narla; An, Xiuli

    2011-01-01

    Protein 4.1R is a membrane-cytoskeleton adaptor protein that has diverse roles in controlling the cell surface expression and/or function of transmembrane proteins, and in organizing F-actin. 4.1R is expressed in keratinocytes, but its role in these cells has not been explored. Here, we have investigated the role of 4.1R in skin using 4.1R−/− mice. Cell adhesion, spreading, migration and motility were significantly impaired in 4.1R−/− keratinocytes, and 4.1R−/− mice exhibited defective epidermal wound healing. Cultured 4.1R−/− keratinocytes on fibronectin failed to form actin stress fibres and focal adhesions. Furthermore, in the absence of 4.1R, the surface expression, and consequently the activity of β1 integrin were reduced. These data enabled the identification of a functional role for protein 4.1R in keratinocytes by modulating the surface expression of β1 integrin, possibly through a direct association between 4.1R and β1 integrin. PMID:21693581

  1. Protein 4.1R regulates cell adhesion, spreading, migration and motility of mouse keratinocytes by modulating surface expression of beta1 integrin.

    PubMed

    Chen, Lixiang; Hughes, Richard A; Baines, Anthony J; Conboy, John; Mohandas, Narla; An, Xiuli

    2011-07-15

    Protein 4.1R is a membrane-cytoskeleton adaptor protein that has diverse roles in controlling the cell surface expression and/or function of transmembrane proteins, and in organizing F-actin. 4.1R is expressed in keratinocytes, but its role in these cells has not been explored. Here, we have investigated the role of 4.1R in skin using 4.1R(-/-) mice. Cell adhesion, spreading, migration and motility were significantly impaired in 4.1R(-/-) keratinocytes, and 4.1R(-/-) mice exhibited defective epidermal wound healing. Cultured 4.1R(-/-) keratinocytes on fibronectin failed to form actin stress fibres and focal adhesions. Furthermore, in the absence of 4.1R, the surface expression, and consequently the activity of β1 integrin were reduced. These data enabled the identification of a functional role for protein 4.1R in keratinocytes by modulating the surface expression of β1 integrin, possibly through a direct association between 4.1R and β1 integrin. PMID:21693581

  2. Targeting tumor cell motility to prevent metastasis

    PubMed Central

    Palmer, Trenis D.; Ashby, William J.; Lewis, John D.; Zijlstra, Andries

    2011-01-01

    Mortality and morbidity in patients with solid tumors invariably results from the disruption of normal biological function caused by disseminating tumor cells. Tumor cell migration is under intense investigation as the underlying cause of cancer metastasis. The need for tumor cell motility in the progression of metastasis has been established experimentally and is supported empirically by basic and clinical research implicating a large collection of migration-related genes. However, there are few clinical interventions designed to specifically target the motility of tumor cells and adjuvant therapy to specifically prevent cancer cell dissemination is severely limited. In an attempt to define motility targets suitable for treating metastasis, we have parsed the molecular determinants of tumor cell motility into five underlying principles including cell autonomous ability, soluble communication, cell-cell adhesion, cell-matrix adhesion, and integrating these determinants of migration on molecular scaffolds. The current challenge is to implement meaningful and sustainable inhibition of metastasis by developing clinically viable disruption of molecular targets that control these fundamental capabilities. PMID:21664937

  3. The cag-pathogenicity island encoded CncR1 sRNA oppositely modulates Helicobacter pylori motility and adhesion to host cells.

    PubMed

    Vannini, Andrea; Roncarati, Davide; Danielli, Alberto

    2016-08-01

    Small regulatory RNAs (sRNAs) are emerging as key post-transcriptional regulators in many bacteria. In the human pathobiont Helicobacter pylori a plethora of trans- and cis-encoded sRNAs have been pinpointed by a global transcriptome study. However, only two have been studied in depth at the functional level. Here we report the characterization of CncR1, an abundant and conserved sRNA encoded by the virulence-associated cag pathogenicity island (cag-PAI) of H. pylori. Growth-phase dependent transcription of CncR1 is directed by the PcagP promoter, which resulted to be a target of the essential transcriptional regulator HsrA (HP1043). We demonstrate that the 213 nt transcript arising from this promoter ends at an intrinsic terminator, few bases upstream of the annotated cagP open reading frame, establishing CncR1 as the predominant gene product encoded by the cagP (cag15) locus. Interestingly, the deletion of the locus resulted in the deregulation en masse of σ(54)-dependent genes, linking CncR1 to flagellar functions. Accordingly, the enhanced motility recorded for cncR1 deletion mutants was complemented by ectopic reintroduction of the allele in trans. In silico prediction identified fliK, encoding a flagellar checkpoint protein, as likely regulatory target of CncR1. The interaction of CncR1 with the fliK mRNA was thus further investigated in vitro, demonstrating the formation of strand-specific interactions between the two RNA molecules. Accordingly, the full-length translational fusions of fliK with a lux reporter gene were induced in a cncR1 deletion mutant in vivo. These data suggest the involvement of CncR1 in the post-transcriptional modulation of H. pylori motility functions through down-regulation of a critical flagellar checkpoint factor. Concurrently, the cncR1 mutant revealed a decrease of transcript levels for several H. pylori adhesins, resulting in a phenotypically significant impairment of bacterial adhesion to a host gastric cell line. The data

  4. Hydrodynamic Contributions to Amoeboid Cell Motility

    NASA Astrophysics Data System (ADS)

    Lewis, Owen; Guy, Robert

    2012-11-01

    Understanding the methods by which cells move is a fundamental problem in modern biology. Recent evidence has shown that the fluid dynamics of cytoplasm can play a vital role in cellular motility. The slime mold Physarum polycephalum provides an excellent model organism for the study of amoeboid motion. In this research, we use a simply analytic model in conjuction with computational experiments to investigate intracellular fluid flow in a simple model of Physarum. Of particlar interest are stresses generated by cytoplasmic flow which may be used to aid in cellular motility. In our numerical model, the Immersed Boundary Method is used to account for such stresses. We investigate the relationship between contraction waves, flow waves, adhesion, and locomotive forces in an attempt to characterize conditions necessary to generate directed motion.

  5. A mechanism for cell motility by active polar gels

    PubMed Central

    Marth, W.; Praetorius, S.; Voigt, A.

    2015-01-01

    We analyse a generic motility model, with the motility mechanism arising by contractile stress due to the interaction of myosin and actin. A hydrodynamic active polar gel theory is used to model the cytoplasm of a cell and is combined with a Helfrich-type model to account for membrane properties. The overall model allows consideration of the motility without the necessity for local adhesion. Besides a detailed numerical approach together with convergence studies for the highly nonlinear free boundary problem, we also compare the induced flow field of the motile cell with that of classical squirmer models and identify the motile cell as a puller or pusher, depending on the strength of the myosin–actin interactions. PMID:25926698

  6. Alternative Splicing in Adhesion- and Motility-Related Genes in Breast Cancer

    PubMed Central

    Aversa, Rosanna; Sorrentino, Anna; Esposito, Roberta; Ambrosio, Maria Rosaria; Amato, Angela; Zambelli, Alberto; Ciccodicola, Alfredo; D’Apice, Luciana; Costa, Valerio

    2016-01-01

    Breast cancer is the most common tumor and the second leading cause of cancer death among woman, mainly caused by the metastatic spread. Tumor invasiveness is due to an altered expression of adhesion molecules. Among them, semaphorins are of peculiar interest. Cancer cells can manipulate alternative splicing patterns to modulate the expression of adhesion- and motility-related molecules, also at the isoform level. In this study, combining RNA-Sequencing on MCF-7 to targeted experimental validations—in human breast cell lines and breast tumor biopsies—we identified 12 new alternative splicing transcripts in genes encoding adhesion- and motility-related molecules, including semaphorins, their receptors and co-receptors. Among them, a new SEMA3F transcript is expressed in all breast cell lines and breast cancer biopsies, and is translated into a new semaphorin 3F isoform. In silico analysis predicted that most of the new putative proteins lack functional domains, potentially missing some functions and acquiring new ones. Our findings better describe the extent of alternative splicing in breast cancer and highlight the need to further investigate adhesion- and motility-related molecules to gain insights into breast cancer progression. PMID:26784191

  7. CD44-mediated Adhesion to Hyaluronic Acid Contributes to Mechanosensing and Invasive Motility

    PubMed Central

    Kim, Yushan; Kumar, Sanjay

    2014-01-01

    The high molecular weight glycosaminoglycan, hyaluronic acid (HA), makes up a significant portion of the brain extracellular matrix (ECM). Glioblastoma multiforme (GBM), a highly invasive brain tumor, is associated with aberrant HA secretion, tissue stiffening, and overexpression of the HA receptor CD44. Here, transcriptomic analysis, engineered materials, and measurements of adhesion, migration, and invasion were used to investigate how HA/CD44 ligation contributes to the mechanosensing and invasive motility of GBM tumor cells, both intrinsically and in the context of RGD/integrin adhesion. Analysis of transcriptomic data from The Cancer Genome Atlas (TCGA) reveals up-regulation of transcripts associated with HA/CD44 adhesion. CD44 suppression in culture reduces cell adhesion to HA on short time scales (0.5h post-incubation) even if RGD is present, whereas maximal adhesion on longer time scales (3h) requires both CD44 and integrins. Moreover, time-lapse imaging demonstrates that cell adhesive structures formed during migration on bare HA matrices are more short-lived than cellular protrusions formed on surfaces containing RGD. Interestingly, adhesion and migration speed were dependent on HA hydrogel stiffness, implying that CD44-based signaling is intrinsically mechanosensitive. Finally, CD44 expression paired with an HA-rich microenvironment maximized three-dimensional invasion, whereas CD44 suppression or abundant integrin-based adhesion limited it. These findings demonstrate that CD44 transduces HA-based stiffness cues, temporally precedes integrin-based adhesion maturation, and facilitates invasion. PMID:24962319

  8. Elastic mismatch enhances cell motility

    NASA Astrophysics Data System (ADS)

    Bresler, Yony; Palmieri, Benoit; Grant, Martin

    In recent years, the study of physics phenomena in cancer has drawn considerable attention. In cancer metastasis, a soft cancer cell leaves the tumor, and must pass through the endothelium before reaching the bloodstream. Using a phase-field model we have shown that the elasticity mismatch between cells alone is sufficient to enhance the motility of thesofter cancer cell by means of bursty migration, in agreement with experiment. We will present further characterization of these behaviour, as well as new possible applications for this model.

  9. Balance between cell−substrate adhesion and myosin contraction determines the frequency of motility initiation in fish keratocytes

    PubMed Central

    Barnhart, Erin; Lee, Kun-Chun; Allen, Greg M.; Theriot, Julie A.; Mogilner, Alex

    2015-01-01

    Cells are dynamic systems capable of spontaneously switching among stable states. One striking example of this is spontaneous symmetry breaking and motility initiation in fish epithelial keratocytes. Although the biochemical and mechanical mechanisms that control steady-state migration in these cells have been well characterized, the mechanisms underlying symmetry breaking are less well understood. In this work, we have combined experimental manipulations of cell−substrate adhesion strength and myosin activity, traction force measurements, and mathematical modeling to develop a comprehensive mechanical model for symmetry breaking and motility initiation in fish epithelial keratocytes. Our results suggest that stochastic fluctuations in adhesion strength and myosin localization drive actin network flow rates in the prospective cell rear above a critical threshold. Above this threshold, high actin flow rates induce a nonlinear switch in adhesion strength, locally switching adhesions from gripping to slipping and further accelerating actin flow in the prospective cell rear, resulting in rear retraction and motility initiation. We further show, both experimentally and with model simulations, that the global levels of adhesion strength and myosin activity control the stability of the stationary state: The frequency of symmetry breaking decreases with increasing adhesion strength and increases with increasing myosin contraction. Thus, the relative strengths of two opposing mechanical forces—contractility and cell−substrate adhesion—determine the likelihood of spontaneous symmetry breaking and motility initiation. PMID:25848042

  10. 3D Timelapse Analysis of Muscle Satellite Cell Motility

    PubMed Central

    Siegel, Ashley L; Atchison, Kevin; Fisher, Kevin E; Davis, George E; Cornelison, DDW

    2009-01-01

    Skeletal muscle repair and regeneration requires the activity of satellite cells, a population of myogenic stem cells scattered throughout the tissue and activated to proliferate and differentiate in response to myotrauma or disease. While it seems likely that satellite cells would need to navigate local muscle tissue to reach damaged areas, relatively little data on such motility exist, and most studies have been with immortalized cell lines. We find that primary satellite cells are significantly more motile than myoblast cell lines, and that adhesion to laminin promotes primary cell motility more than fourfold over other substrates. Using timelapse videomicroscopy to assess satellite cell motility on single living myofibers, we have identified a requirement for the laminin-binding integrin α7β1 in satellite cell motility, as well as a role for hepatocyte growth factor in promoting directional persistence. The extensive migratory behavior of satellite cells resident on muscle fibers suggests caution when determining, based on fixed specimens, whether adjacent cells are daughters from the same mother cell. We also observed more persistent long-term contact between individual satellite cells than has been previously supposed, potential cell-cell attractive and repulsive interactions, and migration between host myofibers. Based on such activity, we assayed for expression of “pathfinding” cues, and found that satellite cells express multiple guidance ligands and receptors. Together, these data suggest that satellite cell migration in vivo may be more extensive than currently thought, and could be regulated by combinations of signals, including adhesive haptotaxis, soluble factors, and guidance cues. Stem Cells 2009;27:2527–2538 PMID:19609936

  11. 3D timelapse analysis of muscle satellite cell motility.

    PubMed

    Siegel, Ashley L; Atchison, Kevin; Fisher, Kevin E; Davis, George E; Cornelison, D D W

    2009-10-01

    Skeletal muscle repair and regeneration requires the activity of satellite cells, a population of myogenic stem cells scattered throughout the tissue and activated to proliferate and differentiate in response to myotrauma or disease. While it seems likely that satellite cells would need to navigate local muscle tissue to reach damaged areas, relatively little data on such motility exist, and most studies have been with immortalized cell lines. We find that primary satellite cells are significantly more motile than myoblast cell lines, and that adhesion to laminin promotes primary cell motility more than fourfold over other substrates. Using timelapse videomicroscopy to assess satellite cell motility on single living myofibers, we have identified a requirement for the laminin-binding integrin alpha 7 beta 1 in satellite cell motility, as well as a role for hepatocyte growth factor in promoting directional persistence. The extensive migratory behavior of satellite cells resident on muscle fibers suggests caution when determining, based on fixed specimens, whether adjacent cells are daughters from the same mother cell. We also observed more persistent long-term contact between individual satellite cells than has been previously supposed, potential cell-cell attractive and repulsive interactions, and migration between host myofibers. Based on such activity, we assayed for expression of "pathfinding" cues, and found that satellite cells express multiple guidance ligands and receptors. Together, these data suggest that satellite cell migration in vivo may be more extensive than currently thought, and could be regulated by combinations of signals, including adhesive haptotaxis, soluble factors, and guidance cues. PMID:19609936

  12. Extending the molecular clutch beyond actin-based cell motility

    NASA Astrophysics Data System (ADS)

    Havrylenko, Svitlana; Mezanges, Xavier; Batchelder, Ellen; Plastino, Julie

    2014-10-01

    Many cell movements occur via polymerization of the actin cytoskeleton beneath the plasma membrane at the front of the cell, forming a protrusion called a lamellipodium, while myosin contraction squeezes forward the back of the cell. In what is known as the ‘molecular clutch’ description of cell motility, forward movement results from the engagement of the acto-myosin motor with cell-matrix adhesions, thus transmitting force to the substrate and producing movement. However during cell translocation, clutch engagement is not perfect, and as a result, the cytoskeleton slips with respect to the substrate, undergoing backward (retrograde) flow in the direction of the cell body. Retrograde flow is therefore inversely proportional to cell speed and depends on adhesion and acto-myosin dynamics. Here we asked whether the molecular clutch was a general mechanism by measuring motility and retrograde flow for the Caenorhabditis elegans sperm cell in different adhesive conditions. These cells move by adhering to the substrate and emitting a dynamic lamellipodium, but the sperm cell does not contain an acto-myosin cytoskeleton. Instead the lamellipodium is formed by the assembly of major sperm protein, which has no biochemical or structural similarity to actin. We find that these cells display the same molecular clutch characteristics as acto-myosin containing cells. We further show that retrograde flow is produced both by cytoskeletal assembly and contractility in these cells. Overall this study shows that the molecular clutch hypothesis of how polymerization is transduced into motility via adhesions is a general description of cell movement regardless of the composition of the cytoskeleton.

  13. Cooperative cell motility during tandem locomotion of amoeboid cells.

    PubMed

    Bastounis, Effie; Álvarez-González, Begoña; Del Álamo, Juan C; Lasheras, Juan C; Firtel, Richard A

    2016-04-15

    Streams of migratory cells are initiated by the formation of tandem pairs of cells connected head to tail to which other cells subsequently adhere. The mechanisms regulating the transition from single to streaming cell migration remain elusive, although several molecules have been suggested to be involved. In this work, we investigate the mechanics of the locomotion ofDictyosteliumtandem pairs by analyzing the spatiotemporal evolution of their traction adhesions (TAs). We find that in migrating wild-type tandem pairs, each cell exerts traction forces on stationary sites (∼80% of the time), and the trailing cell reuses the location of the TAs of the leading cell. Both leading and trailing cells form contractile dipoles and synchronize the formation of new frontal TAs with ∼54-s time delay. Cells not expressing the lectin discoidin I or moving on discoidin I-coated substrata form fewer tandems, but the trailing cell still reuses the locations of the TAs of the leading cell, suggesting that discoidin I is not responsible for a possible chemically driven synchronization process. The migration dynamics of the tandems indicate that their TAs' reuse results from the mechanical synchronization of the leading and trailing cells' protrusions and retractions (motility cycles) aided by the cell-cell adhesions. PMID:26912787

  14. Cell adhesion force microscopy

    PubMed Central

    Sagvolden, G.; Giaever, I.; Pettersen, E. O.; Feder, J.

    1999-01-01

    The adhesion forces of cervical carcinoma cells in tissue culture were measured by using the manipulation force microscope, a novel atomic force microscope. The forces were studied as a function of time and temperature for cells cultured on hydrophilic and hydrophobic polystyrene substrates with preadsorbed proteins. The cells attached faster and stronger at 37°C than at 23°C and better on hydrophilic than on hydrophobic substrates, even though proteins adsorb much better to the hydrophobic substrates. Because cell adhesion serves to control several stages in the cell cycle, we anticipate that the manipulation force microscope can help clarify some cell-adhesion related issues. PMID:9892657

  15. LRRK2 G2019S mutation attenuates microglial motility by inhibiting focal adhesion kinase

    PubMed Central

    Choi, Insup; Kim, Beomsue; Byun, Ji-Won; Baik, Sung Hoon; Huh, Yun Hyun; Kim, Jong-Hyeon; Mook-Jung, Inhee; Song, Woo Keun; Shin, Joo-Ho; Seo, Hyemyung; Suh, Young Ho; Jou, Ilo; Park, Sang Myun; Kang, Ho Chul; Joe, Eun-Hye

    2015-01-01

    In response to brain injury, microglia rapidly extend processes that isolate lesion sites and protect the brain from further injury. Here we report that microglia carrying a pathogenic mutation in the Parkinson's disease (PD)-associated gene, G2019S-LRRK2 (GS-Tg microglia), show retarded ADP-induced motility and delayed isolation of injury, compared with non-Tg microglia. Conversely, LRRK2 knockdown microglia are highly motile compared with control cells. In our functional assays, LRRK2 binds to focal adhesion kinase (FAK) and phosphorylates its Thr–X–Arg/Lys (TXR/K) motif(s), eventually attenuating FAK activity marked by decreased pY397 phosphorylation (pY397). GS-LRRK2 decreases the levels of pY397 in the brain, microglia and HEK cells. In addition, treatment with an inhibitor of LRRK2 kinase restores pY397 levels, decreased pTXR levels and rescued motility of GS-Tg microglia. These results collectively suggest that G2019S mutation of LRRK2 may contribute to the development of PD by inhibiting microglial response to brain injury. PMID:26365310

  16. T Cell Motility as Modulator of Interactions with Dendritic Cells

    PubMed Central

    Stein, Jens V.

    2015-01-01

    It is well established that the balance of costimulatory and inhibitory signals during interactions with dendritic cells (DCs) determines T cell transition from a naïve to an activated or tolerant/anergic status. Although many of these molecular interactions are well reproduced in reductionist in vitro assays, the highly dynamic motility of naïve T cells in lymphoid tissue acts as an additional lever to fine-tune their activation threshold. T cell detachment from DCs providing suboptimal stimulation allows them to search for DCs with higher levels of stimulatory signals, while storing a transient memory of short encounters. In turn, adhesion of weakly reactive T cells to DCs presenting peptides presented on major histocompatibility complex with low affinity is prevented by lipid mediators. Finally, controlled recruitment of CD8+ T cells to cognate DC–CD4+ T cell clusters shapes memory T cell formation and the quality of the immune response. Dynamic physiological lymphocyte motility therefore constitutes a mechanism to mitigate low avidity T cell activation and to improve the search for “optimal” DCs, while contributing to peripheral tolerance induction in the absence of inflammation. PMID:26579132

  17. Cooperative cell motility during tandem locomotion of amoeboid cells

    PubMed Central

    Bastounis, Effie; Álvarez-González, Begoña; del Álamo, Juan C.; Lasheras, Juan C.; Firtel, Richard A.

    2016-01-01

    Streams of migratory cells are initiated by the formation of tandem pairs of cells connected head to tail to which other cells subsequently adhere. The mechanisms regulating the transition from single to streaming cell migration remain elusive, although several molecules have been suggested to be involved. In this work, we investigate the mechanics of the locomotion of Dictyostelium tandem pairs by analyzing the spatiotemporal evolution of their traction adhesions (TAs). We find that in migrating wild-type tandem pairs, each cell exerts traction forces on stationary sites (∼80% of the time), and the trailing cell reuses the location of the TAs of the leading cell. Both leading and trailing cells form contractile dipoles and synchronize the formation of new frontal TAs with ∼54-s time delay. Cells not expressing the lectin discoidin I or moving on discoidin I–coated substrata form fewer tandems, but the trailing cell still reuses the locations of the TAs of the leading cell, suggesting that discoidin I is not responsible for a possible chemically driven synchronization process. The migration dynamics of the tandems indicate that their TAs’ reuse results from the mechanical synchronization of the leading and trailing cells’ protrusions and retractions (motility cycles) aided by the cell–cell adhesions. PMID:26912787

  18. Endothelial cell motility, coordination and pattern formation during vasculogenesis.

    PubMed

    Czirok, Andras

    2013-01-01

    How vascular networks assemble is a fundamental problem of developmental biology that also has medical importance. To explain the organizational principles behind vascular patterning, we must understand how can tissue level structures be controlled through cell behavior patterns like motility and adhesion that, in turn, are determined by biochemical signal transduction processes? We discuss the various ideas that have been proposed as mechanisms for vascular network assembly: cell motility guided by extracellular matrix alignment (contact guidance), chemotaxis guided by paracrine and autocrine morphogens, and multicellular sprouting guided by cell-cell contacts. All of these processes yield emergent patterns, thus endothelial cells can form an interconnected structure autonomously, without guidance from an external pre-pattern. PMID:23857825

  19. Computational and Modeling Strategies for Cell Motility

    NASA Astrophysics Data System (ADS)

    Wang, Qi; Yang, Xiaofeng; Adalsteinsson, David; Elston, Timothy C.; Jacobson, Ken; Kapustina, Maryna; Forest, M. Gregory

    A predictive simulation of the dynamics of a living cell remains a fundamental modeling and computational challenge. The challenge does not even make sense unless one specifies the level of detail and the phenomena of interest, whether the focus is on near-equilibrium or strongly nonequilibrium behavior, and on localized, subcellular, or global cell behavior. Therefore, choices have to be made clear at the outset, ranging from distinguishing between prokaryotic and eukaryotic cells, specificity within each of these types, whether the cell is "normal," whether one wants to model mitosis, blebs, migration, division, deformation due to confined flow as with red blood cells, and the level of microscopic detail for any of these processes. The review article by Hoffman and Crocker [48] is both an excellent overview of cell mechanics and an inspiration for our approach. One might be interested, for example, in duplicating the intricate experimental details reported in [43]: "actin polymerization periodically builds a mechanical link, the lamellipodium, connecting myosin motors with the initiation of adhesion sites, suggesting that the major functions driving motility are coordinated by a biomechanical process," or to duplicate experimental evidence of traveling waves in cells recovering from actin depolymerization [42, 35]. Modeling studies of lamellipodial structure, protrusion, and retraction behavior range from early mechanistic models [84] to more recent deterministic [112, 97] and stochastic [51] approaches with significant biochemical and structural detail. Recent microscopic-macroscopic models and algorithms for cell blebbing have been developed by Young and Mitran [116], which update cytoskeletal microstructure via statistical sampling techniques together with fluid variables. Alternatively, whole cell compartment models (without spatial details) of oscillations in spreading cells have been proposed [35, 92, 109] which show positive and negative feedback

  20. Mechanism of shape determination in motile cells

    PubMed Central

    Keren, Kinneret; Pincus, Zachary; Allen, Greg M.; Barnhart, Erin L.; Marriott, Gerard; Mogilner, Alex; Theriot, Julie A.

    2010-01-01

    The shape of motile cells is determined by many dynamic processes spanning several orders of magnitude in space and time, from local polymerization of actin monomers at subsecond timescales to global, cell-scale geometry that may persist for hours. Understanding the mechanism of shape determination in cells has proved to be extremely challenging due to the numerous components involved and the complexity of their interactions. Here we harness the natural phenotypic variability in a large population of motile epithelial keratocytes from fish (Hypsophrys nicaraguensis) to reveal mechanisms of shape determination. We find that the cells inhabit a low-dimensional, highly correlated spectrum of possible functional states. We further show that a model of actin network treadmilling in an inextensible membrane bag can quantitatively recapitulate this spectrum and predict both cell shape and speed. Our model provides a simple biochemical and biophysical basis for the observed morphology and behaviour of motile cells. PMID:18497816

  1. Epithelial Cell Adhesion Molecule

    PubMed Central

    Trzpis, Monika; McLaughlin, Pamela M.J.; de Leij, Lou M.F.H.; Harmsen, Martin C.

    2007-01-01

    The epithelial cell adhesion molecule (EpCAM, CD326) is a glycoprotein of ∼40 kd that was originally identified as a marker for carcinoma, attributable to its high expression on rapidly proliferating tumors of epithelial origin. Normal epithelia express EpCAM at a variable but generally lower level than carcinoma cells. In early studies, EpCAM was proposed to be a cell-cell adhesion molecule. However, recent insights revealed a more versatile role for EpCAM that is not limited only to cell adhesion but includes diverse processes such as signaling, cell migration, proliferation, and differentiation. Cell surface expression of EpCAM may actually prevent cell-cell adhesion. Here, we provide a comprehensive review of the current knowledge on EpCAM biology in relation to other cell adhesion molecules. We discuss the implications of the newly identified functions of EpCAM in view of its prognostic relevance in carcinoma, inflammatory pathophysiology, and tissue development and regeneration as well as its role in normal epithelial homeostasis. PMID:17600130

  2. Radiation-induced motility alterations in medulloblastoma cells.

    PubMed

    Rieken, Stefan; Rieber, Juliane; Brons, Stephan; Habermehl, Daniel; Rief, Harald; Orschiedt, Lena; Lindel, Katja; Weber, Klaus J; Debus, Jürgen; Combs, Stephanie E

    2015-05-01

    Photon irradiation has been repeatedly suspected of increasing tumor cell motility and promoting locoregional recurrence of disease. This study was set up to analyse possible mechanisms underlying the potentially radiation-altered motility in medulloblastoma cells. Medulloblastoma cell lines D425 and Med8A were analyzed in migration and adhesion experiments with and without photon and carbon ion irradiation. Expression of integrins was determined by quantitative FACS analysis. Matrix metalloproteinase concentrations within cell culture supernatants were investigated by enzyme-linked immunosorbent assay (ELISA). Statistical analysis was performed using Student's t-test. Both photon and carbon ion irradiation significantly reduced chemotactic medulloblastoma cell transmigration through 8-μm pore size membranes, while simultaneously increasing adherence to fibronectin- and collagen I- and IV-coated surfaces. Correspondingly, both photon and carbon ion irradiation downregulate soluble MMP9 concentrations, while upregulating cell surface expression of proadhesive extracellular matrix protein-binding integrin α5. The observed phenotype of radiation-altered motility is more pronounced following carbon ion than photon irradiation. Both photon and (even more so) carbon ion irradiation are effective in inhibiting medulloblastoma cell migration through downregulation of matrix metalloproteinase 9 and upregulation of proadhesive cell surface integrin α5, which lead to increased cell adherence to extracellular matrix proteins. PMID:25736470

  3. The mysterious nature of bacterial surface (gliding) motility: A focal adhesion-based mechanism in Myxococcus xanthus.

    PubMed

    Islam, Salim T; Mignot, Tâm

    2015-10-01

    Motility of bacterial cells promotes a range of important physiological phenomena such as nutrient detection, harm avoidance, biofilm formation, and pathogenesis. While much research has been devoted to the mechanism of bacterial swimming in liquid via rotation of flagellar filaments, the mechanisms of bacterial translocation across solid surfaces are poorly understood, particularly when cells lack external appendages such as rotary flagella and/or retractile type IV pili. Under such limitations, diverse bacteria at the single-cell level are still able to "glide" across solid surfaces, exhibiting smooth translocation of the cell along its long axis. Though multiple gliding mechanisms have evolved in different bacterial classes, most remain poorly characterized. One exception is the gliding motility mechanism used by the Gram-negative social predatory bacterium Myxococcus xanthus. The available body of research suggests that M. xanthus gliding motility is mediated by trafficked multi-protein (Glt) cell envelope complexes, powered by proton-driven flagellar stator homologues (Agl). Through coupling to the substratum via polysaccharide slime, Agl-Glt assemblies can become fixed relative to the substratum, forming a focal adhesion site. Continued directional transport of slime-associated substratum-fixed Agl-Glt complexes would result in smooth forward movement of the cell. In this review, we have provided a comprehensive synthesis of the latest mechanistic and structural data for focal adhesion-mediated gliding motility in M. xanthus, with emphasis on the role of each Agl and Glt protein. Finally, we have also highlighted the possible connection between the motility complex and a new type of spore coat assembly system, suggesting that gliding and cell envelope synthetic complexes are evolutionarily linked. PMID:26520023

  4. Two-Dimensional Motility of a Macrophage Cell Line on Microcontact-Printed Fibronectin

    PubMed Central

    Hind, Laurel E.; MacKay, Joanna L.; Cox, Dianne; Hammer, Daniel A.

    2014-01-01

    The ability of macrophages to migrate to sites of infection and inflammation is critical for their role in the innate immune response. Macrophage cell lines have made it possible to study the roles of individual proteins responsible for migration using molecular biology, but it has not been possible to reliably elicit the motility of macrophage cell lines in two-dimensions. In the past, measurements of the motility of macrophage cell lines have been largely limited to transwell assays which provide limited quantitative information on motility and limited ability to visualize cell morphology. We used microcontact printing to create polydimethylsiloxane (PDMS) surfaces functionalized with fibronectin that otherwise support little macrophage adhesion. We used these surfaces to measure macrophage migration in two-dimensions and found that these cells migrate efficiently in a uniform field of colony-stimulating factor-1, CSF-1. Knockdown of Cdc42 led to a non-statistically significant reduction in motility, whereas chemical inhibition of PI3K activity led to a complete loss of motility. Inhibition of the RhoA kinase, ROCK, did not abolish the motility of these cells but caused a quantitative change in motility, reducing motility significantly on high concentrations of fibronectin but not on low concentrations. This study illustrates the importance of studying cell motility on well controlled materials to better understand the exact roles of specific proteins on macrophage migration. PMID:25186818

  5. Transglutaminase 2 expression in acute myeloid leukemia: Association with adhesion molecule expression and leukemic blast motility

    PubMed Central

    Meyer, Stefan; Ravandi-Kashani, Farhad; Borthakur, Gautam; Coombes, Kevin R.; Zhang, Nianxiang; Kornblau, Steven

    2016-01-01

    Acute myeloid leukemia (AML) is a heterogenous disease with differential oncogene association, outcome and treatment regimens. Treatment strategies for AML have improved outcome but despite increased molecular biological information AML is still associated with poor prognosis. Proteomic analysis on the effects of a range of leukemogenic oncogenes showed that the protein transglutaminase 2 (TG2) is expressed at greater levels as a consequence of oncogenic transformation. Further analysis of this observation was performed with 511 AML samples using reverse phase proteomic arrays, demonstrating that TG2 expression was higher at relapse than diagnosis in many cases. In addition elevated TG2 expression correlated with increased expression of numerous adhesion proteins and many apoptosis regulating proteins, two processes related to leukemogenesis. TG2 has previously been linked to drug resistance in cancer and given the negative correlation between TG2 levels and peripheral blasts observed increased TG2 levels may lead to the protection of the leukemic stem cell due to increased adhesion/reduced motility. TG2 may therefore form part of a network of proteins that define poor outcome in AML patients and potentially offer a target to sensitize AML stem cells to drug treatment. PMID:23576428

  6. Stathmin Activity Influences Sarcoma Cell Shape, Motility, and Metastatic Potential

    PubMed Central

    Belletti, Barbara; Nicoloso, Milena S.; Schiappacassi, Monica; Berton, Stefania; Lovat, Francesca; Wolf, Katarina; Canzonieri, Vincenzo; D'Andrea, Sara; Zucchetto, Antonella; Friedl, Peter; Colombatti, Alfonso

    2008-01-01

    The balanced activity of microtubule-stabilizing and -destabilizing proteins determines the extent of microtubule dynamics, which is implicated in many cellular processes, including adhesion, migration, and morphology. Among the destabilizing proteins, stathmin is overexpressed in different human malignancies and has been recently linked to the regulation of cell motility. The observation that stathmin was overexpressed in human recurrent and metastatic sarcomas prompted us to investigate stathmin contribution to tumor local invasiveness and distant dissemination. We found that stathmin stimulated cell motility in and through the extracellular matrix (ECM) in vitro and increased the metastatic potential of sarcoma cells in vivo. On contact with the ECM, stathmin was negatively regulated by phosphorylation. Accordingly, a less phosphorylable stathmin point mutant impaired ECM-induced microtubule stabilization and conferred a higher invasive potential, inducing a rounded cell shape coupled with amoeboid-like motility in three-dimensional matrices. Our results indicate that stathmin plays a significant role in tumor metastasis formation, a finding that could lead to exploitation of stathmin as a target of new antimetastatic drugs. PMID:18305103

  7. Paxillin controls directional cell motility in response to physical cues

    PubMed Central

    Sero, Julia E.; German, Alexandra E.; Mammoto, Akiko; Ingber, Donald E.

    2012-01-01

    Physical cues from the extracellular environment that influence cell shape and directional migration are transduced into changes in cytoskeletal organization and biochemistry through integrin-based cell adhesions to extracellular matrix (ECM). Paxillin is a focal adhesion (FA) scaffold protein that mediates integrin anchorage to the cytoskeleton, and has been implicated in regulation of FA assembly and cell migration. To determine whether paxillin is involved in coupling mechanical distortion with directional movement, cell shape was physically constrained by culturing cells on square-shaped fibronectin-coated adhesive islands surrounded by non-adhesive barrier regions that were created with a microcontact printing technique. Square-shaped cells preferentially formed FAs and extended lamellipodia from their corner regions when stimulated with PDGF, and loss of paxillin resulted in loss of this polarized response. Selective expression of the N- and C-terminal domains of paxillin produced opposite, but complementary, effects on suppressing or promoting lamellipodia formation in different regions of square cells, which corresponded to directional motility defects in vitro. Paxillin loss or mutation was also shown to affect the formation of circular dorsal ruffles, and this corresponded to changes in cell invasive behavior in 3D. This commentary addresses the implications of these findings in terms of how a multifunctional FA scaffold protein can link physical cues to cell adhesion, protrusion and membrane trafficking so as to control directional migration in 2D and 3D. We also discuss how microengineered ECM islands and in vivo model systems can be used to further elucidate the functions of paxillin in directional migration. PMID:23076140

  8. Hyaluronan stimulates pancreatic cancer cell motility

    PubMed Central

    Cheng, Xiao-Bo; Kohi, Shiro; Koga, Atsuhiro; Hirata, Keiji; Sato, Norihiro

    2016-01-01

    Hyaluronan (HA) accumulates in pancreatic ductal adenocarcinoma (PDAC), but functional significance of HA in the aggressive phenotype remains unknown. We used different models to investigate the effect of HA on PDAC cell motility by wound healing and transwell migration assay. Changes in cell motility were examined in 8 PDAC cell lines in response to inhibition of HA production by treatment with 4-methylumbelliferone (4-MU) and to promotion by treatment with 12-O-tetradecanoyl-phorbol-13-acetate (TPA) or by co-culture with tumor-derived stromal fibroblasts. We also investigated changes in cell motility by adding exogenous HA. Additionally, mRNA expressions of hyaluronan synthases and hyaluronidases were examined using real time RT-PCR. Inhibition of HA by 4-MU significantly decreased the migration, whereas promotion of HA by TPA or co-culture with tumor-derived fibroblasts significantly increased the migration of PDAC cells. The changes in HA production by these treatments tended to be associated with changes in HAS3 mRNA expression. Furthermore, addition of exogenous HA, especially low-molecular-weight HA, significantly increased the migration of PDAC cells. These findings suggest that HA stimulates PDAC cell migration and thus represents an ideal therapeutic target to prevent invasion and metastasis. PMID:26684359

  9. Motile responses in outer hair cells.

    PubMed

    Zenner, H P

    1986-01-01

    Motile responses of cochlear hair cells open new perspectives for the understanding of cochlear hearing mechanisms and hearing disorders located in hair cells. Direct visualization of hair cell motility was achieved by a method for the study of living isolated mammalian outer hair cells (OHCs) which has overcome some of the complexities in dealing with the heterogeneous organ of Corti. Electrophysiological giga-seal whole-cell recordings of single OHC prepared by this approach had revealed negative cell potentials ranging from -32 mV to -70 mV (Gitter et al. (1986) Oto-Rhino-Laryngol. in press). Elucidation of HC motility has come from two lines of experiments. One follows from the observation that exposure of the lateral and basal membrane parts of living OHCs to increasing bath K+ concentrations resulted in a sustained reversible depolarization of the cell. Here, we report that by depolarization of the cell membrane in the presence of 25-125 mM K+/Cl- a sustained contraction of OHC was induced. This was followed by relaxation in the presence of artificial perilymph containing 5.4 mM K+/Cl-. By alternating these procedures OHCs were made to undergo as many as five cycles of contraction and relaxation. External Ca2+ was not required for the initial contraction but was essential for relaxation. Following repeated contraction/relaxation cycles the cytoplasm of individual OHCs exhibited a filamentous network, correlating with a new infracuticular anti-actin binding capacity. The second series of experiments originates in the observation that permeabilized OHCs contracted in the presence of ATP. No response was seen in the presence of control nucleotides.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3733547

  10. Hydrodynamic Contributions to Amoeboid Cell Motility

    NASA Astrophysics Data System (ADS)

    Lewis, Owen; Guy, Robert

    2011-11-01

    Understanding the methods by which cells move is a fundamental problem in modern biology. Recent evidence has shown that the fluid dynamics of cytoplasm can play a vital role in cellular motility. The slime mold Physarum polycephalum provides an excellent model organism for the study of amoeboid motion. In this research, we use both analytic and computational models to investigate intracellular fluid flow in a simple model of Physarum. In both models, of we are specifically interested in stresses generated by cytoplasmic flow which act in the direction of cellular motility. In our numerical model, the Immersed Boundary Method is used to account for such stresses. We investigate the relationship between contraction waves, low waves and locomotive forces, and attempt characterize conditions necessary to generate directed motion.

  11. Interstitial flows promote an amoeboid cell phenotype and motility of breast cancer cells

    NASA Astrophysics Data System (ADS)

    Tung, Chih-Kuan; Huang, Yu Ling; Zheng, Angela; Wu, Mingming

    2015-03-01

    Lymph nodes, the drainage systems for interstitial flows, are clinically known to be the first metastatic sites of many cancer types including breast and prostate cancers. Here, we demonstrate that breast cancer cell morphology and motility is modulated by interstitial flows in a cell-ECM adhesion dependent manner. The average aspect ratios of the cells are significantly lower (or are more amoeboid like) in the presence of the flow in comparison to the case when the flow is absent. The addition of exogenous adhesion molecules within the extracellular matrix (type I collagen) enhances the overall aspect ratio (or are more mesenchymal like) of the cell population. Using measured cell trajectories, we find that the persistence of the amoeboid cells (aspect ratio less than 2.0) is shorter than that of mesenchymal cells. However, the maximum speed of the amoeboid cells is larger than that of mesenchymal cells. Together these findings provide the novel insight that interstitial flows promote amoeboid cell morphology and motility and highlight the plasticity of tumor cell motility in response to its biophysical environment. Supported by NIH Grant R21CA138366.

  12. Mathematics of cell motility: have we got its number?

    PubMed Central

    2010-01-01

    Mathematical and computational modeling is rapidly becoming an essential research technique complementing traditional experimental biological methods. However, lack of standard modeling methods, difficulties of translating biological phenomena into mathematical language, and differences in biological and mathematical mentalities continue to hinder the scientific progress. Here we focus on one area—cell motility—characterized by an unusually high modeling activity, largely due to a vast amount of quantitative, biophysical data, ‘modular’ character of motility, and pioneering vision of the area’s experimental leaders. In this review, after brief introduction to biology of cell movements, we discuss quantitative models of actin dynamics, protrusion, adhesion, contraction, and cell shape and movement that made an impact on the process of biological discovery. We also comment on modeling approaches and open questions. PMID:18461331

  13. Both contractile axial and lateral traction force dynamics drive amoeboid cell motility

    PubMed Central

    Bastounis, Effie; Meili, Ruedi; Álvarez-González, Begoña; Francois, Joshua; del Álamo, Juan C.; Lasheras, Juan C.

    2014-01-01

    Chemotaxing Dictyostelium discoideum cells adapt their morphology and migration speed in response to intrinsic and extrinsic cues. Using Fourier traction force microscopy, we measured the spatiotemporal evolution of shape and traction stresses and constructed traction tension kymographs to analyze cell motility as a function of the dynamics of the cell’s mechanically active traction adhesions. We show that wild-type cells migrate in a step-wise fashion, mainly forming stationary traction adhesions along their anterior–posterior axes and exerting strong contractile axial forces. We demonstrate that lateral forces are also important for motility, especially for migration on highly adhesive substrates. Analysis of two mutant strains lacking distinct actin cross-linkers (mhcA− and abp120− cells) on normal and highly adhesive substrates supports a key role for lateral contractions in amoeboid cell motility, whereas the differences in their traction adhesion dynamics suggest that these two strains use distinct mechanisms to achieve migration. Finally, we provide evidence that the above patterns of migration may be conserved in mammalian amoeboid cells. PMID:24637328

  14. Subinhibitory Concentrations of Allicin Decrease Uropathogenic Escherichia coli (UPEC) Biofilm Formation, Adhesion Ability, and Swimming Motility.

    PubMed

    Yang, Xiaolong; Sha, Kaihui; Xu, Guangya; Tian, Hanwen; Wang, Xiaoying; Chen, Shanze; Wang, Yi; Li, Jingyu; Chen, Junli; Huang, Ning

    2016-01-01

    Uropathogenic Escherichia coli (UPEC) biofilm formation enables the organism to avoid the host immune system, resist antibiotics, and provide a reservoir for persistent infection. Once the biofilm is established, eradication of the infection becomes difficult. Therefore, strategies against UPEC biofilm are urgently required. In this study, we investigated the effect of allicin, isolated from garlic essential oil, on UPEC CFT073 and J96 biofilm formation and dispersal, along with its effect on UPEC adhesion ability and swimming motility. Sub-inhibitory concentrations (sub-MICs) of allicin decreased UPEC biofilm formation and affected its architecture. Allicin was also capable of dispersing biofilm. Furthermore, allicin decreased the bacterial adhesion ability and swimming motility, which are important for biofilm formation. Real-time quantitative polymerase chain reaction (RT-qPCR) revealed that allicin decreased the expression of UPEC type 1 fimbriae adhesin gene fimH. Docking studies suggested that allicin was located within the binding pocket of heptyl α-d-mannopyrannoside in FimH and formed hydrogen bonds with Phe1 and Asn135. In addition, allicin decreased the expression of the two-component regulatory systems (TCSs) cognate response regulator gene uvrY and increased the expression of the RNA binding global regulatory protein gene csrA of UPEC CFT073, which is associated with UPEC biofilm. The findings suggest that sub-MICs of allicin are capable of affecting UPEC biofilm formation and dispersal, and decreasing UPEC adhesion ability and swimming motility. PMID:27367677

  15. Subinhibitory Concentrations of Allicin Decrease Uropathogenic Escherichia coli (UPEC) Biofilm Formation, Adhesion Ability, and Swimming Motility

    PubMed Central

    Yang, Xiaolong; Sha, Kaihui; Xu, Guangya; Tian, Hanwen; Wang, Xiaoying; Chen, Shanze; Wang, Yi; Li, Jingyu; Chen, Junli; Huang, Ning

    2016-01-01

    Uropathogenic Escherichia coli (UPEC) biofilm formation enables the organism to avoid the host immune system, resist antibiotics, and provide a reservoir for persistent infection. Once the biofilm is established, eradication of the infection becomes difficult. Therefore, strategies against UPEC biofilm are urgently required. In this study, we investigated the effect of allicin, isolated from garlic essential oil, on UPEC CFT073 and J96 biofilm formation and dispersal, along with its effect on UPEC adhesion ability and swimming motility. Sub-inhibitory concentrations (sub-MICs) of allicin decreased UPEC biofilm formation and affected its architecture. Allicin was also capable of dispersing biofilm. Furthermore, allicin decreased the bacterial adhesion ability and swimming motility, which are important for biofilm formation. Real-time quantitative polymerase chain reaction (RT-qPCR) revealed that allicin decreased the expression of UPEC type 1 fimbriae adhesin gene fimH. Docking studies suggested that allicin was located within the binding pocket of heptyl α-d-mannopyrannoside in FimH and formed hydrogen bonds with Phe1 and Asn135. In addition, allicin decreased the expression of the two-component regulatory systems (TCSs) cognate response regulator gene uvrY and increased the expression of the RNA binding global regulatory protein gene csrA of UPEC CFT073, which is associated with UPEC biofilm. The findings suggest that sub-MICs of allicin are capable of affecting UPEC biofilm formation and dispersal, and decreasing UPEC adhesion ability and swimming motility. PMID:27367677

  16. Mechanics and polarity in cell motility

    NASA Astrophysics Data System (ADS)

    Ambrosi, D.; Zanzottera, A.

    2016-09-01

    The motility of a fish keratocyte on a flat substrate exhibits two distinct regimes: the non-migrating and the migrating one. In both configurations the shape is fixed in time and, when the cell is moving, the velocity is constant in magnitude and direction. Transition from a stable configuration to the other one can be produced by a mechanical or chemotactic perturbation. In order to point out the mechanical nature of such a bistable behaviour, we focus on the actin dynamics inside the cell using a minimal mathematical model. While the protein diffusion, recruitment and segregation govern the polarization process, we show that the free actin mass balance, driven by diffusion, and the polymerized actin retrograde flow, regulated by the active stress, are sufficient ingredients to account for the motile bistability. The length and velocity of the cell are predicted on the basis of the parameters of the substrate and of the cell itself. The key physical ingredient of the theory is the exchange among actin phases at the edges of the cell, that plays a central role both in kinematics and in dynamics.

  17. Cortical Contractility Triggers a Stochastic Switch to Fast Amoeboid Cell Motility

    PubMed Central

    Ruprecht, Verena; Wieser, Stefan; Callan-Jones, Andrew; Smutny, Michael; Morita, Hitoshi; Sako, Keisuke; Barone, Vanessa; Ritsch-Marte, Monika; Sixt, Michael; Voituriez, Raphaël; Heisenberg, Carl-Philipp

    2015-01-01

    Summary 3D amoeboid cell migration is central to many developmental and disease-related processes such as cancer metastasis. Here, we identify a unique prototypic amoeboid cell migration mode in early zebrafish embryos, termed stable-bleb migration. Stable-bleb cells display an invariant polarized balloon-like shape with exceptional migration speed and persistence. Progenitor cells can be reversibly transformed into stable-bleb cells irrespective of their primary fate and motile characteristics by increasing myosin II activity through biochemical or mechanical stimuli. Using a combination of theory and experiments, we show that, in stable-bleb cells, cortical contractility fluctuations trigger a stochastic switch into amoeboid motility, and a positive feedback between cortical flows and gradients in contractility maintains stable-bleb cell polarization. We further show that rearward cortical flows drive stable-bleb cell migration in various adhesive and non-adhesive environments, unraveling a highly versatile amoeboid migration phenotype. PMID:25679761

  18. From molecular signal activation to locomotion: an integrated, multiscale analysis of cell motility on defined matrices.

    PubMed

    Pathak, Amit; Kumar, Sanjay

    2011-01-01

    The adhesion, mechanics, and motility of eukaryotic cells are highly sensitive to the ligand density and stiffness of the extracellular matrix (ECM). This relationship bears profound implications for stem cell engineering, tumor invasion and metastasis. Yet, our quantitative understanding of how ECM biophysical properties, mechanotransductive signals, and assembly of contractile and adhesive structures collude to control these cell behaviors remains extremely limited. Here we present a novel multiscale model of cell migration on ECMs of defined biophysical properties that integrates local activation of biochemical signals with adhesion and force generation at the cell-ECM interface. We capture the mechanosensitivity of individual cellular components by dynamically coupling ECM properties to the activation of Rho and Rac GTPases in specific portions of the cell with actomyosin contractility, cell-ECM adhesion bond formation and rupture, and process extension and retraction. We show that our framework is capable of recreating key experimentally-observed features of the relationship between cell migration and ECM biophysical properties. In particular, our model predicts for the first time recently reported transitions from filopodial to "stick-slip" to gliding motility on ECMs of increasing stiffness, previously observed dependences of migration speed on ECM stiffness and ligand density, and high-resolution measurements of mechanosensitive protrusion dynamics during cell motility we newly obtained for this study. It also relates the biphasic dependence of cell migration speed on ECM stiffness to the tendency of the cell to polarize. By enabling the investigation of experimentally-inaccessible microscale relationships between mechanotransductive signaling, adhesion, and motility, our model offers new insight into how these factors interact with one another to produce complex migration patterns across a variety of ECM conditions. PMID:21483802

  19. GAR22β regulates cell migration, sperm motility, and axoneme structure

    PubMed Central

    Gamper, Ivonne; Fleck, David; Barlin, Meltem; Spehr, Marc; Sayad, Sara El; Kleine, Henning; Maxeiner, Sebastian; Schalla, Carmen; Aydin, Gülcan; Hoss, Mareike; Litchfield, David W.; Lüscher, Bernhard; Zenke, Martin; Sechi, Antonio

    2016-01-01

    Spatiotemporal cytoskeleton remodeling is pivotal for cell adhesion and migration. Here we investigated the function of Gas2-related protein on chromosome 22 (GAR22β), a poorly characterized protein that interacts with actin and microtubules. Primary and immortalized GAR22β−/− Sertoli cells moved faster than wild-type cells. In addition, GAR22β−/− cells showed a more prominent focal adhesion turnover. GAR22β overexpression or its reexpression in GAR22β−/− cells reduced cell motility and focal adhesion turnover. GAR22β–actin interaction was stronger than GAR22β–microtubule interaction, resulting in GAR22β localization and dynamics that mirrored those of the actin cytoskeleton. Mechanistically, GAR22β interacted with the regulator of microtubule dynamics end-binding protein 1 (EB1) via a novel noncanonical amino acid sequence, and this GAR22β–EB1 interaction was required for the ability of GAR22β to modulate cell motility. We found that GAR22β is highly expressed in mouse testes, and its absence resulted in reduced spermatozoa generation, lower actin levels in testes, and impaired motility and ultrastructural disorganization of spermatozoa. Collectively our findings identify GAR22β as a novel regulator of cell adhesion and migration and provide a foundation for understanding the molecular basis of diverse cytoskeleton-dependent processes. PMID:26564797

  20. Correlation of cell membrane dynamics and cell motility

    PubMed Central

    2011-01-01

    Background Essential events of cell development and homeostasis are revealed by the associated changes of cell morphology and therefore have been widely used as a key indicator of physiological states and molecular pathways affecting various cellular functions via cytoskeleton. Cell motility is a complex phenomenon primarily driven by the actin network, which plays an important role in shaping the morphology of the cells. Most of the morphology based features are approximated from cell periphery but its dynamics have received none to scant attention. We aim to bridge the gap between membrane dynamics and cell states from the perspective of whole cell movement by identifying cell edge patterns and its correlation with cell dynamics. Results We present a systematic study to extract, classify, and compare cell dynamics in terms of cell motility and edge activity. Cell motility features extracted by fitting a persistent random walk were used to identify the initial set of cell subpopulations. We propose algorithms to extract edge features along the entire cell periphery such as protrusion and retraction velocity. These constitute a unique set of multivariate time-lapse edge features that are then used to profile subclasses of cell dynamics by unsupervised clustering. Conclusions By comparing membrane dynamic patterns exhibited by each subclass of cells, correlated trends of edge and cell movements were identified. Our findings are consistent with published literature and we also identified that motility patterns are influenced by edge features from initial time points compared to later sampling intervals. PMID:22372978

  1. Colony Expansion of Socially Motile Myxococcus xanthus Cells Is Driven by Growth, Motility, and Exopolysaccharide Production

    PubMed Central

    Patra, Pintu; Kissoon, Kimberley; Cornejo, Isabel; Kaplan, Heidi B.; Igoshin, Oleg A.

    2016-01-01

    Myxococcus xanthus, a model organism for studies of multicellular behavior in bacteria, moves exclusively on solid surfaces using two distinct but coordinated motility mechanisms. One of these, social (S) motility is powered by the extension and retraction of type IV pili and requires the presence of exopolysaccharides (EPS) produced by neighboring cells. As a result, S motility requires close cell-to-cell proximity and isolated cells do not translocate. Previous studies measuring S motility by observing the colony expansion of cells deposited on agar have shown that the expansion rate increases with initial cell density, but the biophysical mechanisms involved remain largely unknown. To understand the dynamics of S motility-driven colony expansion, we developed a reaction-diffusion model describing the effects of cell density, EPS deposition and nutrient exposure on the expansion rate. Our results show that at steady state the population expands as a traveling wave with a speed determined by the interplay of cell motility and growth, a well-known characteristic of Fisher’s equation. The model explains the density-dependence of the colony expansion by demonstrating the presence of a lag phase–a transient period of very slow expansion with a duration dependent on the initial cell density. We propose that at a low initial density, more time is required for the cells to accumulate enough EPS to activate S-motility resulting in a longer lag period. Furthermore, our model makes the novel prediction that following the lag phase the population expands at a constant rate independent of the cell density. These predictions were confirmed by S motility experiments capturing long-term expansion dynamics. PMID:27362260

  2. Cell-cell signaling and adhesion in phagocytosis and early development of Dictyostelium.

    PubMed

    Bracco, E; Pergolizzi, B; Peracino, B; Ponte, E; Balbo, A; Mai, A; Ceccarelli, A; Bozzaro, S

    2000-01-01

    Cell-cell signaling and adhesion regulate transition from the unicellular to the multicellular stage of development in the cellular slime mold Dictyostelium. Essential gene networks involved in these processes have been identified and their interplay dissected. Heterotrimeric G protein-linked signal transduction plays a key role in regulating expression of genes mediating chemotaxis or cell adhesion, as well as coordinating actin-based cell motility during phagocytosis and chemotaxis. Two classes of cell adhesion molecules, one cadherin-like and the second belonging to the IgG superfamily, contribute to the strength of adhesion in Dictyostelium aggregates. The developmental role of genes involved in motility and adhesion, and their degree of redundancy, have been re-assessed by using novel developmental assay conditions which are closer to development in nature. PMID:11061438

  3. Swimming motility plays a key role in the stochastic dynamics of cell clumping

    NASA Astrophysics Data System (ADS)

    Qi, Xianghong; Nellas, Ricky B.; Byrn, Matthew W.; Russell, Matthew H.; Bible, Amber N.; Alexandre, Gladys; Shen, Tongye

    2013-04-01

    Dynamic cell-to-cell interactions are a prerequisite to many biological processes, including development and biofilm formation. Flagellum induced motility has been shown to modulate the initial cell-cell or cell-surface interaction and to contribute to the emergence of macroscopic patterns. While the role of swimming motility in surface colonization has been analyzed in some detail, a quantitative physical analysis of transient interactions between motile cells is lacking. We examined the Brownian dynamics of swimming cells in a crowded environment using a model of motorized adhesive tandem particles. Focusing on the motility and geometry of an exemplary motile bacterium Azospirillum brasilense, which is capable of transient cell-cell association (clumping), we constructed a physical model with proper parameters for the computer simulation of the clumping dynamics. By modulating mechanical interaction (‘stickiness’) between cells and swimming speed, we investigated how equilibrium and active features affect the clumping dynamics. We found that the modulation of active motion is required for the initial aggregation of cells to occur at a realistic time scale. Slowing down the rotation of flagellar motors (and thus swimming speeds) is correlated to the degree of clumping, which is consistent with the experimental results obtained for A. brasilense.

  4. Fibroblastic reticular cell-derived lysophosphatidic acid regulates confined intranodal T-cell motility

    PubMed Central

    Takeda, Akira; Kobayashi, Daichi; Aoi, Keita; Sasaki, Naoko; Sugiura, Yuki; Igarashi, Hidemitsu; Tohya, Kazuo; Inoue, Asuka; Hata, Erina; Akahoshi, Noriyuki; Hayasaka, Haruko; Kikuta, Junichi; Scandella, Elke; Ludewig, Burkhard; Ishii, Satoshi; Aoki, Junken; Suematsu, Makoto; Ishii, Masaru; Takeda, Kiyoshi; Jalkanen, Sirpa; Miyasaka, Masayuki; Umemoto, Eiji

    2016-01-01

    Lymph nodes (LNs) are highly confined environments with a cell-dense three-dimensional meshwork, in which lymphocyte migration is regulated by intracellular contractile proteins. However, the molecular cues directing intranodal cell migration remain poorly characterized. Here we demonstrate that lysophosphatidic acid (LPA) produced by LN fibroblastic reticular cells (FRCs) acts locally to LPA2 to induce T-cell motility. In vivo, either specific ablation of LPA-producing ectoenzyme autotaxin in FRCs or LPA2 deficiency in T cells markedly decreased intranodal T cell motility, and FRC-derived LPA critically affected the LPA2-dependent T-cell motility. In vitro, LPA activated the small GTPase RhoA in T cells and limited T-cell adhesion to the underlying substrate via LPA2. The LPA-LPA2 axis also enhanced T-cell migration through narrow pores in a three-dimensional environment, in a ROCK-myosin II-dependent manner. These results strongly suggest that FRC-derived LPA serves as a cell-extrinsic factor that optimizes T-cell movement through the densely packed LN reticular network. DOI: http://dx.doi.org/10.7554/eLife.10561.001 PMID:26830463

  5. Shielding of the Geomagnetic Field Alters Actin Assembly and Inhibits Cell Motility in Human Neuroblastoma Cells

    PubMed Central

    Mo, Wei-Chuan; Zhang, Zi-Jian; Wang, Dong-Liang; Liu, Ying; Bartlett, Perry F.; He, Rong-Qiao

    2016-01-01

    Accumulating evidence has shown that absence of the geomagnetic field (GMF), the so-called hypomagnetic field (HMF) environment, alters the biological functions in seemingly non-magnetosensitive cells and organisms, which indicates that the GMF could be sensed by non-iron-rich and non-photo-sensing cells. The underlying mechanisms of the HMF effects on those cells are closely related to their GMF sensation but remain poorly understood so far. Previously, we found that the HMF represses expressions of genes associated with cell migration and cytoskeleton assembly in human neuroblastoma cells (SH-SY5Y cell line). Here, we measured the HMF-induced changes on cell morphology, adhesion, motility and actin cytoskeleton in SH-SY5Y cells. The HMF inhibited cell adhesion and migration accompanied with a reduction in cellular F-actin amount. Moreover, following exposure to the HMF, the number of cell processes was reduced and cells were smaller in size and more round in shape. Furthermore, disordered kinetics of actin assembly in vitro were observed during exposure to the HMF, as evidenced by the presence of granule and meshed products. These results indicate that elimination of the GMF affects assembly of the motility-related actin cytoskeleton, and suggest that F-actin is a target of HMF exposure and probably a mediator of GMF sensation. PMID:27029216

  6. Plakoglobin regulates cell motility through Rho- and fibronectin-dependent Src signaling

    PubMed Central

    Todorović, Viktor; Desai, Bhushan V.; Patterson, Melanie J. Schroeder; Amargo, Evangeline V.; Dubash, Adi D.; Yin, Taofei; Jones, Jonathan C. R.; Green, Kathleen J.

    2010-01-01

    We previously showed that the cell–cell junction protein plakoglobin (PG) not only suppresses motility of keratinocytes in contact with each other, but also, unexpectedly, of single cells. Here we show that PG deficiency results in extracellular matrix (ECM)-dependent disruption of mature focal adhesions and cortical actin organization. Plating PG−/− cells onto ECM deposited by PG+/− cells partially restored normal cell morphology and inhibited PG−/− cell motility. In over 70 adhesion molecules whose expression we previously showed to be altered in PG−/− cells, a substantial decrease in fibronectin (FN) in PG−/− cells stood out. Re-introduction of PG into PG−/− cells restored FN expression, and keratinocyte motility was reversed by plating PG−/− cells onto FN. Somewhat surprisingly, based on previously reported roles for PG in regulating gene transcription, PG-null cells exhibited an increase, not a decrease, in FN promoter activity. Instead, PG was required for maintenance of FN mRNA stability. PG−/− cells exhibited an increase in activated Src, one of the kinases controlled by FN, a phenotype reversed by plating PG−/− cells on ECM deposited by PG+/− keratinocytes. PG−/− cells also exhibited Src-independent activation of the small GTPases Rac1 and RhoA. Both Src and RhoA inhibition attenuated PG−/− keratinocyte motility. We propose a novel role for PG in regulating cell motility through distinct ECM–Src and RhoGTPase-dependent pathways, influenced in part by PG-dependent regulation of FN mRNA stability. PMID:20876660

  7. Cortactin Controls Cell Motility and Lamellipodial Dynamics by Regulating ECM Secretion

    PubMed Central

    Sung, Bong Hwan; Zhu, Xiaodong; Kaverina, Irina; Weaver, Alissa

    2011-01-01

    Background Branched actin assembly is critical for both cell motility and membrane trafficking. The branched actin regulator, cortactin, is generally considered to promote cell migration by controlling leading edge lamellipodial dynamics. However, recent reports indicate that lamellipodia are not required for cell movement, suggesting an alternate mechanism. Results Since cortactin also regulates membrane trafficking and adhesion dynamics, we hypothesized that altered secretion of extracellular matrix (ECM) and/or integrin trafficking might underlie motility defects of cortactin-knockdown (KD) cells. Consistent with a primary defect in ECM secretion, both motility and lamellipodial defects of cortactin-KD cells were fully rescued by plating on increasing concentrations of exogenous ECM. Furthermore, cortactin-KD cell speed defects were rescued on cell-free autocrine ECM produced by control cells but not on ECM produced by cortactin-KD cells. Investigation of the mechanism revealed that whereas endocytosed FN is redeposited at the basal cell surface by control cells, cortactin-KD cells exhibit defective FN secretion and abnormal FN retention in a late endocytic/lysosomal compartment. Cortactin-KD motility and FN deposition defects were phenocopied by KD in control cells of the lysosomal fusion regulator Synaptotagmin-7. Rescue of cortactin-KD cells by expression of cortactin binding domain mutants revealed that interaction with Arp2/3 complex and actin filaments is essential for rescue of both cell motility and autocrine ECM secretion phenotypes whereas binding of SH3 domain partners is not required. Conclusions Efficient cell motility, promoted by cortactin regulation of branched actin networks, involves processing and resecretion of internalized ECM from a late endosomal/lysosomal compartment. PMID:21856159

  8. Differential Function of N-Cadherin and Cadherin-7 in the Control of Embryonic Cell Motility

    PubMed Central

    Dufour, Sylvie; Beauvais-Jouneau, Alice; Delouvée, Annie; Thiery, Jean Paul

    1999-01-01

    Similar amounts of N-cadherin and cadherin-7, the prototypes of type I and type II cadherin, induced cell-cell adhesion in murine sarcoma 180 transfectants, Ncad-1 and cad7-29, respectively. However, in the initial phase of aggregation, Ncad-1 cells aggregated more rapidly than cad7-29 cells. Isolated Ncad-1 and cad7-29 cells adhered and spread in a similar manner on fibronectin (FN), whereas aggregated cad7-29 cells were more motile and dispersed than aggregated Ncad-1 cells. cad7-29 cells established transient contacts with their neighbors which were stabilized if FN-cell interactions were perturbed. In contrast, Ncad-1 cells remained in close contact when they migrated on FN. Both β-catenin and cadherin were more rapidly downregulated in cad7-29 than in Ncad-1 cells treated with cycloheximide, suggesting a higher turnover rate for cadherin-7–mediated cell-cell contacts than for those mediated by N-cadherin. The extent of FN-dependent focal adhesion kinase phosphorylation was much lower if the cells had initiated N-cadherin–mediated rather than cadherin-7–mediated cell adhesion before plating. On grafting into the embryo, Ncad-1 cells did not migrate and remained at or close to the graft site, even after 48 h, whereas grafted cad7-29 cells dispersed efficiently into embryonic structures. Thus, the adhesive phenotype of cadherin-7–expressing cells is regulated by the nature of the extracellular matrix environment which also controls the migratory behavior of the cells. In addition, adhesions mediated by different cadherins differentially regulate FN-dependent signaling. The transient contacts specifically observed in cadherin- 7–expressing cells may also be important in the control of cell motility. PMID:10427101

  9. Cell-substrate impedance fluctuations of single amoeboid cells encode cell-shape and adhesion dynamics

    NASA Astrophysics Data System (ADS)

    Leonhardt, Helmar; Gerhardt, Matthias; Höppner, Nadine; Krüger, Kirsten; Tarantola, Marco; Beta, Carsten

    2016-01-01

    We show systematic electrical impedance measurements of single motile cells on microelectrodes. Wild-type cells and mutant strains were studied that differ in their cell-substrate adhesion strength. We recorded the projected cell area by time-lapse microscopy and observed irregular oscillations of the cell shape. These oscillations were correlated with long-term variations in the impedance signal. Superposed to these long-term trends, we observed fluctuations in the impedance signal. Their magnitude clearly correlated with the adhesion strength, suggesting that strongly adherent cells display more dynamic cell-substrate interactions.

  10. Daucus carota Pentane/Diethyl Ether Fraction Inhibits Motility and Reduces Invasion of Cancer Cells.

    PubMed

    Zgheib, Perla; Daher, Costantine F; Mroueh, Mohamad; Nasrallah, Anita; Taleb, Robin I; El-Sibai, Mirvat

    2014-01-01

    Daucus carota (DC) is a herb used in folklore medicine in Lebanon to treat numerous diseases including cancer. Recent studies in our laboratory on DC oil and its fractions revealed potent anticancer activities in vitro and in vivo. The present study aims to investigate the effect of the most potent DC fraction, pentane/diethyl ether (50:50), on lung, skin, breast and glioblastoma cancer cell motility and invasion. Upon treatment, a pronounced decrease in cancer cell motility was observed in the 4 cell lines. The treatment also led to a decrease in cancer cell invasion and an increased cell adhesion. Additionally, the DC fraction caused a decrease in the activation of the ρ-GTPases Rac and CDC42, a finding that may partially explain the treatment-induced decrease in cell motility. The current study demonstrates a crucial effect of the DC pentane/diethyl ether fraction on cancer cell motility and metastasis, making it a potential candidate for cancer therapy specifically targeting cancer motility and metastasis. PMID:26088465

  11. SHP-2 phosphatase activity is required for PECAM-1-dependent cell motility.

    PubMed

    Zhu, Jing-Xu; Cao, Gaoyuan; Williams, James T; Delisser, Horace M

    2010-10-01

    Platelet endothelial cell adhesion molecule-1 (PECAM-1) has been implicated in endothelial cell motility during angiogenesis. Although there is evidence that SHP-2 plays a role in PECAM-1-dependent cell motility, the molecular basis of the activity of SHP-2 in this process has not been defined. To investigate the requirement of SHP-2 in PECAM-1-dependent cell motility, studies were done in which various constructs of SHP-2 were expressed in cell transfectants expressing PECAM-1. We observed that the levels of PECAM-1 tyrosine phosphorylation and SHP-2 association with PECAM-1 were significantly increased in cells expressing a phosphatase-inactive SHP-2 mutant, suggesting that the level of PECAM-1 tyrosine phosphorylation, and thus SHP-2 binding are regulated in part by bound, catalytically active SHP-2. We subsequently found that expression of PECAM-1 stimulated wound-induced migration and the formation of filopodia (a morphological feature of motile cells). These activities were associated with increased mitogen-activated protein kinase (MAPK) activation and the dephosphorylation of paxillin (an event implicated in the activation of MAPK). The phosphatase-inactive SHP-2 mutant, however, suppressed these PECAM-1-dependent phenomena, whereas the activity of PECAM-1 expressing cells was not altered by expression of wild-type SHP-2 or SHP-2 in which the scaffold/adaptor function had been disabled. Pharmacological inhibition of SHP-2 phosphatase activity also suppressed PECAM-1-dependent motility. Furthermore, PECAM-1 expression also stimulates tube formation, but none of the SHP-2 constructs affected this process. These findings therefore suggest a model for the involvement of SHP-2 in PECAM-1-dependent motility in which SHP-2, recruited by its interaction with PECAM-1, targets paxillin to ultimately activate the MAPK pathway and downstream events required for cell motility. PMID:20631249

  12. Notch-Mediated Cell Adhesion.

    PubMed

    Murata, Akihiko; Hayashi, Shin-Ichi

    2016-01-01

    Notch family members are generally recognized as signaling molecules that control various cellular responses in metazoan organisms. Early fly studies and our mammalian studies demonstrated that Notch family members are also cell adhesion molecules; however, information on the physiological roles of this function and its origin is limited. In this review, we discuss the potential present and ancestral roles of Notch-mediated cell adhesion in order to explore its origin and the initial roles of Notch family members dating back to metazoan evolution. We hypothesize that Notch family members may have initially emerged as cell adhesion molecules in order to mediate multicellularity in the last common ancestor of metazoan organisms. PMID:26784245

  13. Notch-Mediated Cell Adhesion

    PubMed Central

    Murata, Akihiko; Hayashi, Shin-Ichi

    2016-01-01

    Notch family members are generally recognized as signaling molecules that control various cellular responses in metazoan organisms. Early fly studies and our mammalian studies demonstrated that Notch family members are also cell adhesion molecules; however, information on the physiological roles of this function and its origin is limited. In this review, we discuss the potential present and ancestral roles of Notch-mediated cell adhesion in order to explore its origin and the initial roles of Notch family members dating back to metazoan evolution. We hypothesize that Notch family members may have initially emerged as cell adhesion molecules in order to mediate multicellularity in the last common ancestor of metazoan organisms. PMID:26784245

  14. Vimentin-mediated regulation of cell motility through modulation of beta4 integrin protein levels in oral tumor derived cells.

    PubMed

    Dmello, Crismita; Sawant, Sharada; Alam, Hunain; Gangadaran, Prakash; Tiwari, Richa; Dongre, Harsh; Rana, Neha; Barve, Sai; Costea, Daniela Elena; Chaukar, Davendra; Kane, Shubhada; Pant, Harish; Vaidya, Milind

    2016-01-01

    Vimentin expression correlates well with migratory and invasive potential of the carcinoma cells. The molecular mechanism by which vimentin regulates cell motility is not yet clear. Here, we addressed this issue by depleting vimentin in oral squamous cell carcinoma derived cell line. Vimentin knockdown cells showed enhanced adhesion and spreading to laminin-5. However, we found that they were less invasive as compared to the vector control cells. In addition, signaling associated with adhesion behavior of the cell was increased in vimentin knockdown clones. These findings suggest that the normal function of β4 integrin as mechanical adhesive device is enhanced upon vimentin downregulation. As a proof of principle, the compromised invasive potential of vimentin depleted cells could be rescued upon blocking with β4 integrin adhesion-blocking (ASC-8) antibody or downregulation of β4 integrin in vimentin knockdown background. Interestingly, plectin which associates with α6β4 integrin in the hemidesmosomes, was also found to be upregulated in vimentin knockdown clones. Furthermore, experiments on lysosome and proteasome inhibition revealed that perhaps vimentin regulates the turnover of β4 integrin and plectin. Moreover, an inverse association was observed between vimentin expression and β4 integrin in oral squamous cell carcinoma (OSCC). Collectively, our results show a novel role of vimentin in modulating cell motility by destabilizing β4 integrin-mediated adhesive interactions. Further, vimentin-β4 integrin together may prove to be useful markers for prognostication of human oral cancer. PMID:26646105

  15. Role of the RNA-binding protein IMP-2 in muscle cell motility.

    PubMed

    Boudoukha, Selim; Cuvellier, Sylvain; Polesskaya, Anna

    2010-12-01

    Insulin-like growth factor 2 (IGF-2) mRNA-binding proteins (IMPs) are a family of posttranscriptional regulatory factors with well-understood roles in embryonic development and cancer but with poorly characterized functions in normal adult cells and tissues. We now show that IMP-2, the most ubiquitously expressed member of the family, is abundant in human and mouse adult skeletal myoblasts, where it is indispensable for cell motility and for stabilization of microtubules. To explore the functions of IMP-2, we analyzed the transcripts that were differentially regulated in IMP-2-depleted myoblasts and bound to IMP-2 in normal myoblasts. Among them were the mRNAs of PINCH-2, an important mediator of cell adhesion and motility, and MURF-3, a microtubule-stabilizing protein. By gain- and loss-of-function assays and gel shift experiments, we show that IMP-2 regulates the expression of PINCH-2 and MURF-3 proteins via direct binding to their mRNAs. Upregulation of PINCH-2 in IMP-2-depleted myoblasts is the key event responsible for their decreased motility. Our data reveal how the posttranscriptional regulation of gene expression by IMP-2 contributes to the control of adhesion structures and stable microtubules and demonstrate an important function for IMP-2 in cellular motility. PMID:20956565

  16. Microfabricated ratchet structures for concentrating and patterning motile bacterial cells

    NASA Astrophysics Data System (ADS)

    Yub Kim, Sang; Lee, Eun Se; Lee, Ho Jae; Lee, Se Yeon; Kuk Lee, Sung; Kim, Taesung

    2010-09-01

    We present a novel microfabricated concentrator for Escherichia coli that can be a stand-alone and self-contained microfluidic device because it utilizes the motility of cells. First of all, we characterize the motility of E. coli cells and various ratcheting structures that can guide cells to move in a desired direction in straight and circular channels. Then, we combine these ratcheting microstructures with the intrinsic tendency of cells to swim on the right side in microchannels to enhance the concentration rates up to 180 fold until the concentrators are fully filled with cells. Furthermore, we demonstrate that cells can be positioned and concentrated with a constant spacing distance on a surface, allowing spatial patterning of motile cells. These results can be applied to biosorption or biosensor devices that are powered by motile cells because they can be highly concentrated without any external mechanical and electrical energy sources. Hence, we believe that the concentrator design holds considerable potential to be applied for concentrating and patterning other motile microbes and providing a versatile structure for motility study of bacterial cells.

  17. Epithelial to mesenchymal transition-the roles of cell morphology, labile adhesion and junctional coupling.

    PubMed

    Abdulla, Tariq; Luna-Zurita, Luis; de la Pompa, José Luis; Schleich, Jean-Marc; Summers, Ron

    2013-08-01

    Epithelial to mesenchymal transition (EMT) is a fundamental process during development and disease, including development of the heart valves and tumour metastases. An extended cellular Potts model was implemented to represent the behaviour emerging from autonomous cell morphology, labile adhesion, junctional coupling and cell motility. Computer simulations normally focus on these functional changes independently whereas this model facilitates exploration of the interplay between cell shape changes, adhesion and migration. The simulation model is fitted to an in vitro model of endocardial EMT, and agrees with the finding that Notch signalling increases cell-matrix adhesion in addition to modulating cell-cell adhesion. PMID:23787029

  18. A Comparison of Computational Models for Eukaryotic Cell Shape and Motility

    PubMed Central

    Holmes, William R.; Edelstein-Keshet, Leah

    2012-01-01

    Eukaryotic cell motility involves complex interactions of signalling molecules, cytoskeleton, cell membrane, and mechanics interacting in space and time. Collectively, these components are used by the cell to interpret and respond to external stimuli, leading to polarization, protrusion, adhesion formation, and myosin-facilitated retraction. When these processes are choreographed correctly, shape change and motility results. A wealth of experimental data have identified numerous molecular constituents involved in these processes, but the complexity of their interactions and spatial organization make this a challenging problem to understand. This has motivated theoretical and computational approaches with simplified caricatures of cell structure and behaviour, each aiming to gain better understanding of certain kinds of cells and/or repertoire of behaviour. Reaction–diffusion (RD) equations as well as equations of viscoelastic flows have been used to describe the motility machinery. In this review, we describe some of the recent computational models for cell motility, concentrating on simulations of cell shape changes (mainly in two but also three dimensions). The problem is challenging not only due to the difficulty of abstracting and simplifying biological complexity but also because computing RD or fluid flow equations in deforming regions, known as a “free-boundary” problem, is an extremely challenging problem in applied mathematics. Here we describe the distinct approaches, comparing their strengths and weaknesses, and the kinds of biological questions that they have been able to address. PMID:23300403

  19. PRL-3 promotes cell adhesion by interacting with JAM2 in colon cancer

    PubMed Central

    Lian, Shenyi; Meng, Lin; Xing, Xiaofang; Yang, Yongyong; Qu, Like; Shou, Chengchao

    2016-01-01

    Phosphatase of regenerating liver-3 (PRL-3), also termed PTP4A3, is a metastasis-related protein tyrosine phosphatase. Its expression levels are significantly correlated with the progression and survival of a wide range of malignant tumors. However, the mechanism by which PRL-3 promotes tumor invasion and metastasis is not clear. In the present study, the functions of PRL-3 were systemically analyzed in the key events of metastasis including, motility and adhesion. A cell wounding assay, cell spread assay and cell-matrix adhesion assay were carried out to analyze the cell movement and cell adhesion ability of colon cancer, immunoprecipitation and immunofluorescence assay was confirmed the interaction of PRL-3 and JAM2. It was demonstrated that PRL-3 promoted the motility of Flp-In-293 and LoVo colon cancer cells and increased the distribution of cell skeleton proteins on the cell protrusions. In addition, stably expressing PRL-3 reduced the spreading speed of colon cancer cells and cell adhesion on uncoated, fibronectin-coated and collagen I-coated plates. Mechanistically, junction adhesion molecular 2 (JAM2) was identified as a novel interacting protein of PRL-3. The findings of the present study revealed the roles of PRL-3 in cancer cell motility and adhesion process, and provided information on the possibility of PRL-3 increase cell-cell adhesion by associating with JAM2.

  20. Single cell motility and trail formation in populations of microglia

    NASA Astrophysics Data System (ADS)

    Lee, Kyoung Jin

    2009-03-01

    Microglia are a special type of glia cell in brain that has immune responses. They constitute about 20 % of the total glia population within the brain. Compared to other glia cells, microglia are very motile, constantly moving to destroy pathogens and to remove dead neurons. While doing so, they exhibit interesting body shapes, have cell-to-cell communications, and have chemotatic responses to each other. Interestingly, our recent in vitro studies show that their unusual motile behaviors can self-organize to form trails, similar to those in populations of ants. We have studied the changes in the physical properties of these trails by varying the cell population density and by changing the degree of spatial inhomogeneities (``pathogens''). Our experimental observations can be quite faithfully reproduced by a simple mathematical model involving many motile cells whose mechanical motion are driven by actin polymerization and depolymerization process within the individual cell body and by external chemical gradients.

  1. Cell motility and antibiotic tolerance of bacterial swarms

    NASA Astrophysics Data System (ADS)

    Zuo, Wenlong

    Many bacteria species can move across moist surfaces in a coordinated manner known as swarming. It is reported that swarm cells show higher tolerance to a wide variety of antibiotics than planktonic cells. We used the model bacterium E. coli to study how motility affects the antibiotic tolerance of swarm cells. Our results provide new insights for the control of pathogenic invasion via regulating cell motility. Mailing address: Room 306 Science Centre North Block, The Chinese University of Hong Kong, Shatin, N.T. Hong Kong SAR. Phone: +852-3943-6354. Fax: +852-2603-5204. E-mail: zwlong@live.com.

  2. Form and Function in Cell Motility: From Fibroblasts to Keratocytes

    PubMed Central

    Herant, Marc; Dembo, Micah

    2010-01-01

    Abstract It is plain enough that a horse is made for running, but similar statements about motile cells are not so obvious. Here the basis for structure-function relations in cell motility is explored by application of a new computational technique that allows realistic three-dimensional simulations of cells migrating on flat substrata. With this approach, some cyber cells spontaneously display the classic irregular protrusion cycles and handmirror morphology of a crawling fibroblast, and others the steady gliding motility and crescent morphology of a fish keratocyte. The keratocyte motif is caused by optimal recycling of the cytoskeleton from the back to the front so that more of the periphery can be devoted to protrusion. These calculations are a step toward bridging the gap between the integrated mechanics and biophysics of whole cells and the microscopic molecular biology of cytoskeletal components. PMID:20409459

  3. Alterations in cell adhesion proteins and cardiomyopathy

    PubMed Central

    Li, Jifen

    2014-01-01

    Cell adhesive junction is specialized intercellular structure composed of cell adhesion proteins. They are essential to connect adjacent heart muscle cell and make heart contraction effectively and properly. Clinical and genetic studies have revealed close relationship between cell adhesive proteins and the occurrence of various cardiomyopathies. Here we will review recent development on the disease phenotype, potential cellular and molecular mechanism related to cell adhesion molecules, with particular disease pathogenesis learned from genetic manipulated murine models. PMID:24944760

  4. Knockdown of Golgi phosphoprotein 2 inhibits hepatocellular carcinoma cell proliferation and motility

    PubMed Central

    Liu, Yiming; Zhang, Xiaodi; Sun, Ting; Jiang, Junchang; Li, Ying; Chen, Mingliang; Wei, Zhen; Jiang, Weiqin; Zhou, Linfu

    2016-01-01

    Golgi phosphoprotein 2 (GP73) is highly expressed in hepatocellular carcinoma (HCC) cells, where it serves as a biomarker and indicator of disease progression. We used MTS assays, anchorage-independent cell colony formation assays and a xenograft tumor model to show that GP73-specific siRNAs inhibit HCC proliferation in HepG2, SMMC-7721, and Huh7 cell lines and in vivo. Following GP73 silencing, levels of p-Rb, a factor related to metastasis, were reduced, but cell cycle progression was unaffected. Our results suggest that GP73 silencing may not directly suppress proliferation, but may instead inhibit cell motility. Results from proliferation assays suggest GP73 reduces expression of epithelial mesenchymal transition (EMT)-related factors and promotes cell motility, while transwell migration and invasion assays indicated a possible role in metastasis. Immunofluorescence co-localization microscopy and immunoblotting showed that GP73 decreases expression of N-cadherin and E-cadherin, two key factors in EMT, which may in turn decrease intracellular adhesive forces and promote cell motility. This study confirmed that GP73 expression leads to increased expression of EMT-related proteins and that GP73 silencing reduces HCC cell migration in vitro. These findings suggest that GP73 silencing through siRNA delivery may provide a novel low-toxicity therapy for the inhibition of tumor proliferation and metastasis. PMID:26870893

  5. Stimulation of glioma cell motility by expression, proteolysis, and release of the L1 neural cell recognition molecule

    PubMed Central

    Yang, Muhua; Adla, Shalini; Temburni, Murali K; Patel, Vivek P; Lagow, Errin L; Brady, Owen A; Tian, Jing; Boulos, Magdy I; Galileo, Deni S

    2009-01-01

    Background Malignant glioma cells are particularly motile and can travel diffusely through the brain parenchyma, apparently without following anatomical structures to guide their migration. The neural adhesion/recognition protein L1 (L1CAM; CD171) has been implicated in contributing to stimulation of motility and metastasis of several non-neural cancer types. We explored the expression and function of L1 protein as a stimulator of glioma cell motility using human high-grade glioma surgical specimens and established rat and human glioma cell lines. Results L1 protein expression was found in 17 out of 18 human high-grade glioma surgical specimens by western blotting. L1 mRNA was found to be present in human U-87/LacZ and rat C6 and 9L glioma cell lines. The glioma cell lines were negative for surface full length L1 by flow cytometry and high resolution immunocytochemistry of live cells. However, fixed and permeablized cells exhibited positive staining as numerous intracellular puncta. Western blots of cell line extracts revealed L1 proteolysis into a large soluble ectodomain (~180 kDa) and a smaller transmembrane proteolytic fragment (~32 kDa). Exosomal vesicles released by the glioma cell lines were purified and contained both full-length L1 and the proteolyzed transmembrane fragment. Glioma cell lines expressed L1-binding αvβ5 integrin cell surface receptors. Quantitative time-lapse analyses showed that motility was reduced significantly in glioma cell lines by 1) infection with an antisense-L1 retroviral vector and 2) L1 ectodomain-binding antibodies. Conclusion Our novel results support a model of autocrine/paracrine stimulation of cell motility in glioma cells by a cleaved L1 ectodomain and/or released exosomal vesicles containing L1. This mechanism could explain the diffuse migratory behavior of high-grade glioma cancer cells within the brain. PMID:19874583

  6. Helical motion of the cell body enhances Caulobacter crescentus motility

    PubMed Central

    Liu, Bin; Gulino, Marco; Morse, Michael; Tang, Jay X.; Powers, Thomas R.; Breuer, Kenneth S.

    2014-01-01

    We resolve the 3D trajectory and the orientation of individual cells for extended times, using a digital tracking technique combined with 3D reconstructions. We have used this technique to study the motility of the uniflagellated bacterium Caulobacter crescentus and have found that each cell displays two distinct modes of motility, depending on the sense of rotation of the flagellar motor. In the forward mode, when the flagellum pushes the cell, the cell body is tilted with respect to the direction of motion, and it precesses, tracing out a helical trajectory. In the reverse mode, when the flagellum pulls the cell, the precession is smaller and the cell has a lower translation distance per rotation period and thus a lower motility. Using resistive force theory, we show how the helical motion of the cell body generates thrust and can explain the direction-dependent changes in swimming motility. The source of the cell body precession is believed to be associated with the flexibility of the hook that connects the flagellum to the cell body. PMID:25053810

  7. Cell-Substrate Adhesion by Amoeboid Cells

    NASA Astrophysics Data System (ADS)

    Flanders, Bret; Panta, Krishna

    Amoeboid migration is a rapid (10 μm min-1) mode of migration that some tumor cells exhibit. To permit such rapid movement, the adhesive contacts between the cell and the substrate must be relatively short-lived and weak. In this study, we investigate the basic adhesive character of amoeboid cells (D. discoideum) in contact with silanized glass substrates. We observe the initiation and spreading of the adhesive contacts that these cells establish as they settle under gravity onto the substrate and relax towards mechanical equilibrium. The use of interference reflection microscopy and cellular tethering measurements have allowed us to determine the basic adhesive properties of the cell: the membrane-medium interfacial energy; the bending modulus; the equilibrium contact angle; and the work of adhesion. We find the time scale on which settling occurs to be longer than expected. Implications of these results on adhesion and migration will be discussed. The authors are grateful for support from NSF (CBET-1451903) and NIH (1R21EY026392).

  8. Cystinosin deficiency causes podocyte damage and loss associated with increased cell motility.

    PubMed

    Ivanova, Ekaterina A; Arcolino, Fanny O; Elmonem, Mohamed A; Rastaldi, Maria P; Giardino, Laura; Cornelissen, Elisabeth M; van den Heuvel, Lambertus P; Levtchenko, Elena N

    2016-05-01

    The involvement of the glomerulus in the pathogenesis of cystinosis, caused by loss-of-function mutations in cystinosin (CTNS, 17p13), is a matter of controversy. Although patients with cystinosis demonstrate glomerular lesions and high-molecular-weight proteinuria starting from an early age, a mouse model of cystinosis develops only signs of proximal tubular dysfunction. Here we studied podocyte damage in patients with cystinosis by analyzing urinary podocyte excretion and by in vitro studies of podocytes deficient in cystinosin. Urine from patients with cystinosis presented a significantly higher amount of podocytes compared with controls. In culture, cystinotic podocytes accumulated cystine compatible with cystinosin deficiency. The expression of podocyte specific genes CD2AP, podocalyxin, and synaptopodin and of the WT1 protein was evident in all cell lines. Conditionally immortalized podocyte lines of 2 patients with different CTNS mutations had altered cytoskeleton, impaired cell adhesion sites, and increased individual cell motility. Moreover, these cells showed enhanced phosphorylation of both Akt1 and Akt2 (isoforms of protein kinase B). Inhibition of Akt by a specific inhibitor (Akti inhibitor 1/2) resulted in normalization of the hypermotile phenotype. Thus, our study extends the list of genetic disorders causing podocyte damage and provides the evidence of altered cell signaling cascades resulting in impaired cell adhesion and enhanced cell motility in cystinosis. PMID:27083281

  9. RHOA and PRKCZ control different aspects of cell motility in pancreatic cancer metastatic clones

    PubMed Central

    2010-01-01

    Background Our understanding of the mechanism regulating pancreatic cancer metastatic phenotype is limited. We analyzed the role of RHOA and PRKCZ in the motility attitude of two subclones of the pancreatic adenocarcinoma cell line SUIT-2 (S2), with different in vivo metastatic potential in nude mice: S2-m with a low metastatic potential and highly metastatic S2-CP9 using RHOA and PRKCZ cell-permeable inhibitory peptides. Methods Adhesion assays, cell permeable peptides, RHOA activity assay, western blotting Results When used in combination cell-permeable inhibitory peptides partially inhibited cell adhesion by about 50% in clone S2-CP9. In clone S2-m, the effect was limited to 15% inhibition. In a wound healing assay, S2-CP9 was sensitive only to treatment with the combination of both RHOA and PRKCZ inhibitory peptides. Conversely, S2-m was unable to migrate toward both ends of the wound in basal conditions. Migration of cells through a membrane with 8 μm pores was completely abolished in both clones by individual treatment with RHOA and PRKCZ inhibitory peptides. Conclusion Herein, we demonstrate a critical role for RHOA and PRKCZ in the regulation of different aspects of cell motility of pancreatic adenocarcinoma and demonstrate the need to inhibit both pathways to obtain a functionally relevant effect in most assays. These results indicate that RHOA and PRKCZ, and their downstream effectors, can represent important pharmacological targets that could potentially control the highly metastatic attitude of PDAC. PMID:20236512

  10. Rapid Actin-Dependent Viral Motility in Live Cells

    PubMed Central

    Vaughan, Joshua C.; Brandenburg, Boerries; Hogle, James M.; Zhuang, Xiaowei

    2009-01-01

    During the course of an infection, viruses take advantage of a variety of mechanisms to travel in cells, ranging from diffusion within the cytosol to active transport along cytoskeletal filaments. To study viral motility within the intrinsically heterogeneous environment of the cell, we have developed a motility assay that allows for the global and unbiased analysis of tens of thousands of virus trajectories in live cells. Using this assay, we discovered that poliovirus exhibits anomalously rapid intracellular movement that was independent of microtubules, a common track for fast and directed cargo transport. Such rapid motion, with speeds of up to 5 μm/s, allows the virus particles to quickly explore all regions of the cell with the exception of the nucleus. The rapid, microtubule-independent movement of poliovirus was observed in multiple human-derived cell lines, but appeared to be cargo-specific. Other cargo, including a closely related picornavirus, did not exhibit similar motility. Furthermore, the motility is energy-dependent and requires an intact actin cytoskeleton, suggesting an active transport mechanism. The speed of this microtubule-independent but actin-dependent movement is nearly an order of magnitude faster than the fastest speeds reported for actin-dependent transport in animal cells, either by actin polymerization or by myosin motor proteins. PMID:19751669

  11. Spatial anisotropy and heterogeneity in contractility and adhesion distribution may contribute to cell steering during migration

    NASA Astrophysics Data System (ADS)

    Soumya S S; Kolwankar, Subodh; George, Edna; Basu, Santanu K.; Sen, Shamik; Inamdar, Mandar M.

    2014-02-01

    Transition from random to persistent cell motility requires spatiotemporal organization of the cytoskeleton and focal adhesions. The influence of these two structures on cell steering can also be gleaned from trypsin de-adhesion experiments, wherein cells exposed to trypsin round up, exhibiting a combination of rotation and translation. Here, we present a model to evaluate the contributions of contractility and bond distribution to experimentally observed de-adhesion. We show that while asymmetry in bond distribution causes only cell translation, a combination of asymmetric bond distribution and non-uniform contractility is required for translation and rotation and may guide cell migration.

  12. PTP1B inhibitor promotes endothelial cell motility by activating the DOCK180/Rac1 pathway

    PubMed Central

    Wang, Yuan; Yan, Feng; Ye, Qing; Wu, Xiao; Jiang, Fan

    2016-01-01

    Promoting endothelial cell (EC) migration is important not only for therapeutic angiogenesis, but also for accelerating re-endothelialization after vessel injury. Several recent studies have shown that inhibition of protein tyrosine phosphatase 1B (PTP1B) may promote EC migration and angiogenesis by enhancing the vascular endothelial growth factor receptor-2 (VEGFR2) signalling. In the present study, we demonstrated that PTP1B inhibitor could promote EC adhesion, spreading and migration, which were abolished by the inhibitor of Rac1 but not RhoA GTPase. PTP1B inhibitor significantly increased phosphorylation of p130Cas, and the interactions among p130Cas, Crk and DOCK180; whereas the phosphorylation levels of focal adhesion kinase, Src, paxillin, or Vav2 were unchanged. Gene silencing of DOCK180, but not Vav2, abrogated the effects of PTP1B inhibitor on EC motility. The effects of PTP1B inhibitor on EC motility and p130Cas/DOCK180 activation persisted in the presence of the VEGFR2 antagonist. In conclusion, we suggest that stimulation of the DOCK180 pathway represents an alternative mechanism of PTP1B inhibitor-stimulated EC motility, which does not require concomitant VEGFR2 activation as a prerequisite. Therefore, PTP1B inhibitor may be a useful therapeutic strategy for promoting EC migration in cardiovascular patients in which the VEGF/VEGFR functions are compromised. PMID:27052191

  13. HES6 enhances the motility of alveolar rhabdomyosarcoma cells

    SciTech Connect

    Wickramasinghe, Caroline M; Domaschenz, Renae; Amagase, Yoko; Williamson, Daniel; Missiaglia, Edoardo; Shipley, Janet; Murai, Kasumi; Jones, Philip H

    2013-01-01

    Absract: HES6, a member of the hairy-enhancer-of-split family of transcription factors, plays multiple roles in myogenesis. It is a direct target of the myogenic transcription factor MyoD and has been shown to regulate the formation of the myotome in development, myoblast cell cycle exit and the organization of the actin cytoskeleton during terminal differentiation. Here we investigate the expression and function of HES6 in rhabdomyosarcoma, a soft tissue tumor which expresses myogenic genes but fails to differentiate into muscle. We show that HES6 is expressed at high levels in the subset of alveolar rhabdomyosarcomas expressing PAX/FOXO1 fusion genes (ARMSp). Knockdown of HES6 mRNA in the ARMSp cell line RH30 reduces proliferation and cell motility. This phenotype is rescued by expression of mouse Hes6 which is insensitive to HES6 siRNA. Furthermore, expression microarray analysis indicates that the HES6 knockdown is associated with a decrease in the levels of Transgelin, (TAGLN), a regulator of the actin cytoskeleton. Knockdown of TAGLN decreases cell motility, whilst TAGLN overexpression rescues the motility defect resulting from HES6 knockdown. These findings indicate HES6 contributes to the pathogenesis of ARMSp by enhancing both proliferation and cell motility.

  14. Attachment of motile bacterial cells to prealigned holed microarrays.

    PubMed

    Rozhok, Sergey; Fan, Zhifang; Nyamjav, Dorjderem; Liu, Chang; Mirkin, Chad A; Holz, Richard C

    2006-12-19

    Construction of biomotors is an exciting area of scientific research that holds great promise for the development of new technologies with broad potential applications in areas such as the energy industry and medicine. Herein, we demonstrate the fabrication of prealigned microarrays of motile Escherichia coli bacterial cells on SiOx substrates. To prepare these arrays, holed surfaces with a gold layer on the bottom of the holes were utilized. The attachment of bacteria to the holes was achieved via nonspecific interactions using poly-l-lysine hydrobromide (PLL). Our data suggest that a single motile bacterial cell can be selectively attached to an individual hole on a surface and bacterial cell binding can be controlled by altering the pH, with the greatest occupancy occurring at pH 7.8. Cells attached to hole arrays remained motile for at least 4 h. These data indicate that holed surface structures provide a promising footprint for the attachment of motile bacterial cells to form high-density site-specific functional bacterial microarrays. PMID:17154612

  15. Na,K-ATPase β-Subunit Is Required for Epithelial Polarization, Suppression of Invasion, and Cell Motility

    PubMed Central

    Rajasekaran, Sigrid A.; Palmer, Lawrence G.; Quan, Karina; Harper, Jeffrey F.; Ball, William J.; Bander, Neil H.; Soler, Alejandro Peralta; Rajasekaran, Ayyappan K.

    2001-01-01

    The cell adhesion molecule E-cadherin has been implicated in maintaining the polarized phenotype of epithelial cells and suppression of invasiveness and motility of carcinoma cells. Na,K-ATPase, consisting of an α- and β-subunit, maintains the sodium gradient across the plasma membrane. A functional relationship between E-cadherin and Na,K-ATPase has not previously been described. We present evidence that the Na,K-ATPase plays a crucial role in E-cadherin–mediated development of epithelial polarity, and suppression of invasiveness and motility of carcinoma cells. Moloney sarcoma virus-transformed Madin-Darby canine kidney cells (MSV-MDCK) have highly reduced levels of E-cadherin and β1-subunit of Na,K-ATPase. Forced expression of E-cadherin in MSV-MDCK cells did not reestablish epithelial polarity or inhibit the invasiveness and motility of these cells. In contrast, expression of E-cadherin and Na,K-ATPase β1-subunit induced epithelial polarization, including the formation of tight junctions and desmosomes, abolished invasiveness, and reduced cell motility in MSV-MDCK cells. Our results suggest that E-cadherin–mediated cell-cell adhesion requires the Na,K-ATPase β-subunit's function to induce epithelial polarization and suppress invasiveness and motility of carcinoma cells. Involvement of the β1-subunit of Na,K-ATPase in the polarized phenotype of epithelial cells reveals a novel link between the structural organization and vectorial ion transport function of epithelial cells. PMID:11179415

  16. α-Actinin-4 Enhances Colorectal Cancer Cell Invasion by Suppressing Focal Adhesion Maturation

    PubMed Central

    Yamada, Tesshi; Takenawa, Tadaomi

    2015-01-01

    α-Actinins (ACTNs) are known to crosslink actin filaments at focal adhesions in migrating cells. Among the four isoforms of mammalian ACTNs, ACTN1 and ACTN4 are ubiquitously expressed. Recently, ACTN4 was reported to enhance cancer cell motility, invasion, and metastasis. However, the mechanism by which ACTN4 drives these malignant phenotypes remains unclear. Here, we show that ACTN4, but not ACTN1, induces the formation of immature focal adhesions in DLD-1 cells, leading to the rapid turnover of focal adhesions. Interestingly, zyxin (ZYX) assembly to focal adhesions was markedly decreased in ACTN4-expressing DLD-1 cells, while the recruitment of paxillin (PAX) occurred normally. On the other hand, in ACTN1-expressing DLD-1 cells, PAX and ZYX were normally recruited to focal adhesions, suggesting that ACTN4 specifically impairs focal adhesion maturation by inhibiting the recruitment of ZYX to focal complexes. Using purified recombinant proteins, we found that ZYX binding to ACTN4 was defective under conditions where ZYX binding to ACTN1 was observed. Furthermore, Matrigel invasion of SW480 cells that express high endogenous levels of ACTN4 protein was inhibited by ectopic expression of ACTN1. Altogether, our results suggest that ZYX defective binding to ACTN4, which occupies focal adhesions instead of ACTN1, induces the formation of immature focal adhesions, resulting in the enhancement of cell motility and invasion. PMID:25860875

  17. ALDH isozymes downregulation affects cell growth, cell motility and gene expression in lung cancer cells

    PubMed Central

    Moreb, Jan S; Baker, Henry V; Chang, Lung-Ji; Amaya, Maria; Lopez, M Cecilia; Ostmark, Blanca; Chou, Wayne

    2008-01-01

    Background Aldehyde dehydrogenase isozymes ALDH1A1 and ALDH3A1 are highly expressed in non small cell lung cancer. Neither the mechanisms nor the biologic significance for such over expression have been studied. Methods We have employed oligonucleotide microarrays to analyze changes in gene profiles in A549 lung cancer cell line in which ALDH activity was reduced by up to 95% using lentiviral mediated expression of siRNA against both isozymes (Lenti 1+3). Stringent analysis methods were used to identify gene expression patterns that are specific to the knock down of ALDH activity and significantly different in comparison to wild type A549 cells (WT) or cells similarly transduced with green fluorescent protein (GFP) siRNA. Results We confirmed significant and specific down regulation of ALDH1A1 and ALDH3A1 in Lenti 1+3 cells and in comparison to 12 other ALDH genes detected. The results of the microarray analysis were validated by real time RT-PCR on RNA obtained from Lenti 1+3 or WT cells treated with ALDH activity inhibitors. Detailed functional analysis was performed on 101 genes that were significantly different (P < 0.001) and their expression changed by ≥ 2 folds in the Lenti 1+3 group versus the control groups. There were 75 down regulated and 26 up regulated genes. Protein binding, organ development, signal transduction, transcription, lipid metabolism, and cell migration and adhesion were among the most affected pathways. Conclusion These molecular effects of the ALDH knock-down are associated with in vitro functional changes in the proliferation and motility of these cells and demonstrate the significance of ALDH enzymes in cell homeostasis with a potentially significant impact on the treatment of lung cancer. PMID:19025616

  18. Cell Motility Resulting form Spontaneous Polymerization Waves

    NASA Astrophysics Data System (ADS)

    Kruse, Karsten

    2014-03-01

    The crawling of living cells on solid substrates is often driven by the actin cytoskeleton, a network of structurally polar filamentous proteins that is intrinsically driven by the hydrolysis of ATP. How cells organize their actin network during crawling is still poorly understood. A possible general mechanism underlying actin organization has been offered by the observation of spontaneous actin polymerization waves in various different cell types. We use a theoretical approach to investigate the possible role of spontaneous actin waves on cell crawling. To this end, we develop a meanfield framework for studying spatiotemporal aspects of actin assembly dynamics, which helped to identify possible origins of self-organized actin waves. The impact of these waves on cell crawling is then investigated by using a phase-field approach to confine the actin network to a cellular domain. We find that spontaneous actin waves can lead to directional or amoeboidal crawling. In the latter case, the cell performs a random walk. Within our deterministic framework, this behavior is due to complex spiral waves inside the cell. Finally, we compare the seemingly random motion of our model cells to the dynamics of cells of the human immune system. These cells patrol the body in search for infected cells and we discuss possible implications of our theory for the search process' efficiency. Work was funded by the DFG through KR3430/1, GK1276, and SFB 1027.

  19. Plasma polymerization for cell adhesive/anti-adhesive implant coating

    NASA Astrophysics Data System (ADS)

    Meichsner, Juergen; Testrich, Holger; Rebl, Henrike; Nebe, Barbara

    2015-09-01

    Plasma polymerization of ethylenediamine (C2H8N2, EDA) and perfluoropropane (C3F8, PFP) with admixture of argon and hydrogen, respectively, was studied using an asymmetric 13.56 MHz CCP. The analysis of the plasma chemical gas phase processes for stable molecules revealed consecutive reactions: C2H8N2 consumption, intermediate product NH3, and main final product HCN. In C3F8- H2 plasma the precursor molecule C3F8 and molecular hydrogen are consumed and HF as well as CF4 and C2F6 are found as main gaseous reaction products. The deposited plasma polymer films on the powered electrode are strongly cross-linked due to ion bombardment. The stable plasma polymerized films from EDA are characterized by high content of nitrogen with N/C ratio of about 0.35. The plasma polymerized fluorocarbon film exhibit a reduced F/C ratio of about 1.2. Adhesion tests with human osteoblast cell line MG-63 on coated Ti6Al4V samples (polished) compared with uncoated reference sample yielded both, the enhanced cell adhesion for plasma polymerized EDA and significantly reduced cell adhesion for fluorocarbon coating, respectively. Aging of the plasma polymerized EDA film, in particular due to the reactions with oxygen from air, showed no significant change in the cell adhesion. The fluorocarbon coating with low cell adhesion is of interest for temporary implants. Funded by the Campus PlasmaMed.

  20. The actin-bundling protein L-plastin supports T-cell motility and activation

    PubMed Central

    Morley, Sharon Celeste

    2013-01-01

    Summary Tight regulation of actin dynamics is essential for T-cell trafficking and activation. Recent studies in human and murine T cells reveal that T-cell motility and full T-cell activation require the hematopoietic-specific, actin-bundling protein L-plastin. T cells lacking L-plastin do not form fully mature synapses and thus demonstrate reduced cytokine production and proliferation. Reduction or loss of L-plastin expression also reduces the velocity of T cells and impairs thymic egress and intranodal motility. While dispensable for proximal T-cell receptor and chemokine receptor signaling, L-plastin is critical to the later stages of synapse maturation and cellular polarization. Serine phosphorylation, calcium, and calmodulin binding regulate the bundling activity and localization of LPL following T-cell receptor and chemokine receptor engagement. However, the interaction between these regulatory domains and resulting changes in local control of actin cytoskeletal structures has not been fully elucidated. Circumstantial evidence suggests a function for L-plastin in either the formation or maintenance of integrin-associated adhesion structures. As L-plastin may be a target of the commonly used immunosuppressive agent dexamethasone, full elucidation of the regulation and function of L-plastin in T-cell biology may illuminate new pathways for clinically useful immunotherapeutics. PMID:24117812

  1. Where to Go: Breaking the Symmetry in Cell Motility

    PubMed Central

    2016-01-01

    Cell migration in the “correct” direction is pivotal for many biological processes. Although most work is devoted to its molecular mechanisms, the cell’s preference for one direction over others, thus overcoming intrinsic random motility, epitomizes a profound principle that underlies all complex systems: the choice of one axis, in structure or motion, from a uniform or symmetric set of options. Explaining directional motility by an external chemo-attractant gradient does not solve but only shifts the problem of causation: whence the gradient? A new study in PLOS Biology shows cell migration in a self-generated gradient, offering an opportunity to take a broader look at the old dualism of extrinsic instruction versus intrinsic symmetry-breaking in cell biology. PMID:27196433

  2. Possible roles of the endocytic cycle in cell motility.

    PubMed

    Traynor, David; Kay, Robert R

    2007-07-15

    Starving, highly motile Dictyostelium cells maintain an active endocytic cycle, taking up their surface about every 11 minutes. Cell motility depends on a functional NSF (N-ethylmaleimide sensitive factor) protein--also essential for endocytosis and membrane trafficking generally--and we, therefore, investigated possible ways in which the endocytic cycle might be required for cell movement. First, NSF, and presumably membrane trafficking, are not required for the initial polarization of the leading edge in a cyclic-AMP gradient. Second, we can detect no evidence for membrane flow from the leading edge, as photobleached or photoactivated marks in the plasma membrane move forward roughly in step with the leading edge, rather than backwards from it. Third, we find that the surface area of a cell--measured from confocal reconstructions--constantly fluctuates during movement as it projects pseudopodia and otherwise changes shape; increases of 20-30% can often occur over a few minutes. These fluctuations cannot be explained by reciprocal changes in filopodial surface area and they substantially exceed the 2-3% by which membranes can stretch. We propose that the endocytic cycle has a key function in motility by allowing adjustment of cell surface area to match changes in shape and that, without this function, movement is severely impaired. PMID:17606987

  3. Synaptic Cell Adhesion Molecules in Alzheimer's Disease

    PubMed Central

    Leshchyns'ka, Iryna

    2016-01-01

    Alzheimer's disease (AD) is a neurodegenerative brain disorder associated with the loss of synapses between neurons in the brain. Synaptic cell adhesion molecules are cell surface glycoproteins which are expressed at the synaptic plasma membranes of neurons. These proteins play key roles in formation and maintenance of synapses and regulation of synaptic plasticity. Genetic studies and biochemical analysis of the human brain tissue, cerebrospinal fluid, and sera from AD patients indicate that levels and function of synaptic cell adhesion molecules are affected in AD. Synaptic cell adhesion molecules interact with Aβ, a peptide accumulating in AD brains, which affects their expression and synaptic localization. Synaptic cell adhesion molecules also regulate the production of Aβ via interaction with the key enzymes involved in Aβ formation. Aβ-dependent changes in synaptic adhesion affect the function and integrity of synapses suggesting that alterations in synaptic adhesion play key roles in the disruption of neuronal networks in AD. PMID:27242933

  4. The Influence of Electric Field and Confinement on Cell Motility

    PubMed Central

    Huang, Yu-Ja; Samorajski, Justin; Kreimer, Rachel; Searson, Peter C.

    2013-01-01

    The ability of cells to sense and respond to endogenous electric fields is important in processes such as wound healing, development, and nerve regeneration. In cell culture, many epithelial and endothelial cell types respond to an electric field of magnitude similar to endogenous electric fields by moving preferentially either parallel or antiparallel to the field vector, a process known as galvanotaxis. Here we report on the influence of dc electric field and confinement on the motility of fibroblast cells using a chip-based platform. From analysis of cell paths we show that the influence of electric field on motility is much more complex than simply imposing a directional bias towards the cathode or anode. The cell velocity, directedness, as well as the parallel and perpendicular components of the segments along the cell path are dependent on the magnitude of the electric field. Forces in the directions perpendicular and parallel to the electric field are in competition with one another in a voltage-dependent manner, which ultimately govern the trajectories of the cells in the presence of an electric field. To further investigate the effects of cell reorientation in the presence of a field, cells are confined within microchannels to physically prohibit the alignment seen in 2D environment. Interestingly, we found that confinement results in an increase in cell velocity both in the absence and presence of an electric field compared to migration in 2D. PMID:23555674

  5. Quantitation of Endothelial Cell Adhesiveness In Vitro

    PubMed Central

    Lowe, Donna J.; Raj, Kenneth

    2015-01-01

    One of the cardinal processes of inflammation is the infiltration of immune cells from the lumen of the blood vessel to the surrounding tissue. This occurs when endothelial cells, which line blood vessels, become adhesive to circulating immune cells such as monocytes. In vitro measurement of this adhesiveness has until now been done by quantifying the total number of monocytes that adhere to an endothelial layer either as a direct count or by indirect measurement of the fluorescence of adherent monocytes. While such measurements do indicate the average adhesiveness of the endothelial cell population, they are confounded by a number of factors, such as cell number, and do not reveal the proportion of endothelial cells that are actually adhesive. Here we describe and demonstrate a method which allows the enumeration of adhesive cells within a tested population of endothelial monolayer. Endothelial cells are grown on glass coverslips and following desired treatment are challenged with monocytes (that may be fluorescently labeled). After incubation, a rinsing procedure, involving multiple rounds of immersion and draining, the cells are fixed. Adhesive endothelial cells, which are surrounded by monocytes are readily identified and enumerated, giving an adhesion index that reveals the actual proportion of endothelial cells within the population that are adhesive. PMID:26132714

  6. ADAM17 Promotes Motility, Invasion, and Sprouting of Lymphatic Endothelial Cells.

    PubMed

    Mężyk-Kopeć, Renata; Wyroba, Barbara; Stalińska, Krystyna; Próchnicki, Tomasz; Wiatrowska, Karolina; Kilarski, Witold W; Swartz, Melody A; Bereta, Joanna

    2015-01-01

    Tumor-associated lymphatic vessels actively participate in tumor progression and dissemination. ADAM17, a sheddase for numerous growth factors, cytokines, receptors, and cell adhesion molecules, is believed to promote tumor development, facilitating both tumor cell proliferation and migration, as well as tumor angiogenesis. In this work we addressed the issue of whether ADAM17 may also promote tumor lymphangiogenesis. First, we found that ADAM17 is important for the migratory potential of immortalized human dermal lymphatic endothelial cells (LEC). When ADAM17 was stably silenced in LEC, their proliferation was not affected, but: (i) single-cell motility, (ii) cell migration through a 3D Matrigel/collagen type I matrix, and (iii) their ability to form sprouts in a 3D matrix were significantly diminished. The differences in the cell motility between ADAM17-proficient and ADAM17-silenced cells were eliminated by inhibitors of EGFR and HER2, indicating that ADAM17-mediated shedding of growth factors accounts for LEC migratory potential. Interestingly, ADAM17 depletion affected the integrin surface expression/functionality in LEC. ADAM17-silenced cells adhered to plastic, type I collagen, and fibronectin faster than their ADAM17-proficient counterparts. The difference in adhesion to fibronectin was abolished by a cyclic RGD peptide, emphasizing the involvement of integrins in the process. Using a soluble receptor array, we identified BIG-H3 among several candidate proteins involved in the phenotypic and behavioral changes of LEC upon ADAM17 silencing. In additional assays, we confirmed the increased expression of BIG-H3, as well as TGFβ2 in ADAM17-silenced LEC. The antilymphangiogenic effects of ADAM17 silencing in lymphatic endothelial cells suggest further relevance of ADAM17 as a potential target in cancer therapy. PMID:26176220

  7. Quantitative methods for analyzing cell-cell adhesion in development.

    PubMed

    Kashef, Jubin; Franz, Clemens M

    2015-05-01

    During development cell-cell adhesion is not only crucial to maintain tissue morphogenesis and homeostasis, it also activates signalling pathways important for the regulation of different cellular processes including cell survival, gene expression, collective cell migration and differentiation. Importantly, gene mutations of adhesion receptors can cause developmental disorders and different diseases. Quantitative methods to measure cell adhesion are therefore necessary to understand how cells regulate cell-cell adhesion during development and how aberrations in cell-cell adhesion contribute to disease. Different in vitro adhesion assays have been developed in the past, but not all of them are suitable to study developmentally-related cell-cell adhesion processes, which usually requires working with low numbers of primary cells. In this review, we provide an overview of different in vitro techniques to study cell-cell adhesion during development, including a semi-quantitative cell flipping assay, and quantitative single-cell methods based on atomic force microscopy (AFM)-based single-cell force spectroscopy (SCFS) or dual micropipette aspiration (DPA). Furthermore, we review applications of Förster resonance energy transfer (FRET)-based molecular tension sensors to visualize intracellular mechanical forces acting on cell adhesion sites. Finally, we describe a recently introduced method to quantitate cell-generated forces directly in living tissues based on the deformation of oil microdroplets functionalized with adhesion receptor ligands. Together, these techniques provide a comprehensive toolbox to characterize different cell-cell adhesion phenomena during development. PMID:25448695

  8. Collective cell motility promotes chemotactic prowess and resistance to chemorepulsion.

    PubMed

    Malet-Engra, Gema; Yu, Weimiao; Oldani, Amanda; Rey-Barroso, Javier; Gov, Nir S; Scita, Giorgio; Dupré, Loïc

    2015-01-19

    Collective cell migration is a widespread biological phenomenon, whereby groups of highly coordinated, adherent cells move in a polarized fashion. This migration mode is a hallmark of tissue morphogenesis during development and repair and of solid tumor dissemination. In addition to circulating as solitary cells, lymphoid malignancies can assemble into tissues as multicellular aggregates. Whether malignant lymphocytes are capable of coordinating their motility in the context of chemokine gradients is, however, unknown. Here, we show that, upon exposure to CCL19 or CXCL12 gradients, malignant B and T lymphocytes assemble into clusters that migrate directionally and display a wider chemotactic sensitivity than individual cells. Physical modeling recapitulates cluster motility statistics and shows that intracluster cell cohesion results in noise reduction and enhanced directionality. Quantitative image analysis reveals that cluster migration runs are periodically interrupted by transitory rotation and random phases that favor leader cell turnover. Additionally, internalization of CCR7 in leader cells is accompanied by protrusion retraction, loss of polarity, and the ensuing replacement by new leader cells. These mechanisms ensure sustained forward migration and resistance to chemorepulsion, a behavior of individual cells exposed to steep CCL19 gradients that depends on CCR7 endocytosis. Thus, coordinated cluster dynamics confer distinct chemotactic properties, highlighting unexpected features of lymphoid cell migration. PMID:25578904

  9. Modelling cell motility and chemotaxis with evolving surface finite elements

    PubMed Central

    Elliott, Charles M.; Stinner, Björn; Venkataraman, Chandrasekhar

    2012-01-01

    We present a mathematical and a computational framework for the modelling of cell motility. The cell membrane is represented by an evolving surface, with the movement of the cell determined by the interaction of various forces that act normal to the surface. We consider external forces such as those that may arise owing to inhomogeneities in the medium and a pressure that constrains the enclosed volume, as well as internal forces that arise from the reaction of the cells' surface to stretching and bending. We also consider a protrusive force associated with a reaction–diffusion system (RDS) posed on the cell membrane, with cell polarization modelled by this surface RDS. The computational method is based on an evolving surface finite-element method. The general method can account for the large deformations that arise in cell motility and allows the simulation of cell migration in three dimensions. We illustrate applications of the proposed modelling framework and numerical method by reporting on numerical simulations of a model for eukaryotic chemotaxis and a model for the persistent movement of keratocytes in two and three space dimensions. Movies of the simulated cells can be obtained from http://homepages.warwick.ac.uk/∼maskae/CV_Warwick/Chemotaxis.html. PMID:22675164

  10. Membrane tension and cytoskeleton organization in cell motility

    NASA Astrophysics Data System (ADS)

    Sens, Pierre; Plastino, Julie

    2015-07-01

    Cell membrane shape changes are important for many aspects of normal biological function, such as tissue development, wound healing and cell division and motility. Various disease states are associated with deregulation of how cells move and change shape, including notably tumor initiation and cancer cell metastasis. Cell motility is powered, in large part, by the controlled assembly and disassembly of the actin cytoskeleton. Much of this dynamic happens in close proximity to the plasma membrane due to the fact that actin assembly factors are membrane-bound, and thus actin filaments are generally oriented such that their growth occurs against or near the membrane. For a long time, the membrane was viewed as a relatively passive scaffold for signaling. However, results from the last five years show that this is not the whole picture, and that the dynamics of the actin cytoskeleton are intimately linked to the mechanics of the cell membrane. In this review, we summarize recent findings concerning the role of plasma membrane mechanics in cell cytoskeleton dynamics and architecture, showing that the cell membrane is not just an envelope or a barrier for actin assembly, but is a master regulator controlling cytoskeleton dynamics and cell polarity.

  11. Live cell imaging of neuronal growth cone motility and guidance in vitro

    PubMed Central

    Suter, Daniel M.

    2013-01-01

    Summary The neuronal growth cone, a highly motile structure at the tip of neuronal processes, is an excellent model system for studying directional cell movements. While biochemical and genetic approaches unveiled molecular interactions between ligand, receptor, signaling and cytoskeleton-associated proteins controlling axonal growth and guidance, in vitro live cell imaging has emerged as a crucial approach for dissecting cellular mechanisms of growth cone motility and guidance. Important insights into these mechanisms have been gained from studies using the large growth cones elaborated by Aplysia californica neurons, an outstanding model system for live cell imaging for a number of reasons. Identified neurons can be isolated and imaged at room temperature. Aplysia growth cones are 5–10 times larger than growth cones from other species, making them suitable for quantitative high-resolution imaging of cytoskeletal protein dynamics and biophysical approaches. Lastly, protein, RNA, fluorescent probes and small molecules can be microinjected into the neuronal cell body for localization and functional studies. The following chapter describes culturing of Aplysia bag cell neurons, live cell imaging of neuronal growth cones using differential interference contrast and fluorescent speckle microscopy as well as the restrained bead interaction assay to induce adhesion-mediated growth cone guidance in vitro. PMID:21748670

  12. Modulation of Intracellular Calcium Levels by Calcium Lactate Affects Colon Cancer Cell Motility through Calcium-Dependent Calpain

    PubMed Central

    Sundaramoorthy, Pasupathi; Sim, Jae Jun; Jang, Yeong-Su; Mishra, Siddhartha Kumar; Jeong, Keun-Yeong; Mander, Poonam; Chul, Oh Byung; Shim, Won-Sik; Oh, Seung Hyun; Nam, Ky-Youb; Kim, Hwan Mook

    2015-01-01

    Cancer cell motility is a key phenomenon regulating invasion and metastasis. Focal adhesion kinase (FAK) plays a major role in cellular adhesion and metastasis of various cancers. The relationship between dietary supplementation of calcium and colon cancer has been extensively investigated. However, the effect of calcium (Ca2+) supplementation on calpain-FAK-motility is not clearly understood. We sought to identify the mechanism of FAK cleavage through Ca2+ bound lactate (CaLa), its downstream signaling and role in the motility of human colon cancer cells. We found that treating HCT116 and HT-29 cells with CaLa immediately increased the intracellular Ca2+ (iCa2+) levels for a prolonged period of time. Ca2+ influx induced cleavage of FAK into an N-terminal FAK (FERM domain) in a dose-dependent manner. Phosphorylated FAK (p-FAK) was also cleaved in to its p-N-terminal FAK. CaLa increased colon cancer cells motility. Calpeptin, a calpain inhibitor, reversed the effects of CaLa on FAK and pFAK cleavage in both cancer cell lines. The cleaved FAK translocates into the nucleus and modulates p53 stability through MDM2-associated ubiquitination. CaLa-induced Ca2+ influx increased the motility of colon cancer cells was mediated by calpain activity through FAK and pFAK protein destabilization. In conclusion, these results suggest that careful consideration may be given in deciding dietary Ca2+ supplementation to patient undergoing treatment for metastatic cancer. PMID:25629974

  13. Membrane tension feedback on shape and motility of eukaryotic cells

    NASA Astrophysics Data System (ADS)

    Winkler, Benjamin; Aranson, Igor S.; Ziebert, Falko

    2016-04-01

    In the framework of a phase field model of a single cell crawling on a substrate, we investigate how the properties of the cell membrane affect the shape and motility of the cell. Since the membrane influences the cell dynamics on multiple levels and provides a nontrivial feedback, we consider the following fundamental interactions: (i) the reduction of the actin polymerization rate by membrane tension; (ii) area conservation of the cell's two-dimensional cross-section vs. conservation of the circumference (i.e. membrane inextensibility); and (iii) the contribution from the membrane's bending energy to the shape and integrity of the cell. As in experiments, we investigate two pertinent observables - the cell's velocity and its aspect ratio. We find that the most important effect is the feedback of membrane tension on the actin polymerization. Bending rigidity has only minor effects, visible mostly in dynamic reshaping events, as exemplified by collisions of the cell with an obstacle.

  14. Interstitial flows promote an amoeboid over mesenchymal motility of breast cancer cells revealed by a three dimensional microfluidic model

    PubMed Central

    Huang, Yu Ling; Tung, Chih-kuan; Zheng, Anqi; Kim, Beum Jun; Wu, Mingming

    2015-01-01

    Malignant tumors are often associated with an elevated fluid pressure due to the abnormal growth of vascular vessels, and thus an increased interstitial flow out of the tumor. Recent in vitro work revealed that interstitial flows critically regulated tumor cell migration within a three dimensional biomatrix, and breast cancer cell migration behavior depended sensitively on the cell seeding density, chemokine availability and flow rates. In this paper, we focus on roles of interstitial flows in modulating heterogeneity of cancer cell motility phenotype within a three dimensional biomatrix. Using a newly developed microfluidic model, we show that breast cancer cells (MDA-MB-231) embedded in a 3D type I collagen matrix exhibit both an amoeboid and a mesenchymal motility, and interstitial flows promote the cell population towards the amoeboid motility phenotype. Furthermore, the addition of exogenous adhesion molecules (fibronectin) within the extracellular matrix (type I collagen) partially rescues the mesenchymal phenotype in the presence of the flow. Quantitative analysis of cell tracks and cell shape shows distinct differential migration characteristics of amoeboid and mesenchymal cells. Notably, the fastest moving cells belong to the subpopulation of amoeboid cells. Together, these findings highlight the important roles of biophysical forces in modulating tumor cell migration heterogeneity and plasticity, as well as the suitability of microfluidic models in interrogating tumor cell dynamics at single-cell and subpopulation level. PMID:26235230

  15. Interstitial flows promote amoeboid over mesenchymal motility of breast cancer cells revealed by a three dimensional microfluidic model.

    PubMed

    Huang, Yu Ling; Tung, Chih-Kuan; Zheng, Anqi; Kim, Beum Jun; Wu, Mingming

    2015-11-01

    Malignant tumors are often associated with an elevated fluid pressure due to the abnormal growth of vascular vessels, and thus an increased interstitial flow out of the tumors. Recent in vitro works revealed that interstitial flows critically regulated tumor cell migration within a three dimensional biomatrix, and breast cancer cell migration behavior depended sensitively on the cell seeding density, chemokine availability and flow rates. In this paper, we focus on the role of interstitial flows in modulating the heterogeneity of cancer cell motility phenotype within a three dimensional biomatrix. Using a newly developed microfluidic model, we show that breast cancer cells (MDA-MB-231) embedded in a 3D type I collagen matrix exhibit both amoeboid and mesenchymal motility, and interstitial flows promote the cell population towards the amoeboid motility phenotype. Furthermore, the addition of exogenous adhesion molecules (fibronectin) within the extracellular matrix (type I collagen) partially rescues the mesenchymal phenotype in the presence of the flow. Quantitative analysis of cell tracks and cell shapes shows distinct differential migration characteristics of amoeboid and mesenchymal cells. Notably, the fastest moving cells belong to the subpopulation of amoeboid cells. Together, these findings highlight the important role of biophysical forces in modulating tumor cell migration heterogeneity and plasticity, as well as the suitability of microfluidic models in interrogating tumor cell dynamics at single-cell and subpopulation level. PMID:26235230

  16. Interplay of differential cell mechanical properties, motility, and proliferation in emergent collective behavior of cell co-cultures

    NASA Astrophysics Data System (ADS)

    Sutter, Leo; Kolbman, Dan; Wu, Mingming; Ma, Minglin; Das, Moumita

    The biophysics of cell co-cultures, i.e. binary systems of cell populations, is of great interest in many biological processes including formation of embryos, and tumor progression. During these processes, different types of cells with different physical properties are mixed with each other, with important consequences for cell-cell interaction, aggregation, and migration. The role of the differences in their physical properties in their collective behavior remains poorly understood. Furthermore, until recently most theoretical studies of collective cell migration have focused on two dimensional systems. Under physiological conditions, however, cells often have to navigate three dimensional and confined micro-environments. We study a confined, three-dimensional binary system of interacting, active, and deformable particles with different physical properties such as deformability, motility, adhesion, and division rates using Langevin Dynamics simulations. Our findings may provide insights into how the differences in and interplay between cell mechanical properties, division, and motility influence emergent collective behavior such as cell aggregation and segregation experimentally observed in co-cultures of breast cancer cells and healthy breast epithelial cells. This work was partially supported by a Cottrell College Science Award.

  17. Tetanus neurotoxin-mediated cleavage of cellubrevin impairs epithelial cell migration and integrin-dependent cell adhesion

    PubMed Central

    Proux-Gillardeaux, Véronique; Gavard, Julie; Irinopoulou, Theano; Mège, René-Marc; Galli, Thierry

    2005-01-01

    A role for endocytosis and exocytosis in cell migration has been proposed but not yet demonstrated. Here, we show that cellubrevin (Cb), an early endosomal v-SNARE, mediates trafficking in the lamellipod of migrating epithelial cells and partially colocalizes with markers of focal contacts. Expression of tetanus neurotoxin, which selectively cleaves Cb, significantly reduced the speed of migrating epithelial cells. Furthermore, expression of tetanus neurotoxin enhanced the adhesion of epithelial cells to collagen, laminin, fibronectin, and E-cadherin; altered spreading on collagen; and impaired the recycling of β1 integrins. These results suggest that Cb-dependent membrane trafficking participates in cell motility through the regulation of cell adhesion. PMID:15851685

  18. Diminished expression of h2-calponin in prostate cancer cells promotes cell proliferation, migration and the dependence of cell adhesion on substrate stiffness.

    PubMed

    Moazzem Hossain, M; Wang, Xin; Bergan, Raymond C; Jin, J-P

    2014-01-01

    Calponin is an actin filament-associated protein and its h2 isoform inhibits cell motility. Here we report significant expression of h2-calponin in prostate epithelial cells, which is diminished in cancerous cells. Comparison between a prostate cancer cell line PC3 and its metastatic derivative PC3-M showed lower levels of h2-calponin in PC3-M, corresponding to faster rates of cell proliferation and migration. Substrate adhesion of PC3 and PC3-M cells was positively correlated to the level of h2-calponin and the adhesion of PC3-M exhibited a higher dependence on substrate stiffness. Such effects of h2-calponin on cell proliferation, migration and substrate adhesion were also seen in normal versus cancerous primary prostate cells. Further supporting the role of h2-calponin in inhibiting cell motility, fibroblasts isolated from h2-calponin knockout mice proliferated and migrated faster than that of wild type fibroblasts. Transfective over-expression of h2-calponin in PC3-M cells effectively inhibited cell proliferation and migration. The results suggest that the diminished expression of h2-calponin in prostate cancer cells increases cell motility, decreases substrate adhesion, and promotes adhesion on high stiffness substrates. PMID:25161871

  19. Diminished expression of h2-calponin in prostate cancer cells promotes cell proliferation, migration and the dependence of cell adhesion on substrate stiffness

    PubMed Central

    Moazzem Hossain, M.; Wang, Xin; Bergan, Raymond C.; Jin, J.-P.

    2014-01-01

    Calponin is an actin filament-associated protein and its h2 isoform inhibits cell motility. Here we report significant expression of h2-calponin in prostate epithelial cells, which is diminished in cancerous cells. Comparison between a prostate cancer cell line PC3 and its metastatic derivative PC3-M showed lower levels of h2-calponin in PC3-M, corresponding to faster rates of cell proliferation and migration. Substrate adhesion of PC3 and PC3-M cells was positively correlated to the level of h2-calponin and the adhesion of PC3-M exhibited a higher dependence on substrate stiffness. Such effects of h2-calponin on cell proliferation, migration and substrate adhesion were also seen in normal versus cancerous primary prostate cells. Further supporting the role of h2-calponin in inhibiting cell motility, fibroblasts isolated from h2-calponin knockout mice proliferated and migrated faster than that of wild type fibroblasts. Transfective over-expression of h2-calponin in PC3-M cells effectively inhibited cell proliferation and migration. The results suggest that the diminished expression of h2-calponin in prostate cancer cells increases cell motility, decreases substrate adhesion, and promotes adhesion on high stiffness substrates. PMID:25161871

  20. Loss of SNAP29 Impairs Endocytic Recycling and Cell Motility

    PubMed Central

    Rapaport, Debora; Lugassy, Yevgenia; Sprecher, Eli; Horowitz, Mia

    2010-01-01

    Intracellular membrane trafficking depends on the ordered formation and consumption of transport intermediates and requires that membranes fuse with each other in a tightly regulated and highly specific manner. Membrane anchored SNAREs assemble into SNARE complexes that bring membranes together to promote fusion. SNAP29 is a ubiquitous synaptosomal-associated SNARE protein. It interacts with several syntaxins and with the EH domain containing protein EHD1. Loss of functional SNAP29 results in CEDNIK syndrome (Cerebral Dysgenesis, Neuropathy, Ichthyosis and Keratoderma). Using fibroblast cell lines derived from CEDNIK patients, we show that SNAP29 mediates endocytic recycling of transferrin and β1-integrin. Impaired β1-integrin recycling affected cell motility, as reflected by changes in cell spreading and wound healing. No major changes were detected in exocytosis of VSVG protein from the Golgi apparatus, although the Golgi system acquired a dispersed morphology in SNAP29 deficient cells. Our results emphasize the importance of SNAP29 mediated membrane fusion in endocytic recycling and consequently, in cell motility. PMID:20305790

  1. Lattice-free models of directed cell motility

    NASA Astrophysics Data System (ADS)

    Irons, Carolyn; Plank, Michael J.; Simpson, Matthew J.

    2016-01-01

    Directed cell migration often occurs when individual cells move in response to an external chemical stimulus. Cells can respond by moving in either the direction of increasing (chemoattraction) or decreasing (chemorepulsion) concentration. Many previous models of directed cell migration use a lattice-based framework where agents undergo a lattice-based random walk and the direction of nearest-neighbour motility events is biased in a preferred direction. Such lattice-based models can lead to unrealistic configurations of agents, since the agents always move on an artificial lattice structure which is never observed experimentally. We present a lattice-free model of directed cell migration that incorporates two key features. First, agents move on a continuous domain, with the possibility that there is some preferred direction of motion. Second, to be consistent with experimental observations, we enforce a crowding mechanism so that motility events that would lead to agent overlap are not permitted. We compare simulation data from the new lattice-free model with a more traditional lattice-based model. To provide additional insight into the lattice-free model, we construct an approximate conservation statement which corresponds to a nonlinear advection-diffusion equation in the continuum limit. The solution of this mean-field model compares well with averaged data from the individual-based model.

  2. Rab11-FIP3 is a Rab11-binding protein that regulates breast cancer cell motility by modulating the actin cytoskeleton

    PubMed Central

    Jing, Jian; Tarbutton, Elizabeth; Wilson, Gayle; Prekeris, Rytis

    2009-01-01

    Cell adhesion and motility are very dynamic processes that require the temporal and spatial coordination of many cellular structures. ADP-ribosylation factor 6 (Arf6) has emerged as master regulator of endocytic membrane traffic and cytoskeletal dynamics during cell movement. Recently, a novel Arf6-binding protein known as FIP3/arfophilin/eferin has been identified. In addition to Arf6, FIP3 also interacts with Rab11, a small monomeric GTPase that regulates endocytic membrane transport. Both Arf6 and Rab11 GTPases have been implicated in regulation of cell motility. Here we test the role of FIP3 in breast carcinoma cell motility. First, we demonstrate that FIP3 is associated with recycling endosomes that are present at the leading edge of motile cells. Second, we show that FIP3 is required for the motility of MDA-MB-231 breast carcinoma cells. Third, we demonstrate that FIP3 regulates Rac1-dependent actin cytoskeleton dynamics and modulates the formation and ruffling of lamellipodia. Finally, we demonstrate that FIP3 regulates the localization of Arf6 at the plasma membrane of MDA-MB-231 cells. Based on our data we propose that FIP3 affects cell motility by regulating Arf6 localization to the plasma membrane of the leading edge, thus regulating polarized Rac1 activation and actin dynamics. PMID:19327867

  3. Lichen Secondary Metabolite, Physciosporin, Inhibits Lung Cancer Cell Motility

    PubMed Central

    Yang, Yi; Park, So-Yeon; Nguyen, Thanh Thi; Yu, Young Hyun; Nguyen, Tru Van; Sun, Eun Gene; Udeni, Jayalal; Jeong, Min-Hye; Pereira, Iris; Moon, Cheol; Ha, Hyung-Ho; Kim, Kyung Keun; Hur, Jae-Seoun; Kim, Hangun

    2015-01-01

    Lichens produce various unique chemicals that can be used for pharmaceutical purposes. To screen for novel lichen secondary metabolites showing inhibitory activity against lung cancer cell motility, we tested acetone extracts of 13 lichen samples collected in Chile. Physciosporin, isolated from Pseudocyphellaria coriacea (Hook f. & Taylor) D.J. Galloway & P. James, was identified as an effective compound and showed significant inhibitory activity in migration and invasion assays against human lung cancer cells. Physciosporin treatment reduced both protein and mRNA levels of N-cadherin with concomitant decreases in the levels of epithelial-mesenchymal transition markers such as snail and twist. Physciosporin also suppressed KITENIN (KAI1 C-terminal interacting tetraspanin)-mediated AP-1 activity in both the absence and presence of epidermal growth factor stimulation. Quantitative real-time PCR analysis showed that the expression of the metastasis suppressor gene, KAI1, was increased while that of the metastasis enhancer gene, KITENIN, was dramatically decreased by physciosporin. Particularly, the activity of 3’-untranslated region of KITENIN was decreased by physciosporin. Moreover, Cdc42 and Rac1 activities were decreased by physciosporin. These results demonstrated that the lichen secondary metabolite, physciosporin, inhibits lung cancer cell motility through novel mechanisms of action. PMID:26371759

  4. Patterns of periodic holes created by increased cell motility

    PubMed Central

    Chen, Ting-Hsuan; Guo, Chunyan; Zhao, Xin; Yao, Yucheng; Boström, Kristina I.; Wong, Margaret N.; Tintut, Yin; Demer, Linda L.; Ho, Chih-Ming; Garfinkel, Alan

    2012-01-01

    The reaction and diffusion of morphogens is a mechanism widely used to explain many spatial patterns in physics, chemistry and developmental biology. However, because experimental control is limited in most biological systems, it is often unclear what mechanisms account for the biological patterns that arise. Here, we study a biological model of cultured vascular mesenchymal cells (VMCs), which normally self-organize into aggregates that form into labyrinthine configurations. We use an experimental control and a mathematical model that includes reacting and diffusing morphogens and a third variable reflecting local cell density. With direct measurements showing that cell motility was increased ninefold and threefold by inhibiting either Rho kinase or non-muscle myosin-II, respectively, our experimental results and mathematical modelling demonstrate that increased motility alters the multicellular pattern of the VMC cultures, from labyrinthine to a pattern of periodic holes. These results suggest implications for the tissue engineering of functional replacements for trabecular or spongy tissue such as endocardium and bone. PMID:22649581

  5. Lichen Secondary Metabolite, Physciosporin, Inhibits Lung Cancer Cell Motility.

    PubMed

    Yang, Yi; Park, So-Yeon; Nguyen, Thanh Thi; Yu, Young Hyun; Nguyen, Tru Van; Sun, Eun Gene; Udeni, Jayalal; Jeong, Min-Hye; Pereira, Iris; Moon, Cheol; Ha, Hyung-Ho; Kim, Kyung Keun; Hur, Jae-Seoun; Kim, Hangun

    2015-01-01

    Lichens produce various unique chemicals that can be used for pharmaceutical purposes. To screen for novel lichen secondary metabolites showing inhibitory activity against lung cancer cell motility, we tested acetone extracts of 13 lichen samples collected in Chile. Physciosporin, isolated from Pseudocyphellaria coriacea (Hook f. & Taylor) D.J. Galloway & P. James, was identified as an effective compound and showed significant inhibitory activity in migration and invasion assays against human lung cancer cells. Physciosporin treatment reduced both protein and mRNA levels of N-cadherin with concomitant decreases in the levels of epithelial-mesenchymal transition markers such as snail and twist. Physciosporin also suppressed KITENIN (KAI1 C-terminal interacting tetraspanin)-mediated AP-1 activity in both the absence and presence of epidermal growth factor stimulation. Quantitative real-time PCR analysis showed that the expression of the metastasis suppressor gene, KAI1, was increased while that of the metastasis enhancer gene, KITENIN, was dramatically decreased by physciosporin. Particularly, the activity of 3'-untranslated region of KITENIN was decreased by physciosporin. Moreover, Cdc42 and Rac1 activities were decreased by physciosporin. These results demonstrated that the lichen secondary metabolite, physciosporin, inhibits lung cancer cell motility through novel mechanisms of action. PMID:26371759

  6. CD34 Promotes Satellite Cell Motility and Entry into Proliferation to Facilitate Efficient Skeletal Muscle Regeneration

    PubMed Central

    Alfaro, Leslie Ann So; Dick, Sarah A.; Siegel, Ashley L.; Anonuevo, Adam S.; McNagny, Kelly M.; Megeney, Lynn A.; Cornelison, Dawn D.W.; Rossi, Fabio M.V.

    2013-01-01

    Expression of the cell surface sialomucin CD34 is common to many adult stem cell types, including muscle satellite cells. However, no clear stem cell or regeneration-related phenotype has ever been reported in mice lacking CD34, and its function on these cells remains poorly understood. Here, we assess the functional role of CD34 on satellite cell-mediated muscle regeneration. We show that Cd34−/− mice, which have no obvious developmental phenotype, display a defect in muscle regeneration when challenged with either acute or chronic muscle injury. This regenerative defect is caused by impaired entry into proliferation and delayed myogenic progression. Consistent with the reported anti-adhesive function of CD34, knock out satellite cells also show decreased motility along their host myofiber. Altogether, our results identify a role for CD34 in the poorly understood early steps of satellite cell activation, and provide the first evidence that beyond being a stem cell marker, CD34 may play an important function in modulating stem cell activity. PMID:21997891

  7. Fibulin-3 is uniquely upregulated in malignant gliomas and promotes tumor cell motility and invasion.

    PubMed

    Hu, Bin; Thirtamara-Rajamani, Keerthi K; Sim, Hosung; Viapiano, Mariano S

    2009-11-01

    Malignant gliomas are highly invasive tumors with an almost invariably rapid and lethal outcome. Surgery and chemoradiotherapy fail to remove resistant tumor cells that disperse within normal tissue, which are a major cause for disease progression and therapy failure. Infiltration of the neural parenchyma is a distinctive property of malignant gliomas compared with other solid tumors. Thus, glioma cells are thought to produce unique molecular changes that remodel the neural extracellular matrix and form a microenvironment permissive for their motility. Here, we describe the unique expression and proinvasive role of fibulin-3, a mesenchymal matrix protein specifically upregulated in gliomas. Fibulin-3 is downregulated in peripheral tumors and is thought to inhibit tumor growth. However, we found fibulin-3 highly upregulated in gliomas and cultured glioma cells, although the protein was undetectable in normal brain or cultured astrocytes. Overexpression and knockdown experiments revealed that fibulin-3 did not seem to affect glioma cell morphology or proliferation, but enhanced substrate-specific cell adhesion and promoted cell motility and dispersion in organotypic cultures. Moreover, orthotopic implantation of fibulin-3-overexpressing glioma cells resulted in diffuse tumors with increased volume and rostrocaudal extension compared with controls. Tumors and cultured cells overexpressing fibulin-3 also showed elevated expression and activity of matrix metalloproteases, such as MMP-2/MMP-9 and ADAMTS-5. Taken together, our results suggest that fibulin-3 has a unique expression and protumoral role in gliomas, and could be a potential target against tumor progression. Strategies against this glioma-specific matrix component could disrupt invasive mechanisms and restrict the dissemination of these tumors. PMID:19887559

  8. Exendin-4 induces cell adhesion and differentiation and counteracts the invasive potential of human neuroblastoma cells.

    PubMed

    Luciani, Paola; Deledda, Cristiana; Benvenuti, Susanna; Squecco, Roberta; Cellai, Ilaria; Fibbi, Benedetta; Marone, Ilaria Maddalena; Giuliani, Corinna; Modi, Giulia; Francini, Fabio; Vannelli, Gabriella Barbara; Peri, Alessandro

    2013-01-01

    Exendin-4 is a molecule currently used, in its synthetic form exenatide, for the treatment of type 2 diabetes mellitus. Exendin-4 binds and activates the Glucagon-Like Peptide-1 Receptor (GLP-1R), thus inducing insulin release. More recently, additional biological properties have been associated to molecules that belong to the GLP-1 family. For instance, Peptide YY and Vasoactive Intestinal Peptide have been found to affect cell adhesion and migration and our previous data have shown a considerable actin cytoskeleton rearrangement after exendin-4 treatment. However, no data are currently available on the effects of exendin-4 on tumor cell motility. The aim of this study was to investigate the effects of this molecule on cell adhesion, differentiation and migration in two neuroblastoma cell lines, SH-SY5Y and SK-N-AS. We first demonstrated, by Extra Cellular Matrix cell adhesion arrays, that exendin-4 increased cell adhesion, in particular on a vitronectin substrate. Subsequently, we found that this molecule induced a more differentiated phenotype, as assessed by i) the evaluation of neurite-like protrusions in 3D cell cultures, ii) the analysis of the expression of neuronal markers and iii) electrophysiological studies. Furthermore, we demonstrated that exendin-4 reduced cell migration and counteracted anchorage-independent growth in neuroblastoma cells. Overall, these data indicate for the first time that exendin-4 may have anti-tumoral properties. PMID:23990978

  9. Micropatterning cell adhesion on polyacrylamide hydrogels.

    PubMed

    Zhang, Jian; Guo, Wei-Hui; Rape, Andrew; Wang, Yu-Li

    2013-01-01

    Cell shape and substrate rigidity play critical roles in regulating cell behaviors and fate. Controlling cell shape on elastic adhesive materials holds great promise for creating a physiologically relevant culture environment for basic and translational research and clinical applications. However, it has been technically challenging to create high-quality adhesive patterns on compliant substrates. We have developed an efficient and economical method to create precise micron-scaled adhesive patterns on the surface of a hydrogel (Rape et al., Biomaterials 32:2043-2051, 2011). This method will facilitate the research on traction force generation, cellular mechanotransduction, and tissue engineering, where precise controls of both materials rigidity and adhesive patterns are important. PMID:23955741

  10. Synchronization of Spontaneous Active Motility of Hair Cell Bundles

    PubMed Central

    Zhang, Tracy-Ying; Ji, Seung; Bozovic, Dolores

    2015-01-01

    Hair cells of the inner ear exhibit an active process, believed to be crucial for achieving the sensitivity of auditory and vestibular detection. One of the manifestations of the active process is the occurrence of spontaneous hair bundle oscillations in vitro. Hair bundles are coupled by overlying membranes in vivo; hence, explaining the potential role of innate bundle motility in the generation of otoacoustic emissions requires an understanding of the effects of coupling on the active bundle dynamics. We used microbeads to connect small groups of hair cell bundles, using in vitro preparations that maintain their innate oscillations. Our experiments demonstrate robust synchronization of spontaneous oscillations, with either 1:1 or multi-mode phase-locking. The frequency of synchronized oscillation was found to be near the mean of the innate frequencies of individual bundles. Coupling also led to an improved regularity of entrained oscillations, demonstrated by an increase in the quality factor. PMID:26540409

  11. Synchronization of Spontaneous Active Motility of Hair Cell Bundles.

    PubMed

    Zhang, Tracy-Ying; Ji, Seung; Bozovic, Dolores

    2015-01-01

    Hair cells of the inner ear exhibit an active process, believed to be crucial for achieving the sensitivity of auditory and vestibular detection. One of the manifestations of the active process is the occurrence of spontaneous hair bundle oscillations in vitro. Hair bundles are coupled by overlying membranes in vivo; hence, explaining the potential role of innate bundle motility in the generation of otoacoustic emissions requires an understanding of the effects of coupling on the active bundle dynamics. We used microbeads to connect small groups of hair cell bundles, using in vitro preparations that maintain their innate oscillations. Our experiments demonstrate robust synchronization of spontaneous oscillations, with either 1:1 or multi-mode phase-locking. The frequency of synchronized oscillation was found to be near the mean of the innate frequencies of individual bundles. Coupling also led to an improved regularity of entrained oscillations, demonstrated by an increase in the quality factor. PMID:26540409

  12. Bistability of Cell Adhesion in Shear Flow

    PubMed Central

    Efremov, Artem; Cao, Jianshu

    2011-01-01

    Cell adhesion plays a central role in multicellular organisms helping to maintain their integrity and homeostasis. This complex process involves many different types of adhesion proteins, and synergetic behavior of these proteins during cell adhesion is frequently observed in experiments. A well-known example is the cooperation of rolling and stationary adhesion proteins during the leukocytes extravasation. Despite the fact that such cooperation is vital for proper functioning of the immune system, its origin is not fully understood. In this study we constructed a simple analytic model of the interaction between a leukocyte and the blood vessel wall in shear flow. The model predicts existence of cell adhesion bistability, which results from a tug-of-war between two kinetic processes taking place in the cell-wall contact area—bond formation and rupture. Based on the model results, we suggest an interpretation of several cytoadhesion experiments and propose a simple explanation of the existing synergy between rolling and stationary adhesion proteins, which is vital for effective cell adherence to the blood vessel walls in living organisms. PMID:21889439

  13. Promotion of Cell Migration by Neural Cell Adhesion Molecule (NCAM) Is Enhanced by PSA in a Polysialyltransferase-Specific Manner

    PubMed Central

    Guan, Feng; Wang, Xin; He, Fa

    2015-01-01

    Neural cell adhesion molecule 140 (NCAM-140) is a glycoprotein and always highly polysialylated in cancer. Functions of polysialic acid (PSA) that binds to N-glycan termini on NCAM remain unclear. ldlD-14 cells, a CHO cell mutant deficient in UDP-Gal 4-epimerase, are useful for structural and functional studies of Gal-containing glycoproteins because their abnormal glycosylation can be converted to normal status by exogenous addition of galactose (Gal). We cloned the genes for NCAM-140 and for polysialyltransferases STX and PST (responsible for PSA synthesis) from normal murine mammary gland epithelial (NMuMG) cells and transfected them into ldlD-14 and human breast cancer cells MCF-7. The effect of PSA on NCAM-mediated cell proliferation, motility, migration and adhesion was studied. We found that NCAM-140 significantly promoted cell proliferation, motility and migration, while polysialylation of NCAM-140 catalyzed by STX, but not by PST, enhanced NCAM-mediated cell migration, but not cell proliferation or motility. In addition, PSA catalyzed by different polysialyltransferases affected the adhesion of NCAM to different extracellular matrix (ECM) components. PMID:25885924

  14. Promotion of cell migration by neural cell adhesion molecule (NCAM) is enhanced by PSA in a polysialyltransferase-specific manner.

    PubMed

    Guan, Feng; Wang, Xin; He, Fa

    2015-01-01

    Neural cell adhesion molecule 140 (NCAM-140) is a glycoprotein and always highly polysialylated in cancer. Functions of polysialic acid (PSA) that binds to N-glycan termini on NCAM remain unclear. ldlD-14 cells, a CHO cell mutant deficient in UDP-Gal 4-epimerase, are useful for structural and functional studies of Gal-containing glycoproteins because their abnormal glycosylation can be converted to normal status by exogenous addition of galactose (Gal). We cloned the genes for NCAM-140 and for polysialyltransferases STX and PST (responsible for PSA synthesis) from normal murine mammary gland epithelial (NMuMG) cells and transfected them into ldlD-14 and human breast cancer cells MCF-7. The effect of PSA on NCAM-mediated cell proliferation, motility, migration and adhesion was studied. We found that NCAM-140 significantly promoted cell proliferation, motility and migration, while polysialylation of NCAM-140 catalyzed by STX, but not by PST, enhanced NCAM-mediated cell migration, but not cell proliferation or motility. In addition, PSA catalyzed by different polysialyltransferases affected the adhesion of NCAM to different extracellular matrix (ECM) components. PMID:25885924

  15. Migratory and adhesive properties of Xenopus laevis primordial germ cells in vitro

    PubMed Central

    Dzementsei, Aliaksandr; Schneider, David; Janshoff, Andreas; Pieler, Tomas

    2013-01-01

    Summary The directional migration of primordial germ cells (PGCs) to the site of gonad formation is an advantageous model system to study cell motility. The embryonic development of PGCs has been investigated in different animal species, including mice, zebrafish, Xenopus and Drosophila. In this study we focus on the physical properties of Xenopus laevis PGCs during their transition from the passive to the active migratory state. Pre-migratory PGCs from Xenopus laevis embryos at developmental stages 17–19 to be compared with migratory PGCs from stages 28–30 were isolated and characterized in respect to motility and adhesive properties. Using single-cell force spectroscopy, we observed a decline in adhesiveness of PGCs upon reaching the migratory state, as defined by decreased attachment to extracellular matrix components like fibronectin, and a reduced adhesion to somatic endodermal cells. Data obtained from qPCR analysis with isolated PGCs reveal that down-regulation of E-cadherin might contribute to this weakening of cell-cell adhesion. Interestingly, however, using an in vitro migration assay, we found that movement of X. laevis PGCs can also occur independently of specific interactions with their neighboring cells. The reduction of cellular adhesion during PGC development is accompanied by enhanced cellular motility, as reflected in increased formation of bleb-like protrusions and inferred from electric cell-substrate impedance sensing (ECIS) as well as time-lapse image analysis. Temporal alterations in cell shape, including contraction and expansion of the cellular body, reveal a higher degree of cellular dynamics for the migratory PGCs in vitro. PMID:24285703

  16. The interplay between cell motility and tissue architecture

    NASA Astrophysics Data System (ADS)

    Tanner, Kandice

    2013-03-01

    Glandular tissue form arboreal networks comprised of acini and tubes. Loss of structure is concomitant with the in vivo pathologic state. In vitro models have been shown to recapitulate the functional units of the mammary gland and other organs. Despite our much improved understanding gleaned from both in vitro and in vivo interrogation, the mechanisms by which cells are able to achieve the correct tissue organization remain elusive. How do single mammary epithelial cells form polarized acini when cultured in a surrogate basement membrane gel but not on 2D surfaces? Simply put, how does a cell know which way is up? Why do malignant breast cells show a differential response in that they form non-polarized aggregates? Recently, it was determined that non-malignant cells undergo multiple rotations to establish acini while tumor cells are randomly motile during tumor formation. Can it be that a tumor cell has simply lost its way. This research was supported by the Intramural Research Program of the NIH, National Cancer Institute.

  17. Lrs14 transcriptional regulators influence biofilm formation and cell motility of Crenarchaea

    PubMed Central

    Orell, Alvaro; Peeters, Eveline; Vassen, Victoria; Jachlewski, Silke; Schalles, Sven; Siebers, Bettina; Albers, Sonja-Verena

    2013-01-01

    Like bacteria, archaea predominately exist as biofilms in nature. However, the environmental cues and the molecular mechanisms driving archaeal biofilm development are not characterized. Here we provide data suggesting that the transcriptional regulators belonging to the Lrs14-like protein family constitute a key regulatory factor during Sulfolobus biofilm development. Among the six lrs14-like genes encoded by Sulfolobus acidocaldarius, the deletion of three led to markedly altered biofilm phenotypes. Although Δsaci1223 and Δsaci1242 deletion mutants were impaired in biofilm formation, the Δsaci0446 deletion strain exhibited a highly increased extracellular polymeric substance (EPS) production, leading to a robust biofilm structure. Moreover, although the expression of the adhesive pili (aap) genes was upregulated, the genes of the motility structure, the archaellum (fla), were downregulated rendering the Δsaci0446 strain non-motile. Gel shift assays confirmed that Saci0446 bound to the promoter regions of fla and aap thus controlling the expression of both cell surface structures. In addition, genetic epistasis analysis using Δsaci0446 as background strain identified a gene cluster involved in the EPS biosynthetic pathway of S. acidocaldarius. These results provide insights into both the molecular mechanisms that govern biofilm formation in Crenarchaea and the functionality of the Lrs14-like proteins, an archaea-specific class of transcriptional regulators. PMID:23657363

  18. Characterizing cell adhesion by using micropipette aspiration.

    PubMed

    Hogan, Brenna; Babataheri, Avin; Hwang, Yongyun; Barakat, Abdul I; Husson, Julien

    2015-07-21

    We have developed a technique to directly quantify cell-substrate adhesion force using micropipette aspiration. The micropipette is positioned perpendicular to the surface of an adherent cell and a constant-rate aspiration pressure is applied. Since the micropipette diameter and the aspiration pressure are our control parameters, we have direct knowledge of the aspiration force, whereas the cell behavior is monitored either in brightfield or interference reflection microscopy. This setup thus allows us to explore a range of geometric parameters, such as projected cell area, adhesion area, or pipette size, as well as dynamical parameters such as the loading rate. We find that cell detachment is a well-defined event occurring at a critical aspiration pressure, and that the detachment force scales with the cell adhesion area (for a given micropipette diameter and loading rate), which defines a critical stress. Taking into account the cell adhesion area, intrinsic parameters of the adhesion bonds, and the loading rate, a minimal model provides an expression for the critical stress that helps rationalize our experimental results. PMID:26200857

  19. Characterizing Cell Adhesion by Using Micropipette Aspiration

    PubMed Central

    Hogan, Brenna; Babataheri, Avin; Hwang, Yongyun; Barakat, Abdul I.; Husson, Julien

    2015-01-01

    We have developed a technique to directly quantify cell-substrate adhesion force using micropipette aspiration. The micropipette is positioned perpendicular to the surface of an adherent cell and a constant-rate aspiration pressure is applied. Since the micropipette diameter and the aspiration pressure are our control parameters, we have direct knowledge of the aspiration force, whereas the cell behavior is monitored either in brightfield or interference reflection microscopy. This setup thus allows us to explore a range of geometric parameters, such as projected cell area, adhesion area, or pipette size, as well as dynamical parameters such as the loading rate. We find that cell detachment is a well-defined event occurring at a critical aspiration pressure, and that the detachment force scales with the cell adhesion area (for a given micropipette diameter and loading rate), which defines a critical stress. Taking into account the cell adhesion area, intrinsic parameters of the adhesion bonds, and the loading rate, a minimal model provides an expression for the critical stress that helps rationalize our experimental results. PMID:26200857

  20. The Molecular Architecture of Cell Adhesion: Dynamic Remodeling Revealed by Videonanoscopy.

    PubMed

    Sergé, Arnauld

    2016-01-01

    The plasma membrane delimits the cell, which is the basic unit of living organisms, and is also a privileged site for cell communication with the environment. Cell adhesion can occur through cell-cell and cell-matrix contacts. Adhesion proteins such as integrins and cadherins also constitute receptors for inside-out and outside-in signaling within proteolipidic platforms. Adhesion molecule targeting and stabilization relies on specific features such as preferential segregation by the sub-membrane cytoskeleton meshwork and within membrane proteolipidic microdomains. This review presents an overview of the recent insights brought by the latest developments in microscopy, to unravel the molecular remodeling occurring at cell contacts. The dynamic aspect of cell adhesion was recently highlighted by super-resolution videomicroscopy, also named videonanoscopy. By circumventing the diffraction limit of light, nanoscopy has allowed the monitoring of molecular localization and behavior at the single-molecule level, on fixed and living cells. Accessing molecular-resolution details such as quantitatively monitoring components entering and leaving cell contacts by lateral diffusion and reversible association has revealed an unexpected plasticity. Adhesion structures can be highly specialized, such as focal adhesion in motile cells, as well as immune and neuronal synapses. Spatiotemporal reorganization of adhesion molecules, receptors, and adaptors directly relates to structure/function modulation. Assembly of these supramolecular complexes is continuously balanced by dynamic events, remodeling adhesions on various timescales, notably by molecular conformation switches, lateral diffusion within the membrane and endo/exocytosis. Pathological alterations in cell adhesion are involved in cancer evolution, through cancer stem cell interaction with stromal niches, growth, extravasation, and metastasis. PMID:27200348

  1. The Molecular Architecture of Cell Adhesion: Dynamic Remodeling Revealed by Videonanoscopy

    PubMed Central

    Sergé, Arnauld

    2016-01-01

    The plasma membrane delimits the cell, which is the basic unit of living organisms, and is also a privileged site for cell communication with the environment. Cell adhesion can occur through cell-cell and cell-matrix contacts. Adhesion proteins such as integrins and cadherins also constitute receptors for inside-out and outside-in signaling within proteolipidic platforms. Adhesion molecule targeting and stabilization relies on specific features such as preferential segregation by the sub-membrane cytoskeleton meshwork and within membrane proteolipidic microdomains. This review presents an overview of the recent insights brought by the latest developments in microscopy, to unravel the molecular remodeling occurring at cell contacts. The dynamic aspect of cell adhesion was recently highlighted by super-resolution videomicroscopy, also named videonanoscopy. By circumventing the diffraction limit of light, nanoscopy has allowed the monitoring of molecular localization and behavior at the single-molecule level, on fixed and living cells. Accessing molecular-resolution details such as quantitatively monitoring components entering and leaving cell contacts by lateral diffusion and reversible association has revealed an unexpected plasticity. Adhesion structures can be highly specialized, such as focal adhesion in motile cells, as well as immune and neuronal synapses. Spatiotemporal reorganization of adhesion molecules, receptors, and adaptors directly relates to structure/function modulation. Assembly of these supramolecular complexes is continuously balanced by dynamic events, remodeling adhesions on various timescales, notably by molecular conformation switches, lateral diffusion within the membrane and endo/exocytosis. Pathological alterations in cell adhesion are involved in cancer evolution, through cancer stem cell interaction with stromal niches, growth, extravasation, and metastasis. PMID:27200348

  2. A Continuum Approach to Modelling Cell-Cell Adhesion

    PubMed Central

    Armstrong, Nicola J.; Painter, Kevin J.; Sherratt, Jonathan A.

    2007-01-01

    Cells adhere to each other through the binding of cell adhesion molecules at the cell surface. This process, known as cell-cell adhesion, is fundamental in many areas of biology, including early embryo development, tissue homeostasis and tumour growth. In this paper we develop a new continuous mathematical model of this phenomenon by considering the movement of cells in response to the adhesive forces generated through binding. We demonstrate that our model predicts the aggregation behaviour of a disassociated adhesive cell population. Further, when the model is extended to represent the interactions between multiple populations, we demonstrate that it is capable of replicating the different types of cell sorting behaviour observed experimentally. The resulting pattern formation is a direct consequence of the relative strengths of self-population and cross-population adhesive bonds in the model. While cell sorting behaviour has been captured previously with discrete approaches, it has not, until now, been observed with a fully continuous model. PMID:16860344

  3. Yielding Elastic Tethers Stabilize Robust Cell Adhesion

    PubMed Central

    Whitfield, Matt J.; Luo, Jonathon P.; Thomas, Wendy E.

    2014-01-01

    Many bacteria and eukaryotic cells express adhesive proteins at the end of tethers that elongate reversibly at constant or near constant force, which we refer to as yielding elasticity. Here we address the function of yielding elastic adhesive tethers with Escherichia coli bacteria as a model for cell adhesion, using a combination of experiments and simulations. The adhesive bond kinetics and tether elasticity was modeled in the simulations with realistic biophysical models that were fit to new and previously published single molecule force spectroscopy data. The simulations were validated by comparison to experiments measuring the adhesive behavior of E. coli in flowing fluid. Analysis of the simulations demonstrated that yielding elasticity is required for the bacteria to remain bound in high and variable flow conditions, because it allows the force to be distributed evenly between multiple bonds. In contrast, strain-hardening and linear elastic tethers concentrate force on the most vulnerable bonds, which leads to failure of the entire adhesive contact. Load distribution is especially important to noncovalent receptor-ligand bonds, because they become exponentially shorter lived at higher force above a critical force, even if they form catch bonds. The advantage of yielding is likely to extend to any blood cells or pathogens adhering in flow, or to any situation where bonds are stretched unequally due to surface roughness, unequal native bond lengths, or conditions that act to unzip the bonds. PMID:25473833

  4. Cyclin D1 interacts and collaborates with Ral GTPases enhancing cell detachment and motility.

    PubMed

    Fernández, R M H; Ruiz-Miró, M; Dolcet, X; Aldea, M; Garí, E

    2011-04-21

    Alterations in the levels of adhesion and motility of cells are critical events in the development of metastasis. Cyclin D1 (CycD1) is one of the most frequently amplified oncogenes in many types of cancers and it is also associated with the development of metastasis. Despite this, we still do not know which are all the relevant pathways by which CycD1 induces oncogenic processes. CycD1 functions can be either dependent or independent of the cyclin-dependent kinase Cdk4, and they affect several cellular aspects such as proliferation, cell attachment and migration. In this work, we reveal a novel function of CycD1 that fosters our understanding of the oncogenic potential of CycD1. We show that CycD1 binds to the small GTPases Ral A and B, which are involved, through exocyst regulation, in the progression of metastatic cancers, inducing anchorage-independent growth and cell survival of transformed cells. We show that CycD1 binds active Ral complexes and the exocyst protein Sec6, and co-localizes with Ral GTPases in trans-Golgi and exocyst-rich regions. We have also observed that CycD1-Cdk4 phosphorylates the Ral GEF Rgl2 'in vitro' and that CycD1-Cdk4 activity stimulates accumulation of the Ral GTP active forms. In accordance with this, our data suggest that CycD1-Cdk4 enhances cell detachment and motility in collaboration with Ral GTPases. This new function may help explain the contribution of CycD1 to tumor spreading. PMID:21242975

  5. Local anesthetics inhibit kinesin motility and microtentacle protrusions in human epithelial and breast tumor cells.

    PubMed

    Yoon, Jennifer R; Whipple, Rebecca A; Balzer, Eric M; Cho, Edward H; Matrone, Michael A; Peckham, Michelle; Martin, Stuart S

    2011-10-01

    Detached breast tumor cells produce dynamic microtubule protrusions that promote reattachment of cells and are termed tubulin microtentacles (McTNs) due to their mechanistic distinctions from actin-based filopodia/invadopodia and tubulin-based cilia. McTNs are enriched with vimentin and detyrosinated α-tubulin, (Glu-tubulin). Evidence suggests that vimentin and Glu-tubulin are cross-linked by kinesin motor proteins. Using known kinesin inhibitors, Lidocaine and Tetracaine, the roles of kinesins in McTN formation and function were tested. Live-cell McTN counts, adhesion assays, immunofluorescence, and video microscopy were performed to visualize inhibitor effects on McTNs. Viability and apoptosis assays were used to confirm the non-toxicity of the inhibitors. Treatments of human non-tumorigenic mammary epithelial and breast tumor cells with Lidocaine or Tetracaine caused rapid collapse of vimentin filaments. Live-cell video microscopy demonstrated that Tetracaine reduces motility of intracellular GFP-kinesin and causes centripetal collapse of McTNs. Treatment with Tetracaine inhibited the extension of McTNs and their ability to promote tumor cell aggregation and reattachment. Lidocaine showed similar effects but to a lesser degree. Our current data support a model in which the inhibition of kinesin motor proteins by Tetracaine leads to the reductions in McTNs, and provides a novel mechanism for the ability of this anesthetic to decrease metastatic progression. PMID:21069453

  6. Physics of cell elasticity, shape and adhesion

    NASA Astrophysics Data System (ADS)

    Safran, S. A.; Gov, N.; Nicolas, A.; Schwarz, U. S.; Tlusty, T.

    2005-07-01

    We review recent theoretical work that analyzes experimental measurements of the shape, fluctuations and adhesion properties of biological cells. Particular emphasis is placed on the role of the cytoskeleton and cell elasticity and we contrast the shape and adhesion of elastic cells with fluid-filled vesicles. In red blood cells (RBC), the cytoskeleton consists of a two-dimensional network of spectrin proteins. Our analysis of the wavevector and frequency dependence of the fluctuation spectrum of RBC indicates that the spectrin network acts as a confining potential that reduces the fluctuations of the lipid bilayer membrane. However, since the cytoskeleton is only sparsely connected to the bilayer, one cannot regard the composite cytoskeleton-membrane as a polymerized object with a shear modulus. The sensitivity of RBC fluctuations and shapes to ATP concentration may reflect topological defects induced in the cytoskeleton network by ATP. The shapes of cells that adhere to a substrate are strongly determined by the cytoskeletal elasticity that can be varied experimentally by drugs that depolymerize the cytoskeleton. This leads to a tension-driven retraction of the cell body and a pearling instability of the resulting ray-like protrusions. Recent experiments have shown that adhering cells exert polarized forces on substrates. The interactions of such “force dipoles” in either bulk gels or on surfaces can be used to predict the nature of self-assembly of cell aggregates and may be important in the formation of artificial tissues. Finally, we note that cell adhesion strongly depends on the forces exerted on the adhesion sites by the tension of the cytoskeleton. The size and shape of the adhesion regions are strongly modified as the tension is varied and we present an elastic model that relates this tension to deformations that induce the recruitment of new molecules to the adhesion region. In all these examples, cell shape and adhesion differ from vesicle shape and

  7. Id-1 promotes TGF-{beta}1-induced cell motility through HSP27 activation and disassembly of adherens junction in prostate epithelial cells

    SciTech Connect

    Di Kaijun; Wong, Y.C. Wang Xianghong

    2007-11-15

    Id-1 (inhibitor of differentiation or DNA binding-1) has been positively associated with cell proliferation, cell cycle progression, and invasiveness during tumorigenesis. In addition, Id-1 has been shown to modulate cellular sensitivity to TGF-{beta}1 (transforming growth factor {beta}1). Here we demonstrate a novel role of Id-1 in promoting TGF-{beta}1-induced cell motility in a non-malignant prostate epithelial cell line, NPTX. We found that Id-1 promoted F-actin stress fiber formation in response to TGF-{beta}1, which was associated with increased cell-substrate adhesion and cell migration in NPTX cells. In addition, this positive effect of Id-1 on TGF-{beta}1-induced cell motility was mediated through activation of MEK-ERK signaling pathway and subsequent phosphorylation of HSP27 (heat shock protein 27). Furthermore, Id-1 disrupted the adherens junction complex in TGF-{beta}1-treated cells through down-regulation of E-cadherin, redistribution of {beta}-catenin, along with up-regulation of N-cadherin. These lines of evidence reveal a novel tumorigenic role of Id-1 through reorganization of actin cytoskeleton and disassembly of cell-cell adhesion in response to TGF-{beta}1 in human prostate epithelial cells, and suggest that intracellular Id-1 levels might be a determining factor for switching TGF-{beta}1 from a growth inhibitor to a tumor promoter during prostate carcinogenesis.

  8. Integrative analysis of T cell motility from multi-channel microscopy data using TIAM.

    PubMed

    Mayya, Viveka; Neiswanger, Willie; Medina, Ricardo; Wiggins, Chris H; Dustin, Michael L

    2015-01-01

    Integrative analytical approaches are needed to study and understand T cell motility as it is a highly coordinated and complex process. Several computational algorithms and tools are available to track motile cells in time-lapse microscopy images. In contrast, there has only been limited effort towards the development of tools that take advantage of multi-channel microscopy data and facilitate integrative analysis of cell-motility. We have implemented algorithms for detecting, tracking, and analyzing cell motility from multi-channel time-lapse microscopy data. We have integrated these into a MATLAB-based toolset we call TIAM (Tool for Integrative Analysis of Motility). The cells are detected by a hybrid approach involving edge detection and Hough transforms from transmitted light images. Cells are tracked using a modified nearest-neighbor association followed by an optimization routine to join shorter segments. Cell positions are used to perform local segmentation for extracting features from transmitted light, reflection and fluorescence channels and associating them with cells and cell-tracks to facilitate integrative analysis. We found that TIAM accurately captures the motility behavior of T cells and performed better than DYNAMIK, Icy, Imaris, and Volocity in detecting and tracking motile T cells. Extraction of cell-associated features from reflection and fluorescence channels was also accurate with less than 10% median error in measurements. Finally, we obtained novel insights into T cell motility that were critically dependent on the unique capabilities of TIAM. We found that 1) the CD45RO subset of human CD8 T cells moved faster and exhibited an increased propensity to attach to the substratum during CCL21-driven chemokinesis when compared to the CD45RA subset; and 2) attachment area and arrest coefficient during antigen-induced motility of the CD45A subset is correlated with surface density of integrin LFA1 at the contact. PMID:25445324

  9. Moscatilin inhibits lung cancer cell motility and invasion via suppression of endogenous reactive oxygen species.

    PubMed

    Kowitdamrong, Akkarawut; Chanvorachote, Pithi; Sritularak, Boonchoo; Pongrakhananon, Varisa

    2013-01-01

    Lung cancer is the leading cause of death among cancer patients worldwide, and most of them have died from metastasis. Migration and invasion are prerequisite processes associated with high metastasis potential in cancers. Moscatilin, a bibenzyl derivative isolated from the Thai orchid Dendrobium pulchellum, has been shown to have anticancer effect against numerous cancer cell lines. However, little is known regarding the effect of moscatilin on cancer cell migration and invasion. The present study demonstrates that nontoxic concentrations of moscatilin were able to inhibit human nonsmall cell lung cancer H23 cell migration and invasion. The inhibitory effect of moscatilin was associated with an attenuation of endogenous reactive oxygen species (ROS), in which hydroxyl radical (OH(∙)) was identified as a dominant species in the suppression of filopodia formation. Western blot analysis also revealed that moscatilin downregulated activated focal adhesion kinase (phosphorylated FAK, Tyr 397) and activated ATP-dependent tyrosine kinase (phosphorylated Akt, Ser 473), whereas their parental counterparts were not detectable changed. In conclusion, our results indicate the novel molecular basis of moscalitin-inhibiting lung cancer cell motility and invasion and demonstrate a promising antimetastatic potential of such an agent for lung cancer therapy. PMID:23738332

  10. Moscatilin Inhibits Lung Cancer Cell Motility and Invasion via Suppression of Endogenous Reactive Oxygen Species

    PubMed Central

    Kowitdamrong, Akkarawut; Chanvorachote, Pithi; Sritularak, Boonchoo

    2013-01-01

    Lung cancer is the leading cause of death among cancer patients worldwide, and most of them have died from metastasis. Migration and invasion are prerequisite processes associated with high metastasis potential in cancers. Moscatilin, a bibenzyl derivative isolated from the Thai orchid Dendrobium pulchellum, has been shown to have anticancer effect against numerous cancer cell lines. However, little is known regarding the effect of moscatilin on cancer cell migration and invasion. The present study demonstrates that nontoxic concentrations of moscatilin were able to inhibit human nonsmall cell lung cancer H23 cell migration and invasion. The inhibitory effect of moscatilin was associated with an attenuation of endogenous reactive oxygen species (ROS), in which hydroxyl radical (OH∙) was identified as a dominant species in the suppression of filopodia formation. Western blot analysis also revealed that moscatilin downregulated activated focal adhesion kinase (phosphorylated FAK, Tyr 397) and activated ATP-dependent tyrosine kinase (phosphorylated Akt, Ser 473), whereas their parental counterparts were not detectable changed. In conclusion, our results indicate the novel molecular basis of moscalitin-inhibiting lung cancer cell motility and invasion and demonstrate a promising antimetastatic potential of such an agent for lung cancer therapy. PMID:23738332

  11. Heme-oxygenase-1 implications in cell morphology and the adhesive behavior of prostate cancer cells

    PubMed Central

    Gueron, Geraldine; Giudice, Jimena; Valacco, Pia; Paez, Alejandra; Elguero, Belen; Toscani, Martin; Jaworski, Felipe; Leskow, Federico Coluccio; Cotignola, Javier; Marti, Marcelo; Binaghi, Maria; Navone, Nora; Vazquez, Elba

    2014-01-01

    Prostate cancer (PCa) is the second leading cause of cancer death in men. Although previous studies in PCa have focused on cell adherens junctions (AJs), key players in metastasis, they have left the molecular mechanisms unexplored. Inflammation and the involvement of reactive oxygen species (ROS) are critical in the regulation of cell adhesion and the integrity of the epithelium. Heme oxygenase-1 (HO-1) counteracts oxidative and inflammatory damage. Here, we investigated whether HO-1 is implicated in the adhesive and morphological properties of tumor cells. Genes differentially regulated by HO-1 were enriched for cell motility and adhesion biological processes. HO-1 induction, increased E-cadherin and β-catenin levels. Immunofluorescence analyses showed a striking remodeling of E-cadherin/β-catenin based AJs under HO-1 modulation. Interestingly, the enhanced levels of E-cadherin and β-catenin coincided with a markedly change in cell morphology. To further our analysis we sought to identify HO-1 binding proteins that might participate in the regulation of cell morphology. A proteomics approach identified Muskelin, as a novel HO-1 partner, strongly implicated in cell morphology regulation. These results define a novel role for HO-1 in modulating the architecture of cell-cell interactions, favoring a less aggressive phenotype and further supporting its anti-tumoral function in PCa. PMID:24961479

  12. Cell adhesion molecules involved in intrathymic T cell development.

    PubMed

    Patel, D D; Haynes, B F

    1993-08-01

    During stem cell migration to the thymus, intrathymic maturation of T cells, and emigration of mature T cells out of the thymus, intercellular interactions of developing T cells with a myriad of cell types are required for normal T cell development. Intercellular interactions of T cell precursors with endothelial cells, thymic epithelial cells, fibroblasts, thymic macrophages and dendritic cells are all mediated by adhesion molecules on immature T cells binding to ligands on thymic microenvironment cells. While many receptor-ligand interactions that are important in intrathymic T cell development are known, the adhesion molecules that are important for migration of T cell precursors to the thymus and for emigration of mature thymocytes from the thymus are poorly understood. An emerging concept is that select adhesion molecules at discrete stages of T cell maturation participate in and regulate the complex processes of T cell development. PMID:7693023

  13. Local 3D matrix microenvironment regulates cell migration through spatiotemporal dynamics of contractility-dependent adhesions.

    PubMed

    Doyle, Andrew D; Carvajal, Nicole; Jin, Albert; Matsumoto, Kazue; Yamada, Kenneth M

    2015-01-01

    The physical properties of two-dimensional (2D) extracellular matrices (ECMs) modulate cell adhesion dynamics and motility, but little is known about the roles of local microenvironmental differences in three-dimensional (3D) ECMs. Here we generate 3D collagen gels of varying matrix microarchitectures to characterize their regulation of 3D adhesion dynamics and cell migration. ECMs containing bundled fibrils demonstrate enhanced local adhesion-scale stiffness and increased adhesion stability through balanced ECM/adhesion coupling, whereas highly pliable reticular matrices promote adhesion retraction. 3D adhesion dynamics are locally regulated by ECM rigidity together with integrin/ECM association and myosin II contractility. Unlike 2D migration, abrogating contractility stalls 3D migration regardless of ECM pore size. We find force is not required for clustering of activated integrins on 3D native collagen fibrils. We propose that efficient 3D migration requires local balancing of contractility with ECM stiffness to stabilize adhesions, which facilitates the detachment of activated integrins from ECM fibrils. PMID:26548801

  14. Local 3D matrix microenvironment regulates cell migration through spatiotemporal dynamics of contractility-dependent adhesions

    PubMed Central

    Doyle, Andrew D.; Carvajal, Nicole; Jin, Albert; Matsumoto, Kazue; Yamada, Kenneth M.

    2015-01-01

    The physical properties of two-dimensional (2D) extracellular matrices (ECMs) modulate cell adhesion dynamics and motility, but little is known about the roles of local microenvironmental differences in three-dimensional (3D) ECMs. Here we generate 3D collagen gels of varying matrix microarchitectures to characterize their regulation of 3D adhesion dynamics and cell migration. ECMs containing bundled fibrils demonstrate enhanced local adhesion-scale stiffness and increased adhesion stability through balanced ECM/adhesion coupling, whereas highly pliable reticular matrices promote adhesion retraction. 3D adhesion dynamics are locally regulated by ECM rigidity together with integrin/ECM association and myosin II contractility. Unlike 2D migration, abrogating contractility stalls 3D migration regardless of ECM pore size. We find force is not required for clustering of activated integrins on 3D native collagen fibrils. We propose that efficient 3D migration requires local balancing of contractility with ECM stiffness to stabilize adhesions, which facilitates the detachment of activated integrins from ECM fibrils. PMID:26548801

  15. Local 3D matrix microenvironment regulates cell migration through spatiotemporal dynamics of contractility-dependent adhesions

    NASA Astrophysics Data System (ADS)

    Doyle, Andrew D.; Carvajal, Nicole; Jin, Albert; Matsumoto, Kazue; Yamada, Kenneth M.

    2015-11-01

    The physical properties of two-dimensional (2D) extracellular matrices (ECMs) modulate cell adhesion dynamics and motility, but little is known about the roles of local microenvironmental differences in three-dimensional (3D) ECMs. Here we generate 3D collagen gels of varying matrix microarchitectures to characterize their regulation of 3D adhesion dynamics and cell migration. ECMs containing bundled fibrils demonstrate enhanced local adhesion-scale stiffness and increased adhesion stability through balanced ECM/adhesion coupling, whereas highly pliable reticular matrices promote adhesion retraction. 3D adhesion dynamics are locally regulated by ECM rigidity together with integrin/ECM association and myosin II contractility. Unlike 2D migration, abrogating contractility stalls 3D migration regardless of ECM pore size. We find force is not required for clustering of activated integrins on 3D native collagen fibrils. We propose that efficient 3D migration requires local balancing of contractility with ECM stiffness to stabilize adhesions, which facilitates the detachment of activated integrins from ECM fibrils.

  16. In vitro cell motility as a potential mesenchymal stem cell marker for multipotency.

    PubMed

    Bertolo, Alessandro; Gemperli, Armin; Gruber, Marco; Gantenbein, Benjamin; Baur, Martin; Pötzel, Tobias; Stoyanov, Jivko

    2015-01-01

    Mesenchymal stem cells (MSCs) are expected to have a fundamental role in future cell-based therapies because of their high proliferative ability, multilineage potential, and immunomodulatory properties. Autologous transplantations have the "elephant in the room" problem of wide donor variability, reflected by variability in MSC quality and characteristics, leading to uncertain outcomes in the use of these cells. We propose life imaging as a tool to characterize populations of human MSCs. Bone marrow MSCs from various donors and in vitro passages were evaluated for their in vitro motility, and the distances were correlated to the adipogenic, chondrogenic, and osteogenic differentiation potentials and the levels of senescence and cell size. Using life-image measuring of track lengths of 70 cells per population for a period of 24 hours, we observed that slow-moving cells had the higher proportion of senescent cells compared with fast ones. Larger cells moved less than smaller ones, and spindle-shaped cells had an average speed. Both fast cells and slow cells were characterized by a low differentiation potential, and average-moving cells were more effective in undergoing all three lineage differentiations. Furthermore, heterogeneity in single cell motility within a population correlated with the average-moving cells, and fast- and slow-moving cells tended toward homogeneity (i.e., a monotonous moving pattern). In conclusion, in vitro cell motility might be a useful tool to quickly characterize and distinguish the MSC population's differentiation potential before additional use. PMID:25473086

  17. Asynchrony in the growth and motility responses to environmental changes by individual bacterial cells

    SciTech Connect

    Umehara, Senkei; Hattori, Akihiro; Inoue, Ippei; Yasuda, Kenji . E-mail: yasuda.bmi@tmd.ac.jp

    2007-05-04

    Knowing how individual cells respond to environmental changes helps one understand phenotypic diversity in a bacterial cell population, so we simultaneously monitored the growth and motility of isolated motile Escherichia coli cells over several generations by using a method called on-chip single-cell cultivation. Starved cells quickly stopped growing but remained motile for several hours before gradually becoming immotile. When nutrients were restored the cells soon resumed their growth and proliferation but remained immotile for up to six generations. A flagella visualization assay suggested that deflagellation underlies the observed loss of motility. This set of results demonstrates that single-cell transgenerational study under well-characterized environmental conditions can provide information that will help us understand distinct functions within individual cells.

  18. Collective cell streams in epithelial monolayers depend on cell adhesion

    NASA Astrophysics Data System (ADS)

    Czirók, András; Varga, Katalin; Méhes, Előd; Szabó, András

    2013-07-01

    We report spontaneously emerging, randomly oriented, collective streaming behavior within a monolayer culture of a human keratinocyte cell line, and explore the effect of modulating cell adhesions by perturbing the function of calcium-dependent cell adhesion molecules. We demonstrate that decreasing cell adhesion induces narrower and more anisotropic cell streams, reminiscent of decreasing the Taylor scale of turbulent liquids. To explain our empirical findings, we propose a cell-based model that represents the dual nature of cell-cell adhesions. Spring-like connections provide mechanical stability, while a cellular Potts model formalism represents surface-tension driven attachment. By changing the relevance and persistence of mechanical links between cells, we are able to explain the experimentally observed changes in emergent flow patterns.

  19. Cell adhesion during bullet motion in capillaries.

    PubMed

    Takeishi, Naoki; Imai, Yohsuke; Ishida, Shunichi; Omori, Toshihiro; Kamm, Roger D; Ishikawa, Takuji

    2016-08-01

    A numerical analysis is presented of cell adhesion in capillaries whose diameter is comparable to or smaller than that of the cell. In contrast to a large number of previous efforts on leukocyte and tumor cell rolling, much is still unknown about cell motion in capillaries. The solid and fluid mechanics of a cell in flow was coupled with a slip bond model of ligand-receptor interactions. When the size of a capillary was reduced, the cell always transitioned to "bullet-like" motion, with a consequent decrease in the velocity of the cell. A state diagram was obtained for various values of capillary diameter and receptor density. We found that bullet motion enables firm adhesion of a cell to the capillary wall even for a weak ligand-receptor binding. We also quantified effects of various parameters, including the dissociation rate constant, the spring constant, and the reactive compliance on the characteristics of cell motion. Our results suggest that even under the interaction between P-selectin glycoprotein ligand-1 (PSGL-1) and P-selectin, which is mainly responsible for leukocyte rolling, a cell is able to show firm adhesion in a small capillary. These findings may help in understanding such phenomena as leukocyte plugging and cancer metastasis. PMID:27261363

  20. Influence of Helical Cell Shape on Motility of Helicobacter Pylori

    NASA Astrophysics Data System (ADS)

    Hardcastle, Joseph; Martinez, Laura; Salama, Nina; Bansil, Rama; Boston University Collaboration; University of Washington Collaboration

    2014-03-01

    Bacteria's body shape plays an important role in motility by effecting chemotaxis, swimming mechanisms, and swimming speed. A prime example of this is the bacteria Helicobacter Pylori;whose helical shape has long been believed to provide an advantage in penetrating the viscous mucus layer protecting the stomach lining, its niche environment. To explore this we have performed bacteria tracking experiments of both wild-type bacteria along with mutants, which have a straight rod shape. A wide distribution of speeds was found. This distribution reflects both a result of temporal variation in speed and different shape morphologies in the bacterial population. Our results show that body shape plays less role in a simple fluid. However, in a more viscous solution the helical shape results in increased swimming speeds. In addition, we use experimentally obtained cell shape measurements to model the hydrodynamic influence of cell shape on swimming speed using resistive force theory. The results agree with the experiment, especially when we fold in the temporal distribution. Interestingly, our results suggest distinct wild-type subpopulations with varying number of half helices can lead to different swimming speeds. NSF PHY

  1. High-Resolution Quantification of Focal Adhesion Spatiotemporal Dynamics in Living Cells

    PubMed Central

    Hahn, Klaus M.; Gomez, Shawn M.

    2011-01-01

    Focal adhesions (FAs) are macromolecular complexes that provide a linkage between the cell and its external environment. In a motile cell, focal adhesions change size and position to govern cell migration, through the dynamic processes of assembly and disassembly. To better understand the dynamic regulation of focal adhesions, we have developed an analysis system for the automated detection, tracking, and data extraction of these structures in living cells. This analysis system was used to quantify the dynamics of fluorescently tagged Paxillin and FAK in NIH 3T3 fibroblasts followed via Total Internal Reflection Fluorescence Microscopy (TIRF). High content time series included the size, shape, intensity, and position of every adhesion present in a living cell. These properties were followed over time, revealing adhesion lifetime and turnover rates, and segregation of properties into distinct zones. As a proof-of-concept, we show how a single point mutation in Paxillin at the Jun-kinase phosphorylation site Serine 178 changes FA size, distribution, and rate of assembly. This study provides a detailed, quantitative picture of FA spatiotemporal dynamics as well as a set of tools and methodologies for advancing our understanding of how focal adhesions are dynamically regulated in living cells. A full, open-source software implementation of this pipeline is provided at http://gomezlab.bme.unc.edu/tools. PMID:21779367

  2. Multiple scale model for cell migration in monolayers: Elastic mismatch between cells enhances motility.

    PubMed

    Palmieri, Benoit; Bresler, Yony; Wirtz, Denis; Grant, Martin

    2015-01-01

    We propose a multiscale model for monolayer of motile cells that comprise normal and cancer cells. In the model, the two types of cells have identical properties except for their elasticity; cancer cells are softer and normal cells are stiffer. The goal is to isolate the role of elasticity mismatch on the migration potential of cancer cells in the absence of other contributions that are present in real cells. The methodology is based on a phase-field description where each cell is modeled as a highly-deformable self-propelled droplet. We simulated two types of nearly confluent monolayers. One contains a single cancer cell in a layer of normal cells and the other contains normal cells only. The simulation results demonstrate that elasticity mismatch alone is sufficient to increase the motility of the cancer cell significantly. Further, the trajectory of the cancer cell is decorated by several speed "bursts" where the cancer cell quickly relaxes from a largely deformed shape and consequently increases its translational motion. The increased motility and the amplitude and frequency of the bursts are in qualitative agreement with recent experiments. PMID:26134134

  3. Repulsive cues combined with physical barriers and cell-cell adhesion determine progenitor cell positioning during organogenesis.

    PubMed

    Paksa, Azadeh; Bandemer, Jan; Hoeckendorf, Burkhard; Razin, Nitzan; Tarbashevich, Katsiaryna; Minina, Sofia; Meyen, Dana; Biundo, Antonio; Leidel, Sebastian A; Peyrieras, Nadine; Gov, Nir S; Keller, Philipp J; Raz, Erez

    2016-01-01

    The precise positioning of organ progenitor cells constitutes an essential, yet poorly understood step during organogenesis. Using primordial germ cells that participate in gonad formation, we present the developmental mechanisms maintaining a motile progenitor cell population at the site where the organ develops. Employing high-resolution live-cell microscopy, we find that repulsive cues coupled with physical barriers confine the cells to the correct bilateral positions. This analysis revealed that cell polarity changes on interaction with the physical barrier and that the establishment of compact clusters involves increased cell-cell interaction time. Using particle-based simulations, we demonstrate the role of reflecting barriers, from which cells turn away on contact, and the importance of proper cell-cell adhesion level for maintaining the tight cell clusters and their correct positioning at the target region. The combination of these developmental and cellular mechanisms prevents organ fusion, controls organ positioning and is thus critical for its proper function. PMID:27088892

  4. Hydrogen peroxide stimulates cell motile activity through LPA receptor-3 in liver epithelial WB-F344 cells

    SciTech Connect

    Shibata, Ayano; Tanabe, Eriko; Inoue, Serina; Kitayoshi, Misaho; Okimoto, Souta; Hirane, Miku; Araki, Mutsumi; Fukushima, Nobuyuki; Tsujiuchi, Toshifumi

    2013-04-12

    Highlights: •Hydrogen peroxide stimulates cell motility of WB-F344 cells. •LPA{sub 3} is induced by hydrogen peroxide in WB-F344 cells. •Cell motility by hydrogen peroxide is inhibited in LPA{sub 3} knockdown cells. •LPA signaling is involved in cell migration by hydrogen peroxide. -- Abstract: Hydrogen peroxide which is one of reactive oxygen species (ROS) mediates a variety of biological responses, including cell proliferation and migration. In the present study, we investigated whether lysophosphatidic acid (LPA) signaling is involved in cell motile activity stimulated by hydrogen peroxide. The rat liver epithelial WB-F344 cells were treated with hydrogen peroxide at 0.1 or 1 μM for 48 h. In cell motility assays, hydrogen peroxide treated cells showed significantly high cell motile activity, compared with untreated cells. To measure the expression levels of LPA receptor genes, quantitative real time RT-PCR analysis was performed. The expressions of LPA receptor-3 (Lpar3) in hydrogen peroxide treated cells were significantly higher than those in control cells, but not Lpar1 and Lpar2 genes. Next, to assess the effect of LPA{sub 3} on cell motile activity, the Lpar3 knockdown cells from WB-F344 cells were also treated with hydrogen peroxide. The cell motile activity of the knockdown cells was not stimulated by hydrogen peroxide. Moreover, in liver cancer cells, hydrogen peroxide significantly activated cell motility of Lpar3-expressing cells, but not Lpar3-unexpressing cells. These results suggest that LPA signaling via LPA{sub 3} may be mainly involved in cell motile activity of WB-F344 cells stimulated by hydrogen peroxide.

  5. Cell adhesion in regulation of asymmetric stem cell division

    PubMed Central

    Yamashita, Yukiko M.

    2010-01-01

    Adult stem cells inevitably communicate with their cellular neighbors within the tissues they sustain. Indeed, such communication, particularly with components of the stem cell niche, is essential for many aspects of stem cell behavior, including the maintenance of stem cell identity and asymmetric cell division. Cell adhesion mediates this communication by placing stem cells in close proximity to the signaling source and by providing a polarity cue that orients stem cells. Here, I review the recent discovery that cell adhesion molecules govern the behavior of stem cells. PMID:20724132

  6. CHRNA5 as negative regulator of nicotine signaling in normal and cancer bronchial cells: effects on motility, migration and p63 expression.

    PubMed

    Krais, Annette M; Hautefeuille, Agnès H; Cros, Marie-Pierre; Krutovskikh, Vladimir; Tournier, Jean-Marie; Birembaut, Philippe; Thépot, Amélie; Paliwal, Anupam; Herceg, Zdenko; Boffetta, Paolo; Brennan, Paul; Hainaut, Pierre L

    2011-09-01

    Genome-wide association studies have linked lung cancer risk with a region of chromosome 15q25.1 containing CHRNA3, CHRNA5 and CHRNB4 encoding α3, α5 and β4 subunits of nicotinic acetylcholine receptors (nAChR), respectively. One of the strongest associations was observed for a non-silent single-nucleotide polymorphism at codon 398 in CHRNA5. Here, we have used pharmacological (antagonists) or genetic (RNA interference) interventions to modulate the activity of CHRNA5 in non-transformed bronchial cells and in lung cancer cell lines. In both cell types, silencing CHRNA5 or inhibiting receptors containing nAChR α5 with α-conotoxin MII exerted a nicotine-like effect, with increased motility and invasiveness in vitro and increasing calcium influx. The effects on motility were enhanced by addition of nicotine but blocked by inhibiting CHRNA7, which encodes the homopentameric receptor α7 subunit. Silencing CHRNA5 also decreased the expression of cell adhesion molecules P120 and ZO-1 in lung cancer cells as well as the expression of DeltaNp63α in squamous cell carcinoma cell lines. These results demonstrate a role for CHRNA5 in modulating adhesion and motility in bronchial cells, as well as in regulating p63, a potential oncogene in squamous cell carcinoma. PMID:21586512

  7. CHRNA5 as negative regulator of nicotine signaling in normal and cancer bronchial cells: effects on motility, migration and p63 expression

    PubMed Central

    Krais, Annette M.; Hautefeuille, Agnès H.; Cros, Marie-Pierre; Krutovskikh, Vladimir; Tournier, Jean-Marie; Birembaut, Philippe; Thépot, Amélie; Paliwal, Anupam; Herceg, Zdenko; Boffetta, Paolo; Brennan, Paul; Hainaut, Pierre L.

    2011-01-01

    Genome-wide association studies have linked lung cancer risk with a region of chromosome 15q25.1 containing CHRNA3, CHRNA5 and CHRNB4 encoding α3, α5 and β4 subunits of nicotinic acetylcholine receptors (nAChR), respectively. One of the strongest associations was observed for a non-silent single-nucleotide polymorphism at codon 398 in CHRNA5. Here, we have used pharmacological (antagonists) or genetic (RNA interference) interventions to modulate the activity of CHRNA5 in non-transformed bronchial cells and in lung cancer cell lines. In both cell types, silencing CHRNA5 or inhibiting receptors containing nAChR α5 with α-conotoxin MII exerted a nicotine-like effect, with increased motility and invasiveness in vitro and increasing calcium influx. The effects on motility were enhanced by addition of nicotine but blocked by inhibiting CHRNA7, which encodes the homopentameric receptor α7 subunit. Silencing CHRNA5 also decreased the expression of cell adhesion molecules P120 and ZO-1 in lung cancer cells as well as the expression of DeltaNp63α in squamous cell carcinoma cell lines. These results demonstrate a role for CHRNA5 in modulating adhesion and motility in bronchial cells, as well as in regulating p63, a potential oncogene in squamous cell carcinoma. PMID:21586512

  8. Theory of deformable substrates for cell motility studies.

    PubMed Central

    Peterson, M A

    1996-01-01

    Linear theory is used to relate the tractions F applied by a cell to the resulting deformation of fluid, viscoelastic, or solid substrates. The theory is used to fit data in which the motion of a fluid surface in the neighborhood of a motile keratocyte is visualized with the aid of embedded beads. The data are best fit by modeling the surface layer as a two-dimensional, nearly incompressible fluid. The data favor this model over another plausible model, the planar free boundary of a three-dimensional fluid. In the resulting diagrams for the distribution of F, it is found that both curl F and div F are concentrated in the lateral extrema of the lamellipodium. In a second investigation, a nonlinear theory of weak wrinkles in a solid substrate is proposed. The in-plane stress tensor plays the role of a metric. Compression wrinkles are found in regions where this metric is negative definite. Tension wrinkles arise, in linear approximation, at points on the boundary between positive definite and indefinite regions, and are conjectured to be stabilized by nonlinear effects. Data for the wrinkles that would be produced by keratocyte traction are computed, and these agree qualitatively with observed keratocyte wrinkles. Images FIGURE 7 PMID:8842205

  9. Effects of cochlear loading on the motility of active outer hair cells

    PubMed Central

    Ó Maoiléidigh, Dáibhid; Hudspeth, A. J.

    2013-01-01

    Outer hair cells (OHCs) power the amplification of sound-induced vibrations in the mammalian inner ear through an active process that involves hair-bundle motility and somatic motility. It is unclear, though, how either mechanism can be effective at high frequencies, especially when OHCs are mechanically loaded by other structures in the cochlea. We address this issue by developing a model of an active OHC on the basis of observations from isolated cells, then we use the model to predict the response of an active OHC in the intact cochlea. We find that active hair-bundle motility amplifies the receptor potential that drives somatic motility. Inertial loading of a hair bundle by the tectorial membrane reduces the bundle’s reactive load, allowing the OHC’s active motility to influence the motion of the cochlear partition. The system exhibits enhanced sensitivity and tuning only when it operates near a dynamical instability, a Hopf bifurcation. This analysis clarifies the roles of cochlear structures and shows how the two mechanisms of motility function synergistically to create the cochlear amplifier. The results suggest that somatic motility evolved to enhance a preexisting amplifier based on active hair-bundle motility, thus allowing mammals to hear high-frequency sounds. PMID:23509256

  10. Cell locomotion and focal adhesions are regulated by substrate flexibility

    PubMed Central

    Pelham, Robert J.; Wang, Yu-li

    1997-01-01

    Responses of cells to mechanical properties of the adhesion substrate were examined by culturing normal rat kidney epithelial and 3T3 fibroblastic cells on a collagen-coated polyacrylamide substrate that allows the flexibility to be varied while maintaining a constant chemical environment. Compared with cells on rigid substrates, those on flexible substrates showed reduced spreading and increased rates of motility or lamellipodial activity. Microinjection of fluorescent vinculin indicated that focal adhesions on flexible substrates were irregularly shaped and highly dynamic whereas those on firm substrates had a normal morphology and were much more stable. Cells on flexible substrates also contained a reduced amount of phosphotyrosine at adhesion sites. Treatment of these cells with phenylarsine oxide, a tyrosine phosphatase inhibitor, induced the formation of normal, stable focal adhesions similar to those on firm substrates. Conversely, treatment of cells on firm substrates with myosin inhibitors 2,3-butanedione monoxime or KT5926 caused the reduction of both vinculin and phosphotyrosine at adhesion sites. These results demonstrate the ability of cells to survey the mechanical properties of their surrounding environment and suggest the possible involvement of both protein tyrosine phosphorylation and myosin-generated cortical forces in this process. Such response to physical parameters likely represents an important mechanism of cellular interaction with the surrounding environment within a complex organism. PMID:9391082

  11. Three-dimensional patterning of multiple cell populations through orthogonal genetic control of cell motility

    PubMed Central

    MacKay, Joanna L.; Sood, Anshum

    2013-01-01

    The ability to independently assemble multiple cell types within a three-dimensional matrix would be a powerful enabling tool for modeling and engineering complex tissues. Here we introduce a strategy to dynamically pattern distinct subpopulations of cells through genetic regulation of cell motility. We first describe glioma cell lines that were genetically engineered to stably express constitutively active or dominant negative Rac1 GTPase mutants under the control of either a doxycycline-inducible or cumate-inducible promoter. We culture each population as multicellular spheroids and show that by adding or withdrawing the appropriate inducer at specific times, we can control the timing and extent of Rac1-dependent cell migration into three-dimensional collagen matrices. We then report results with mixed spheroids in which one subpopulation of cells expresses dominant negative Rac1 under a doxycycline-inducible promoter and the other expresses dominant negative Rac1 under a cumate-inducible promoter. Using this system, we demonstrate that doxycycline and cumate addition suppress Rac1-dependent motility in a subpopulation-specific and temporally-controlled manner. This allows us to orthogonally control the motility of each subpopulation and spatially assemble the cells into radially symmetric three-dimensional patterns through the synchronized addition and removal of doxycycline and cumate. This synthetic biology-inspired strategy offers a novel means of spatially organizing multiple cell populations in conventional matrix scaffolds and complements the emerging suite of technologies that seek to pattern cells by engineering extracellular matrix properties. PMID:24622945

  12. Loss of Myoferlin Redirects Breast Cancer Cell Motility towards Collective Migration

    PubMed Central

    Volakis, Leonithas I.; Li, Ruth; Ackerman, William E.; Mihai, Cosmin; Bechel, Meagan; Summerfield, Taryn L.; Ahn, Christopher S.; Powell, Heather M.; Zielinski, Rachel; Rosol, Thomas J.

    2014-01-01

    Cell migration plays a central role in the invasion and metastasis of tumors. As cells leave the primary tumor, they undergo an epithelial to mesenchymal transition (EMT) and migrate as single cells. Epithelial tumor cells may also migrate in a highly directional manner as a collective group in some settings. We previously discovered that myoferlin (MYOF) is overexpressed in breast cancer cells and depletion of MYOF results in a mesenchymal to epithelial transition (MET) and reduced invasion through extracellular matrix (ECM). However, the biomechanical mechanisms governing cell motility during MYOF depletion are poorly understood. We first demonstrated that lentivirus-driven shRNA-induced MYOF loss in MDA-MB-231 breast cancer cells (MDA-231MYOF-KD) leads to an epithelial morphology compared to the mesenchymal morphology observed in control (MDA- 231LTVC) and wild-type cells. Knockdown of MYOF led to significant reductions in cell migration velocity and MDA- 231MYOF-KD cells migrated directionally and collectively, while MDA-231LTVC cells exhibited single cell migration. Decreased migration velocity and collective migration were accompanied by significant changes in cell mechanics. MDA-231MYOF-KD cells exhibited a 2-fold decrease in cell stiffness, a 2-fold increase in cell-substrate adhesion and a 1.5-fold decrease in traction force generation. In vivo studies demonstrated that when immunocompromised mice were implanted with MDA- 231MYOF-KD cells, tumors were smaller and demonstrated lower tumor burden. Moreover, MDA- 231MYOF-KD tumors were highly circularized and did not invade locally into the adventia in contrast to MDA- 231LTVC-injected animals. Thus MYOF loss is associated with a change in tumor formation in xenografts and leads to smaller, less invasive tumors. These data indicate that MYOF, a previously unrecognized protein in cancer, is involved in MDA-MB-231 cell migration and contributes to biomechanical alterations. Our results indicate that changes in

  13. Cell Division Resets Polarity and Motility for the Bacterium Myxococcus xanthus

    PubMed Central

    Harvey, Cameron W.; Madukoma, Chinedu S.; Mahserejian, Shant; Alber, Mark S.

    2014-01-01

    Links between cell division and other cellular processes are poorly understood. It is difficult to simultaneously examine division and function in most cell types. Most of the research probing aspects of cell division has experimented with stationary or immobilized cells or distinctly asymmetrical cells. Here we took an alternative approach by examining cell division events within motile groups of cells growing on solid medium by time-lapse microscopy. A total of 558 cell divisions were identified among approximately 12,000 cells. We found an interconnection of division, motility, and polarity in the bacterium Myxococcus xanthus. For every division event, motile cells stop moving to divide. Progeny cells of binary fission subsequently move in opposing directions. This behavior involves M. xanthus Frz proteins that regulate M. xanthus motility reversals but is independent of type IV pilus “S motility.” The inheritance of opposing polarity is correlated with the distribution of the G protein RomR within these dividing cells. The constriction at the point of division limits the intracellular distribution of RomR. Thus, the asymmetric distribution of RomR at the parent cell poles becomes mirrored at new poles initiated at the site of division. PMID:25157084

  14. CLIC4 regulates cell adhesion and β1 integrin trafficking.

    PubMed

    Argenzio, Elisabetta; Margadant, Coert; Leyton-Puig, Daniela; Janssen, Hans; Jalink, Kees; Sonnenberg, Arnoud; Moolenaar, Wouter H

    2014-12-15

    Chloride intracellular channel protein 4 (CLIC4) exists in both soluble and membrane-associated forms, and is implicated in diverse cellular processes, ranging from ion channel formation to intracellular membrane remodeling. CLIC4 is rapidly recruited to the plasma membrane by lysophosphatidic acid (LPA) and serum, suggesting a possible role for CLIC4 in exocytic-endocytic trafficking. However, the function and subcellular target(s) of CLIC4 remain elusive. Here, we show that in HeLa and MDA-MB-231 cells, CLIC4 knockdown decreases cell-matrix adhesion, cell spreading and integrin signaling, whereas it increases cell motility. LPA stimulates the recruitment of CLIC4 to β1 integrin at the plasma membrane and in Rab35-positive endosomes. CLIC4 is required for both the internalization and the serum- or LPA-induced recycling of β1 integrin, but not for EGF receptor trafficking. Furthermore, we show that CLIC4 suppresses Rab35 activity and antagonizes Rab35-dependent regulation of β1 integrin trafficking. Our results define CLIC4 as a regulator of Rab35 activity and serum- and LPA-dependent integrin trafficking. PMID:25344254

  15. Optical biosensors for cell adhesion.

    PubMed

    Ramsden, Jeremy J; Horvath, Robert

    2009-01-01

    Planar optical waveguides offer an ideal substratum for cells on which to reside. The materials from which the waveguides are made--high refractive index transparent dielectrics--correspond to the coatings of medical implants (e.g., the oxides of niobium, tantalum, and titanium) or the high molecular weight polymers used for culture flasks (e.g., polystyrene). The waveguides can furthermore be modified both chemically and morphologically while retaining their full capability for generating an evanescent optical field that has its greatest strength at the interface between the solid substratum and the liquid phase with which it is invariably in contact (i.e., the culture medium bathing the cells), decaying exponentially perpendicular to the interface at a rate controllable by varying the material parameters of the waveguide. Analysis of the perturbation of the evanescent field by the presence of living cells within it enables their size, number density, shape, refractive index (linked to their constitution) and so forth to be determined, the number of parameters depending on the number of waveguide lightmodes analyzed. No labeling of any kind is necessary, and convenient measurement setups are fully compatible with maintaining the cells in their usual environment. If the temporal evolution of the perturbation is analyzed, even more information can be obtained, such as the amount of material (microexudate) secreted by the cell while residing on the surface. Separation of parallel effects simultaneously contributing to the perturbation of the evanescent field can be accomplished by analysis of coupling peak shape when a grating coupler is used to measure the propagation constants of the waveguide lightmodes. PMID:19635032

  16. Anchoring stem cells in the niche by cell adhesion molecules

    PubMed Central

    2009-01-01

    Adult stem cells generally reside in supporting local micro environments or niches, and intimate stem cell and niche association is critical for their long-term maintenance and function. Recent studies in model organisms especially Drosophila have started to unveil the underlying mechanisms of stem anchorage in the niche at the molecular and cellular level. Two types of cell adhesion molecules are emerging as essential players: cadherin-mediated cell adhesion for keeping stem cells within stromal niches, whereas integrin-mediated cell adhesion for keeping stem cells within epidermal niches. Further understanding stem cell anchorage and release in coupling with environmental changes should provide further insights into homeostasis control in tissues that harbor stem cells. PMID:19421010

  17. Control cell adhesion with dynamic bilayer films

    NASA Astrophysics Data System (ADS)

    Kourouklis, Andreas; Lerum, Ronald; Bermudez, Harry

    2012-02-01

    Interfacially-directed assembly of amphiphilic block copolymers was employed to create ultrathin films having the potential to correlate the dynamics of ECM cues with cell adhesion and cytoskeletally-generated forces. The mobility of the polymeric bilayer films were tuned by the incorporation of hydrophobic homopolymer chains, which are thought to reduce interlayer friction. Labeling of the block copolymer chains with an adhesive peptide ligand (RGD) provided a specific means to study integrin-mediated cellular processes and the corresponding mechanotransduction. By seeding anchorage-dependent cells on ``dynamic'' (laterally mobile) and ``static'' films that display the same amount of RGD, we have found that cells recognize the difference in RGD diffusivity and develop distinct responses over time. We intend to examine changes in cell response by controlling the extent of cytoskeletally-generated forces and the assembly dynamics of focal adhesion complexes. Such films provide a unique platform to unveil the biomechanical signals related with ECM dynamics, and may ultimately facilitate a deeper understanding of cellular processes.

  18. Vaginal epithelial cells regulate membrane adhesiveness to co-ordinate bacterial adhesion.

    PubMed

    Younes, Jessica A; Klappe, Karin; Kok, Jan Willem; Busscher, Henk J; Reid, Gregor; van der Mei, Henny C

    2016-04-01

    Vaginal epithelium is colonized by different bacterial strains and species. The bacterial composition of vaginal biofilms controls the balance between health and disease. Little is known about the relative contribution of the epithelial and bacterial cell surfaces to bacterial adhesion and whether and how adhesion is regulated over cell membrane regions. Here, we show that bacterial adhesion forces with cell membrane regions not located above the nucleus are stronger than with regions above the nucleus both for vaginal pathogens and different commensal and probiotic lactobacillus strains involved in health. Importantly, adhesion force ratios over membrane regions away from and above the nucleus coincided with the ratios between numbers of adhering bacteria over both regions. Bacterial adhesion forces were dramatically decreased by depleting the epithelial cell membrane of cholesterol or sub-membrane cortical actin. Thus, epithelial cells can regulate membrane regions to which bacterial adhesion is discouraged, possibly to protect the nucleus. PMID:26477544

  19. Weak Power Frequency Magnetic Field Acting Similarly to EGF Stimulation, Induces Acute Activations of the EGFR Sensitive Actin Cytoskeleton Motility in Human Amniotic Cells

    PubMed Central

    Wu, Xia; Cao, Mei-Ping; Shen, Yun-Yun; Chu, Ke-Ping; Tao, Wu-Bin; Song, Wei-Tao; Liu, Li-Ping; Wang, Xiang-Hui; Zheng, Yu-Fang; Chen, Shu-De; Zeng, Qun-Li; Xia, Ruo-Hong

    2014-01-01

    In this article, we have examined the motility-related effects of weak power frequency magnetic fields (MFs) on the epidermal growth factor receptor (EGFR)-sensitive motility mechanism, including the F-actin cytoskeleton, growth of invasive protrusions and the levels of signal molecules in human amniotic epithelial (FL) cells. Without extracellular EGF stimulation, the field stimulated a large growth of new protrusions, especially filopodia and lamellipodia, an increased population of vinculin-associated focal adhesions. And, an obvious reduction of stress fiber content in cell centers was found, corresponding to larger cell surface areas and decreased efficiency of actin assembly of FL cells in vitro, which was associated with a decrease in overall F-actin content and special distributions. These effects were also associated with changes in protein content or distribution patterns of the EGFR downstream motility-related signaling molecules. All of these effects are similar to those following epidermal growth factor (EGF) stimulation of the cells and are time dependent. These results suggest that power frequency MF exposure acutely affects the migration/motility-related actin cytoskeleton reorganization that is regulated by the EGFR-cytoskeleton signaling pathway. Therefore, upon the MF exposure, cells are likely altered to be ready to transfer into a state of migration in response to the stimuli. PMID:24505297

  20. Force nanoscopy of cell mechanics and cell adhesion

    NASA Astrophysics Data System (ADS)

    Dufrêne, Yves F.; Pelling, Andrew E.

    2013-05-01

    Cells are constantly exposed to mechanical stimuli in their environment and have several evolved mechanisms to sense and respond to these cues. It is becoming increasingly recognized that many cell types, from bacteria to mammalian cells, possess a diverse set of proteins to translate mechanical cues into biochemical signalling and to mediate cell surface interactions such as cell adhesion. Moreover, the mechanical properties of cells are involved in regulating cell function as well as serving as indicators of disease states. Importantly, the recent development of biophysical tools and nanoscale methods has facilitated a deeper understanding of the role that physical forces play in modulating cell mechanics and cell adhesion. Here, we discuss how atomic force microscopy (AFM) has recently been used to investigate cell mechanics and cell adhesion at the single-cell and single-molecule levels. This knowledge is critical to our understanding of the molecular mechanisms that govern mechanosensing, mechanotransduction, and mechanoresponse in living cells. While pushing living cells with the AFM tip provides a means to quantify their mechanical properties and examine their response to nanoscale forces, pulling single surface proteins with a functionalized tip allows one to understand their role in sensing and adhesion. The combination of these nanoscale techniques with modern molecular biology approaches, genetic engineering and optical microscopies provides a powerful platform for understanding the sophisticated functions of the cell surface machinery, and its role in the onset and progression of complex diseases.

  1. NMU signaling promotes endometrial cancer cell progression by modulating adhesion signaling.

    PubMed

    Lin, Ting-Yu; Wu, Fang-Ju; Chang, Chia-Lin; Li, Zhongyou; Luo, Ching-Wei

    2016-03-01

    Neuromedin U (NMU) was originally named based on its strong uterine contractile activity, but little is known regarding its signaling/functions in utero. We identified that NMU and one of its receptors, NMUR2, are not only present in normal uterine endometrium but also co-expressed in endometrial cancer tissues, where the NMU level is correlated with the malignant grades and survival of patients. Cell-based assays further confirmed that NMU signaling can promote cell motility and proliferation of endometrial cancer cells derived from grade II tumors. Activation of NMU pathway in these endometrial cancer cells is required in order to sustain expression of various adhesion molecules, such as CD44 and integrin alpha1, as well as production of their corresponding extracellular matrix ligands, hyaluronan and collagen IV; it also increased the activity of SRC and its downstream proteins RHOA and RAC1. Thus, it is concluded that NMU pathway positively controls the adhesion signaling-SRC-Rho GTPase axis in the tested endometrial cancer cells and that changes in cell motility and proliferation can occur when there is manipulation of NMU signaling in these cells either in vitro or in vivo. Intriguingly, this novel mechanism also explains how NMU signaling promotes the EGFR-driven and TGFβ receptor-driven mesenchymal transitions. Through the above axis, NMU signaling not only can promote malignancy of the tested endometrial cancer cells directly, but also helps these cells to become more sensitive to niche growth factors in their microenvironment. PMID:26849234

  2. NMU signaling promotes endometrial cancer cell progression by modulating adhesion signaling

    PubMed Central

    Lin, Ting-Yu; Wu, Fang-Ju; Chang, Chia-Lin; Li, Zhongyou; Luo, Ching-Wei

    2016-01-01

    Neuromedin U (NMU) was originally named based on its strong uterine contractile activity, but little is known regarding its signaling/functions in utero. We identified that NMU and one of its receptors, NMUR2, are not only present in normal uterine endometrium but also co-expressed in endometrial cancer tissues, where the NMU level is correlated with the malignant grades and survival of patients. Cell-based assays further confirmed that NMU signaling can promote cell motility and proliferation of endometrial cancer cells derived from grade II tumors. Activation of NMU pathway in these endometrial cancer cells is required in order to sustain expression of various adhesion molecules, such as CD44 and integrin alpha1, as well as production of their corresponding extracellular matrix ligands, hyaluronan and collagen IV; it also increased the activity of SRC and its downstream proteins RHOA and RAC1. Thus, it is concluded that NMU pathway positively controls the adhesion signaling-SRC-Rho GTPase axis in the tested endometrial cancer cells and that changes in cell motility and proliferation can occur when there is manipulation of NMU signaling in these cells either in vitro or in vivo. Intriguingly, this novel mechanism also explains how NMU signaling promotes the EGFR-driven and TGFβ receptor-driven mesenchymal transitions. Through the above axis, NMU signaling not only can promote malignancy of the tested endometrial cancer cells directly, but also helps these cells to become more sensitive to niche growth factors in their microenvironment. PMID:26849234

  3. Cell Proliferation and Motility Are Inhibited by G1 Phase Arrest in 15-kDa Selenoprotein-Deficient Chang Liver Cells

    PubMed Central

    Bang, Jeyoung; Huh, Jang Hoe; Na, Ji-Woon; Lu, Qiao; Carlson, Bradley A.; Tobe, Ryuta; Tsuji, Petra A.; Gladyshev, Vadim N.; Hatfield, Dolph L.; Lee, Byeong Jae

    2015-01-01

    The 15-kDa selenoprotein (Sep15) is a selenoprotein residing in the lumen of the endoplasmic reticulum (ER) and implicated in quality control of protein folding. Herein, we established an inducible RNAi cell line that targets Sep15 mRNA in Chang liver cells. RNAi-induced Sep15 deficiency led to inhibition of cell proliferation, whereas cell growth was resumed after removal of the knockdown inducer. Sep15-deficient cells were arrested at the G1 phase by upregulating p21 and p27, and these cells were also characterized by ER stress. In addition, Sep15 deficiency led to the relocation of focal adhesions to the periphery of the cell basement and to the decrease of the migratory and invasive ability. All these changes were reversible depending on Sep15 status. Rescuing the knockdown state by expressing a silent mutant Sep15 mRNA that is resistant to siRNA also reversed the phenotypic changes. Our results suggest that SEP15 plays important roles in the regulation of the G1 phase during the cell cycle as well as in cell motility in Chang liver cells, and that this selenoprotein offers a novel functional link between the cell cycle and cell motility. PMID:25728752

  4. Automated detection of whole-cell mitochondrial motility and its dependence on cytoarchitectural integrity.

    PubMed

    Kandel, Judith; Chou, Philip; Eckmann, David M

    2015-07-01

    Current methodologies used for mitochondrial motility analysis tend to either overlook individual mitochondrial tracks or analyze only peripheral mitochondria instead of mitochondria in all regions of the cell. Furthermore, motility analysis of an individual mitochondrion is usually quantified by establishing an arbitrary threshold for "directed" motion. In this work, we created a custom, publicly available computational algorithm based on a previously published approach (Giedt et al., 2012. Ann Biomed Eng 40:1903-1916) in order to characterize the distribution of mitochondrial movements at the whole-cell level, while still preserving information about single mitochondria. Our technique is easy to use, robust, and computationally inexpensive. Images are first pre-processed for increased resolution, and then individual mitochondria are tracked based on object connectivity in space and time. When our method is applied to microscopy fields encompassing entire cells, we reveal that the mitochondrial net distances in fibroblasts follow a lognormal distribution within a given cell or group of cells. The ability to model whole-cell mitochondrial motility as a lognormal distribution provides a new quantitative paradigm for comparing mitochondrial motility in naïve and treated cells. We further demonstrate that microtubule and microfilament depolymerization shift the lognormal distribution in directions which indicate decreased and increased mitochondrial movement, respectively. These findings advance earlier work on neuronal axons (Morris and Hollenbeck, 1993. J Cell Sci 104:917-927) by relating them to a different cell type, applying them on a global scale, and automating measurement of mitochondrial motility in general. PMID:25678368

  5. Automated single-cell motility analysis on a chip using lensfree microscopy

    NASA Astrophysics Data System (ADS)

    Pushkarsky, Ivan; Lyb, Yunbo; Weaver, Westbrook; Su, Ting-Wei; Mudanyali, Onur; Ozcan, Aydogan; di Carlo, Dino

    2014-04-01

    Quantitative cell motility studies are necessary for understanding biophysical processes, developing models for cell locomotion and for drug discovery. Such studies are typically performed by controlling environmental conditions around a lens-based microscope, requiring costly instruments while still remaining limited in field-of-view. Here we present a compact cell monitoring platform utilizing a wide-field (24 mm2) lensless holographic microscope that enables automated single-cell tracking of large populations that is compatible with a standard laboratory incubator. We used this platform to track NIH 3T3 cells on polyacrylamide gels over 20 hrs. We report that, over an order of magnitude of stiffness values, collagen IV surfaces lead to enhanced motility compared to fibronectin, in agreement with biological uses of these structural proteins. The increased throughput associated with lensfree on-chip imaging enables higher statistical significance in observed cell behavior and may facilitate rapid screening of drugs and genes that affect cell motility.

  6. Cell Shapes and Traction Forces Determine Stress in Motile Confluent Tissue

    NASA Astrophysics Data System (ADS)

    Yang, Xingbo; Bi, Dapeng; Czajkowski, Michael; Manning, Lisa; Marchetti, Cristina

    Collective cell migration is a highly regulated process involved in wound healing, cancer metastasis and morphogenesis. The understanding of the regulatory mechanism requires the study of mechanical interactions among cells that coordinate their active motion. To this end, we develop a method that determines cellular forces and tissue stresses from experimentally accessible cell shapes and traction forces. This approach allows us for the first time to calculate membrane tensions and hydrostatic pressures at a cellular level in collective migrating cell layers out of equilibrium. It helps us understand the mechanical origin of tissue stresses as previous inferred using Traction Force Microscopy (TFM). We test this approach on a new model of motile confluent tissue, which we term Self-propelled Voronoi Model (SPV) that incorporates cell elasticity, Contractility and motility. With the model, we explore the mechanical properties of confluent motile tissue as a function of cell activities and cell shapes in various geometries.

  7. Regulation of Motility, Invasion and Metastatic Potential of Squamous Cell Carcinoma by 1,25D3

    PubMed Central

    Ma, Yingyu; Yu, Wei-Dong; Su, Bing; Seshadri, Mukund; Luo, Wei; Trump, Donald L.; Johnson, Candace S.

    2012-01-01

    BACKGROUND 1,25D3, the active metabolite of vitamin D, has been shown to exhibit broad spectrum anti-tumor activity in xenograft animal models. However, its activity against metastatic disease has not been extensively investigated. METHODS Squamous cell carcinoma (SCC) or 1,25D3-resistant variant SCC-DR cells were treated with 1,25D3. Actin organization was examined by immunofluorescence assay. Cell migration was assessed by “wound” healing and chemotactic migration assay. Cell invasion was assessed by Matrigel-based invasion assay and in situ zymography. MMP-2 and MMP-9 expression and secretion was examined by immunoblot analysis and ELISA, respectively. E-cadherin expression was assessed by flow cytometry, immunoblot analysis and immunohistochemistry. Knockdown of E-cadherin was achieved by siRNA. Experimental metastasis mouse model was done by intravenous injection of tumor cells. Lung tumor development was assessed by magnetic resonance imaging, gross observation and histology. RESULTS SCC cellular morphology and actin organization were altered by 10 nM of 1,25D3. 1,25D3 inhibited SCC cell motility and invasion, which was associated with reduced expression and secretion of MMP-2 and MMP-9. 1,25D3 promoted the expression of E-cadherin. These findings were not observed in SCC-DR cells. Knock down of E-cadherin rescued 1,25D3-inhibited cell migration. Intravenous injection of SCC or SCC-DR cells resulted in the establishment of extensive pulmonary lesions in saline-treated C3H mice. Treatment with 1,25D3 resulted in a marked reduction in the formation of lung tumor colonies in animals injected with SCC but not SCC-DR cells. CONCLUSIONS 1,25D3 suppresses SCC cell motility, invasion and metastasis, partially through the promotion of E-cadherin-mediated cell-cell adhesion. PMID:22833444

  8. Computer-assisted quantification of motile and invasive capabilities of cancer cells

    PubMed Central

    Kumar, Karthiga Santhana; Pillong, Max; Kunze, Jens; Burghardt, Isabel; Weller, Michael; Grotzer, Michael A.; Schneider, Gisbert; Baumgartner, Martin

    2015-01-01

    High-throughput analysis of cancer cell dissemination and its control by extrinsic and intrinsic cellular factors is hampered by the lack of adequate and efficient analytical tools for quantifying cell motility. Oncology research would greatly benefit from such a methodology that allows to rapidly determine the motile behaviour of cancer cells under different environmental conditions, including inside three-dimensional matrices. We combined automated microscopy imaging of two- and three-dimensional cell cultures with computational image analysis into a single assay platform for studying cell dissemination in high-throughput. We have validated this new approach for medulloblastoma, a metastatic paediatric brain tumour, in combination with the activation of growth factor signalling pathways with established pro-migratory functions. The platform enabled the detection of primary tumour and patient-derived xenograft cell sensitivity to growth factor-dependent motility and dissemination and identified tumour subgroup-specific responses to selected growth factors of excellent diagnostic value. PMID:26486848

  9. Cellular adhesome screen identifies critical modulators of focal adhesion dynamics, cellular traction forces and cell migration behaviour

    PubMed Central

    Fokkelman, Michiel; Balcıoğlu, Hayri E.; Klip, Janna E.; Yan, Kuan; Verbeek, Fons J.; Danen, Erik H. J.; van de Water, Bob

    2016-01-01

    Cancer cells migrate from the primary tumour into surrounding tissue in order to form metastasis. Cell migration is a highly complex process, which requires continuous remodelling and re-organization of the cytoskeleton and cell-matrix adhesions. Here, we aimed to identify genes controlling aspects of tumour cell migration, including the dynamic organization of cell-matrix adhesions and cellular traction forces. In a siRNA screen targeting most cell adhesion-related genes we identified 200+ genes that regulate size and/or dynamics of cell-matrix adhesions in MCF7 breast cancer cells. In a subsequent secondary screen, the 64 most effective genes were evaluated for growth factor-induced cell migration and validated by tertiary RNAi pool deconvolution experiments. Four validated hits showed significantly enlarged adhesions accompanied by reduced cell migration upon siRNA-mediated knockdown. Furthermore, loss of PPP1R12B, HIPK3 or RAC2 caused cells to exert higher traction forces, as determined by traction force microscopy with elastomeric micropillar post arrays, and led to considerably reduced force turnover. Altogether, we identified genes that co-regulate cell-matrix adhesion dynamics and traction force turnover, thereby modulating overall motility behaviour. PMID:27531518

  10. PD-1 promotes immune exhaustion by inducing antiviral T cell motility paralysis

    PubMed Central

    Zinselmeyer, Bernd H.; Heydari, Sara; Sacristán, Catarina; Nayak, Debasis; Cammer, Michael; Herz, Jasmin; Cheng, Xiaoxiao; Davis, Simon J.; Dustin, Michael L.

    2013-01-01

    Immune responses to persistent viral infections and cancer often fail because of intense regulation of antigen-specific T cells—a process referred to as immune exhaustion. The mechanisms that underlie the induction of exhaustion are not completely understood. To gain novel insights into this process, we simultaneously examined the dynamics of virus-specific CD8+ and CD4+ T cells in the living spleen by two-photon microscopy (TPM) during the establishment of an acute or persistent viral infection. We demonstrate that immune exhaustion during viral persistence maps anatomically to the splenic marginal zone/red pulp and is defined by prolonged motility paralysis of virus-specific CD8+ and CD4+ T cells. Unexpectedly, therapeutic blockade of PD-1–PD-L1 restored CD8+ T cell motility within 30 min, despite the presence of high viral loads. This result was supported by planar bilayer data showing that PD-L1 localizes to the central supramolecular activation cluster, decreases antiviral CD8+ T cell motility, and promotes stable immunological synapse formation. Restoration of T cell motility in vivo was followed by recovery of cell signaling and effector functions, which gave rise to a fatal disease mediated by IFN-γ. We conclude that motility paralysis is a manifestation of immune exhaustion induced by PD-1 that prevents antiviral CD8+ T cells from performing their effector functions and subjects them to prolonged states of negative immune regulation. PMID:23530125

  11. Cell Adhesion on Surface-Functionalized Magnesium.

    PubMed

    Wagener, Victoria; Schilling, Achim; Mainka, Astrid; Hennig, Diana; Gerum, Richard; Kelch, Marie-Luise; Keim, Simon; Fabry, Ben; Virtanen, Sannakaisa

    2016-05-18

    The biocompatibility of commercially pure magnesium-based (cp Mg) biodegradable implants is compromised of strong hydrogen evolution and surface alkalization due to high initial corrosion rates of cp Mg in the physiological environment. To mitigate this problem, the addition of corrosion-retarding alloying elements or coating of implant surfaces has been suggested. In the following work, we explored the effect of organic coatings on long-term cell growth. cp Mg was coated with aminopropyltriehtoxysilane + vitamin C (AV), carbonyldiimidazole (CDI), or stearic acid (SA). All three coatings have been previously suggested to reduce initial corrosion and to enhance protein adsorption and hence cell adhesion on magnesium surfaces. Endothelial cells (DH1+/+) and osteosarcoma cells (MG63) were cultured on coated samples for up to 20 days. To quantify Mg corrosion, electrochemical impedance spectroscopy (EIS) was measured after 1, 3, and 5 days of cell culture. We also investigated the speed of initial cell spreading after seeding using fluorescently labeled fibroblasts (NIH/3T3). Hydrogen evolution after contact with cell culture medium was markedly decreased on AV- and SA-coated Mg compared to uncoated Mg. These coatings also showed improved cell adhesion and spreading after 24 h of culture comparable to tissue-treated plastic surfaces. On AV-coated cp Mg, a confluent layer of endothelial cells formed after 5 days and remained intact for up to 20 days. Together, these data demonstrate that surface coating with AV is a viable strategy for improving long-term biocompatibility of cp Mg-based implants. EIS measurements confirmed that the presence of a confluent cell layer increased the corrosion resistance. PMID:27089250

  12. Chronic lymphocytic leukemia cells induce defective LFA-1–directed T-cell motility by altering Rho GTPase signaling that is reversible with lenalidomide

    PubMed Central

    Evans, Rachel; Kiaii, Shahryar; Svensson, Lena; Hogg, Nancy; Gribben, John G.

    2013-01-01

    T lymphocytes have an essential role in adaptive immunity and rely on the activation of integrin lymphocyte function–associated antigen-1 (LFA-1) to mediate cell arrest and migration. In cancer, malignant cells modify the immune microenvironment to block effective host antitumor responses. We show for the first time that CD4 and CD8 T cells from patients with chronic lymphocytic leukemia (CLL) exhibit globally impaired LFA-1–mediated migration and that this defect is mediated by direct tumor cell contact. We show that following the coculture of previously healthy T cells with CLL cells, subsequent LFA-1 engagement leads to altered Rho GTPase activation signaling by downregulating RhoA and Rac1, while upregulating Cdc42. Of clinical relevance, repair of this T-cell defect was demonstrated using the immunomodulatory drug lenalidomide, which completely rescued adhesion and motility function by restoring normal Rho GTPase activation signaling. Our report identifies a novel cancer immune evasion mechanism whereby tumor cells induce Rho GTPase signaling defects in T cells that prevent appropriate LFA-1 activation and motility. We believe these findings identify important biomarkers and highlight the clinical utility of immunotherapy to rescue normal T-cell function in CLLs that are likely to have relevance in other cancers. PMID:23325833

  13. Human NK cell development requires CD56-mediated motility and formation of the developmental synapse

    PubMed Central

    Mace, Emily M.; Gunesch, Justin T.; Dixon, Amera; Orange, Jordan S.

    2016-01-01

    While distinct stages of natural killer (NK) cell development have been defined, the molecular interactions that shape human NK cell maturation are poorly understood. Here we define intercellular interactions between developing NK cells and stromal cells which, through contact-dependent mechanisms, promote the generation of mature, functional human NK cells from CD34+ precursors. We show that developing NK cells undergo unique, developmental stage-specific sustained and transient interactions with developmentally supportive stromal cells, and that the relative motility of NK cells increases as they move through development in vitro and ex vivo. These interactions include the formation of a synapse between developing NK cells and stromal cells, which we term the developmental synapse. Finally, we identify a role for CD56 in developmental synapse structure, NK cell motility and NK cell development. Thus, we define the developmental synapse leading to human NK cell functional maturation. PMID:27435370

  14. Human NK cell development requires CD56-mediated motility and formation of the developmental synapse.

    PubMed

    Mace, Emily M; Gunesch, Justin T; Dixon, Amera; Orange, Jordan S

    2016-01-01

    While distinct stages of natural killer (NK) cell development have been defined, the molecular interactions that shape human NK cell maturation are poorly understood. Here we define intercellular interactions between developing NK cells and stromal cells which, through contact-dependent mechanisms, promote the generation of mature, functional human NK cells from CD34(+) precursors. We show that developing NK cells undergo unique, developmental stage-specific sustained and transient interactions with developmentally supportive stromal cells, and that the relative motility of NK cells increases as they move through development in vitro and ex vivo. These interactions include the formation of a synapse between developing NK cells and stromal cells, which we term the developmental synapse. Finally, we identify a role for CD56 in developmental synapse structure, NK cell motility and NK cell development. Thus, we define the developmental synapse leading to human NK cell functional maturation. PMID:27435370

  15. Cooperative inhibitory effects of antisense oligonucleotide of cell adhesion molecules and cimetidine on cancer cell adhesion

    PubMed Central

    Tang, Nan-Hong; Chen, Yan-Ling; Wang, Xiao-Qian; Li, Xiu-Jin; Yin, Feng-Zhi; Wang, Xiao-Zhong

    2004-01-01

    AIM: To explore the cooperative effects of antisense oligonucleotide (ASON) of cell adhesion molecules and cimetidine on the expression of E-selectin and ICAM-1 in endothelial cells and their adhesion to tumor cells. METHODS: After treatment of endothelial cells with ASON and/or cimetidine and induction with TNF-α, the protein and mRNA changes of E-selectin and ICAM-1 in endothelial cells were examined by flow cytometry and RT-PCR, respectively. The adhesion rates of endothelial cells to tumor cells were measured by cell adhesion experiment. RESULTS: In comparison with TNF-α inducing group, lipo-ASON and lipo-ASON/cimetidine could significantly decrease the protein and mRNA levels of E-selectin and ICAM-1 in endothelial cells, and lipo-ASON/cimetidine had most significant inhibitory effect on E-selectin expression (from 36.37 ± 1.56% to 14.23 ± 1.07%, P < 0.001). Meanwhile, cimetidine alone could inhibit the expression of E-selectin (36.37 ± 1.56% vs 27.2 ± 1.31%, P < 0.001), but not ICAM-1 (69.34 ± 2.50% vs 68.07 ± 2.10%, P > 0.05)and the two kinds of mRNA, either. Compared with TNF-α inducing group, the rate of adhesion was markedly decreased in lipo-E-selectin ASON and lipo-E-selectin ASON/cimetidine treated groups(P < 0.05), and lipo-E-selectin ASON/cimetidine worked better than lipo-E-selectin ASON alone except for HepG2/ECV304 group (P < 0.05). However, the decrease of adhesion was not significant in lipo-ICAM-1 ASON and lipo-ICAM-1 ASON/cimetidine treated groups except for HepG2/ECV304 group (P > 0.05). CONCLUSION: These data demonstrate that ASON in combination with cimetidine in vitro can significantly reduce the adhesion between endothelial cells and hepatic or colorectal cancer cells, which is stronger than ASON or cimetidine alone. This study provides some useful proofs for gene therapy of antiadhesion. PMID:14695770

  16. Effect of surface potential on epithelial cell adhesion, proliferation and morphology.

    PubMed

    Chang, Hsun-Yun; Kao, Wei-Lun; You, Yun-Wen; Chu, Yi-Hsuan; Chu, Kuo-Jui; Chen, Peng-Jen; Wu, Chen-Yi; Lee, Yu-Hsuan; Shyue, Jing-Jong

    2016-05-01

    Cell adhesion is the basis of individual cell survival, division and motility. Hence, understanding the effects that the surface properties have on cell adhesion, proliferation and morphology are crucial. In particular, surface charge/potential has been identified as an important factor that affects cell behavior. However, how cells respond to incremental changes in surface potential remains unclear. By using binary self-assembled monolayer (SAM) modified Au surfaces that are similar in mechanical/chemical properties and provide a series of surface potentials, the effect of surface potential on the behavior of cells can be studied. In this work, the effect of surface potential on epithelial cells, including human embryonic kidney (HEK293T) and human hepatocellular carcinoma (HepG2), were examined. The results showed that the adhesion density of epithelial cells increased with increasing surface potential, which is similar to but varied more significantly compared with fibroblasts. The proliferation rate is found to be independent of surface potential in both cell types. Furthermore, epithelial cells show no morphological change with respect to surface potential, whereas the morphology of the fibroblasts clearly changed with the surface potential. These differences between the cell types were rationalized by considering the difference in extracellular matrix composition. Laminin-dominant epithelial cells showed higher adhesion density and less morphological change than did fibronectin-dominant fibroblasts because the more significant adsorption of positively charged laminin on the surface enhanced the adhesion of epithelial cells. In contrast, due to the dominance of negatively charged fibronectin that adsorbed weakly on the surface, fibroblasts had to change their morphology to fit the inhomogeneous fibronectin-adsorbed area. PMID:26852101

  17. Overexpression of engulfment and cell motility 1 promotes cell invasion and migration of hepatocellular carcinoma.

    PubMed

    Jiang, Jiarui; Liu, Guoqing; Miao, Xiongying; Hua, Songwen; Zhong, Dewu

    2011-05-01

    Engulfment and cell motility 1 (Elmo1) has been linked to the invasive phenotype of glioma cells. The use of Elmo1 inhibitors is currently being evaluated in hepato-cellular carcinoma (HCC), but the molecular mechanisms of their therapeutic effect have yet to be determined. Elmo1 expression in HCC tissue samples from 131 cases and in 5 HCC cell lines was determined by immunohistochemistry, quantitative RT-PCR and Western blotting. To functionally characterize Elmo1 in HCC, Elmo1 expression in the HCCLM3 cell line was blocked by siRNA. Cell migration was measured by wound healing and transwell migration assays in vitro. Elmo1 overexpression was significantly correlated with cell invasion and the poor prognosis of HCC. Elmo1-siRNA-treated HCCLM3 cells demonstrated a reduction in cell migration. The present study demonstrated for the first time that the suppression of Elmo1 expression inhibits cell invasion in HCC. PMID:22977532

  18. β-Catenin–regulated myeloid cell adhesion and migration determine wound healing

    PubMed Central

    Amini-Nik, Saeid; Cambridge, Elizabeth; Yu, Winston; Guo, Anne; Whetstone, Heather; Nadesan, Puviindran; Poon, Raymond; Hinz, Boris; Alman, Benjamin A.

    2014-01-01

    A β-catenin/T cell factor–dependent transcriptional program is critical during cutaneous wound repair for the regulation of scar size; however, the relative contribution of β-catenin activity and function in specific cell types in the granulation tissue during the healing process is unknown. Here, cell lineage tracing revealed that cells in which β-catenin is transcriptionally active express a gene profile that is characteristic of the myeloid lineage. Mice harboring a macrophage-specific deletion of the gene encoding β-catenin exhibited insufficient skin wound healing due to macrophage-specific defects in migration, adhesion to fibroblasts, and ability to produce TGF-β1. In irradiated mice, only macrophages expressing β-catenin were able to rescue wound-healing deficiency. Evaluation of scar tissue collected from patients with hypertrophic and normal scars revealed a correlation between the number of macrophages within the wound, β-catenin levels, and cellularity. Our data indicate that β-catenin regulates myeloid cell motility and adhesion and that β-catenin–mediated macrophage motility contributes to the number of mesenchymal cells and ultimate scar size following cutaneous injury. PMID:24837430

  19. Differential adhesiveness between blood and marrow leukemic cells having similar pattern of VLA adhesion molecule expression.

    PubMed

    Thomas, X; Anglaret, B; Bailly, M; Maritaz, O; Magaud, J P; Archimbaud, E

    1998-10-01

    Functional adhesion of blood and marrow leukemic cells from 14 acute myeloid leukemia patients presenting with hyperleukocytosis was evaluated by performing cytoadhesion assays on purified (extracellular matrix proteins) and non-purified supports (MRC5 fibroblastic cell line). Results, in 30-min chromium release assay, show a mean +/- S.D. adhesion to fibronectin, collagen, and laminin respectively of 30 +/- 17%, 20 +/- 13%, 25 +/- 17% for blood leukemic cells and 18 +/- 11%, 11 +/- 10%, 11 +/- 8% for marrow leukemic cells. These differences between blood and marrow cells were statistically significant (respectively P = 0.005, P = 0.01 and P = 0.002), while no difference was noted regarding adhesion to non-purified supports. The higher adhesion of blood blast cells to purified supports was observed regardless of CD34 expression. No significant difference was observed in the expression of cell surface VLA-molecules (CD29, CD49b, CD49d, CD49e, CD49f) between blood and marrow blast cells. The addition of GM-CSF or G-CSF induced increased adhesion of marrow blasts and decreased adhesion of blood blasts leading to a loss of the difference between blood and marrow cells. In a 60-min chromium release assay, marrow blasts adhered even more than blood leukemic cells to fibronectin. In contrast, marrow blasts from 'aleukemic' acute myeloid leukemia patients did not show any modification regarding their adhesion to extracellular matrix proteins when co-cultured with growth factors. PMID:9766756

  20. Flagellum Density Regulates Proteus mirabilis Swarmer Cell Motility in Viscous Environments

    PubMed Central

    Tuson, Hannah H.; Copeland, Matthew F.; Carey, Sonia; Sacotte, Ryan

    2013-01-01

    Proteus mirabilis is an opportunistic pathogen that is frequently associated with urinary tract infections. In the lab, P. mirabilis cells become long and multinucleate and increase their number of flagella as they colonize agar surfaces during swarming. Swarming has been implicated in pathogenesis; however, it is unclear how energetically costly changes in P. mirabilis cell morphology translate into an advantage for adapting to environmental changes. We investigated two morphological changes that occur during swarming—increases in cell length and flagellum density—and discovered that an increase in the surface density of flagella enabled cells to translate rapidly through fluids of increasing viscosity; in contrast, cell length had a small effect on motility. We found that swarm cells had a surface density of flagella that was ∼5 times larger than that of vegetative cells and were motile in fluids with a viscosity that inhibits vegetative cell motility. To test the relationship between flagellum density and velocity, we overexpressed FlhD4C2, the master regulator of the flagellar operon, in vegetative cells of P. mirabilis and found that increased flagellum density produced an increase in cell velocity. Our results establish a relationship between P. mirabilis flagellum density and cell motility in viscous environments that may be relevant to its adaptation during the infection of mammalian urinary tracts and movement in contact with indwelling catheters. PMID:23144253

  1. Tuning cell adhesion by direct nanostructuring silicon into cell repulsive/adhesive patterns

    SciTech Connect

    Premnath, Priyatha; Venkatakrishnan, Krishnan

    2015-09-10

    Developing platforms that allow tuning cell functionality through incorporating physical, chemical, or mechanical cues onto the material surfaces is one of the key challenges in research in the field of biomaterials. In this respect, various approaches have been proposed and numerous structures have been developed on a variety of materials. Most of these approaches, however, demand a multistep process or post-chemical treatment. Therefore, a simple approach would be desirable to develop bio-functionalized platforms for effectively modulating cell adhesion and consequently programming cell functionality without requiring any chemical or biological surface treatment. This study introduces a versatile yet simple laser approach to structure silicon (Si) chips into cytophobic/cytophilic patterns in order to modulate cell adhesion and proliferation. These patterns are fabricated on platforms through direct laser processing of Si substrates, which renders a desired computer-generated configuration into patterns. We investigate the morphology, chemistry, and wettability of the platform surfaces. Subsequently, we study the functionality of the fabricated platforms on modulating cervical cancer cells (HeLa) behaviour. The results from in vitro studies suggest that the nanostructures efficiently repel HeLa cells and drive them to migrate onto untreated sites. The study of the morphology of the cells reveals that cells evade the cytophobic area by bending and changing direction. Additionally, cell patterning, cell directionality, cell channelling, and cell trapping are achieved by developing different platforms with specific patterns. The flexibility and controllability of this approach to effectively structure Si substrates to cell-repulsive and cell-adhesive patterns offer perceptible outlook for developing bio-functionalized platforms for a variety of biomedical devices. Moreover, this approach could pave the way for developing anti-cancer platforms that selectively repel

  2. The mechanism of binding of neural cell adhesion molecules.

    PubMed

    Hoffman, S; Edelman, G M

    1984-01-01

    The experimental results reviewed in this paper strongly suggest that the molecular mechanism of N-CAM-mediated cell adhesion involves the direct interaction of N-CAM molecules on one cell with N-CAM molecules on a second cell. The rate of this aggregation has a high-order dependence on the local N-CAM concentration, and is inversely related to the sialic acid content of the N-CAM molecules involved. In accordance with their relative sialic acid concentrations, the relative rates of aggregation mediated by E and A forms of N-CAM are A-A greater than A-E greater than E-E. Further removal of sialic acid from N-CAM below the level found in the A form gives little further enhancement of aggregation. These results provide one basis upon which to interpret the modulation hypothesis (Edelman, 1983) for control of N-CAM function, i.e. the adhesive strength of N-CAM bonds in an in vitro system can be altered in a graded manner over a wide range by variations in the local surface density of N-CAM or by chemical modification of N-CAM (differential sialylation). It is important to stress that these results do not preclude the possibility of other forms of modulation of N-CAM function or the function of other molecules in cell-cell interactions. It will be much more difficult to assess the role of N-CAM and the modulation of its function on pattern formation in vivo. It is pertinent to mention, however, that recent experiments on transformed neural cells (Greenberg et al., 1984) show loss of N-CAM following transformation with accompanying loss of aggregation and increased motility of the transformed cells. Aside from the possible implications for metastasis (transformation has for the first time been shown to affect a defined CAM and alter cellular sociology), these findings are consonant with the notion that alteration of surface N-CAM affects expression of other cellular processes. Clearly additional experiments are required to define the mechanisms by which this occurs. In

  3. Suppressive effects of 3-bromopyruvate on the proliferation and the motility of hepatocellular carcinoma cells.

    PubMed

    Tomizawa, Minoru; Shinozaki, Fuminobu; Motoyoshi, Yasufumi; Sugiyama, Takao; Yamamoto, Shigenori; Ishige, Naoki

    2016-01-01

    The compound 3-bromopyruvate (3BP) is an analogue of pyruvate, which is the final product of glycolysis that enters the citric acid cycle. The present study aimed to investigate the suppressive effects of 3BP on the proliferation and motility of hepatocellular carcinoma (HCC) cells. HLF and PLC/PRF/5 cells were cultured with 3BP and subjected to an MTS assay. Apoptosis was analyzed by hematoxylin and eosin staining. Cell motility was analyzed using a scratch assay. Real-time quantitative polymerase chain reaction (PCR) was performed to determine the expression levels of cyclin D1 and matrix metalloproteinase (MMP)9. Proliferation of both cell lines was significantly suppressed by 3BP at 100 µM (P<0.05). The expression level of cyclin D1 was decreased after 3BP treatment at 100 µM in both cell lines (P<0.05). Pyknotic nuclei were observed in the cells cultured with 3BP at 100 µM. These results revealed that 3BP suppressed cell proliferation, decreased the expression of cyclin D1, and induced apoptosis in HCC cells. 3BP significantly suppressed motility in both cell lines (P<0.05). The expression level of MMP9 was significantly decreased (P<0.05). 3BP suppressed the proliferation and motility of HCC cells by decreasing the expression of cyclin D1 and MMP9. PMID:26530887

  4. Cadherin Cell Adhesion System in Canine Mammary Cancer: A Review

    PubMed Central

    Gama, Adelina; Schmitt, Fernando

    2012-01-01

    Cadherin-catenin adhesion complexes play important roles by providing cell-cell adhesion and communication in different organ systems. Abnormal expression of cadherin adhesion molecules constitutes a common phenomenon in canine mammary cancer and has been frequently implicated in tumour progression. This paper summarizes the current knowledge on cadherin/catenin adhesion molecules (E-cadherin, β-catenin, and P-cadherin) in canine mammary cancer, focusing on the putative biological functions and clinical significance of these molecules in this disease. This paper highlights the need for further research studies in this setting in order to elucidate the role of these adhesion molecules during tumour progression and metastasis. PMID:22973534

  5. SPAG9 controls the cell motility, invasion and angiogenesis of human osteosarcoma cells

    PubMed Central

    YANG, XIAORONG; ZHOU, WENLAI; LIU, SHIQING

    2016-01-01

    Sperm-associated antigen 9 (SPAG9) is an oncoprotein involved in the progression of various human malignancies; however, its role in osteosarcoma (OS) remains poorly evaluated. The present study used Matrigel™ cell migration and invasion assays, tube formation assay, Cell Counting kit-8, quantitative polymerase chain reaction, western blotting, and enzyme-linked immunosorbent assay to investigate the role of SPAG9 in OS cell motility, invasion and angiogenesis. The results of the present study demonstrated that SPAG9 expression was upregulated in OS tissues, as compared with adjacent normal tissues, and knockdown of SPAG9 in an OS cell line inhibited cell motility and invasion via inactivation of metalloproteinase (MMP)-2 and MMP-9. Furthermore, the present study demonstrated that silencing of SPAG9 in OS cells inhibited tube formation, the proliferation of human umbilical vascular endothelial cells, and suppressed vascular endothelial growth factor (VEGF) expression and secretion, contributing to a reduction in angiogenesis. The results of the present study indicated that SPAG9 may be an important regulator in OS and may be involved in metastasis. Therefore SPAG9 may be a promising target for the treatment of metastatic OS. PMID:26893659

  6. Repulsive cues combined with physical barriers and cell–cell adhesion determine progenitor cell positioning during organogenesis

    PubMed Central

    Paksa, Azadeh; Bandemer, Jan; Hoeckendorf, Burkhard; Razin, Nitzan; Tarbashevich, Katsiaryna; Minina, Sofia; Meyen, Dana; Biundo, Antonio; Leidel, Sebastian A.; Peyrieras, Nadine; Gov, Nir S.; Keller, Philipp J.; Raz, Erez

    2016-01-01

    The precise positioning of organ progenitor cells constitutes an essential, yet poorly understood step during organogenesis. Using primordial germ cells that participate in gonad formation, we present the developmental mechanisms maintaining a motile progenitor cell population at the site where the organ develops. Employing high-resolution live-cell microscopy, we find that repulsive cues coupled with physical barriers confine the cells to the correct bilateral positions. This analysis revealed that cell polarity changes on interaction with the physical barrier and that the establishment of compact clusters involves increased cell–cell interaction time. Using particle-based simulations, we demonstrate the role of reflecting barriers, from which cells turn away on contact, and the importance of proper cell–cell adhesion level for maintaining the tight cell clusters and their correct positioning at the target region. The combination of these developmental and cellular mechanisms prevents organ fusion, controls organ positioning and is thus critical for its proper function. PMID:27088892

  7. Metastasis-associated 5T4 antigen disrupts cell-cell contacts and induces cellular motility in epithelial cells.

    PubMed

    Carsberg, C J; Myers, K A; Stern, P L

    1996-09-27

    The 5T4 antigen is defined by a monoclonal antibody (MAb) specific for human trophoblast. It is also expressed by many types of tumour cell and has been associated with metastasis and poor clinical outcome in a number of cancers. This pattern of expression is consistent with a mechanistic involvement of 5T4 molecules in the spread of cancer cells. The 5T4 antigen is a transmembrane glycoprotein with a 310 amino acid extracellular domain and a 44 amino acid cytoplasmic domain. Transfection of full-length 5T4 cDNA into epithelial cells alters cell-cell contacts and cellular motility. Thus, in 5T4-transfected CL-S1 murine mammary cells, 5T4 expression is associated with dendritic morphology, accompanied by abrogation of actin/cadherin-containing contacts and increased motility. In transfected MDCK canine kidney epithelial cells, 5T4 over-expression also results in increased motility, but disruption of cell-cell contacts, either by culturing cells in low calcium medium or by addition of HGF/SF, is needed. The effects of 5T4 expression on morphology and motility are separable since cells transfected with a truncated form of 5T4 cDNA in which the cytoplasmic domain is deleted reveal that the latter is necessary to abrogate actin/cadherin-containing contacts but does not influence the effects on motility. Thus, 5T4 molecules can deliver signals through both the extracellular and intracellular domains, and the resultant effects are consistent with a role for 5T4 molecules in invasion processes. PMID:8895545

  8. Collective epithelial cell sheet adhesion and migration on polyelectrolyte multilayers with uniform and gradients of compliance.

    PubMed

    Martinez, Jessica S; Schlenoff, Joseph B; Keller, Thomas C S

    2016-08-01

    Polyelectrolyte multilayers (PEMUs) are tunable thin films that could serve as coatings for biomedical implants. PEMUs built layer by layer with the polyanion poly(acrylic acid) (PAA) modified with a photosensitive 4-(2-hydroxyethoxy) benzophenone (PAABp) group and the polycation poly(allylamine hydrochloride) (PAH) are mechanically tunable by UV irradiation, which forms covalent bonds between the layers and increases PEMU stiffness. PAH-terminated PEMUs (PAH-PEMUs) that were uncrosslinked, UV-crosslinked to a uniform stiffness, or UV-crosslinked with an edge mask or through a neutral density optical gradient filter to form continuous compliance gradients were used to investigate how differences in PEMU stiffness affect the adhesion and migration of epithelial cell sheets from scales of the fish Poecilia sphenops (Black Molly) and Carassius auratus (Comet Goldfish). During the progressive collective cell migration, the edge cells (also known as 'leader' cells) in the sheets on softer uncrosslinked PEMUs and less crosslinked regions of the gradient formed more actin filaments and vinculin-containing adherens junctions and focal adhesions than formed in the sheet cells on stiffer PEMUs or glass. During sheet migration, the ratio of edge cell to internal cell (also known as 'follower' cells) motilities were greater on the softer PEMUs than on the stiffer PEMUs or glass, causing tension to develop across the sheet and periods of retraction, during which the edge cells lost adhesion to the substrate and regions of the sheet retracted toward the more adherent internal cell region. These retraction events were inhibited by the myosin II inhibitor Blebbistatin, which reduced the motility velocity ratios to those for sheets on the stiffer PEMUs. Blebbistatin also caused disassembly of actin filaments, reorganization of focal adhesions, increased cell spreading at the leading edge, as well as loss of edge cell-cell connections in epithelial cell sheets on all surfaces

  9. Actions of translocator protein ligands on neutrophil adhesion and motility induced by G-protein coupled receptor signaling.

    PubMed

    de Lima, Camila Bento; Tamura, Eduardo K; Montero-Melendez, Trindad; Palermo-Neto, João; Perretti, Mauro; Markus, Regina P; Farsky, Sandra Helena Poliselli

    2012-01-13

    The 18 kDa translocator protein (TSPO) also known as the peripheral benzodiazepine receptor (PBR), mediates the transportation of cholesterol and anions from the outer to the inner mitochondrial membrane in different cells types. Although recent evidences indicate a potential role for TSPO in the development of inflammatory processes, the mechanisms involved have not been elucidated. The present study investigated the ability of the specific TSPO ligands, the isoquinoline carboxamide PK11195 and benzodiazepine Ro5-4864, on neutrophil recruitment promoted by the N-formylmethionyl-leucyl-phenylalanine peptide (fMLP), an agonist of G-protein coupled receptor (GPCR). Pre-treatment with Ro5-4864 abrograted fMLP-induced leukocyte-endothelial interactions in mesenteric postcapillary venules in vivo. Moreover, in vitro Ro5-4864 treatment prevented fMLP-induced: (i) L-selectin shedding and overexpression of PECAM-1 on the neutrophil cell surface; (ii) neutrophil chemotaxis and (iii) enhancement of intracellular calcium cations (iCa(+2)). Intriguingly, the two latter effects were augmented by cell treatment with PK11195. An allosteric agonist/antagonist relation may be suggested, as the effects of Ro5-4864 on fMLP-stimulated neutrophils were reverted by simultaneous treatment with PK11195. Taken together, these data highlight TSPO as a modulator of pathways of neutrophil adhesion and locomotion induced by GPCR, connecting TSPO actions and the onset of an innate inflammatory response. PMID:22209795

  10. Polymerization, bending, tension: What happens at the leading edge of motile cells?

    NASA Astrophysics Data System (ADS)

    Falcke, M.; Zimmermann, J.

    2014-06-01

    The forces experienced by filaments in actin based propulsion in reconstituted systems and cell motility, the mechanical properties of the lamellipodium of motile cells due to filament branching and cross-linking, the free filament contour length between branch points, the mechanisms of the force-velocity relation and velocity oscillations are all topics of ongoing debate. Here, we review results with a modelling concept considering the F-actin network as weakly cross-linked in a region with dynamic depth close to the propelled obstacle and gel-like further back. It offers quantitative explanations for steady motion and oscillation mechanisms in reconstituted systems and motile cells, and the force-velocity relation of fish keratocytes.

  11. The Interplay between Signaling and Metabolism in Breast Cancer Cell Motility and Metastasis

    NASA Astrophysics Data System (ADS)

    Tsarfaty, Ilan

    2013-03-01

    The initiation and growth of tumor metastases require tumor cells go through a transition between collective-to-individual cell migration. Understanding the molecular, cellular and physical mechanisms of these different migration modes is limited. We focus on the tumor cell migration induced by Hepatocyte Growth Factor / Scatter Factor (HGF/SF) - Met-signaling, a master regulator of cell motility in normal and malignant processes. Met has been implicated in tumorigenesis and metastasis and several Met targeting agents have been introduced into the clinic, and are currently in all phases of clinical trials Our analysis demonstrates that Met signaling dramatically alter the morpho-kinetic dynamics of collective migration of tumor cells. It induce a ``wave'' of increasing velocities that propagates back from the leading edge, increases cells' orientation and cooperation capabilities. In parallel Met signaling induces amoeboid cell motility that increased cell individuality. The decision making regarding the motility mode is dependent on the extent of activation of unique signal and metabolic cues. We present a combination of molecular imaging, conceptual and modeling framework for the analysis and assessment of the collective mesenchymal to epithelial versus amoeboid motility. Combined together our analysis can contribute to the understanding of metastasis and personalizing anti Met targeted therapy.

  12. Inhibitory Activity of (+)-Usnic Acid against Non-Small Cell Lung Cancer Cell Motility

    PubMed Central

    Yang, Yi; Nguyen, Thanh Thi; Jeong, Min-Hye; Crişan, Florin; Yu, Young Hyun; Ha, Hyung-Ho; Choi, Kyung Hee; Jeong, Hye Gwang; Jeong, Tae Cheon; Lee, Kwang Youl; Kim, Kyung Keun; Hur, Jae-Seoun; Kim, Hangun

    2016-01-01

    Lichens are symbiotic organisms that produce various unique chemicals that can be used for pharmaceutical purposes. With the aim of screening new anti-cancer agents that inhibit cancer cell motility, we tested the inhibitory activity of seven lichen species collected from the Romanian Carpathian Mountains against migration and invasion of human lung cancer cells and further investigated the molecular mechanisms underlying their anti-metastatic activity. Among them, Alectoria samentosa, Flavocetraria nivalis, Alectoria ochroleuca, and Usnea florida showed significant inhibitory activity against motility of human lung cancer cells. HPLC results showed that usnic acid is the main compound in these lichens, and (+)-usnic acid showed similar inhibitory activity that crude extract have. Mechanistically, β-catenin-mediated TOPFLASH activity and KITENIN-mediated AP-1 activity were decreased by (+)-usnic acid treatment in a dose-dependent manner. The quantitative real-time PCR data showed that (+)-usnic acid decreased the mRNA level of CD44, Cyclin D1 and c-myc, which are the downstream target genes of both β-catenin/LEF and c-jun/AP-1. Also, Rac1 and RhoA activities were decreased by treatment with (+)-usnic acid. Interestingly, higher inhibitory activity for cell invasion was observed when cells were treated with (+)-usnic acid and cetuximab. These results implied that (+)-usnic acid might have potential activity in inhibition of cancer cell metastasis, and (+)-usnic acid could be used for anti-cancer therapy with a distinct mechanisms of action. PMID:26751081

  13. Inhibitory Activity of (+)-Usnic Acid against Non-Small Cell Lung Cancer Cell Motility.

    PubMed

    Yang, Yi; Nguyen, Thanh Thi; Jeong, Min-Hye; Crişan, Florin; Yu, Young Hyun; Ha, Hyung-Ho; Choi, Kyung Hee; Jeong, Hye Gwang; Jeong, Tae Cheon; Lee, Kwang Youl; Kim, Kyung Keun; Hur, Jae-Seoun; Kim, Hangun

    2016-01-01

    Lichens are symbiotic organisms that produce various unique chemicals that can be used for pharmaceutical purposes. With the aim of screening new anti-cancer agents that inhibit cancer cell motility, we tested the inhibitory activity of seven lichen species collected from the Romanian Carpathian Mountains against migration and invasion of human lung cancer cells and further investigated the molecular mechanisms underlying their anti-metastatic activity. Among them, Alectoria samentosa, Flavocetraria nivalis, Alectoria ochroleuca, and Usnea florida showed significant inhibitory activity against motility of human lung cancer cells. HPLC results showed that usnic acid is the main compound in these lichens, and (+)-usnic acid showed similar inhibitory activity that crude extract have. Mechanistically, β-catenin-mediated TOPFLASH activity and KITENIN-mediated AP-1 activity were decreased by (+)-usnic acid treatment in a dose-dependent manner. The quantitative real-time PCR data showed that (+)-usnic acid decreased the mRNA level of CD44, Cyclin D1 and c-myc, which are the downstream target genes of both β-catenin/LEF and c-jun/AP-1. Also, Rac1 and RhoA activities were decreased by treatment with (+)-usnic acid. Interestingly, higher inhibitory activity for cell invasion was observed when cells were treated with (+)-usnic acid and cetuximab. These results implied that (+)-usnic acid might have potential activity in inhibition of cancer cell metastasis, and (+)-usnic acid could be used for anti-cancer therapy with a distinct mechanisms of action. PMID:26751081

  14. Targeting the Metastasis Suppressor, N-Myc Downstream Regulated Gene-1, with Novel Di-2-Pyridylketone Thiosemicarbazones: Suppression of Tumor Cell Migration and Cell-Collagen Adhesion by Inhibiting Focal Adhesion Kinase/Paxillin Signaling.

    PubMed

    Wangpu, Xiongzhi; Lu, Jiaoyang; Xi, Ruxing; Yue, Fei; Sahni, Sumit; Park, Kyung Chan; Menezes, Sharleen; Huang, Michael L H; Zheng, Minhua; Kovacevic, Zaklina; Richardson, Des R

    2016-05-01

    Metastasis is a complex process that is regulated by multiple signaling pathways, with the focal adhesion kinase (FAK)/paxillin pathway playing a major role in the formation of focal adhesions and cell motility. N-myc downstream regulated gene-1 (NDRG1) is a potent metastasis suppressor in many solid tumor types, including prostate and colon cancer. Considering the antimetastatic effect of NDRG1 and the crucial involvement of the FAK/paxillin pathway in cellular migration and cell-matrix adhesion, we assessed the effects of NDRG1 on this important oncogenic pathway. In the present study, NDRG1 overexpression and silencing models of HT29 colon cancer and DU145 prostate cancer cells were used to examine the activation of FAK/paxillin signaling and the formation of focal adhesions. The expression of NDRG1 resulted in a marked and significant decrease in the activating phosphorylation of FAK and paxillin, whereas silencing of NDRG1 resulted in an opposite effect. The expression of NDRG1 also inhibited the formation of focal adhesions as well as cell migration and cell-collagen adhesion. Incubation of cells with novel thiosemicarbazones, namely di-2-pyridylketone 4,4-dimethyl-3-thiosemicarbazone and di-2-pyridylketone 4-cyclohexyl-4-methyl-3-thiosemicarbazone, that upregulate NDRG1 also resulted in decreased phosphorylation of FAK and paxillin. The ability of these thiosemicarbazones to inhibit cell migration and metastasis could be mediated, at least in part, through the FAK/paxillin pathway. PMID:26895766

  15. The cell adhesion molecules Echinoid and Friend of Echinoid coordinate cell adhesion and cell signaling to regulate the fidelity of ommatidial rotation in the Drosophila eye.

    PubMed

    Fetting, Jennifer L; Spencer, Susan A; Wolff, Tanya

    2009-10-01

    Directed cellular movements are a universal feature of morphogenesis in multicellular organisms. Differential adhesion between the stationary and motile cells promotes these cellular movements to effect spatial patterning of cells. A prominent feature of Drosophila eye development is the 90 degrees rotational movement of the multicellular ommatidial precursors within a matrix of stationary cells. We demonstrate that the cell adhesion molecules Echinoid (Ed) and Friend of Echinoid (Fred) act throughout ommatidial rotation to modulate the degree of ommatidial precursor movement. We propose that differential levels of Ed and Fred between stationary and rotating cells at the initiation of rotation create a permissive environment for cell movement, and that uniform levels in these two populations later contribute to stopping the movement. Based on genetic data, we propose that ed and fred impart a second, independent, ;brake-like' contribution to this process via Egfr signaling. Ed and Fred are localized in largely distinct and dynamic patterns throughout rotation. However, ed and fred are required in only a subset of cells - photoreceptors R1, R7 and R6 - for normal rotation, cells that have only recently been linked to a role in planar cell polarity (PCP). This work also provides the first demonstration of a requirement for cone cells in the ommatidial rotation aspect of PCP. ed and fred also genetically interact with the PCP genes, but affect only the degree-of-rotation aspect of the PCP phenotype. Significantly, we demonstrate that at least one PCP protein, Stbm, is required in R7 to control the degree of ommatidial rotation. PMID:19736327

  16. Adhesion in the stem cell niche: biological roles and regulation

    PubMed Central

    Chen, Shuyi; Lewallen, Michelle; Xie, Ting

    2013-01-01

    Stem cell self-renewal is tightly controlled by the concerted action of stem cell-intrinsic factors and signals within the niche. Niche signals often function within a short range, allowing cells in the niche to self-renew while their daughters outside the niche differentiate. Thus, in order for stem cells to continuously self-renew, they are often anchored in the niche via adhesion molecules. In addition to niche anchoring, however, recent studies have revealed other important roles for adhesion molecules in the regulation of stem cell function, and it is clear that stem cell-niche adhesion is crucial for stem cell self-renewal and is dynamically regulated. Here, we highlight recent progress in understanding adhesion between stem cells and their niche and how this adhesion is regulated. PMID:23250203

  17. Actin–myosin network reorganization breaks symmetry at the cell rear to spontaneously initiate polarized cell motility

    PubMed Central

    Yam, Patricia T.; Wilson, Cyrus A.; Ji, Lin; Hebert, Benedict; Barnhart, Erin L.; Dye, Natalie A.; Wiseman, Paul W.; Danuser, Gaudenz; Theriot, Julie A.

    2007-01-01

    We have analyzed the spontaneous symmetry breaking and initiation of actin-based motility in keratocytes (fish epithelial cells). In stationary keratocytes, the actin network flow was inwards and radially symmetric. Immediately before motility initiation, the actin network flow increased at the prospective cell rear and reoriented in the perinuclear region, aligning with the prospective axis of movement. Changes in actin network flow at the cell front were detectable only after cell polarization. Inhibition of myosin II or Rho kinase disrupted actin network organization and flow in the perinuclear region and decreased the motility initiation frequency, whereas increasing myosin II activity with calyculin A increased the motility initiation frequency. Local stimulation of myosin activity in stationary cells by the local application of calyculin A induced directed motility initiation away from the site of stimulation. Together, these results indicate that large-scale actin–myosin network reorganization and contractility at the cell rear initiate spontaneous symmetry breaking and polarized motility of keratocytes. PMID:17893245

  18. High Avidity CD8+ T Cells Efficiently Eliminate Motile HIV-Infected Targets and Execute a Locally Focused Program of Anti-Viral Function

    PubMed Central

    Foley, Maria Hottelet; Forcier, Talitha; McAndrew, Elizabeth; Gonzalez, Michael; Chen, Huabiao; Juelg, Boris; Walker, Bruce D.; Irvine, Darrell J.

    2014-01-01

    The dissemination of HIV from an initial site of infection is facilitated by motile HIV-infected CD4+ T-cells. However, the impact of infected target cell migration on antigen recognition by HIV-specific CD8+ T-cells is unclear. Using a 3D in vitro model of tissue, we visualized dynamic interactions between HIV-infected or peptide-pulsed CD4+ T-cells and HIV-specific CD8+ T-cells. CTLs engaged motile HIV-infected targets, but ∼50% of targets broke contact and escaped. In contrast, immobilized target cells were readily killed, indicating target motility directly inhibits CD8+ T-cell function. Strong calcium signals occurred in CTLs killing a motile target but calcium signaling was weak or absent in CTLs which permitted target escape. Neutralization of adhesion receptors LFA-1 and CD58 inhibited CD8+ T-cell function within the 3D matrix, demonstrating that efficient motile target lysis as dependent on adhesive engagement of targets. Antigen sensitivity (a convolution of antigen density, TCR avidity and CD8 coreceptor binding) is also critical for target recognition. We modulated this parameter (known as functional avidity but referred to here as “avidity” for the sake of simplicity) by exploiting common HIV escape mutations and measured their impact on CTL function at the single-cell level. Targets pulsed with low avidity mutant antigens frequently escaped while CTLs killed targets bearing high avidity antigen with near-perfect efficiency. CTLs engaged, arrested, and killed an initial target bearing high avidity antigen within minutes, but serial killing was surprisingly rare. CD8 cells remained committed to their initial dead target for hours, accumulating TCR signals that sustained secretion of soluble antiviral factors. These data indicate that high-avidity CD8+ T-cells execute an antiviral program in the precise location where antigen has been sensed: CTL effector functions are spatiotemporally coordinated with an early lytic phase followed by a sustained

  19. Synapses: Sites of Cell Recognition, Adhesion, and Functional Specification

    PubMed Central

    Yamada, Soichiro; Nelson, W. James

    2012-01-01

    Synapses are specialized adhesive contacts characteristic of many types of cell-cell interactions involving neurons, immune cells, epithelial cells, and even pathogens and host cells. Cell-cell adhesion is mediated by structurally diverse classes of cell-surface glycoproteins, which form homophilic or heterophilic interactions across the intercellular space. Adhesion proteins bind to a cytoplasmic network of scaffolding proteins, regulators of the actin cytoskeleton, and signal transduction pathways that control the structural and functional organization of synapses. The themes of this review are to compare the organization of synapses in different cell types and to understand how different classes of cell adhesion proteins and cytoplasmic protein networks specify the assembly of functionally distinct synapses in different cell contexts. PMID:17506641

  20. Homotypic RANK signaling differentially regulates proliferation, motility and cell survival in osteosarcoma and mammary epithelial cells.

    PubMed

    Beristain, Alexander G; Narala, Swami R; Di Grappa, Marco A; Khokha, Rama

    2012-02-15

    RANKL (receptor activator of NF-κB ligand) is a crucial cytokine for regulating diverse biological systems such as innate immunity, bone homeostasis and mammary gland differentiation, operating through activation of its cognate receptor RANK. In these normal physiological processes, RANKL signals through paracrine and/or heterotypic mechanisms where its expression and function is tightly controlled. Numerous pathologies involve RANKL deregulation, such as bone loss, inflammatory diseases and cancer, and aberrant RANK expression has been reported in bone cancer. Here, we investigated the significance of RANK in tumor cells with a particular emphasis on homotypic signaling. We selected RANK-positive mouse osteosarcoma and RANK-negative preosteoblastic MC3T3-E1 cells and subjected them to loss- and gain-of-RANK function analyses. By examining a spectrum of tumorigenic properties, we demonstrate that RANK homotypic signaling has a negligible effect on cell proliferation, but promotes cell motility and anchorage-independent growth of osteosarcoma cells and preosteoblasts. By contrast, establishment of RANK signaling in non-tumorigenic mammary epithelial NMuMG cells promotes their proliferation and anchorage-independent growth, but not motility. Furthermore, RANK activation initiates multiple signaling pathways beyond its canonical target, NF-κB. Among these, biochemical inhibition reveals that Erk1/2 is dominant and crucial for the promotion of anchorage-independent survival and invasion of osteoblastic cells, as well as the proliferation of mammary epithelial cells. Thus, RANK signaling functionally contributes to key tumorigenic properties through a cell-autonomous homotypic mechanism. These data also identify the likely inherent differences between epithelial and mesenchymal cell responsiveness to RANK activation. PMID:22421365

  1. Cell morphology and focal adhesion location alters internal cell stress.

    PubMed

    Mullen, C A; Vaughan, T J; Voisin, M C; Brennan, M A; Layrolle, P; McNamara, L M

    2014-12-01

    Extracellular mechanical cues have been shown to have a profound effect on osteogenic cell behaviour. However, it is not known precisely how these cues alter intracellular mechanics to initiate changes in cell behaviour. In this study, a combination of in vitro culture of MC3T3-E1 cells and finite-element modelling was used to investigate the effects of passive differences in substrate stiffness on intracellular mechanics. Cells on collagen-based substrates were classified based on the presence of cell processes and the dimensions of various cellular features were quantified. Focal adhesion (FA) density was quantified from immunohistochemical staining, while cell and substrate stiffnesses were measured using a live-cell atomic force microscope. Computational models of cell morphologies were developed using an applied contraction of the cell body to simulate active cell contraction. The results showed that FA density is directly related to cell morphology, while the effect of substrate stiffness on internal cell tension was modulated by both cell morphology and FA density, as investigated by varying the number of adhesion sites present in each morphological model. We propose that the cells desire to achieve a homeostatic stress state may play a role in osteogenic cell differentiation in response to extracellular mechanical cues. PMID:25297316

  2. Cell morphology and focal adhesion location alters internal cell stress

    PubMed Central

    Mullen, C. A.; Vaughan, T. J.; Voisin, M. C.; Brennan, M. A.; Layrolle, P.; McNamara, L. M.

    2014-01-01

    Extracellular mechanical cues have been shown to have a profound effect on osteogenic cell behaviour. However, it is not known precisely how these cues alter intracellular mechanics to initiate changes in cell behaviour. In this study, a combination of in vitro culture of MC3T3-E1 cells and finite-element modelling was used to investigate the effects of passive differences in substrate stiffness on intracellular mechanics. Cells on collagen-based substrates were classified based on the presence of cell processes and the dimensions of various cellular features were quantified. Focal adhesion (FA) density was quantified from immunohistochemical staining, while cell and substrate stiffnesses were measured using a live-cell atomic force microscope. Computational models of cell morphologies were developed using an applied contraction of the cell body to simulate active cell contraction. The results showed that FA density is directly related to cell morphology, while the effect of substrate stiffness on internal cell tension was modulated by both cell morphology and FA density, as investigated by varying the number of adhesion sites present in each morphological model. We propose that the cells desire to achieve a homeostatic stress state may play a role in osteogenic cell differentiation in response to extracellular mechanical cues. PMID:25297316

  3. Glycolysis is the primary bioenergetic pathway for cell motility and cytoskeletal remodeling in human prostate and breast cancer cells

    PubMed Central

    Shiraishi, Takumi; Verdone, James E.; Huang, Jessie; Kahlert, Ulf D.; Hernandez, James R.; Torga, Gonzalo; Zarif, Jelani C.; Epstein, Tamir; Gatenby, Robert; McCartney, Annemarie; Elisseeff, Jennifer H.; Mooney, Steven M.; An, Steven S.; Pienta, Kenneth J.

    2015-01-01

    The ability of a cancer cell to detach from the primary tumor and move to distant sites is fundamental to a lethal cancer phenotype. Metabolic transformations are associated with highly motile aggressive cellular phenotypes in tumor progression. Here, we report that cancer cell motility requires increased utilization of the glycolytic pathway. Mesenchymal cancer cells exhibited higher aerobic glycolysis compared to epithelial cancer cells while no significant change was observed in mitochondrial ATP production rate. Higher glycolysis was associated with increased rates of cytoskeletal remodeling, greater cell traction forces and faster cell migration, all of which were blocked by inhibition of glycolysis, but not by inhibition of mitochondrial ATP synthesis. Thus, our results demonstrate that cancer cell motility and cytoskeleton rearrangement is energetically dependent on aerobic glycolysis and not oxidative phosphorylation. Mitochondrial derived ATP is insufficient to compensate for inhibition of the glycolytic pathway with regard to cellular motility and CSK rearrangement, implying that localization of ATP derived from glycolytic enzymes near sites of active CSK rearrangement is more important for cell motility than total cellular ATP production rate. These results extend our understanding of cancer cell metabolism, potentially providing a target metabolic pathway associated with aggressive disease. PMID:25426557

  4. S100A4 is frequently overexpressed in lung cancer cells and promotes cell growth and cell motility

    SciTech Connect

    Chen, Na; Sato, Daisuke; Saiki, Yuriko; Sunamura, Makoto; Fukushige, Shinichi; Horii, Akira

    2014-05-09

    Highlights: • We observed frequent overexpression of S100A4 in lung cancer cell lines. • Knockdown of S100A4 suppressed proliferation in lung cancer cells. • Forced expression of S100A4 accelerated cell motility in lung cancer cells. • PRDM2 was found to be one of the downstream suppressed genes of S100A4. - Abstract: S100A4, a small calcium-binding protein belonging to the S100 protein family, is commonly overexpressed in a variety of tumor types and is widely accepted to associate with metastasis by regulating the motility and invasiveness of cancer cells. However, its biological role in lung carcinogenesis is largely unknown. In this study, we found that S100A4 was frequently overexpressed in lung cancer cells, irrespective of histological subtype. Then we performed knockdown and forced expression of S100A4 in lung cancer cell lines and found that specific knockdown of S100A4 effectively suppressed cell proliferation only in lung cancer cells with S100A4-overexpression; forced expression of S100A4 accelerated cell motility only in S100A4 low-expressing lung cancer cells. PRDM2 and VASH1, identified as novel upregulated genes by microarray after specific knockdown of S100A4 in pancreatic cancer, were also analyzed, and we found that PRDM2 was significantly upregulated after S100A4-knockdown in one of two analyzed S100A4-overexpressing lung cancer cells. Our present results suggest that S100A4 plays an important role in lung carcinogenesis by means of cell proliferation and motility by a pathway similar to that in pancreatic cancer.

  5. Cell Adhesion on Amyloid Fibrils Lacking Integrin Recognition Motif.

    PubMed

    Jacob, Reeba S; George, Edna; Singh, Pradeep K; Salot, Shimul; Anoop, Arunagiri; Jha, Narendra Nath; Sen, Shamik; Maji, Samir K

    2016-03-01

    Amyloids are highly ordered, cross-β-sheet-rich protein/peptide aggregates associated with both human diseases and native functions. Given the well established ability of amyloids in interacting with cell membranes, we hypothesize that amyloids can serve as universal cell-adhesive substrates. Here, we show that, similar to the extracellular matrix protein collagen, amyloids of various proteins/peptides support attachment and spreading of cells via robust stimulation of integrin expression and formation of integrin-based focal adhesions. Additionally, amyloid fibrils are also capable of immobilizing non-adherent red blood cells through charge-based interactions. Together, our results indicate that both active and passive mechanisms contribute to adhesion on amyloid fibrils. The present data may delineate the functional aspect of cell adhesion on amyloids by various organisms and its involvement in human diseases. Our results also raise the exciting possibility that cell adhesivity might be a generic property of amyloids. PMID:26742841

  6. Annexin A6 contributes to the invasiveness of breast carcinoma cells by influencing the organization and localization of functional focal adhesions

    SciTech Connect

    Sakwe, Amos M.; Koumangoye, Rainelli; Guillory, Bobby; Ochieng, Josiah

    2011-04-01

    The interaction of annexin A6 (AnxA6) with membrane phospholipids and either specific extracellular matrix (ECM) components or F-actin suggests that it may influence cellular processes associated with rapid plasma membrane reorganization such as cell adhesion and motility. Here, we examined the putative roles of AnxA6 in adhesion-related cellular processes that contribute to breast cancer progression. We show that breast cancer cells secrete annexins via the exosomal pathway and that the secreted annexins are predominantly cell surface-associated. Depletion of AnxA6 in the invasive BT-549 breast cancer cells is accompanied by enhanced anchorage-independent cell growth but cell-cell cohesion, cell adhesion/spreading onto collagen type IV or fetuin-A, cell motility and invasiveness were strongly inhibited. To explain the loss in adhesion/motility, we show that vinculin-based focal adhesions in the AnxA6-depleted BT-549 cells are elongated and randomly distributed. These focal contacts are also functionally defective because the activation of focal adhesion kinase and the phosphoinositide-3 kinase/Akt pathway were strongly inhibited while the MAP kinase pathway remained constitutively active. Compared with normal human breast tissues, reduced AnxA6 expression in breast carcinoma tissues correlates with enhanced cell proliferation. Together this suggests that reduced AnxA6 expression contributes to breast cancer progression by promoting the loss of functional cell-cell and/or cell-ECM contacts and anchorage-independent cell proliferation.

  7. Directing cell migration using micropatterned and dynamically adhesive polymer brushes.

    PubMed

    Costa, Patricia; Gautrot, Julien E; Connelly, John T

    2014-06-01

    Micropatterning techniques, such as photolithography and microcontact printing, provide robust tools for controlling the adhesive interactions between cells and their extracellular environment. However, the ability to modify these interactions in real time and examine dynamic cellular responses remains a significant challenge. Here we describe a novel strategy to create dynamically adhesive, micropatterned substrates, which afford precise control of cell adhesion and migration over both space and time. Specific functionalization of micropatterned poly(ethylene glycol methacrylate) (POEGMA) brushes with synthetic peptides, containing the integrin-binding arginine-glycine-aspartic acid (RGD) motif, was achieved using thiol-yne coupling reactions. RGD activation of POEGMA brushes promoted fibroblast adhesion, spreading and migration into previously non-adhesive areas, and migration speed could be tuned by adjusting the surface ligand density. We propose that this technique is a robust strategy for creating dynamically adhesive biomaterial surfaces and a useful assay for studying cell migration. PMID:24508539

  8. Disturbed Homeostasis of Lung Intercellular Adhesion Molecule-1 and Vascular Cell Adhesion Molecule-1 During Sepsis

    PubMed Central

    Laudes, Ines J.; Guo, Ren-Feng; Riedemann, Niels C.; Speyer, Cecilia; Craig, Ron; Sarma, J. Vidya; Ward, Peter A.

    2004-01-01

    Cecal ligation and puncture (CLP)-induced sepsis in mice was associated with perturbations in vascular adhesion molecules. In CLP mice, lung vascular binding of 125I-monoclonal antibodies to intercellular adhesion molecule (ICAM)-1 and vascular cell adhesion molecule (VCAM)-1 revealed sharp increases in binding of anti-ICAM-1 and significantly reduced binding of anti-VCAM-1. In whole lung homogenates, intense ICAM-1 up-regulation was found (both in mRNA and in protein levels) during sepsis, whereas very little increase in VCAM-1 could be measured although some increased mRNA was found. During CLP soluble VCAM-1 (sVCAM-1) and soluble ICAM-1 (sICAM-1) appeared in the serum. When mouse dermal microvascular endothelial cells (MDMECs) were incubated with serum from CLP mice, constitutive endothelial VCAM-1 fell in association with the appearance of sVCAM-1 in the supernatant fluids. Under the same conditions, ICAM-1 cell content increased in MDMECs. When MDMECs were evaluated for leukocyte adhesion, exposure to CLP serum caused increased adhesion of neutrophils and decreased adhesion of macrophages and T cells. The progressive build-up in lung myeloperoxidase after CLP was ICAM-1-dependent and independent of VLA-4 and VCAM-1. These data suggest that sepsis disturbs endothelial homeostasis, greatly favoring neutrophil adhesion in the lung microvasculature, thereby putting the lung at increased risk of injury. PMID:15039231

  9. Impact of altered actin gene expression on vinculin, talin, cell spreading, and motility.

    PubMed

    Schevzov, G; Lloyd, C; Gunning, P

    1995-08-01

    Previous studies have demonstrated a strong correlation between the expression of vinculin and the shape and motility of a cell (Rodriguez Fernandez et al., 1992a, b, 1993). This hypothesis was tested by comparing the expression of vinculin and talin with the motility of morphologically altered myoblasts. These mouse C2 myoblasts were previously generated by directly perturbing the cell cytoskeleton via the stable transfection of a mutant-form of the beta-actin gene (beta sm) and three different forms of the gamma-actin gene; gamma, gamma minus 3'UTR (gamma delta'UTR), and gamma minus intron III (gamma delta IVSIII) (Schevzov et al., 1992; Lloyd and Gunning, 1993). In the case of the beta sm and gamma-actin transfectants, a two-fold decrease in the cell surface area was coupled, as predicted, with a decrease in vinculin and talin expression. In contrast, the gamma delta IVSIII transfectants with a seven-fold decrease in the cell surface area showed an unpredicted slight increase in vinculin and talin expression and the gamma delta 3'-UTR transfectants with a slight increase in the cell surface area showed no changes in talin expression and a decrease in vinculin expression. We conclude that changes in actin gene expression alone can impact on the expression of vinculin and talin. Furthermore, we observed that these actin transfectants failed to show a consistent relationship between cell shape, motility, and the expression of vinculin. However, a relationship between talin and cell motility was found to exist, suggesting a role for talin in the establishment of focal contacts necessary for motility. PMID:7646816

  10. Urokinase receptor-dependent and -independent p56/59(hck) activation state is a molecular switch between myelomonocytic cell motility and adherence.

    PubMed Central

    Chiaradonna, F; Fontana, L; Iavarone, C; Carriero, M V; Scholz, G; Barone, M V; Stoppelli, M P

    1999-01-01

    Anchorage-independent myelomonocytic cells acquire adherence within minutes of differentiation stimuli, such as the proteolytically inactive N-terminal fragment of urokinase binding to its cognate glycosylphosphatidylinositol (GPI)-anchored receptor. Here, we report that urokinase-treated differentiating U937 monocyte-like cells exhibit a rapid and transient inhibition of p56/59(hck) and p55(fgr) whereas no changes in the activity of other Src family kinases, such as p53/56(lyn) and p59(fyn) were observed. U937 transfectants expressing a kinase-defective (Lys267 to Met) p56/59(hck) variant exhibit enhanced adhesiveness and a marked F-actin redistribution in thin protruding structures. Conversely, urokinase as well as expression of wild-type or constitutively active (Tyr499 to Phe) p56/59(hck) stimulates the directional migration of uninduced U937 cells. Accordingly, expression of constitutively active or kinase inactive p56/59(hck) selectively prevents urokinase receptor-dependent induction of either adhesion or motility, indicating that a specific activation state of p56/59(hck) is required for each cell response. In conclusion, modulation of the intracellular p56/59(hck) tyrosine kinase activity switches cell motility towards adherence, providing a mutually exclusive mechanism to regulate these properties during monocyte/macrophage differentiation in vivo. PMID:10357814

  11. Motility and Chemotaxis in Tissue Penetration of Oral Epithelial Cell Layers by Treponema denticola

    PubMed Central

    Lux, Renate; Miller, James N.; Park, No-Hee; Shi, Wenyuan

    2001-01-01

    The ability to penetrate tissue is an important virulence factor for pathogenic spirochetes. Previous studies have recognized the role of motility in allowing pathogenic spirochetes to invade tissues and migrate to sites favorable for bacterial proliferation. However, the nature of the movements, whether they are random or controlled by chemotaxis systems, has yet to be established. In this study, we addressed the role of motility and chemotaxis in tissue penetration by the periodontal disease-associated oral spirochete Treponema denticola using an oral epithelial cell line-based experimental approach. Wild-type T. denticola ATCC 35405 was found to penetrate the tissue layers effectively, whereas a nonmotile mutant was unable to overcome the tissue barrier. Interestingly, the chemotaxis mutants also showed impaired tissue penetration. A cheA mutant that is motile but lacks the central kinase of the chemotaxis pathway showed only about 2 to 3% of the wild-type penetration rate. The two known chemoreceptors of T. denticola, DmcA and DmcB, also appear to be involved in the invasion process. The dmc mutants were actively motile but exhibited reduced tissue penetration of about 30 and 10% of the wild-type behavior, respectively. These data suggest that not only motility but also chemotaxis is involved in the tissue penetration by T. denticola. PMID:11553571

  12. Motility and chemotaxis in tissue penetration of oral epithelial cell layers by Treponema denticola.

    PubMed

    Lux, R; Miller, J N; Park, N H; Shi, W

    2001-10-01

    The ability to penetrate tissue is an important virulence factor for pathogenic spirochetes. Previous studies have recognized the role of motility in allowing pathogenic spirochetes to invade tissues and migrate to sites favorable for bacterial proliferation. However, the nature of the movements, whether they are random or controlled by chemotaxis systems, has yet to be established. In this study, we addressed the role of motility and chemotaxis in tissue penetration by the periodontal disease-associated oral spirochete Treponema denticola using an oral epithelial cell line-based experimental approach. Wild-type T. denticola ATCC 35405 was found to penetrate the tissue layers effectively, whereas a nonmotile mutant was unable to overcome the tissue barrier. Interestingly, the chemotaxis mutants also showed impaired tissue penetration. A cheA mutant that is motile but lacks the central kinase of the chemotaxis pathway showed only about 2 to 3% of the wild-type penetration rate. The two known chemoreceptors of T. denticola, DmcA and DmcB, also appear to be involved in the invasion process. The dmc mutants were actively motile but exhibited reduced tissue penetration of about 30 and 10% of the wild-type behavior, respectively. These data suggest that not only motility but also chemotaxis is involved in the tissue penetration by T. denticola. PMID:11553571

  13. Macroscopic limits of individual-based models for motile cell populations with volume exclusion.

    PubMed

    Dyson, Louise; Maini, Philip K; Baker, Ruth E

    2012-09-01

    Partial differential equation models are ubiquitous in studies of motile cell populations, giving a phenomenological description of events which can be analyzed and simulated using a wide range of existing tools. However, these models are seldom derived from individual cell behaviors and so it is difficult to accurately include biological hypotheses on this spatial scale. Moreover, studies which do attempt to link individual- and population-level behavior generally employ lattice-based frameworks in which the artifacts of lattice choice at the population level are unclear. In this work we derive limiting population-level descriptions of a motile cell population from an off-lattice, individual-based model (IBM) and investigate the effects of volume exclusion on the population-level dynamics. While motility with excluded volume in on-lattice IBMs can be accurately described by Fickian diffusion, we demonstrate that this is not the case off lattice. We show that the balance between two key parameters in the IBM (the distance moved in one step and the radius of an individual) determines whether volume exclusion results in enhanced or slowed diffusion. The magnitude of this effect is shown to increase with the number of cells and the rate of their movement. The method we describe is extendable to higher-dimensional and more complex systems and thereby provides a framework for deriving biologically realistic, continuum descriptions of motile populations. PMID:23030940

  14. ANXA2 enhances the progression of hepatocellular carcinoma via remodeling the cell motility associated structures.

    PubMed

    Shi, Hongyan; Xiao, Li; Duan, Wei; He, Huimin; Ma, Lele; Da, Miaomiao; Duan, Yan; Wang, Qian; Wu, Huayi; Song, Xigui; Hou, Yingchun

    2016-06-01

    Hepatocellular carcinoma (HCC) ranks as the fifth most common malignancy worldwide. The detailed mechanism of signal regulation for HCC progression is still not known, and the high motility of cancer cells is known as a core property for cancer progression maintenance. Annexin A2 (ANXA2), a calcium-dependent phospholipids binding protein is highly expressed in HCC. To study the roles the excessively expressed ANXA2 during the progression of HCC, we inhibited the ANXA2 expression in SMMC-7721 cells using RNAi, followed by the analysis of cell growth, apoptosis and cell motility. To explore the relationship between the cell behaviors and its structures, the microstructure changes were observed under fluorescence microscopy, laser scanning confocal microscopy and electron microscopy. Our findings demonstrated that down-regulation of ANXA2 results in decreased the cell proliferation and motility, enhanced apoptosis, suppressed cell pseudopodia/filopodia, inhibited expression of F-actin and β-tubulin, and inhibited or depolymerized Lamin B. The cell contact inhibition was also analyzed in the paper. Take together, our results indicate that ANXA2 plays an important role to enhance the malignant behaviors of HCC cells, and the enhancement is closely based on its remodeling to cell structures. PMID:27060670

  15. The disintegrin tzabcanin inhibits adhesion and migration in melanoma and lung cancer cells.

    PubMed

    Saviola, Anthony J; Burns, Patrick D; Mukherjee, Ashis K; Mackessy, Stephen P

    2016-07-01

    Integrins play an essential role in cancer survival and invasion, and they have been major targets in drug development and design. Disintegrins are small (4-16kDa) viperid snake venom proteins that exhibit a canonical integrin-binding site (often RGD). These non-enzymatic proteins inhibit integrin-mediated cell-cell and cell-extracellular matrix interactions, making them potential candidates as therapeutics in cancer and numerous other human disorders. The present study examined the cytotoxic, anti-adhesion, and anti-migration effects of a recently characterized disintegrin, tzabcanin, towards melanoma (A-375) and lung (A-549) cancer cell lines. Tzabcanin inhibits adhesion of both cells lines to vitronectin and exhibited very weak cytotoxicity towards A-375 cells; however, it had no effect on cell viability of A-549 cells. Further, tzabcanin significantly inhibited migration of both cell lines in cell scratch/wound healing assays. Flow cytometric analysis indicates that both A-375 and A-549 cell lines express integrin αvβ3, a critical integrin in tumor motility and invasion, and a major receptor of the extracellular matrix protein vitronectin. Flow cytometric analysis also identified αvβ3 as a binding site of tzabcanin. These results suggest that tzabcanin may have utility in the development of anticancer therapies, or may be used as a biomarker to detect neoplasms that over-express integrin αvβ3. PMID:27060015

  16. Retinoic acid induces nuclear FAK translocation and reduces breast cancer cell adhesion through Moesin, FAK, and Paxillin.

    PubMed

    Sanchez, Angel Matías; Shortrede, Jorge Eduardo; Vargas-Roig, Laura María; Flamini, Marina Inés

    2016-07-15

    Breast cancer is the most common malignancy in women, with metastases being the cause of death in 98%. In previous works we have demonstrated that retinoic acid (RA), the main retinoic acid receptor (RAR) ligand, is involved in the metastatic process by inhibiting migration through a reduced expression of the specific migration-related proteins Moesin, c-Src, and FAK. At present, our hypothesis is that RA also acts for short periods in a non-genomic action to cooperate with motility reduction and morphology of breast cancer cells. Here we identify that the administration of 10(-6) M RA (10-20 min) induces the activation of the migration-related proteins Moesin, FAK, and Paxillin in T-47D breast cancer cells. The phosphorylation exerted by the selective agonists for RARα and RARβ, on Moesin, FAK, and Paxillin was comparable to the activation exerted by RA. The RARγ agonist only led to a weak activation, suggesting the involvement of RARα and RARβ in this pathway. We then treated the cells with different inhibitors that are involved in cell signaling to regulate the mechanisms of cell motility. RA failed to activate Moesin, FAK, and Paxillin in cells treated with Src inhibitor (PP2) and PI3K inhibitor (WM), suggesting the participation of Src-PI3K in this pathway. Treatment with 10(-6) M RA for 20 min significantly decreased cell adhesion. However, when cells were treated with 10(-6) M RA and FAK inhibitor, the RA did not significantly inhibit adhesion, suggesting a role of FAK in the adhesion inhibited by RA. By immunofluorescence and immunoblotting analysis we demonstrated that RA induced nuclear FAK translocation leading to a reduced cellular adhesion. These findings provide new information on the actions of RA for short periods. RA participates in cell adhesion and subsequent migration, modulating the relocation and activation of proteins involved in cell migration. PMID:27130522

  17. Cell Adhesion to Plasma-Coated PVC

    PubMed Central

    Rangel, Elidiane C.; de Souza, Eduardo S.; de Moraes, Francine S.; Duek, Eliana A. R.; Lucchesi, Carolina; Schreiner, Wido H.; Durrant, Steven F.; Cruz, Nilson C.

    2014-01-01

    To produce environments suitable for cell culture, thin polymer films were deposited onto commercial PVC plates from radiofrequency acetylene-argon plasmas. The proportion of argon in the plasmas, PAr, was varied from 5.3 to 65.8%. The adhesion and growth of Vero cells on the coated surfaces were examined for different incubation times. Cytotoxicity tests were performed using spectroscopic methods. Carbon, O, and N were detected in all the samples using XPS. Roughness remained almost unchanged in the samples prepared with 5.3 and 28.9% but tended to increase for the films deposited with PAr between 28.9 and 55.3%. Surface free energy increased with increasing PAr, except for the sample prepared at 28.9% of Ar, which presented the least reactive surface. Cells proliferated on all the samples, including the bare PVC. Independently of the deposition condition there was no evidence of cytotoxicity, indicating the viability of such coatings for designing biocompatible devices. PMID:25247202

  18. PHLPP negatively regulates cell motility through inhibition of Akt activity and integrin expression in pancreatic cancer cells

    PubMed Central

    Smith, Alena J.; Wen, Yang-An; Stevens, Payton D.; Liu, Jingpeng; Wang, Chi; Gao, Tianyan

    2016-01-01

    Pancreatic adenocarcinoma is currently the fourth leading cause for cancer-related mortality. Malignant progression of pancreatic cancer depends not only on rapid proliferation of tumor cells but also on increased cell motility. In this study, we showed that increased PHLPP expression significantly reduced the rate of migration in pancreatic ductal adenocarcinoma (PDAC) cells whereas knockdown of PHLPP had the opposite effect. In addition, cell motility at the individual cell level was negatively regulated by PHLPP as determined using time-lapse imaging. Interestingly, the expression of β1 and β4 integrin proteins were decreased in PHLPP overexpressing cells and increased in PHLPP knockdown cells whereas the mRNA levels of integrin were not altered by changes in PHLPP expression. In determining the molecular mechanism underlying PHLPP-mediated regulation of integrin expression, we found that inhibition of lysosome activity rescued integrin expression in PHLPP overexpressing cells, thus suggesting that PHLPP negatively controls cell motility by inhibiting Akt activity to promote lysosome-dependent degradation of integrins. Functionally, the increased cell migration observed in PHLPP knockdown cells was effectively blocked by the neutralizing antibodies against β1 or β4 integrin. Taken together, our study identified a tumor suppressor role of PHLPP in suppressing cell motility by negatively regulating integrin expression in pancreatic cancer cells. PMID:26760962

  19. Adhesion

    MedlinePlus

    ... adhesions Ovarian cyst References Munireddy S, Kavalukas SL, Barbul A. Intra-abdominal healing: gastrointestinal tract and adhesions. Surg Clin N Am Kulaylat MN, Dayton, MT. Surgical complications. In: Townsend CM Jr, Beauchamp RD, Evers BM, Mattox KL, ...

  20. Huaier Aqueous Extract Inhibits Ovarian Cancer Cell Motility via the AKT/GSK3β/β-Catenin Pathway

    PubMed Central

    Jia, Nan; Yu, Yinhua; Hua, Keqin; Feng, Weiwei

    2013-01-01

    Traditional Chinese medicine has gained popularity due to its ability to kill tumor cells. Recently, the apoptotic and anti-angiogenic effects of Trametes robiniophila murr (Huaier) have been investigated. The aim of this study was to investigate its effect on cell mobility and tumor growth in ovarian cancer. Cell viability and motility were measured using SRB, scratch and migration assays. Cell apoptosis was analysed by annexin V/PI staining. Using a reverse-phase protein array (RPPA) assay, we analyzed the levels of 153 proteins and/or phosphorylations in Huaier-treated and untreated cells. Huaier inhibited cell viability and induced both early and late apoptosis in SKOV3, SKOV3.ip1 and Hey cells in a time- and dose-dependent manner. Cell invasiveness and migration were also suppressed significantly. The RPPA results showed significant differences (of at least 30%; P <0.05) in the levels of 7 molecules in SKOV3 cells and 10 in SKOV3.ip1 cells between the untreated and treated cells. Most of the molecules identified play roles in cell proliferation, apoptosis or cell adhesion/invasion. Western blot analysis further validated that Huaier treatment resulted in decreased AKT phosphorylation, enhanced expression of total GSK3β, inhibition of the phosphorylation of GSK3β on S9, reduction of both cytoplasmic β-catenin expression and nuclear β-catenin translocation, and transcriptional repression of several Wnt/β-catenin target genes (DIXDC1, LRP6, WNT5A, and cyclin D1). After knocking down GSK3β, β-catenin expression could not be inhibited by Huaier. Finally, Huaier inhibited the growth of ovarian tumor xenografts in vivo. These studies indicate that Huaier inhibits tumor cell mobility in ovarian cancer via the AKT/GSK3β/β-catenin signaling pathway. PMID:23667667

  1. Huaier aqueous extract inhibits ovarian cancer cell motility via the AKT/GSK3β/β-catenin pathway.

    PubMed

    Yan, Xiaohui; Lyu, Tianjiao; Jia, Nan; Yu, Yinhua; Hua, Keqin; Feng, Weiwei

    2013-01-01

    Traditional Chinese medicine has gained popularity due to its ability to kill tumor cells. Recently, the apoptotic and anti-angiogenic effects of Trametes robiniophila murr (Huaier) have been investigated. The aim of this study was to investigate its effect on cell mobility and tumor growth in ovarian cancer. Cell viability and motility were measured using SRB, scratch and migration assays. Cell apoptosis was analysed by annexin V/PI staining. Using a reverse-phase protein array (RPPA) assay, we analyzed the levels of 153 proteins and/or phosphorylations in Huaier-treated and untreated cells. Huaier inhibited cell viability and induced both early and late apoptosis in SKOV3, SKOV3.ip1 and Hey cells in a time- and dose-dependent manner. Cell invasiveness and migration were also suppressed significantly. The RPPA results showed significant differences (of at least 30%; P <0.05) in the levels of 7 molecules in SKOV3 cells and 10 in SKOV3.ip1 cells between the untreated and treated cells. Most of the molecules identified play roles in cell proliferation, apoptosis or cell adhesion/invasion. Western blot analysis further validated that Huaier treatment resulted in decreased AKT phosphorylation, enhanced expression of total GSK3β, inhibition of the phosphorylation of GSK3β on S9, reduction of both cytoplasmic β-catenin expression and nuclear β-catenin translocation, and transcriptional repression of several Wnt/β-catenin target genes (DIXDC1, LRP6, WNT5A, and cyclin D1). After knocking down GSK3β, β-catenin expression could not be inhibited by Huaier. Finally, Huaier inhibited the growth of ovarian tumor xenografts in vivo. These studies indicate that Huaier inhibits tumor cell mobility in ovarian cancer via the AKT/GSK3β/β-catenin signaling pathway. PMID:23667667

  2. Tyrosine kinase-mediated axial motility of basal cells revealed by intravital imaging

    PubMed Central

    Roy, Jeremy; Kim, Bongki; Hill, Eric; Visconti, Pablo; Krapf, Dario; Vinegoni, Claudio; Weissleder, Ralph; Brown, Dennis; Breton, Sylvie

    2016-01-01

    Epithelial cells are generally considered to be static relative to their neighbours. Basal cells in pseudostratified epithelia display a single long cytoplasmic process that can cross the tight junction barrier to reach the lumen. Using in vivo microscopy to visualize the epididymis, a model system for the study of pseudostratified epithelia, we report here the surprising discovery that these basal cell projections—which we call axiopodia—periodically extend and retract over time. We found that axiopodia extensions and retractions follow an oscillatory pattern. This movement, which we refer to as periodic axial motility (PAM), is controlled by c-Src and MEK1/2–ERK1/2. Therapeutic inhibition of tyrosine kinase activity induces a retraction of these projections. Such unexpected cell motility may reflect a novel mechanism by which specialized epithelial cells sample the luminal environment. PMID:26868824

  3. Tyrosine kinase-mediated axial motility of basal cells revealed by intravital imaging.

    PubMed

    Roy, Jeremy; Kim, Bongki; Hill, Eric; Visconti, Pablo; Krapf, Dario; Vinegoni, Claudio; Weissleder, Ralph; Brown, Dennis; Breton, Sylvie

    2016-01-01

    Epithelial cells are generally considered to be static relative to their neighbours. Basal cells in pseudostratified epithelia display a single long cytoplasmic process that can cross the tight junction barrier to reach the lumen. Using in vivo microscopy to visualize the epididymis, a model system for the study of pseudostratified epithelia, we report here the surprising discovery that these basal cell projections--which we call axiopodia--periodically extend and retract over time. We found that axiopodia extensions and retractions follow an oscillatory pattern. This movement, which we refer to as periodic axial motility (PAM), is controlled by c-Src and MEK1/2-ERK1/2. Therapeutic inhibition of tyrosine kinase activity induces a retraction of these projections. Such unexpected cell motility may reflect a novel mechanism by which specialized epithelial cells sample the luminal environment. PMID:26868824

  4. Cell adhesion strength from cortical tension - an integration of concepts.

    PubMed

    Winklbauer, Rudolf

    2015-10-15

    Morphogenetic mechanisms such as cell movement or tissue separation depend on cell attachment and detachment processes, which involve adhesion receptors as well as the cortical cytoskeleton. The interplay between the two components is of stunning complexity. Most strikingly, the binding energy of adhesion molecules is usually too small for substantial cell-cell attachment, pointing to a main deficit in our present understanding of adhesion. In this Opinion article, I integrate recent findings and conceptual advances in the field into a coherent framework for cell adhesion. I argue that active cortical tension is best viewed as an integral part of adhesion, and propose on this basis a non-arbitrary measure of adhesion strength - the tissue surface tension of cell aggregates. This concept of adhesion integrates heterogeneous molecular inputs into a single mechanical property and simplifies the analysis of attachment-detachment processes. It draws attention to the enormous variation of adhesion strengths among tissues, whose origin and function is little understood. PMID:26471994

  5. Extracellular Vesicles from Vascular Endothelial Cells Promote Survival, Proliferation and Motility of Oligodendrocyte Precursor Cells

    PubMed Central

    Kurachi, Masashi; Mikuni, Masahiko; Ishizaki, Yasuki

    2016-01-01

    We previously examined the effect of brain microvascular endothelial cell (MVEC) transplantation on rat white matter infarction, and found that MVEC transplantation promoted remyelination of demyelinated axons in the infarct region and reduced apoptotic death of oligodendrocyte precursor cells (OPCs). We also found that the conditioned medium (CM) from cultured MVECs inhibited apoptosis of cultured OPCs. In this study, we examined contribution of extracellular vesicles (EVs) contained in the CM to its inhibitory effect on OPC apoptosis. Removal of EVs from the CM by ultracentrifugation reduced its inhibitory effect on OPC apoptosis. To confirm whether EVs derived from MVECs are taken up by cultured OPCs, we labeled EVs with PKH67, a fluorescent dye, and added them to OPC cultures. Many vesicular structures labeled with PKH67 were found within OPCs immediately after their addition. Next we examined the effect of MVEC-derived EVs on OPC behaviors. After 2 days in culture with EVs, there was significantly less pyknotic and more BrdU-positive OPCs when compared to control. We also examined the effect of EVs on motility of OPCs. OPCs migrated longer in the presence of EVs when compared to control. To examine whether these effects on cultured OPCs are shared by EVs from endothelial cells, we prepared EVs from conditioned media of several types of endothelial cells, and tested their effects on cultured OPCs. EVs from all types of endothelial cells we examined reduced apoptosis of OPCs and promoted their motility. Identification of the molecules contained in EVs from endothelial cells may prove helpful for establishment of effective therapies for demyelinating diseases. PMID:27403742

  6. Laminin-332 Cleavage by Matriptase Alters Motility Parameters of Prostate Cancer Cells

    PubMed Central

    Tripathi, Manisha; Potdar, Alka A.; Yamashita, Hironobu; Weidow, Brandy; Cummings, Peter T.; Kirchhofer, Daniel; Quaranta, Vito

    2013-01-01

    BACKGROUND Matriptase, a type II transmembrane serine protease, has been linked to initiation and promotion of epidermal carcinogenesis in a murine model, suggesting that deregulation of its role in epithelia contributes to transformation. In human prostate cancer, matriptase expression correlates with progression. It is therefore of interest to determine how matriptase may contribute to epithelial neoplastic progression. One approach for studying this is to identify potential matriptase substrates involved in epithelial integrity and/or transformation like the extracellular matrix macromolecule, laminin-332 (Ln-332), which is found in the basement membrane of many epithelia, including prostate. Proteolytic processing of Ln-332 regulates cell motility of both normal and transformed cells, which has implications in cancer progression. METHODS In vitro cleavage experiments were performed with purified Ln-332 protein and matriptase. Western blotting, enzyme inhibition assays, and mass spectrometry were used to confirm cleavage events. Matriptase overexpressing LNCaP prostate cancer cells were generated and included in Transwell migration assays and single cell motility assays, along with other prostate cells. RESULTS We report that matriptase proteolytically cleaves Ln-332 in the β3 chain. Substrate specificity was confirmed by blocking cleavage with the matriptase inhibitor, Kunitz domain-1. Transwell migration assays showed that DU145 cell motility was significantly enhanced when plated on matriptase-cleaved Ln-332. Similarly, Transwell migration of matriptase-overexpressing LNCaP cells was significantly increased on Ln-332 and, as determined by live single-cell microscopy, two motility parameters of this cell line, speed and directional persistence, were also higher. CONCLUSIONS Proteolytic processing of Ln-332 by matriptase enhances speed and directional persistence of prostate cancer cells. PMID:20672321

  7. A Cronobacter turicensis O1 Antigen-Specific Monoclonal Antibody Inhibits Bacterial Motility and Entry into Epithelial Cells

    PubMed Central

    Lehner, Angelika; Dietrich, Richard; Kleinsteuber, Ina; Canals, Rocío; Zurfluh, Katrin; Weiner, Kerstin; Märtlbauer, Erwin

    2014-01-01

    Cronobacter turicensis is an opportunistic foodborne pathogen that can cause a rare but sometimes lethal infection in neonates. Little is known about the virulence mechanisms and intracellular lifestyle of this pathogen. In this study, we developed an IgG monoclonal antibody (MAb; MAb 2G4) that specifically recognizes the O1 antigen of C. turicensis cells. The antilipopolysaccharide antibody bound predominantly monovalently to the O antigen and reduced bacterial growth without causing cell agglutination. Furthermore, binding of the antibody to the O1 antigen of C. turicensis cells caused a significant reduction of the membrane potential which is required to energize flagellar rotation, accompanied by a decreased flagellum-based motility. These results indicate that binding of IgG to the O antigen of C. turicensis causes a direct antimicrobial effect. In addition, this feature of the antibody enabled new insight into the pathogenicity of C. turicensis. In a tissue culture infection model, pretreatment of C. turicensis with MAb 2G4 showed no difference in adhesion to human epithelial cells, whereas invasion of bacteria into Caco-2 cells was significantly inhibited. PMID:25534937

  8. Collective cell migration induced by mechanical stress and substrate adhesiveness

    NASA Astrophysics Data System (ADS)

    Köpf, Michael H.

    2015-01-01

    Mechanical stress normal to the boundary of a tissue sheet can arise in both constrained as well as unconstrained epithelial layers through pushing and pulling of surrounding tissue and substrate adhesiveness, respectively. A continuum model is used to investigate how such stress influences the epithelial dynamics. Four types of spreading and motility can be identified: a uniformly stretched stationary state, uniform sheet migration, active stress compensation by polarization close to the boundary, and a wormlike progression by deformation waves. Analytical and numerical solutions are presented along with bifurcation diagrams using normal stress and active force as control parameters.

  9. Cell adhesion molecules mediate radiation-induced leukocyte adhesion to the vascular endothelium.

    PubMed

    Hallahan, D; Kuchibhotla, J; Wyble, C

    1996-11-15

    The predominant early histological changes in irradiated tissues are edema and leukocyte infiltration. Cell adhesion molecules (CAMs) are required for the extravasation of leukocytes from the circulation. To study the role of CAMs in the pathogenesis of radiation-mediated inflammation, we quantified the expression of P-selectin, E-selectin, intercellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 glycoproteins on the surface of irradiated human endothelial cells. We found that E-selectin and ICAM-1 expression increased after irradiation, whereas there was no increased expression of other cytokine-inducible adhesion molecules (P-selectin or vascular cell adhesion molecule-1). We found a dose- and time-dependent increase in radiation-induced expression of both E-selectin and ICAM-1. Furthermore, the threshold dose for E-selectin expression was 1 Gy, whereas the threshold dose for ICAM-1 synthesis was 5 Gy of X-rays. Northern blot analysis of RNA from irradiated endothelial cells demonstrated that ICAM-1 is expressed at 3-6 h following irradiation. No de novo protein synthesis was required for increased ICAM-1 mRNA expression. The 1.1-kb segment of the 5' untranslated region of the ICAM-1 gene was sufficient for X-ray induction of chloramphenicol acetyltransferase reporter gene expression. We measured whether ICAM-1 mediates adhesion of leukocyte to the irradiated endothelium and found that leukocyte adhesion occurred concurrently with ICAM-1 induction. Radiation-mediated leukocyte adhesion was prevented by anti-ICAM-1 blocking antibodies. These data indicate that ICAM-1 participates in the inflammatory response to ionizing radiation. Moreover, radiation induction of these CAMs occurs in the absence of tumor necrosis factor and interleukin 1 production. PMID:8912850

  10. Single Cell Adhesion Assay Using Computer Controlled Micropipette

    PubMed Central

    Salánki, Rita; Hős, Csaba; Orgovan, Norbert; Péter, Beatrix; Sándor, Noémi; Bajtay, Zsuzsa; Erdei, Anna; Horvath, Robert; Szabó, Bálint

    2014-01-01

    Cell adhesion is a fundamental phenomenon vital for all multicellular organisms. Recognition of and adhesion to specific macromolecules is a crucial task of leukocytes to initiate the immune response. To gain statistically reliable information of cell adhesion, large numbers of cells should be measured. However, direct measurement of the adhesion force of single cells is still challenging and today’s techniques typically have an extremely low throughput (5–10 cells per day). Here, we introduce a computer controlled micropipette mounted onto a normal inverted microscope for probing single cell interactions with specific macromolecules. We calculated the estimated hydrodynamic lifting force acting on target cells by the numerical simulation of the flow at the micropipette tip. The adhesion force of surface attached cells could be accurately probed by repeating the pick-up process with increasing vacuum applied in the pipette positioned above the cell under investigation. Using the introduced methodology hundreds of cells adhered to specific macromolecules were measured one by one in a relatively short period of time (∼30 min). We blocked nonspecific cell adhesion by the protein non-adhesive PLL-g-PEG polymer. We found that human primary monocytes are less adherent to fibrinogen than their in vitro differentiated descendants: macrophages and dendritic cells, the latter producing the highest average adhesion force. Validation of the here introduced method was achieved by the hydrostatic step-pressure micropipette manipulation technique. Additionally the result was reinforced in standard microfluidic shear stress channels. Nevertheless, automated micropipette gave higher sensitivity and less side-effect than the shear stress channel. Using our technique, the probed single cells can be easily picked up and further investigated by other techniques; a definite advantage of the computer controlled micropipette. Our experiments revealed the existence of a sub

  11. Simulation of Cell Adhesion using a Particle Transport Model

    NASA Astrophysics Data System (ADS)

    Chesnutt, Jennifer

    2005-11-01

    An efficient computational method for simulation of cell adhesion through protein binding forces is discussed. In this method, the cells are represented by deformable elastic particles, and the protein binding is represented by a rate equation. The method is first developed for collision and adhesion of two similar cells impacting on each other from opposite directions. The computational method is then applied in a particle-transport model for a cloud of interacting and colliding cells, each of which are represented by particles of finite size. One application might include red blood cells adhering together to form rouleaux, which are chains of red blood cells that are found in different parts of the circulatory system. Other potential applications include adhesion of platelets to a blood vessel wall or mechanical heart valve, which is a precursor of thrombosis formation, or adhesion of cancer cells to organ walls in the lymphatic, circulatory, digestive or pulmonary systems.

  12. Uncovering the mechanism of trapping and cell orientation during Neisseria gonorrhoeae twitching motility.

    PubMed

    Zaburdaev, Vasily; Biais, Nicolas; Schmiedeberg, Michael; Eriksson, Jens; Jonsson, Ann-Beth; Sheetz, Michael P; Weitz, David A

    2014-10-01

    Neisseria gonorrheae bacteria are the causative agent of the second most common sexually transmitted infection in the world. The bacteria move on a surface by means of twitching motility. Their movement is mediated by multiple long and flexible filaments, called type IV pili, that extend from the cell body, attach to the surface, and retract, thus generating a pulling force. Moving cells also use pili to aggregate and form microcolonies. However, the mechanism by which the pili surrounding the cell body work together to propel bacteria remains unclear. Understanding this process will help describe the motility of N. gonorrheae bacteria, and thus the dissemination of the disease which they cause. In this article we track individual twitching cells and observe that their trajectories consist of alternating moving and pausing intervals, while the cell body is preferably oriented with its wide side toward the direction of motion. Based on these data, we propose a model for the collective pili operation of N. gonorrheae bacteria that explains the experimentally observed behavior. Individual pili function independently but can lead to coordinated motion or pausing via the force balance. The geometry of the cell defines its orientation during motion. We show that by changing pili substrate interactions, the motility pattern can be altered in a predictable way. Although the model proposed is tangibly simple, it still has sufficient robustness to incorporate further advanced pili features and various cell geometries to describe other bacteria that employ pili to move on surfaces. PMID:25296304

  13. Automated single-cell motility analysis on a chip using lensfree microscopy

    PubMed Central

    Pushkarsky, Ivan; Lyb, Yunbo; Weaver, Westbrook; Su, Ting-Wei; Mudanyali, Onur; Ozcan, Aydogan; Di Carlo, Dino

    2014-01-01

    Quantitative cell motility studies are necessary for understanding biophysical processes, developing models for cell locomotion and for drug discovery. Such studies are typically performed by controlling environmental conditions around a lens-based microscope, requiring costly instruments while still remaining limited in field-of-view. Here we present a compact cell monitoring platform utilizing a wide-field (24 mm2) lensless holographic microscope that enables automated single-cell tracking of large populations that is compatible with a standard laboratory incubator. We used this platform to track NIH 3T3 cells on polyacrylamide gels over 20 hrs. We report that, over an order of magnitude of stiffness values, collagen IV surfaces lead to enhanced motility compared to fibronectin, in agreement with biological uses of these structural proteins. The increased throughput associated with lensfree on-chip imaging enables higher statistical significance in observed cell behavior and may facilitate rapid screening of drugs and genes that affect cell motility. PMID:24739819

  14. Inhibition of tumor cell proliferation and motility by fibroblasts is both contact and soluble factor dependent

    PubMed Central

    Alkasalias, Twana; Flaberg, Emilie; Kashuba, Vladimir; Alexeyenko, Andrey; Pavlova, Tatiana; Savchenko, Andrii; Szekely, Laszlo; Klein, George; Guven, Hayrettin

    2014-01-01

    Normal human and murine fibroblasts can inhibit proliferation of tumor cells when cocultured in vitro. The inhibitory capacity varies depending on the donor and the site of origin of the fibroblast. We showed previously that effective inhibition requires formation of a morphologically intact fibroblast monolayer before seeding of the tumor cells. Here we show that inhibition is extended to motility of tumor cells and we dissect the factors responsible for these inhibitory functions. We find that inhibition is due to two different sets of molecules: (i) the extracellular matrix (ECM) and other surface proteins of the fibroblasts, which are responsible for contact-dependent inhibition of tumor cell proliferation; and (ii) soluble factors secreted by fibroblasts when confronted with tumor cells (confronted conditioned media, CCM) contribute to inhibition of tumor cell proliferation and motility. However, conditioned media (CM) obtained from fibroblasts alone (nonconfronted conditioned media, NCM) did not inhibit tumor cell proliferation and motility. In addition, quantitative PCR (Q-PCR) data show up-regulation of proinflammatory genes. Moreover, comparison of CCM and NCM with an antibody array for 507 different soluble human proteins revealed differential expression of growth differentiation factor 15, dickkopf-related protein 1, endothelial-monocyte-activating polypeptide II, ectodysplasin A2, Galectin-3, chemokine (C-X-C motif) ligand 2, Nidogen1, urokinase, and matrix metalloproteinase 3. PMID:25404301

  15. Amygdalin influences bladder cancer cell adhesion and invasion in vitro.

    PubMed

    Makarević, Jasmina; Rutz, Jochen; Juengel, Eva; Kaulfuss, Silke; Tsaur, Igor; Nelson, Karen; Pfitzenmaier, Jesco; Haferkamp, Axel; Blaheta, Roman A

    2014-01-01

    The cyanogenic diglucoside amygdalin, derived from Rosaceae kernels, is employed by many patients as an alternative anti-cancer treatment. However, whether amygdalin indeed acts as an anti-tumor agent is not clear. Metastasis blocking properties of amygdalin on bladder cancer cell lines was, therefore, investigated. Amygdalin (10 mg/ml) was applied to UMUC-3, TCCSUP or RT112 bladder cancer cells for 24 h or for 2 weeks. Tumor cell adhesion to vascular endothelium or to immobilized collagen as well as tumor cell migration was examined. Effects of drug treatment on integrin α and β subtypes, on integrin-linked kinase (ILK) and total and activated focal adhesion kinase (FAK) were also determined. Integrin knock-down was carried out to evaluate integrin influence on migration and adhesion. A 24 h or 2 week amygdalin application distinctly reduced tumor cell adhesion and migration of UMUC-3 and RT112 cells. TCCSUP adhesion was also reduced, but migration was elevated under amygdalin. Integrin subtype expression was significantly and specifically altered by amygdalin depending on the cell line. ILK was moderately, and activated FAK strongly, lost in all tumor cell lines in the presence of amygdalin. Knock down of β1 integrin caused a significant decrease in both adhesion and migration of UMUC-3 cells, but a significant increase in TCCSUP adhesion. Knock down of β4 integrin caused a significant decrease in migration of RT112 cells. Since the different actions of amygdalin on the different cell lines was mirrored by β1 or β4 knock down, it is postulated that amygdalin influences adhesion and migratory properties of bladder cancer cells by modulating β1 or β4 integrin expression. The amygdalin induced increase in TCCSUP migratory behavior indicates that any anti-tumor benefits from amygdalin (seen with the other two cell lines) may depend upon the cancer cell type. PMID:25333694

  16. Amygdalin Influences Bladder Cancer Cell Adhesion and Invasion In Vitro

    PubMed Central

    Makarević, Jasmina; Rutz, Jochen; Juengel, Eva; Kaulfuss, Silke; Tsaur, Igor; Nelson, Karen; Pfitzenmaier, Jesco

    2014-01-01

    The cyanogenic diglucoside amygdalin, derived from Rosaceae kernels, is employed by many patients as an alternative anti-cancer treatment. However, whether amygdalin indeed acts as an anti-tumor agent is not clear. Metastasis blocking properties of amygdalin on bladder cancer cell lines was, therefore, investigated. Amygdalin (10 mg/ml) was applied to UMUC-3, TCCSUP or RT112 bladder cancer cells for 24 h or for 2 weeks. Tumor cell adhesion to vascular endothelium or to immobilized collagen as well as tumor cell migration was examined. Effects of drug treatment on integrin α and β subtypes, on integrin-linked kinase (ILK) and total and activated focal adhesion kinase (FAK) were also determined. Integrin knock-down was carried out to evaluate integrin influence on migration and adhesion. A 24 h or 2 week amygdalin application distinctly reduced tumor cell adhesion and migration of UMUC-3 and RT112 cells. TCCSUP adhesion was also reduced, but migration was elevated under amygdalin. Integrin subtype expression was significantly and specifically altered by amygdalin depending on the cell line. ILK was moderately, and activated FAK strongly, lost in all tumor cell lines in the presence of amygdalin. Knock down of β1 integrin caused a significant decrease in both adhesion and migration of UMUC-3 cells, but a significant increase in TCCSUP adhesion. Knock down of β4 integrin caused a significant decrease in migration of RT112 cells. Since the different actions of amygdalin on the different cell lines was mirrored by β1 or β4 knock down, it is postulated that amygdalin influences adhesion and migratory properties of bladder cancer cells by modulating β1 or β4 integrin expression. The amygdalin induced increase in TCCSUP migratory behavior indicates that any anti-tumor benefits from amygdalin (seen with the other two cell lines) may depend upon the cancer cell type. PMID:25333694

  17. Hydrogen peroxide regulates cell adhesion through the redox sensor RPSA.

    PubMed

    Vilas-Boas, Filipe; Bagulho, Ana; Tenente, Rita; Teixeira, Vitor H; Martins, Gabriel; da Costa, Gonçalo; Jerónimo, Ana; Cordeiro, Carlos; Machuqueiro, Miguel; Real, Carla

    2016-01-01

    To become metastatic, a tumor cell must acquire new adhesion properties that allow migration into the surrounding connective tissue, transmigration across endothelial cells to reach the blood stream and, at the site of metastasis, adhesion to endothelial cells and transmigration to colonize a new tissue. Hydrogen peroxide (H2O2) is a redox signaling molecule produced in tumor cell microenvironment with high relevance for tumor development. However, the molecular mechanisms regulated by H2O2 in tumor cells are still poorly known. The identification of H2O2-target proteins in tumor cells and the understanding of their role in tumor cell adhesion are essential for the development of novel redox-based therapies for cancer. In this paper, we identified Ribosomal Protein SA (RPSA) as a target of H2O2 and showed that RPSA in the oxidized state accumulates in clusters that contain specific adhesion molecules. Furthermore, we showed that RPSA oxidation improves cell adhesion efficiency to laminin in vitro and promotes cell extravasation in vivo. Our results unravel a new mechanism for H2O2-dependent modulation of cell adhesion properties and identify RPSA as the H2O2 sensor in this process. This work indicates that high levels of RPSA expression might confer a selective advantage to tumor cells in an oxidative environment. PMID:26603095

  18. van der Waals forces influencing adhesion of cells

    PubMed Central

    Kendall, K.; Roberts, A. D.

    2015-01-01

    Adhesion molecules, often thought to be acting by a ‘lock and key’ mechanism, have been thought to control the adhesion of cells. While there is no doubt that a coating of adhesion molecules such as fibronectin on a surface affects cell adhesion, this paper aims to show that such surface contamination is only one factor in the equation. Starting from the baseline idea that van der Waals force is a ubiquitous attraction between all molecules, and thereby must contribute to cell adhesion, it is clear that effects from geometry, elasticity and surface molecules must all add on to the basic cell attractive force. These effects of geometry, elasticity and surface molecules are analysed. The adhesion force measured between macroscopic polymer spheres was found to be strongest when the surfaces were absolutely smooth and clean, with no projecting protruberances. Values of the measured surface energy were then about 35 mJ m−2, as expected for van der Waals attractions between the non-polar molecules. Surface projections such as abrasion roughness or dust reduced the molecular adhesion substantially. Water cut the measured surface energy to 3.4 mJ m−2. Surface active molecules lowered the adhesion still further to less than 0.3 mJ m−2. These observations do not support the lock and key concept. PMID:25533101

  19. Automated characterization of cell shape changes during amoeboid motility by skeletonization

    PubMed Central

    2010-01-01

    Background The ability of a cell to change shape is crucial for the proper function of many cellular processes, including cell migration. One type of cell migration, referred to as amoeboid motility, involves alternating cycles of morphological expansion and retraction. Traditionally, this process has been characterized by a number of parameters providing global information about shape changes, which are insufficient to distinguish phenotypes based on local pseudopodial activities that typify amoeboid motility. Results We developed a method that automatically detects and characterizes pseudopodial behavior of cells. The method uses skeletonization, a technique from morphological image processing to reduce a shape into a series of connected lines. It involves a series of automatic algorithms including image segmentation, boundary smoothing, skeletonization and branch pruning, and takes into account the cell shape changes between successive frames to detect protrusion and retraction activities. In addition, the activities are clustered into different groups, each representing the protruding and retracting history of an individual pseudopod. Conclusions We illustrate the algorithms on movies of chemotaxing Dictyostelium cells and show that our method makes it possible to capture the spatial and temporal dynamics as well as the stochastic features of the pseudopodial behavior. Thus, the method provides a powerful tool for investigating amoeboid motility. PMID:20334652

  20. HDAC6 Modulates Cell Motility by Altering the Acetylation Level of Cortactin

    PubMed Central

    Zhang, Xiaohong; Yuan, Zhigang; Zhang, Yingtao; Yong, Sarah; Salas-Burgos, Alexis; Koomen, John; Olashaw, Nancy; Parsons, J. Thomas; Yang, Xiang-Jiao; Dent, Sharon R.; Yao, Tso-Pang; Lane, William S.; Seto, Edward

    2009-01-01

    Summary Histone deacetylase 6 (HDAC6) is a tubulin-specific deacetylase that regulates microtubule-dependent cell movement. In this study, we identify the F-actin-binding protein, cortactin, as a HDAC6 substrate. We demonstrate that HDAC6 binds cortactin and that overexpression of HDAC6 leads to hypoacetylation of cortactin, while inhibition of HDAC6 activity leads to cortactin hyperacetylation. HDAC6 alters the ability of cortactin to bind F-actin by modulating a “charge patch” in its repeat region. Introduction of charge-preserving or charge-neutralizing mutations in this cortactin repeat region correlates with the gain or loss of F-actin binding ability, respectively. Cells expressing a charge-neutralizing cortactin mutant were less motile than control cells or cells expressing a charge-preserving mutant. These findings suggest that, in addition to its role in microtubule-dependent cell motility, HDAC6 influences actin-dependent cell motility by altering the acetylation status of cortactin, which, in turn, changes the F-actin binding activity of cortactin. PMID:17643370

  1. ELMO1 increases expression of extracellular matrix proteins and inhibits cell adhesion to ECMs.

    PubMed

    Shimazaki, A; Tanaka, Y; Shinosaki, T; Ikeda, M; Watada, H; Hirose, T; Kawamori, R; Maeda, S

    2006-11-01

    We have previously identified the engulfment and cell motility 1 (ELMO1) as a susceptibility gene for diabetic nephropathy. To elucidate the role of ELMO1 in the pathogenesis of chronic renal injury, we examined the expression of Elmo1 in the kidney of a rat model for chronic glomerulonephritis (uninephrectomy plus anti-Thy1.1 antibody [E30] injection). We found that the expression of the Elmo1 was significantly increased in the renal cortex and glomeruli of uninephrectomized rats injected with E30 compared to controls. By in situ hybridization, the expression of Elmo1 was shown to be elevated in the diseased kidney, especially in glomerular epithelial cells. In COS cells, the overexpression of ELMO1 resulted in a substantial increase in fibronectin expression, whereas the depletion of the ELMO1 by small interfering RNA (siRNA) targeting ELMO1 significantly suppressed the fibronectin expression in ELMO1 overexpressing and control cells. We also found that the expression of integrin-linked kinase (ILK) was significantly increased in ELMO1 overexpressing cells, and the ELMO1-induced increase in fibronectin was partially, but significantly, inhibited by siRNA targeting ILK. Furthermore, we identified that the cell adhesion to ECMs was considerably inhibited in cells overexpressing ELMO1. These results suggest that the ELMO1 contributes to the development and progression of chronic glomerular injury through the dysregulation of ECM metabolism and the reduction in cell adhesive properties to ECMs. PMID:17021600

  2. Cten Is Targeted by Kras Signalling to Regulate Cell Motility in the Colon and Pancreas

    PubMed Central

    Al-Ghamdi, Saleh; Albasri, Abdulkader; Cachat, Julien; Ibrahem, Salih; Muhammad, Belal A.; Jackson, Darryl; Nateri, Abdolrahman S.; Kindle, Karin B.; Ilyas, Mohammad

    2011-01-01

    CTEN/TNS4 is an oncogene in colorectal cancer (CRC) which enhances cell motility although the mechanism of Cten regulation is unknown. We found an association between high Cten expression and KRAS/BRAF mutation in a series of CRC cell lines (p = 0.03) and hypothesised that Kras may regulate Cten. To test this, Kras was knocked-down (using small interfering (si)RNA) in CRC cell lines SW620 and DLD1 (high Cten expressors and mutant for KRAS). In each cell line, Kras knockdown was mirrored by down-regulation of Cten Since Kras signals through Braf, we tested the effect of Kras knockdown in CRC cell line Colo205 (which shows high Cten expression and is mutant for BRAF but wild type for KRAS). Cten levels were unaffected by Kras knockdown whilst Braf knockdown resulted in reduced Cten expression suggesting that Kras signals via Braf to regulate Cten. Quantification of Cten mRNA and protein analysis following proteasome inhibition suggested that regulation was of Cten transcription. Kras knockdown inhibited cell motility. To test whether this could be mediated through Cten, SW620 cells were co-transfected with Kras specific siRNAs and a Cten expression vector. Restoring Cten expression was able to restore cell motility despite Kras knockdown (transwell migration and wounding assay, p<0.001 for both). Since KRAS is mutated in many cancers, we investigated whether this relationship could be demonstrated in other tumour models. The experiments were repeated in the pancreatic cancer cell lines Colo357 & PSN-1(both high Cten expressors and mutant for KRAS). In both cell lines, Kras was shown to regulate Cten and forced expression of Cten was able to rescue loss of cell motility following Kras knockdown in PSN-1 (transwell migration assay, p<0.001). We conclude that, in the colon and pancreas, Cten is a downstream target of Kras and may be a mechanism through which Kras regulates of cell motility. PMID:21698197

  3. Transcriptionally Regulated Cell Adhesion Network Dictates Distal Tip Cell Directionality

    PubMed Central

    Wong, Ming-Ching; Kennedy, William P.; Schwarzbauer, Jean E.

    2015-01-01

    Background The mechanisms that govern directional changes in cell migration are poorly understood. The migratory paths of two distal tip cells (DTC) determine the U-shape of the C. elegans hermaphroditic gonad. The morphogenesis of this organ provides a model system to identify genes necessary for the DTCs to execute two stereotyped turns. Results Using candidate genes for RNAi knockdown in a DTC-specific strain, we identified two transcriptional regulators required for DTC turning: cbp-1, the CBP/p300 transcriptional coactivator homologue, and let-607, a CREBH transcription factor homologue. Further screening of potential target genes uncovered a network of integrin adhesion-related genes that have roles in turning and are dependent on cbp-1 and let-607 for expression. These genes include src-1/Src kinase, tln-1/talin, pat-2/α integrin and nmy-2, a nonmuscle myosin heavy chain. Conclusions Transcriptional regulation by means of cbp-1 and let-607 is crucial for determining directional changes during DTC migration. These regulators coordinate a gene network that is necessary for integrin-mediated adhesion. Overall, these results suggest that directional changes in cell migration rely on the precise gene regulation of adhesion. PMID:24811939

  4. Cell Motility Is Decreased in Macrophages Activated by Cancer Cell-Conditioned Medium

    PubMed Central

    Go, Ahreum; Ryu, Yun-Kyoung; Lee, Jae-Wook; Moon, Eun-Yi

    2013-01-01

    Macrophages play a role in innate immune responses to various foreign antigens. Many products from primary tumors influence the activation and transmigration of macrophages. Here, we investigated a migration of macrophages stimulated with cancer cell culture-conditioned medium (CM). Macrophage activation by treatment with CM of B16F10 cells were judged by the increase in protein levels of inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX2). The location where macrophages were at 4 h-incubation with control medium or CM was different from where they were at 5 h-incubation in culture dish. Percentage of superimposed macrophages at every 1 h interval was gradually increased by CM treatment as compared to control. Total coverage of migrated track expressed in coordinates was smaller and total distance of migration was shorter in CM-treated macrophages than that in control. Rac1 activity in CM-treated macrophages was also decreased as compared to that in control. When macrophages were treated with CM in the presence of dexamethasone (Dex), an increase in COX2 protein levels, and a decrease in Rac1 activity and total coverage of migration were reversed. In the meanwhile, biphasic changes were detected by Dex treatment in section distance of migration at each time interval, which was more decreased at early time and then increased at later time. Taken together, data demonstrate that macrophage motility could be reduced in accordance with activation in response to cancer cell products. It suggests that macrophage motility could be a novel marker to monitor cancer-associated inflammatory diseases and the efficacy of anti-inflammatory agents. PMID:24404340

  5. Amine-functionalized polypyrrole: Inherently cell adhesive conducting polymer.

    PubMed

    Lee, Jae Y; Schmidt, Christine E

    2015-06-01

    Electrically conducting polymers (CPs) have been recognized as novel biomaterials that can electrically communicate with biological systems. For their tissue engineering applications, CPs have been modified to promote cell adhesion for improved interactions between biomaterials and cells/tissues. Conventional approaches to improve cell adhesion involve the surface modification of CPs with biomolecules, such as physical adsorption of cell adhesive proteins and polycationic polymers, or their chemical immobilization; however, these approaches require additional multiple modification steps with expensive biomolecules. In this study, as a simple and effective alternative to such additional biomolecule treatment, we synthesized amine-functionalized polypyrrole (APPy) that inherently presents cell adhesion-supporting positive charges under physiological conditions. The synthesized APPy provides electrical activity in a moderate range and a hydrophilic surface compared to regular polypyrrole (PPy) homopolymers. Under both serum and serum-free conditions, APPy exhibited superior attachment of human dermal fibroblasts and Schwann cells compared to PPy homopolymer controls. Moreover, Schwann cell adhesion onto the APPy copolymer was at least similar to that on poly-l-lysine treated PPy controls. Our results indicate that amine-functionalized CP substrates will be useful to achieve good cell adhesion and potentially electrically stimulate various cells. In addition, amine functionality present on CPs can further serve as a novel and flexible platform to chemically tether various bioactive molecules, such as growth factors, antibodies, and chemical drugs. PMID:25294089

  6. Cell Adhesion Molecules in Chemically-Induced Renal Injury

    PubMed Central

    Prozialeck, Walter C.; Edwards, Joshua R.

    2007-01-01

    Cell adhesion molecules are integral cell-membrane proteins that maintain cell-cell and cell-substrate adhesion, and in some cases, act as regulators of intracellular signaling cascades. In the kidney, cell adhesion molecules such as the cadherins, the catenins, ZO-1, occludin and the claudins are essential for maintaining the epithelial polarity and barrier integrity that are necessary for the normal absorption/excretion of fluid and solutes. A growing volume of evidence indicates that these cell adhesion molecules are important early targets for a variety of nephrotoxic substances including metals, drugs, and venom components. In addition, it is now widely appreciated that molecules such as ICAM-1, the integrins and selectins play important roles in the recruitment of leukocytes and inflammatory responses that are associated with nephrotoxic injury. This review summarizes the results of recent in vitro and in vivo studies indicating that these cell adhesion molecules may be primary molecular targets in many types of chemically-induced renal injury. Some of the specific agents that are discussed include Cd, Hg, Bi, cisplatin, aminoglycoside antibiotics, S-(1,2-dichlorovinyl-L-cysteine) (DCVC) and various venom toxins. This review also includes a discussion of the various mechanisms by which these substances can affect cell adhesion molecules in the kidney. PMID:17316817

  7. Endothelial cell Ca2+ increases upon tumor cell contact and modulates cell-cell adhesion.

    PubMed Central

    Pili, R; Corda, S; Passaniti, A; Ziegelstein, R C; Heldman, A W; Capogrossi, M C

    1993-01-01

    The signal transduction mechanisms involved in tumor cell adhesion to endothelial cells are still largely undefined. The effect of metastatic murine melanoma cell and human prostate carcinoma cell contact on cytosolic [Ca2+] of bovine artery endothelial cells was examined in indo-1-loaded endothelial cell monolayers. A rapid increase in endothelial cell [Ca2+] occurred on contact with tumor cells, but not on contact with 8-microns inert beads. A similar increase in endothelial cell [Ca2+] was observed with human neutrophils or monocyte-like lymphoma cells, but not with endothelial cells, red blood cells, and melanoma cell-conditioned medium. The increase in endothelial cell [Ca2+] was not inhibited by extracellular Ca2+ removal. In contrast, endothelial cell pretreatment with thapsigargin, which releases endoplasmic reticulum Ca2+ into the cytosol and depletes this Ca2+ store site, abolished the cytosolic [Ca2+] rise upon melanoma cell contact. Endothelial cell pretreatment with the membrane-permeant form of the Ca2+ chelator bis-(O-aminophenoxyl)ethane-N,N,N',N'-tetraacetic acid blocked the increase in cytosolic [Ca2+]. Under static and dynamic flow conditions (0.46 dyn/cm2) bis-(O-aminophenoxyl)ethane-N,N,N',N'-tetraacetic acid pretreatment of bovine pulmonary artery endothelial cell monolayers inhibited melanoma cell adhesion to the endothelial cells. Thus, tumor cell contact with endothelial cells induces a rapid Ca2+ release from endothelial intracellular stores, which has a functional role in enhancing cell-cell adhesion. Images PMID:8254056

  8. Synergistic and hierarchical adhesive and topographic guidance of BHK cells.

    PubMed

    Britland, S; Morgan, H; Wojiak-Stodart, B; Riehle, M; Curtis, A; Wilkinson, C

    1996-11-01

    Guided cell movement is a fundamental process in development and regeneration. We have used microengineered culture substrates to study the interaction between model topographic and adhesive guidance cues in steering BHK cell orientation. Grooves 0.1, 0.5, 1.0, 3.0, and 6.0 microm deep together with pitch-matched aminosilane tracks 5, 12, 25, 50, and 100 microm wide were fabricated on fused silica substrates using photolithographic and dry-etching techniques. The cues were presented to the cells individually, simultaneously in parallel and orthogonally opposed. Cells aligned most strongly to 25-microm-wide adhesive tracks and to 5-microm-wide, 6-microm-deep grooves. Stress fibers and vinculin were found to align with the adhesive tracks and to the grooves and ridges. Cell alignment was profoundly enhanced on all surfaces that presented both cues in parallel. Cells were able to switch alignment from ridges to grooves, and vice versa, depending on the location of superimposed adhesive tracks. Cells aligned preferentially to adhesive tracks superimposed orthogonally over grooves of matched pitch, traversing numerous grooves and ridges. The strength of the cues was more closely matched on narrower 3- and 6-microm-deep gratings with cells showing evidence of alignment to both cues. Confocal fluorescence microscopy revealed two groups of mutually opposed f-actin stress fibers within the same cell, one oriented with the topographic cues and the other with the adhesive cues. However, the adhesive response was consistently dominant. We conclude that cells are able to detect and respond to multiple guidance cues simultaneously. The adhesive and topographic guidance cues modeled here were capable of interacting both synergistically and hierarchically to guide cell orientation. PMID:8912725

  9. Urotensin II receptor determines prognosis of bladder cancer regulating cell motility/invasion

    PubMed Central

    2014-01-01

    Background Non Muscle Invasive Bladder Transitional Cancer (NMIBC) and Muscle Invasive Bladder Transitional Cancer (MIBC)/invasive have different gene profile and clinical course. NMIBC prognosis is not completely predictable, since the relapse rate is higher than 20%, even in the form of MIBC. The aim of this study is to evaluate if UTR expression can discriminate between NMIBC and MIBC and predict the risk of relapses in NMIBCs. Methods We have investigated upon urotensin-II (UII) receptor (UTR) expression in vivo in 159 patients affected by NMIBC. The biological role of UTR was also investigated in vitro. UTR expression was evaluated in a tissue-micro-array, consisting of normal, NMIBC and invasive bTCC samples. Results UTR discriminated between NMIBC and MIBC and showed a significant correlation between low UTR expression and shorter disease free survival in NMIBC. The superagonist UPG84 induced growth suppression at nM concentrations on 3/4 cell lines. Bladder cancer cell treatment with the antagonist urantide or the knock-down of UTR with a specific shRNA significantly blocked both the motility and invasion of bladder cancer cells. Conclusions The evaluation of UTR expression can discriminate between NMIBC at high and low risk of relapse. Moreover, our data suggest that UTR is involved in the regulation of motility, invasion and proliferation of bladder cancer cells. High UTR expression is an independent prognostic factor of good prognosis for NMIBC regulating motility and invasion of bladder cancer cells. PMID:24893613

  10. Direct Correlation between Motile Behavior and Protein Abundance in Single Cells.

    PubMed

    Dufour, Yann S; Gillet, Sébastien; Frankel, Nicholas W; Weibel, Douglas B; Emonet, Thierry

    2016-09-01

    Understanding how stochastic molecular fluctuations affect cell behavior requires the quantification of both behavior and protein numbers in the same cells. Here, we combine automated microscopy with in situ hydrogel polymerization to measure single-cell protein expression after tracking swimming behavior. We characterized the distribution of non-genetic phenotypic diversity in Escherichia coli motility, which affects single-cell exploration. By expressing fluorescently tagged chemotaxis proteins (CheR and CheB) at different levels, we quantitatively mapped motile phenotype (tumble bias) to protein numbers using thousands of single-cell measurements. Our results disagreed with established models until we incorporated the role of CheB in receptor deamidation and the slow fluctuations in receptor methylation. Beyond refining models, our central finding is that changes in numbers of CheR and CheB affect the population mean tumble bias and its variance independently. Therefore, it is possible to adjust the degree of phenotypic diversity of a population by adjusting the global level of expression of CheR and CheB while keeping their ratio constant, which, as shown in previous studies, confers functional robustness to the system. Since genetic control of protein expression is heritable, our results suggest that non-genetic diversity in motile behavior is selectable, supporting earlier hypotheses that such diversity confers a selective advantage. PMID:27599206

  11. miR-17 regulates melanoma cell motility by inhibiting the translation of ETV1.

    PubMed

    Cohen, Ronit; Greenberg, Eyal; Nemlich, Yael; Schachter, Jacob; Markel, Gal

    2015-08-01

    Melanoma is an aggressive malignancy with a high metastatic potential. microRNA-17 (miR-17) is a member of the oncogenic miR-17/92 cluster. Here we study the effect of miR-17 on melanoma cell motility. Over expression of the mature or pri-microRNA form of miR-17 in WM-266-4 and 624mel melanoma lines enhances cell motility, evident in both wound healing and transwell migration assays. TargetScan algorithm predicts the PEA3-subfamily member ETV1 as a direct target of miR-17. Indeed, a 3-4-fold decrease of ETV1 protein levels are observed following miR-17 transfection into the various melanoma lines, with no significant change in ETV1 mRNA expression. Dual luciferase experiments demonstrate direct binding of miR-17 to the 3'-untranslated region of ETV1, confirmed by abolishing point mutations in the putative binding site. These combined results suggest regulation of ETV1 by miR-17 by a direct translational repression. Further, in both melanoma cell lines ETV1 knockdown by selective siRNA successfully pheno-copies the facilitated cell migration, while overexpression of ETV1 inhibits cell motility and migration. Altered ETV1 expression does not affect melanoma net-proliferation. In conclusion, we show a new role for miR-17 in melanoma, facilitating cell motility, by targeting the translation of ETV1 protein, which may support the development of metastasis. PMID:26158900

  12. Endothelial cell–cell adhesion during zebrafish vascular development

    PubMed Central

    Lagendijk, Anne Karine; Yap, Alpha S; Hogan, Benjamin M

    2014-01-01

    The vertebrate vasculature is an essential organ network with major roles in health and disease. The establishment of balanced cell–cell adhesion in the endothelium is crucial for the functionality of the vascular system. Furthermore, the correct patterning and integration of vascular endothelial cell–cell adhesion drives the morphogenesis of new vessels, and is thought to couple physical forces with signaling outcomes during development. Here, we review insights into this process that have come from studies in zebrafish. First, we describe mutants in which endothelial adhesion is perturbed, second we describe recent progress using in vivo cell biological approaches that allow the visualization of endothelial cell–cell junctions. These studies underline the profound potential of this model system to dissect in great detail the function of both known and novel regulators of endothelial cell–cell adhesion. PMID:24621476

  13. Manipulating directional cell motility using intracellular superparamagnetic nanoparticles

    NASA Astrophysics Data System (ADS)

    Bradshaw, Michael; Clemons, Tristan D.; Ho, Diwei; Gutiérrez, Lucía; Lázaro, Francisco J.; House, Michael J.; St. Pierre, Timothy G.; Fear, Mark W.; Wood, Fiona M.; Iyer, K. Swaminathan

    2015-03-01

    This study investigated the ability for magnetic nanoparticles to influence cellular migration in the presence of an external magnetic field. We found that the direction of migrating keratinocytes can be controlled and the migration speed of fibroblasts can be increased with the internalisation of these nanoparticles in the presence of a magnetic field. The possibility of shepherding cells towards a region of interest through the use of internalized nanoparticles is an attractive prospect for cell tracking, cell therapies, and tissue engineering applications.This study investigated the ability for magnetic nanoparticles to influence cellular migration in the presence of an external magnetic field. We found that the direction of migrating keratinocytes can be controlled and the migration speed of fibroblasts can be increased with the internalisation of these nanoparticles in the presence of a magnetic field. The possibility of shepherding cells towards a region of interest through the use of internalized nanoparticles is an attractive prospect for cell tracking, cell therapies, and tissue engineering applications. Electronic supplementary information (ESI) available: Nanoparticle characterisation, supporting experimental data, video time course study of cellular uptake of the nanoparticles and complete experimental details are all provided in the ESI. See DOI: 10.1039/c4nr06594h

  14. Dynamic Regulation of Activated Leukocyte Cell Adhesion Molecule–mediated Homotypic Cell Adhesion through the Actin CytoskeletonV⃞

    PubMed Central

    Nelissen, Judith M. D. T.; Peters, Inge M.; de Grooth, Bart G.; van Kooyk, Yvette; Figdor, Carl G.

    2000-01-01

    Restricted expression of activated leukocyte cell adhesion molecule (ALCAM) by hematopoietic cells suggests an important role in the immune system and hematopoiesis. To get insight into the mechanisms that control ALCAM-mediated adhesion we have investigated homotypic ALCAM–ALCAM interactions. Here, we demonstrate that the cytoskeleton regulates ALCAM-mediated cell adhesion because inhibition of actin polymerization by cytochalasin D (CytD) strongly induces homotypic ALCAM–ALCAM interactions. This induction of cell adhesion is likely due to clustering of ALCAM at the cell surface, which is observed after CytD treatment. Single-particle tracking demonstrated that the lateral mobility of ALCAM in the cell membrane is increased 30-fold after CytD treatment. In contrast, both surface distribution and adhesion of a glycosylphosphatidylinositol (GPI)-anchored ALCAM mutant are insensitive to CytD, despite the increase in lateral mobility of GPI-ALCAM upon CytD treatment. This demonstrates that clustering of ALCAM is essential for cell adhesion, whereas enhanced diffusion of ALCAM alone is not sufficient for cluster formation. In addition, upon ligand binding, both free diffusion and the freely dragged distance of wild-type ALCAM, but not of GPI-ALCAM, are reduced over time, suggesting strengthening of the cytoskeleton linkage. From these findings we conclude that activation of ALCAM-mediated adhesion is dynamically regulated through actin cytoskeleton-dependent clustering. PMID:10848629

  15. The sonic hedgehog signaling pathway stimulates anaplastic thyroid cancer cell motility and invasiveness by activating Akt and c-Met.

    PubMed

    Williamson, Ashley J; Doscas, Michelle E; Ye, Jin; Heiden, Katherine B; Xing, Mingzhao; Li, Yi; Prinz, Richard A; Xu, Xiulong

    2016-03-01

    The sonic hedgehog (Shh) pathway is highly activated in thyroid neoplasms and promotes thyroid cancer stem-like cell phenotype, but whether the Shh pathway regulates thyroid tumor cell motility and invasiveness remains unknown. Here, we report that the motility and invasiveness of two anaplastic thyroid tumor cell lines, KAT-18 and SW1736, were inhibited by two inhibitors of the Shh pathway (cyclopamine and GANT61). Consistently, the cell motility and invasiveness was decreased by Shh and Gli1 knockdown, and was increased by Gli1 overexpression in KAT-18 cells. Mechanistic studies revealed that Akt and c-Met phosphorylation was decreased by a Gli1 inhibitor and by Shh and Gli1 knockdown, but was increased by Gli1 overexpression. LY294002, a PI-3 kinase inhibitor, and a c-Met inhibitor inhibited the motility and invasiveness of Gli1-transfected KAT-18 cells more effectively than the vector-transfected cells. Knockdown of Snail, a transcription factor regulated by the Shh pathway, led to decreased cell motility and invasiveness in KAT-18 and SW1736 cells. However, key epithelial-to-mesenchymal transition (EMT) markers including E-cadherin and vimentin as well as Slug were not affected by cyclopamine and GANT61 in either SW1736 or WRO82, a well differentiated follicular thyroid carcinoma cell line. Our data suggest that the Shh pathway-stimulated thyroid tumor cell motility and invasiveness is largely mediated by AKT and c-Met activation with little involvement of EMT. PMID:26859575

  16. The sonic hedgehog signaling pathway stimulates anaplastic thyroid cancer cell motility and invasiveness by activating Akt and c-Met

    PubMed Central

    Williamson, Ashley J.; Doscas, Michelle E.; Ye, Jin; Heiden, Katherine B.; Xing, Mingzhao; Li, Yi; Prinz, Richard A.; Xu, Xiulong

    2016-01-01

    The sonic hedgehog (Shh) pathway is highly activated in thyroid neoplasms and promotes thyroid cancer stem-like cell phenotype, but whether the Shh pathway regulates thyroid tumor cell motility and invasiveness remains unknown. Here, we report that the motility and invasiveness of two anaplastic thyroid tumor cell lines, KAT-18 and SW1736, were inhibited by two inhibitors of the Shh pathway (cyclopamine and GANT61). Consistently, the cell motility and invasiveness was decreased by Shh and Gli1 knockdown, and was increased by Gli1 overexpression in KAT-18 cells. Mechanistic studies revealed that Akt and c-Met phosphorylation was decreased by a Gli1 inhibitor and by Shh and Gli1 knockdown, but was increased by Gli1 overexpression. LY294002, a PI-3 kinase inhibitor, and a c-Met inhibitor inhibited the motility and invasiveness of Gli1-transfected KAT-18 cells more effectively than the vector-transfected cells. Knockdown of Snail, a transcription factor regulated by the Shh pathway, led to decreased cell motility and invasiveness in KAT-18 and SW1736 cells. However, key epithelial-to-mesenchymal transition (EMT) markers including E-cadherin and vimentin as well as Slug were not affected by cyclopamine and GANT61 in either SW1736 or WRO82, a well differentiated follicular thyroid carcinoma cell line. Our data suggest that the Shh pathway-stimulated thyroid tumor cell motility and invasiveness is largely mediated by AKT and c-Met activation with little involvement of EMT. PMID:26859575

  17. Thrombospondin-1 Modulates Actin Filament Remodeling and Cell Motility in Mouse Mammary Tumor cells in Vitro

    PubMed Central

    Ndishabandi, Dorothy; Duquette, Cameron; Billah, Ghita El-Moatassim; Reyes, Millys; Duquette, Mark; Lawler, Jack; Kazerounian, Shideh

    2015-01-01

    It is well established that the secretion of thrombospondin-1 (TSP-1) by activated stromal cells and its accumulation in the tumor microenvironment during dysplasia inhibits primary tumor growth through inhibition of angiogenesis. This inhibitory function of TSP-1 is actuated either by inhibiting MMP9 activation and the release of VEGF from extracellular matrix or by an interaction with CD36 on the surface of endothelial cells resulting in an increase in apoptosis. In contrast, several published articles have also shown that as tumor cells become more invasive and enter the early stage of carcinoma, they up-regulate TSP-1 expression, which may promote invasion and migration. In our in vivo studies using the polyoma middle T antigen (PyT) transgenic mouse model of breast cancer, we observed that the absence of TSP-1 significantly increased the growth of primary tumors, but delayed metastasis to the lungs. In this study, we propose a mechanism for the promigratory function of TSP-1 in mouse mammary tumor cells in vitro. We demonstrate the correlations between expression of TSP-1 and its receptor integrin α3β1, which is considered a promigratory protein in cancer cells. In addition we propose that binding of TSP-1 to integrin α3β1 is important for mediating actin filament polymerization and therefore, cell motility. These findings can help explain the dual functionality of TSP-1 in cancer progression. PMID:26273699

  18. Chemokine-guided cell migration and motility in zebrafish development

    PubMed Central

    Bussmann, Jeroen; Raz, Erez

    2015-01-01

    Chemokines are vertebrate-specific, structurally related proteins that function primarily in controlling cell movements by activating specific 7-transmembrane receptors. Chemokines play critical roles in a large number of biological processes and are also involved in a range of pathological conditions. For these reasons, chemokines are at the focus of studies in developmental biology and of clinically oriented research aimed at controlling cancer, inflammation, and immunological diseases. The small size of the zebrafish embryos, their rapid external development, and optical properties as well as the large number of eggs and the fast expansion in genetic tools available make this model an extremely useful one for studying the function of chemokines and chemokine receptors in an in vivo setting. Here, we review the findings relevant to the role that chemokines play in the context of directed single-cell migration, primarily in neutrophils and germ cells, and compare it to the collective cell migration of the zebrafish lateral line. We present the current knowledge concerning the formation of the chemokine gradient, its interpretation within the cell, and the molecular mechanisms underlying the cellular response to chemokine signals during directed migration. PMID:25762592

  19. Amplified effect of surface charge on cell adhesion by nanostructures

    NASA Astrophysics Data System (ADS)

    Xu, Li-Ping; Meng, Jingxin; Zhang, Shuaitao; Ma, Xinlei; Wang, Shutao

    2016-06-01

    Nano-biointerfaces with varied surface charge can be readily fabricated by integrating a template-based process with maleimide-thiol coupling chemistry. Significantly, nanostructures are employed for amplifying the effect of surface charge on cell adhesion, as revealed by the cell-adhesion performance, cell morphology and corresponding cytoskeletal organization. This study may provide a promising strategy for developing new biomedical materials with tailored cell adhesion for tissue implantation and regeneration.Nano-biointerfaces with varied surface charge can be readily fabricated by integrating a template-based process with maleimide-thiol coupling chemistry. Significantly, nanostructures are employed for amplifying the effect of surface charge on cell adhesion, as revealed by the cell-adhesion performance, cell morphology and corresponding cytoskeletal organization. This study may provide a promising strategy for developing new biomedical materials with tailored cell adhesion for tissue implantation and regeneration. Electronic supplementary information (ESI) available: Experimental details, SEM, KFM AFM, chemical modification and characterization. See DOI: 10.1039/c6nr00649c

  20. A novel chemokine receptor for SDF-1 and I-TAC involved in cell survival, cell adhesion, and tumor development

    PubMed Central

    Burns, Jennifer M.; Summers, Bretton C.; Wang, Yu; Melikian, Anita; Berahovich, Rob; Miao, Zhenhua; Penfold, Mark E. T.; Sunshine, Mary Jean; Littman, Dan R.; Kuo, Calvin J.; Wei, Kevin; McMaster, Brian E.; Wright, Kim; Howard, Maureen C.; Schall, Thomas J.

    2006-01-01

    The chemokine stromal cell–derived factor (SDF-1; also known as chemokine ligand 12 [CXCL12]) regulates many essential biological processes, including cardiac and neuronal development, stem cell motility, neovascularization, angiogenesis, apoptosis, and tumorigenesis. It is generally believed that SDF-1 mediates these many disparate processes via a single cell surface receptor known as chemokine receptor 4 (CXCR4). This paper characterizes an alternate receptor, CXCR7, which binds with high affinity to SDF-1 and to a second chemokine, interferon-inducible T cell α chemoattractant (I-TAC; also known as CXCL11). Membrane-associated CXCR7 is expressed on many tumor cell lines, on activated endothelial cells, and on fetal liver cells, but on few other cell types. Unlike many other chemokine receptors, ligand activation of CXCR7 does not cause Ca2+ mobilization or cell migration. However, expression of CXCR7 provides cells with a growth and survival advantage and increased adhesion properties. Consistent with a role for CXCR7 in cell survival and adhesion, a specific, high affinity small molecule antagonist to CXCR7 impedes in vivo tumor growth in animal models, validating this new receptor as a target for development of novel cancer therapeutics. PMID:16940167

  1. PIVL, a new serine protease inhibitor from Macrovipera lebetina transmediterranea venom, impairs motility of human glioblastoma cells.

    PubMed

    Morjen, Maram; Kallech-Ziri, Olfa; Bazaa, Amine; Othman, Houcemeddine; Mabrouk, Kamel; Zouari-Kessentini, Raoudha; Sanz, Libia; Calvete, Juan José; Srairi-Abid, Najet; El Ayeb, Mohamed; Luis, José; Marrakchi, Naziha

    2013-01-01

    A novel Kunitz-type serine proteinase inhibitor, termed PIVL, was purified to homogeneity from the venom of the Tunisian snake Macrovipera lebetina transmediterranea. It is a monomeric polypeptide chain cross-linked by three disulfide linkages with an isotope-averaged molecular mass of 7691.7 Da. The 67-residue full-length PIVL sequence was deduced from a venom gland cDNA clone. Structurally, PIVL is built by a single Kunitz/BPTI-like domain. Functionally, it is able to specifically inhibit trypsin activity. Interestingly, PIVL exhibits an anti-tumor effect and displays integrin inhibitory activity without being cytotoxic. Here we show that PIVL is able to dose-dependently inhibit the adhesion, migration and invasion of human glioblastoma U87 cells. Our results also show that PIVL impairs the function of αvβ3 and to a lesser extent, the activity of αvβ6, αvβ5, α1β1 and α5β1 integrins. Interestingly, we demonstrate that the (41)RGN(43) motif of PIVL is likely responsible for its anti-cancer effect. By using time lapse videomicroscopy, we found that PIVL significantly reduced U87 cells motility and affected cell directionality persistence by 68%. These findings reveal novel pharmacological effects for a Kunitz-type serine proteinase inhibitor. PMID:23262217

  2. Model for adhesion clutch explains biphasic relationship between actin flow and traction at the cell leading edge

    NASA Astrophysics Data System (ADS)

    Craig, Erin M.; Stricker, Jonathan; Gardel, Margaret; Mogilner, Alex

    2015-05-01

    Cell motility relies on the continuous reorganization of a dynamic actin-myosin-adhesion network at the leading edge of the cell, in order to generate protrusion at the leading edge and traction between the cell and its external environment. We analyze experimentally measured spatial distributions of actin flow, traction force, myosin density, and adhesion density in control and pharmacologically perturbed epithelial cells in order to develop a mechanical model of the actin-adhesion-myosin self-organization at the leading edge. A model in which the F-actin network is treated as a viscous gel, and adhesion clutch engagement is strengthened by myosin but weakened by actin flow, can explain the measured molecular distributions and correctly predict the spatial distributions of the actin flow and traction stress. We test the model by comparing its predictions with measurements of the actin flow and traction stress in cells with fast and slow actin polymerization rates. The model predicts how the location of the lamellipodium-lamellum boundary depends on the actin viscosity and adhesion strength. The model further predicts that the location of the lamellipodium-lamellum boundary is not very sensitive to the level of myosin contraction.

  3. Running with neighbors: coordinating cell migration and cell-cell adhesion.

    PubMed

    Collins, Caitlin; Nelson, W James

    2015-10-01

    Coordinated movement of large groups of cells is required for many biological processes, such as gastrulation and wound healing. During collective cell migration, cell-cell and cell-extracellular matrix (ECM) adhesions must be integrated so that cells maintain strong interactions with neighboring cells and the underlying substratum. Initiation and maintenance of cadherin adhesions at cell-cell junctions and integrin-based cell-ECM adhesions require integration of mechanical cues, dynamic regulation of the actin cytoskeleton, and input from specific signaling cascades, including Rho family GTPases. Here, we summarize recent advances made in understanding the interplay between these pathways at cadherin-based and integrin-based adhesions during collective cell migration and highlight outstanding questions that remain in the field. PMID:26201843

  4. A generic methodological framework for studying single cell motility in high-throughput time-lapse data

    PubMed Central

    Schoenauer Sebag, Alice; Plancade, Sandra; Raulet-Tomkiewicz, Céline; Barouki, Robert; Vert, Jean-Philippe; Walter, Thomas

    2015-01-01

    Motivation: Motility is a fundamental cellular attribute, which plays a major part in processes ranging from embryonic development to metastasis. Traditionally, single cell motility is often studied by live cell imaging. Yet, such studies were so far limited to low throughput. To systematically study cell motility at a large scale, we need robust methods to quantify cell trajectories in live cell imaging data. Results: The primary contribution of this article is to present Motility study Integrated Workflow (MotIW), a generic workflow for the study of single cell motility in high-throughput time-lapse screening data. It is composed of cell tracking, cell trajectory mapping to an original feature space and hit detection according to a new statistical procedure. We show that this workflow is scalable and demonstrates its power by application to simulated data, as well as large-scale live cell imaging data. This application enables the identification of an ontology of cell motility patterns in a fully unsupervised manner. Availability and implementation: Python code and examples are available online (http://cbio.ensmp.fr/∼aschoenauer/motiw.html) Contact: thomas.walter@mines-paristech.fr Supplementary information: Supplementary data are available at Bioinformatics online. PMID:26072499

  5. Concerted Action of Two Formins in Gliding Motility and Host Cell Invasion by Toxoplasma gondii

    PubMed Central

    Daher, Wassim; Plattner, Fabienne; Carlier, Marie-France; Soldati-Favre, Dominique

    2010-01-01

    The invasive forms of apicomplexan parasites share a conserved form of gliding motility that powers parasite migration across biological barriers, host cell invasion and egress from infected cells. Previous studies have established that the duration and direction of gliding motility are determined by actin polymerization; however, regulators of actin dynamics in apicomplexans remain poorly characterized. In the absence of a complete ARP2/3 complex, the formin homology 2 domain containing proteins and the accessory protein profilin are presumed to orchestrate actin polymerization during host cell invasion. Here, we have undertaken the biochemical and functional characterization of two Toxoplasma gondii formins and established that they act in concert as actin nucleators during invasion. The importance of TgFRM1 for parasite motility has been assessed by conditional gene disruption. The contribution of each formin individually and jointly was revealed by an approach based upon the expression of dominant mutants with modified FH2 domains impaired in actin binding but still able to dimerize with their respective endogenous formin. These mutated FH2 domains were fused to the ligand-controlled destabilization domain (DD-FKBP) to achieve conditional expression. This strategy proved unique in identifying the non-redundant and critical roles of both formins in invasion. These findings provide new insights into how controlled actin polymerization drives the directional movement required for productive penetration of parasites into host cells. PMID:20949068

  6. Up-regulation of neogenin-1 increases cell proliferation and motility in gastric cancer.

    PubMed

    Kim, Seok-Jun; Wang, Yuan-Guo; Lee, Hyun-Woo; Kang, Hyeok Gu; La, Sun-Hyuk; Choi, Il Ju; Irimura, Tatsuro; Ro, Jae Y; Bresalier, Robert S; Chun, Kyung-Hee

    2014-05-30

    Although elevated expression of neogenin-1 has been detected in human gastric cancer tissue, its role in gastric tumorigenesis remains unclear due to the lack of neogenin-1 studies in cancer. Therefore, we demonstrated here the function and regulatory mechanism of neogenin-1 in gastric cancer. Neogenin-1 ablation decreased proliferation and migration of gastric cancer cells, whereas its over-expression reversed these effects. Xenografted analyses using gastric cancer cells displayed statistically significant inhibition of tumor growth by neogenin-1 depletion. Interestingly, galectin-3 interacted with HSF-1 directly, which facilitated nuclear-localization and binding on neogenin-1 promoter to drive its transcription and gastric cancer cell motility. The galectin-3-increased gastric cancer cell motility was down-regulated by HSF-1 depletion. Moreover, the parallel expression patterns of galectin-3 and neogenin-1, as well as those of HSF-1 and neogenin-1, were detected in the malignant tissues of gastric cancer patients. Taken together, high-expression of neogenin-1 promotes gastric cancer proliferation and motility and its expression is regulated by HSF-1 and galectin-3 interaction. In addition, we propose further studies for neogenin-1 and its associated pathways to provide them as a proper target for gastric cancer therapy. PMID:24930499

  7. Computer Simulations of Mechano-Chemical Networks Choreographing Actin Dynamics in Cell Motility

    NASA Astrophysics Data System (ADS)

    Zhuravlev, Pavel I.; Hu, Longhua; Papoian, Garegin A.

    In eukaryotic cells, cell motility is largely driven by self-assembly and growth of filamentous networks comprised of actin. Numerous proteins regulate actin network dynamics either biochemically, or through mechanical interactions. This regulation is rather complex, intricately coordinated both spatially and temporally. Although experiments in vivo and in vitro have provided a trove of structural and biochemical information about actin-based cell motility processes, experimental data is not always easy to interpret unambiguously, sometimes various interpretations being in contradiction with each other. Hence, mathematical modeling approaches are necessary for providing a physical foundation for interpreting and guiding experiments. In particular, computer simulations based on physicochemical interactions provide a systems-level description of protrusion dynamics. In this contribution, we review recent progress in modeling actin-based cell motility using detailed computer simulations. We elaborate on the way actin network dynamics is determined by the interplay between chemical reactions, mechanical feedbacks, and transport bottlenecks. We also discuss the role of inherent randomness of elementary chemical reactions in determining the dynamical behavior of the mechano-chemical network controlling actin polymerization and growth.

  8. Programmable manipulation of motile cells in optoelectronic tweezers using a grayscale image

    NASA Astrophysics Data System (ADS)

    Choi, Wonjae; Nam, Seong-Won; Hwang, Hyundoo; Park, Sungsu; Park, Je-Kyun

    2008-10-01

    This paper describes a grayscale optoelectronic tweezers (OET) which allows adjustment of the electric field strength at each position of OET. A grayscale light image was used to pattern vertical electric field strength on an OET. As an electric field depends on the brightness at each point, the brighter light patterns generate the stronger electric field in the OET. Its feasibility for application to cell manipulation was demonstrated by aligning highly motile protozoan cells in vertical direction. Depending on the brightness of each pixel, the behaviors of aligned cells varied due to the different electric field strength to each cell.

  9. Sphingosylphosphorylcholine inhibits macrophage adhesion to vascular smooth muscle cells.

    PubMed

    Wirrig, Christiane; McKean, Jenny S; Wilson, Heather M; Nixon, Graeme F

    2016-09-01

    Inflammation in de-endothelialised arteries contributes to the development of cardiovascular diseases. The process that initiates this inflammatory response is the adhesion of monocytes/macrophages to exposed vascular smooth muscle cells, typically stimulated by cytokines such as tumour necrosis factor-α (TNF). The aim of this study was to determine the effect of the sphingolipid sphingosylphosphorylcholine (SPC) on the interaction of monocytes/macrophages with vascular smooth muscle cells. Rat aortic smooth muscle cells and rat bone marrow-derived macrophages were co-cultured using an in vitro assay following incubation with sphingolipids to assess inter-cellular adhesion. We reveal that SPC inhibits the TNF-induced adhesion of macrophages to smooth muscle cells. This anti-adhesive effect was the result of SPC-induced changes to the smooth muscle cells (but not the macrophages) and was mediated, at least partly, via the sphingosine 1-phosphate receptor subtype 2. Lipid raft domains were also required. Although SPC did not alter expression or membrane distribution of the adhesion proteins intercellular adhesion molecule-1 and vascular cellular adhesion protein-1 in smooth muscle cells, SPC preincubation inhibited the TNF-induced increase in inducible nitric oxide synthase (NOS2) resulting in a subsequent decrease in nitric oxide production. Inhibiting NOS2 activation in smooth muscle cells led to a decrease in the adhesion of macrophages to smooth muscle cells. This study has therefore delineated a novel pathway which can inhibit the interaction between macrophages and vascular smooth muscle cells via SPC-induced repression of NOS2 expression. This mechanism could represent a potential drug target in vascular disease. PMID:27402344

  10. Minimal Synthetic Cells to Study Integrin-Mediated Adhesion

    PubMed Central

    Frohnmayer, Johannes P; Brüggemann, Dorothea; Eberhard, Christian; Neubauer, Stefanie; Mollenhauer, Christine; Boehm, Heike; Kessler, Horst; Geiger, Benjamin; Spatz, Joachim P

    2015-01-01

    To shed light on cell-adhesion-related molecular pathways, synthetic cells offer the unique advantage of a well-controlled model system with reduced molecular complexity. Herein, we show that liposomes with the reconstituted platelet integrin αIIbβ3 as the adhesion-mediating transmembrane protein are a functional minimal cell model for studying cellular adhesion mechanisms in a defined environment. The interaction of these synthetic cells with various extracellular matrix proteins was analyzed using a quartz crystal microbalance with dissipation monitoring. The data indicated that integrin was functionally incorporated into the lipid vesicles, thus enabling integrin-specific adhesion of the engineered liposomes to fibrinogen- and fibronectin-functionalized surfaces. Then, we were able to initiate the detachment of integrin liposomes from these surfaces in the presence of the peptide GRGDSP, a process that is even faster with our newly synthesized peptide mimetic SN529, which specifically inhibits the integrin αIIbβ3. PMID:26257266

  11. Reply to comment on "Polymerization, bending, tension: What happens at the leading edge of motile cells?" by Falko Ziebert and Igor S. Aranson

    NASA Astrophysics Data System (ADS)

    Falcke, M.; Zimmermann, J.

    2014-06-01

    We are grateful to Falko Ziebert and Igor Aranson, who continue with their comment on our publication [5] a discussion on modelling concepts. Ziebert and Aranson present in their contribution to this volume [14] a model concept for cell motility and morphodynamics focusing on gel flow and its determinants. This type of models is particularly useful for describing slow dynamics on the length scale of the whole cell and modelling of cell shape [1,8,11,13,14]. Our approach is set apart from the gel models by taking into account a weakly cross-linked F-actin network region close to the location of polymerization in the lamellipodia of motile cells (semi-flexible region) in addition to the gel in the bulk. This addition explains a variety of non-linear dynamic regimes in cellular and reconstituted systems, and the force-velocity relation of fish keratocytes. Ziebert and Aranson point out in their comment that 1) a more detailed modelling of gel processes may be required to capture large cell deformations, 2) the dynamics of adhesion strength and distribution may be relevant for understanding the relation between cell shape, the dynamic regime of motion and cell velocity, 3) coarse grained models may allow for unifying both concepts, and 4) fluctuations are important in morphodynamics.

  12. Simulated Hypergravity Alters Vascular Smooth Muscle Cell Proliferation and Motility

    NASA Technical Reports Server (NTRS)

    Hunt, Shameka; Bettis, Barika; Harris-Hooker, Sandra; Sanford, Gary L.

    1997-01-01

    The cellular effects of gravity are poorly understood due to its constancy and nonavailability of altered gravitational models. Such an understanding is crucial for prolonged space flights. In these studies, we assessed the influence of centrifugation at 6G (HGrav) on vascular smooth muscle (SMC) mobility and proliferation. Cells were: (a) plated at low density and subjected to HGrav for 24-72 hr for proliferation studies, or (b) grown to confluency, subjected to HGrav, mechanically denuded and monitored for cell movement into the denuded area. Controls were maintained under normogravity. SMC showed a 50% inhibition of growth under HGrav and 10% serum; HGrav and low serum resulted in greater growth inhibition. The rate of movement of SMC into the denuded area was 2-3-fold higher under HGrav in low serum compared to controls, but similar in 10% serum. These studies show that HGrav has significant effects on SMC growth and mobility, which are dependent on serum levels.

  13. Hyaluronan-mediated cellular adhesion

    NASA Astrophysics Data System (ADS)

    Curtis, Jennifer

    2005-03-01

    Many cells surround themselves with a cushioning halo of polysaccharides that is further strengthened and organized by proteins. In fibroblasts and chrondrocytes, the primary component of this pericellular matrix is hyaluronan, a large linear polyanion. Hyaluronan production is linked to a variety of disease, developmental, and physiological processes. Cells manipulate the concentration of hyaluronan and hyaluronan receptors for numerous activities including modulation of cell adhesion, cell motility, and differentiation. Recent investigations by identify hyaluronan's role in mediating early-stage cell adhesion. An open question is how the cell removes the 0.5-10 micron thick pericellular matrix to allow for further mature adhesion events requiring nanometer scale separations. In this investigation, holographic optical tweezers are used to study the adhesion and viscoelastic properties of chondrocytes' pericellular matrix. Ultimately, we aim to shed further light on the spatial and temporal details of the dramatic transition from micron to nanometer gaps between the cell and its adhesive substrate.

  14. Total internal reflection holographic microscopy (TIRHM) for quantitative phase characterization of cell-substrate adhesion

    NASA Astrophysics Data System (ADS)

    Ash, William Mason, III

    Total Internal Reflection Holographic Microscopy (TIRHM) combines near-field microscopy with digital holography to produce a new form of near-field phase microscopy. Using a prism in TIR as a near-field imager, the presence of microscopic organisms, cell-substrate interfaces, and adhesions, causes relative refractive index (RRI) and frustrated TIR (f-TIR) to modulate the object beam's evanescent wave phase front. Quantitative phase images of test specimens such as Amoeba proteus, Dictyostelium Discoideum and cells such as SKOV-3 ovarian cancer and 3T3 fibroblasts are produced without the need to introduce stains or fluorophores. The angular spectrum method of digital holography to compensate for tilt anamorphism due to the inclined TIR plane is also discussed. The results of this work conclusively demonstrate, for the first time, the integration of near-field microscopy with digital holography. The cellular images presented show a correlation between the physical extent of the Amoeba proteus plasma membrane and the adhesions that are quantitatively profiled by phase cross-sectioning of the holographic images obtained by digital holography. With its ability to quantitatively characterise cellular adhesion and motility, it is anticipated that TIRHM can be a tool for characterizing and combating cancer metastasis, as well as improving our understanding of morphogenesis and embryogenesis itself.

  15. Control of cell adhesion on poly(methyl methacrylate).

    PubMed

    Patel, Shyam; Thakar, Rahul G; Wong, Josh; McLeod, Stephen D; Li, Song

    2006-05-01

    Keratoprostheses have been constructed from a wide variety of transparent materials, including poly(methyl methacrylate) (PMMA). However, the success of keratoprosthesis has been plagued by numerous shortcomings that include the weakening of the implant-host interface due to weak cell adhesion and opaque fibrous membrane formation over the inner surface of the implant due to fibroblast attachment. An effective solution requires a surface modification that would selectively allow enhanced cell attachment at the implant-host interface and reduced cell attachment over the interior surface of the implant. Here, we have developed a novel and simple peptide conjugation scheme to modify PMMA surfaces, which allowed for region-specific control of cell adhesion. This method uses di-amino-PEG, which can be grafted onto PMMA using hydrolysis or aminolysis method. PEG can resist cell adhesion and protein adsorption. The functionalization of grafted di-amino-PEG molecules with RGD peptide not only restored cell adhesion to the surfaces, but also enhanced cell attachment and spreading as compared to untreated PMMA surfaces. Long-term cell migration and micropatterning studies clearly indicated that PEG-PMMA surfaces with and without RGD conjugation can be used to differentiate cell adhesion and control cell attachment spatially on PMMA, which will have potential applications in the modification of keratoprostheses. PMID:16439014

  16. BMP promotes motility and represses growth of smooth muscle cells by activation of tandem Wnt pathways

    PubMed Central

    de Jesus Perez, Vinicio A.; Ali, Ziad; Alastalo, Tero-Pekka; Ikeno, Fumiaki; Sawada, Hirofumi; Lai, Ying-Ju; Kleisli, Thomas; Spiekerkoetter, Edda; Qu, Xiumei; Rubinos, Laura H.; Ashley, Euan; Amieva, Manuel; Dedhar, Shoukat

    2011-01-01

    We present a novel cell-signaling paradigm in which bone morphogenetic protein 2 (BMP-2) consecutively and interdependently activates the wingless (Wnt)–β-catenin (βC) and Wnt–planar cell polarity (PCP) signaling pathways to facilitate vascular smooth muscle motility while simultaneously suppressing growth. We show that BMP-2, in a phospho-Akt–dependent manner, induces βC transcriptional activity to produce fibronectin, which then activates integrin-linked kinase 1 (ILK-1) via α4-integrins. ILK-1 then induces the Wnt–PCP pathway by binding a proline-rich motif in disheveled (Dvl) and consequently activating RhoA-Rac1–mediated motility. Transfection of a Dvl mutant that binds βC without activating RhoA-Rac1 not only prevents BMP-2–mediated vascular smooth muscle cell motility but promotes proliferation in association with persistent βC activity. Interfering with the Dvl-dependent Wnt–PCP activation in a murine stented aortic graft injury model promotes extensive neointima formation, as shown by optical coherence tomography and histopathology. We speculate that, in response to injury, factors that subvert BMP-2–mediated tandem activation of Wnt–βC and Wnt–PCP pathways contribute to obliterative vascular disease in both the systemic and pulmonary circulations. PMID:21220513

  17. Effect of cell physicochemical characteristics and motility on bacterial transport in groundwater

    USGS Publications Warehouse

    Becker, M.W.; Collins, S.A.; Metge, D.W.; Harvey, R.W.; Shapiro, A.M.

    2004-01-01

    The influence of physicochemical characteristics and motility on bacterial transport in groundwater were examined in flow-through columns. Four strains of bacteria isolated from a crystalline rock groundwater system were investigated, with carboxylate-modified and amidine-modified latex microspheres and bromide as reference tracers. The bacterial isolates included a gram-positive rod (ML1), a gram-negative motile rod (ML2), a nonmotile mutant of ML2 (ML2m), and a gram-positive coccoid (ML3). Experiments were repeated at two flow velocities, in a glass column packed with glass beads, and in another packed with iron-oxyhydroxide coated glass beads. Bacteria breakthrough curves were interpreted using a transport equation that incorporates a sorption model from microscopic observation of bacterial deposition in flow-cell experiments. The model predicts that bacterial desorption rate will decrease exponentially with the amount of time the cell is attached to the solid surface. Desorption kinetics appeared to influence transport at the lower flow rate, but were not discernable at the higher flow rate. Iron-oxyhydroxide coatings had a lower-than-expected effect on bacterial breakthrough and no effect on the microsphere recovery in the column experiments. Cell wall type and shape also had minor effects on breakthrough. Motility tended to increase the adsorption rate, and decrease the desorption rate. The transport model predicts that at field scale, desorption rate kinetics may be important to the prediction of bacteria transport rates. ?? 2003 Elsevier B.V. All rights reserved.

  18. Single-cell force spectroscopy of pili-mediated adhesion

    NASA Astrophysics Data System (ADS)

    Sullan, Ruby May A.; Beaussart, Audrey; Tripathi, Prachi; Derclaye, Sylvie; El-Kirat-Chatel, Sofiane; Li, James K.; Schneider, Yves-Jacques; Vanderleyden, Jos; Lebeer, Sarah; Dufrêne, Yves F.

    2013-12-01

    Although bacterial pili are known to mediate cell adhesion to a variety of substrates, the molecular interactions behind this process are poorly understood. We report the direct measurement of the forces guiding pili-mediated adhesion, focusing on the medically important probiotic bacterium Lactobacillus rhamnosus GG (LGG). Using non-invasive single-cell force spectroscopy (SCFS), we quantify the adhesion forces between individual bacteria and biotic (mucin, intestinal cells) or abiotic (hydrophobic monolayers) surfaces. On hydrophobic surfaces, bacterial pili strengthen adhesion through remarkable nanospring properties, which - presumably - enable the bacteria to resist high shear forces under physiological conditions. On mucin, nanosprings are more frequent and adhesion forces larger, reflecting the influence of specific pili-mucin bonds. Interestingly, these mechanical responses are no longer observed on human intestinal Caco-2 cells. Rather, force curves exhibit constant force plateaus with extended ruptures reflecting the extraction of membrane nanotethers. These single-cell analyses provide novel insights into the molecular mechanisms by which piliated bacteria colonize surfaces (nanosprings, nanotethers), and offer exciting avenues in nanomedicine for understanding and controlling the adhesion of microbial cells (probiotics, pathogens).

  19. Low-Cost Motility Tracking System (LOCOMOTIS) for Time-Lapse Microscopy Applications and Cell Visualisation

    PubMed Central

    Lynch, Adam E.; Triajianto, Junian; Routledge, Edwin

    2014-01-01

    Direct visualisation of cells for the purpose of studying their motility has typically required expensive microscopy equipment. However, recent advances in digital sensors mean that it is now possible to image cells for a fraction of the price of a standard microscope. Along with low-cost imaging there has also been a large increase in the availability of high quality, open-source analysis programs. In this study we describe the development and performance of an expandable cell motility system employing inexpensive, commercially available digital USB microscopes to image various cell types using time-lapse and perform tracking assays in proof-of-concept experiments. With this system we were able to measure and record three separate assays simultaneously on one personal computer using identical microscopes, and obtained tracking results comparable in quality to those from other studies that used standard, more expensive, equipment. The microscopes used in our system were capable of a maximum magnification of 413.6×. Although resolution was lower than that of a standard inverted microscope we found this difference to be indistinguishable at the magnification chosen for cell tracking experiments (206.8×). In preliminary cell culture experiments using our system, velocities (mean µm/min ± SE) of 0.81±0.01 (Biomphalaria glabrata hemocytes on uncoated plates), 1.17±0.004 (MDA-MB-231 breast cancer cells), 1.24±0.006 (SC5 mouse Sertoli cells) and 2.21±0.01 (B. glabrata hemocytes on Poly-L-Lysine coated plates), were measured and are consistent with previous reports. We believe that this system, coupled with open-source analysis software, demonstrates that higher throughput time-lapse imaging of cells for the purpose of studying motility can be an affordable option for all researchers. PMID:25121722

  20. Implications of caveolae in testicular and epididymal myoid cells to sperm motility.

    PubMed

    Oliveira, Regiana L; Parent, Adam; Cyr, Daniel G; Gregory, Mary; Mandato, Craig A; Smith, Charles E; Hermo, Louis

    2016-06-01

    Seminiferous tubules of the testis and epididymal tubules in adult rodents are enveloped by contractile myoid cells, which move sperm and fluids along the male reproductive tract. Myoid cells in the testis influence Sertoli cells by paracrine signaling, but their role in the epididymis is unknown. Electron microscopy revealed that elongated myoid cells formed several concentric layers arranged in a loose configuration. The edges of some myoid cells in a given layer closely approximated one another, and extended small foot-like processes to cells of overlying layers. Gap junction proteins, connexins 32 and 43, were detected within the myoid cell layers by immunohistochemistry. These myoid cells also had caveolae that contained caveolin-1 and cavin-1 (also known as PTRF). The number of caveolae per unit area of plasma membrane was significantly reduced in caveolin-1-deficient mice (Cav1(-/-) ). Morphometric analyses of Cav1-null testes revealed an enlargement in whole-tubule and epithelial profile areas, whereas these parameters were slightly reduced in the epididymis. Although sperm are non-motile as they pass through the proximal epididymis, statistical analyses of cauda epididymidis sperm concentrations revealed no significant differences between wild-type and Cav1(-/-) mice. Motility analyses, however, indicated that sperm velocity parameters were reduced while beat cross frequency was higher in gametes of Cav1(-/-) mice. Thus while caveolae and their associated proteins are not necessary for myoid cell contractility, they appear to be crucial for signaling with the epididymal epithelium to regulate the proper acquisition of sperm motility. Mol. Reprod. Dev. 83: 526-540, 2016. © 2016 Wiley Periodicals, Inc. PMID:27088550

  1. On-Lattice Simulation of T Cell Motility, Chemotaxis, and Trafficking in the Lymph Node Paracortex

    PubMed Central

    Bogle, Gib; Dunbar, P. Rod

    2012-01-01

    Agent-based simulation is a powerful method for investigating the complex interplay of the processes occurring in a lymph node during an adaptive immune response. We have previously established an agent-based modeling framework for the interactions between T cells and dendritic cells within the paracortex of lymph nodes. This model simulates in three dimensions the “random-walk” T cell motility observed in vivo, so that cells interact in space and time as they process signals and commit to action such as proliferation. On-lattice treatment of cell motility allows large numbers of densely packed cells to be simulated, so that the low frequency of T cells capable of responding to a single antigen can be dealt with realistically. In this paper we build on this model by incorporating new numerical methods to address the crucial processes of T cell ingress and egress, and chemotaxis, within the lymph node. These methods enable simulation of the dramatic expansion and contraction of the T cell population in the lymph node paracortex during an immune response. They also provide a novel probabilistic method to simulate chemotaxis that will be generally useful in simulating other biological processes in which chemotaxis is an important feature. PMID:23028887

  2. Quantifying Cell Adhesion through Impingement of a Controlled Microjet

    PubMed Central

    Visser, Claas Willem; Gielen, Marise V.; Hao, Zhenxia; Le Gac, Séverine; Lohse, Detlef; Sun, Chao

    2015-01-01

    The impingement of a submerged, liquid jet onto a cell-covered surface allows assessing cell attachment on surfaces in a straightforward and quantitative manner and in real time, yielding valuable information on cell adhesion. However, this approach is insufficiently characterized for reliable and routine use. In this work, we both model and measure the shear stress exerted by the jet on the impingement surface in the micrometer-domain, and subsequently correlate this to jet-induced cell detachment. The measured and numerically calculated shear stress data are in good agreement with each other, and with previously published values. Real-time monitoring of the cell detachment reveals the creation of a circular cell-free area upon jet impingement, with two successive detachment regimes: 1), a dynamic regime, during which the cell-free area grows as a function of both the maximum shear stress exerted by the jet and the jet diameter; followed by 2), a stationary regime, with no further evolution of the cell-free area. For the latter regime, which is relevant for cell adhesion strength assessment, a relationship between the jet Reynolds number, the cell-free area, and the cell adhesion strength is proposed. To illustrate the capability of the technique, the adhesion strength of HeLa cervical cancer cells is determined ((34 ± 14) N/m2). Real-time visualization of cell detachment in the dynamic regime shows that cells detach either cell-by-cell or by collectively (for which intact parts of the monolayer detach as cell sheets). This process is dictated by the cell monolayer density, with a typical threshold of (1.8 ± 0.2) × 109 cells/m2, above which the collective behavior is mostly observed. The jet impingement method presents great promises for the field of tissue engineering, as the influence of both the shear stress and the surface characteristics on cell adhesion can be systematically studied. PMID:25564849

  3. On an evolution equation in a cell motility model

    NASA Astrophysics Data System (ADS)

    Mizuhara, Matthew S.; Berlyand, Leonid; Rybalko, Volodymyr; Zhang, Lei

    2016-04-01

    This paper deals with the evolution equation of a curve obtained as the sharp interface limit of a non-linear system of two reaction-diffusion PDEs. This system was introduced as a phase-field model of (crawling) motion of eukaryotic cells on a substrate. The key issue is the evolution of the cell membrane (interface curve) which involves shape change and net motion. This issue can be addressed both qualitatively and quantitatively by studying the evolution equation of the sharp interface limit for this system. However, this equation is non-linear and non-local and existence of solutions presents a significant analytical challenge. We establish existence of solutions for a wide class of initial data in the so-called subcritical regime. Existence is proved in a two step procedure. First, for smooth (H2) initial data we use a regularization technique. Second, we consider non-smooth initial data that are more relevant from the application point of view. Here, uniform estimates on the time when solutions exist rely on a maximum principle type argument. We also explore the long time behavior of the model using both analytical and numerical tools. We prove the nonexistence of traveling wave solutions with nonzero velocity. Numerical experiments show that presence of non-linearity and asymmetry of the initial curve results in a net motion which distinguishes it from classical volume preserving curvature motion. This is done by developing an algorithm for efficient numerical resolution of the non-local term in the evolution equation.

  4. PKCα-Mediated Signals Regulate the Motile Responses of Cochlear Outer Hair Cells

    PubMed Central

    Park, Channy; Kalinec, Federico

    2015-01-01

    There is strong evidence that changes in the actin/spectrin-based cortical cytoskeleton of outer hair cells (OHCs) regulate their motile responses as well as cochlear amplification, the process that optimizes the sensitivity and frequency selectivity of the mammalian inner ear. Since a RhoA/protein kinase C (PKC)-mediated pathway is known to inhibit the actin-spectrin interaction in other cell models, we decided to investigate whether this signaling cascade could also participate in the regulation of OHC motility. We used high-speed video microscopy and confocal microscopy to explore the effects of pharmacological activation of PKCα, PKCβI, PKCβII, PKCδ, PKCε, and PKCζ with lysophosphatidic acid (LPA) and their inhibition with bisindolylmaleimide I, as well as inhibition of RhoA and Rho-associated protein kinase (ROCK) with C3 and Y-27632, respectively. Motile responses were induced in isolated guinea pig OHCs by stimulation with an 8 V/cm external alternating electrical field as 50 Hz bursts of square wave pulses (100 ms on/off). We found that LPA increased expression of PKCα and PKCζ only, with PKCα, but not PKCζ, phosphorylating the cytoskeletal protein adducin of both Ser-726 and Thr-445. Interestingly, however, inhibition of PKCα reduced adducin phosphorylation only at Ser-726. We also determined that LPA activation of a PKCα-mediated signaling pathway simultaneously enhanced OHC electromotile amplitude and cell shortening, and facilitated RhoA/ROCK/LIMK1-mediated cofilin phosphorylation. Altogether, our results suggest that PKCα-mediated signals, probably via adducin-mediated inhibition of actin-spectrin binding and cofilin-mediated depolymerization of actin filaments, play an essential role in the homeostatic regulation of OHC motility and cochlear amplification. PMID:25954875

  5. Cell adhesion molecules and in vitro fertilization.

    PubMed

    Simopoulou, Maria; Nikolopoulou, Elena; Dimakakos, Andreas; Charalabopoulos, Konstantinos; Koutsilieris, Michael

    2014-01-01

    This review addresses issues regarding the need in the in vitro fertilization (IVF) field for further predictive markers enhancing the standing embryo selection criteria. It aims to serve as a source of defining information for an audience interested in factors related to the wide range of multiple roles played by cell adhesion molecules (CAMs) in several aspects of IVF ultimately associated with the success of an IVF cycle. We begin by stressing the importance of enriching the standing embryo selection criteria available aiming for the golden standard: "extract as much information as possible focusing on non-invasive techniques" so as to guide us towards selecting the embryo with the highest implantation potential. We briefly describe the latest trends on how to best select the right embryo, moving closer towards elective single embryo transfer. These trends are: frozen embryo transfer for all, preimplantation genetic screening, non-invasive selection criteria, and time-lapse imaging. The main part of this review is dedicated to categorizing and presenting published research studies focused on the involvement of CAMs in IVF and its final outcome. Specifically, we discuss the association of CAMs with conditions and complications that arise from performing assisted reproductive techniques, such as ovarian hyperstimulation syndrome, the state of the endometrium, and tubal pregnancies, as well as the levels of CAMs in biological materials available in the IVF laboratory such as follicular fluid, trophectoderm, ovarian granulosa cells, oocytes, and embryos. To conclude, since CAMs have been successfully employed as a diagnostic tool in several pathologies in routine clinical work, we suggest that their multi-faceted nature could serve as a prognostic marker in assisted reproduction, aiming to enrich the list of non-invasive selection and predictive criteria in the IVF setting. We propose that in light of the well-documented involvement of CAMs in the developmental

  6. Modeling invasion of brain tissue by glioblastoma cells: ECM alignment and motility

    NASA Astrophysics Data System (ADS)

    Sander, L. M.

    2013-03-01

    A key stage in the development of highly malignant brain tumors (Glioblastoma Multiforme) is invasion of normal brain tissue by motile cells moving through a crowded, complex environment. Evidence from in vitro experiments suggests the cell motion is accompanied by considerable deformation and alignment of the extra-cellular matrix (ECM) of the brain. In the case of breast cancer, alignment effects of this sort have been seen in vivo. We have modeled features of this system including stress confinement in the non-linear elasticity of the ECM and contact guidance of the cell motion.

  7. Reassessing the mechanics of parasite motility and host-cell invasion.

    PubMed

    Tardieux, Isabelle; Baum, Jake

    2016-08-29

    The capacity to migrate is fundamental to multicellular and single-celled life. Apicomplexan parasites, an ancient protozoan clade that includes malaria parasites (Plasmodium) and Toxoplasma, achieve remarkable speeds of directional cell movement. This rapidity is achieved via a divergent actomyosin motor system, housed within a narrow compartment that lies underneath the length of the parasite plasma membrane. How this motor functions at a mechanistic level during motility and host cell invasion is a matter of debate. Here, we integrate old and new insights toward refining the current model for the function of this motor with the aim of revitalizing interest in the mechanics of how these deadly pathogens move. PMID:27573462

  8. The FRIABLE1 Gene Product Affects Cell Adhesion in Arabidopsis

    PubMed Central

    Neumetzler, Lutz; Humphrey, Tania; Lumba, Shelley; Snyder, Stephen; Yeats, Trevor H.; Usadel, Björn; Vasilevski, Aleksandar; Patel, Jignasha; Rose, Jocelyn K. C.; Persson, Staffan; Bonetta, Dario

    2012-01-01

    Cell adhesion in plants is mediated predominantly by pectins, a group of complex cell wall associated polysaccharides. An Arabidopsis mutant, friable1 (frb1), was identified through a screen of T-DNA insertion lines that exhibited defective cell adhesion. Interestingly, the frb1 plants displayed both cell and organ dissociations and also ectopic defects in organ separation. The FRB1 gene encodes a Golgi-localized, plant specific protein with only weak sequence similarities to known proteins (DUF246). Unlike other cell adhesion deficient mutants, frb1 mutants do not have reduced levels of adhesion related cell wall polymers, such as pectins. Instead, FRB1 affects the abundance of galactose- and arabinose-containing oligosaccharides in the Golgi. Furthermore, frb1 mutants displayed alteration in pectin methylesterification, cell wall associated extensins and xyloglucan microstructure. We propose that abnormal FRB1 action has pleiotropic consequences on wall architecture, affecting both the extensin and pectin matrices, with consequent changes to the biomechanical properties of the wall and middle lamella, thereby influencing cell-cell adhesion. PMID:22916179

  9. GH3 tumor pituitary cell cytoskeleton and plasma membrane arrangement are determined by extracellular matrix proteins: implications on motility, proliferation and hormone secretion

    PubMed Central

    Azorín, Erika; Romero-Pérez, Beatriz; Solano-Agama, Carmen; de la Vega, María T; Toriz, César G; Reyes-Márquez, Blanca; González-Pozos, Sirenia; Rosales-García, Víctor H; del Pliego, Margarita González; Sabanero, Myrna; Mendoza-Garrido, María E

    2014-01-01

    The extracellular matrix (ECM) influences different physiological and pathophysiological aspects of the cell. The ECM consists in a complex network of macromolecules with characteristic biochemical properties that allow cells to sense their environments inducing different signals and changing cell behavior. The purpose of the present study was to evaluate the participation of different ECM proteins in cell morphology and its implication on motility, proliferation and hormone secretion in GH3 cells, a tumor pituitary cell. GH3 cells were cultured with a defined medium on collagens I/III and IV, fibronectin and laminin. GH3 cells express α2 integrin subunit de novo. The cells responded to the ECM proteins with differentiated cell surface morphologies and membrane protrusions. A rounded shape with small membrane blebs, weak substrate adhesion and high motility was observed in cells on C I/III and fibronectin, while on C IV and laminin cells were viewed elongated and adhered. Differences on actin cytoskeleton, cytoskeletal-associated vinculin and phospho-MLC showed that ECM proteins determine the cytoskeleton organization. Cell proliferation showed dependency on the ECM protein, observing a higher rate in cells on collagen I/III. Prolactin secretion was higher in cells with small blebs, but an unchangeable response to EGF was obtained with the ECM proteins, suggesting is a consequence of cortical actin arrangement. We ascribe the functional differences of the GH3 cells to the cytoskeletal organization. Overall, the data showed that ECM plays a critical role in GH3 cells modulating different cellular comportment and evidenced the importance of the ECM composition of pituitary adenomas. PMID:25057334

  10. Vascular cell adhesion molecule-1 and the integrin VLA-4 mediate adhesion of human B cell precursors to cultured bone marrow adherent cells.

    PubMed Central

    Ryan, D H; Nuccie, B L; Abboud, C N; Winslow, J M

    1991-01-01

    Adhesion of B cell precursors to accessory cells in the bone marrow microenvironment may be required for normal early B cell development. Human bone marrow B cell precursors adhere more avidly than mature B cells to bone marrow-derived fibroblasts. To determine the mechanism of this adhesion, expression of adhesion proteins on human B precursor cells and cell lines was measured by flow cytometry. The very late antigen (VLA) integrins VLA-4 and VLA-5 were the only adhesion proteins expressed at higher levels in B cell precursors than mature B cells. Antibodies to the alpha and beta chains of VLA-4, but not VLA-5, significantly blocked binding to bone marrow-derived fibroblasts of immature B cells and cell lines. Although fibronectin is a ligand for VLA-4, anti-fibronectin antibody and a soluble fibronectin fragment containing the VLA-4 binding domain did not block adhesion, suggesting that VLA-4 is involved in adhesion of B cell precursors, but not as a fibronectin receptor. Vascular cell adhesion molecule-1 (VCAM-1), the other known counterreceptor for VLA-4, was identified on bone marrow-derived fibroblasts, and anti-VCAM-1 significantly blocked adhesion of normal B cell precursors to bone marrow-derived fibroblasts, indicating that VLA-4/VCAM-1 interactions are important in adhesion of B cell precursors to the bone marrow microenvironment. Images PMID:1715889

  11. Prodigiosin inhibits motility and activates bacterial cell death revealing molecular biomarkers of programmed cell death.

    PubMed

    Darshan, N; Manonmani, H K

    2016-12-01

    The antimicrobial activity of prodigiosin from Serratia nematodiphila darsh1, a bacterial pigment was tested against few food borne bacterial pathogens Bacillus cereus, Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli. The mode of action of prodigiosin was studied. Prodigiosin induced bactericidal activity indicating a stereotypical set of biochemical and morphological feature of Programmed cell death (PCD). PCD involves DNA fragmentation, generation of ROS, and expression of a protein with caspase-like substrate specificity in bacterial cells. Prodigiosin was observed to be internalized into bacterial cells and was localized predominantly in the membrane and the nuclear fraction, thus, facilitating intracellular trafficking and then binding of prodigiosin to the bacterial DNA. Corresponding to an increasing concentration of prodigiosin, the level of certain proteases were observed to increase in bacteria studied, thus initiating the onset of PCD. Prodigiosin at a sub-inhibitory concentration inhibits motility of pathogens. Our observations indicated that prodigiosin could be a promising antibacterial agent and could be used in the prevention of bacterial infections. PMID:27460563

  12. Inhibition of cell adhesion by phosphorylated Ezrin/Radixin/Moesin

    PubMed Central

    Tachibana, Kouichi; Haghparast, Seyed Mohammad Ali; Miyake, Jun

    2015-01-01

    Altered phosphorylation status of the C-terminal Thr residues of Ezrin/Radixin/Moesin (ERM) is often linked to cell shape change. To determine the role of phophorylated ERM, we modified phosphorylation status of ERM and investigated changes in cell adhesion and morphology. Treatment with Calyculin-A (Cal-A), a protein phosphatase inhibitor, dramatically augmented phosphorylated ERM (phospho-ERM). Cal-A-treatment or expression of phospho-mimetic Moesin mutant (Moesin-TD) induced cell rounding in adherent cells. Moreover, reattachment of detached cells to substrate was inhibited by either treatment. Phospho-ERM, Moesin-TD and actin cytoskeleton were observed at the plasma membrane of such round cells. Augmented cell surface rigidity was also observed in both cases. Meanwhile, non-adherent KG-1 cells were rather rich in phospho-ERM. Treatment with Staurosporine, a protein kinase inhibitor that dephosphorylates phospho-ERM, up-regulated the integrin-dependent adhesion of KG-1 cells to substrate. These findings strongly suggest the followings: (1) Phospho-ERM inhibit cell adhesion, and therefore, dephosphorylation of ERM proteins is essential for cell adhesion. (2) Phospho-ERM induce formation and/or maintenance of spherical cell shape. (3) ERM are constitutively both phosphorylated and dephosphorylated in cultured adherent and non-adherent cells. PMID:26555866

  13. Cdc42 is required for EGF-stimulated protrusion and motility in MTLn3 carcinoma cells

    PubMed Central

    El-Sibai, Mirvat; Nalbant, Peri; Pang, Huan; Flinn, Rory J.; Sarmiento, Corina; Macaluso, Frank; Cammer, Michael; Condeelis, John S.; Hahn, Klaus M.; Backer, Jonathan M.

    2014-01-01

    Summary Cdc42 plays a central role in regulating the actin cytoskeleton and maintaining cell polarity. Here, we show that Cdc42 is crucial for epidermal growth factor (EGF)-stimulated protrusion in MTLn3 carcinoma cells. When stimulated with EGF, carcinoma cells showed a rapid increase in activated Cdc42 that is primarily localized to the protruding edge of the cells. siRNA-mediated knockdown of Cdc42 expression caused a decrease in EGF-stimulated protrusion and reduced cell motility in time-lapse studies. These changes were correlated with a decrease in barbed-end formation and Arp2/3 localization at the cell edge, and a marked defect in actin filament branching, as revealed by rotary-shadowing scanning electron microscopy. Upstream of Arp2/3, Cdc42 knockdown inhibited EGF-stimulated activation of PI 3-kinase at early (within 1 minute) but not late (within 3 minutes) time points. Membrane targeting of N-WASP, WAVE2 and IRSp53 were also inhibited. Effects on WAVE2 were not owing to Rac1 inhibition, because WAVE2 recruitment is unaffected by Rac1 knockdown. Our data suggest that Cdc42 activation is crucial for the regulation of actin polymerization in carcinoma cells, and required for both EGF-stimulated protrusion and cell motility independently of effects on Rac. PMID:17855387

  14. Motile activities of Dictyostelium discoideum differ from those in Protista or vertebrate animal cells.

    PubMed

    Waligórska, Agnieszka; Wianecka-Skoczeń, Magdalena; Korohoda, Włodzimierz

    2007-01-01

    Cell movement in the amoebae Dictyostelium discoideum has been examined in media differing in monovalent cation concentration (i.e. Na+ and K+). Under isotonic or even slightly hypertonic conditions, the cells move equally well in solutions in which either potassium or sodium ions dominate. However, in strongly hypertonic solutions the amoebae showed motility in a 2% potassium chloride solution, but remained motionless in a hypertonic 2% sodium chloride solution. This inhibition of D. discoideum amoebae movement in a hypertonic sodium chloride solution was fully reversible. Such behaviour corresponds to that of plant, fungi, and some invertebrate animal cells rather than protozoan or vertebrate cells. These observations suggest that studies using D. discoideum as a model for cell motility in vertebrate animal tissue cells should be considered with caution, and would seem to confirm the classification of cellular slime moulds as related rather to Fungi than to Protista. This also shows that the cell membrane models should consider the asymmetry in sodium/potassium ion concentrations found in vertebrate animal cells as one of various possibilities. PMID:18274250

  15. Cells as Active Particles in Asymmetric Potentials: Motility under External Gradients

    PubMed Central

    Comelles, Jordi; Caballero, David; Voituriez, Raphaël; Hortigüela, Verónica; Wollrab, Viktoria; Godeau, Amélie Luise; Samitier, Josep; Martínez, Elena; Riveline, Daniel

    2014-01-01

    Cell migration is a crucial event during development and in disease. Mechanical constraints and chemical gradients can contribute to the establishment of cell direction, but their respective roles remain poorly understood. Using a microfabricated topographical ratchet, we show that the nucleus dictates the direction of cell movement through mechanical guidance by its environment. We demonstrate that this direction can be tuned by combining the topographical ratchet with a biochemical gradient of fibronectin adhesion. We report competition and cooperation between the two external cues. We also quantitatively compare the measurements associated with the trajectory of a model that treats cells as fluctuating particles trapped in a periodic asymmetric potential. We show that the cell nucleus contributes to the strength of the trap, whereas cell protrusions guided by the adhesive gradients add a constant tunable bias to the direction of cell motion. PMID:25296303

  16. STIM1 overexpression promotes colorectal cancer progression, cell motility and COX-2 expression.

    PubMed

    Wang, J-Y; Sun, J; Huang, M-Y; Wang, Y-S; Hou, M-F; Sun, Y; He, H; Krishna, N; Chiu, S-J; Lin, S; Yang, S; Chang, W-C

    2015-08-13

    Tumor metastasis is the major cause of death among cancer patients, with >90% of cancer-related death attributable to the spreading of metastatic cells to secondary organs. Store-operated Ca(2+) entry (SOCE) is the predominant Ca(2+) entry mechanism in most cancer cells, and stromal interaction molecule 1 (STIM1) is the endoplasmic reticulum (ER) Ca(2+) sensor for store-operated channels. Here we reported that the STIM1 was overexpressed in colorectal cancer (CRC) patients. STIM1 overexpression in CRC was significantly associated with tumor size, depth of invasion, lymph node metastasis status and serum levels of carcinoembryonic antigen. Furthermore, ectopic expression of STIM1 promoted CRC cell motility, while depletion of STIM1 with short hairpin RNA inhibited CRC cell migration. Our data further suggested that STIM1 promoted CRC cell migration through increasing the expression of cyclooxygenase-2 (COX-2) and production of prostaglandin E2 (PGE2). Importantly, ectopically expressed COX-2 or exogenous PGE2 were able to rescue migration defect in STIM1 knockdown CRC cells, and inhibition of COX-2 with ibuprofen and indomethacin abrogated STIM1-mediated CRC cell motility. In short, our data provided clinicopathological significance for STIM1 and SOCE in CRC progression, and implicated a role for COX-2 in STIM1-mediated CRC metastasis. Our studies also suggested a new approach to inhibit STIM1-mediated metastasis with COX-2 inhibitors. PMID:25381814

  17. Shining new light on 3D cell motility and the metastatic process

    PubMed Central

    Provenzano, Paolo P.; Eliceiri, Kevin W.; Keely, Patricia J.

    2009-01-01

    Understanding tissue architecture and physical and chemical reciprocity between cells and their microenvironment provides vital insight into key events in cancer metastasis, such as cell migration through three-dimensional extracellular matrices. Yet many mechanistic details associated with metastasis remain elusive due to difficulty studying cancer cells in relevant three-dimensional microenvironments. Recently optical imaging has facilitated direct observation of single cells undertaking fundamental steps in the metastatic processes. As such, optical imaging is providing novel “optical biomarkers” with diagnostic potential that may be linked to cell motility pathways associated with metastasis, and can help guide new approaches in cancer diagnosis and therapy. Herein, we present recent advances in one subclass of optical imaging of particular promise for cellular imaging, multiphoton microscopy, that can be used to improve detection of malignant cells as well as advance our understanding of the cell biology of cancer metastasis. PMID:19819146

  18. Choreography of Cell Motility and Interaction Dynamics Imaged by Two-Photon Microscopy in Lymphoid Organs

    PubMed Central

    Cahalan, Michael D.; Parker, Ian

    2009-01-01

    The immune system is the most diffuse cellular system in the body. Accordingly, long-range migration of cells and short-range communication by local chemical signaling and by cell-cell contacts are vital to the control of an immune response. Cellular homing and migration within lymphoid organs, antigen recognition, and cell signaling and activation are clearly vital during an immune response, but these events had not been directly observed in vivo until recently. Introduced to the field of immunology in 2002, two-photon microscopy is the method of choice for visualizing living cells deep within native tissue environments, and it is now revealing an elegant cellular choreography that underlies the adaptive immune response to antigen challenge. We review cellular dynamics and molecular factors that contribute to basal motility of lymphocytes in the lymph node and cellular interactions leading to antigen capture and recognition, T cell activation, B cell activation, cytolytic effector function, and antibody production. PMID:18173372

  19. Quantification of Depletion-Induced Adhesion of Red Blood Cells

    NASA Astrophysics Data System (ADS)

    Steffen, P.; Verdier, C.; Wagner, C.

    2013-01-01

    Red blood cells (RBCs) are known to form aggregates in the form of rouleaux due to the presence of plasma proteins under physiological conditions. The formation of rouleaux can also be induced in vitro by the addition of macromolecules to the RBC suspension. Current data on the adhesion strength between red blood cells in their natural discocyte shapes mostly originate from indirect measurements such as flow chamber experiments, but data is lacking at the single cell level. Here, we present measurements on the dextran-induced aggregation of red blood cells using atomic force microscopy-based single cell force spectroscopy. The effects of dextran concentration and molecular weight on the interaction energy of adhering RBCs were determined. The results on adhesion energy are in excellent agreement with a model based on the depletion effect and previous experimental studies. Furthermore, our method allowed to determine the adhesion force, a quantity that is needed in theoretical investigations on blood flow.

  20. Quantification of depletion-induced adhesion of red blood cells.

    PubMed

    Steffen, P; Verdier, C; Wagner, C

    2013-01-01

    Red blood cells (RBCs) are known to form aggregates in the form of rouleaux due to the presence of plasma proteins under physiological conditions. The formation of rouleaux can also be induced in vitro by the addition of macromolecules to the RBC suspension. Current data on the adhesion strength between red blood cells in their natural discocyte shapes mostly originate from indirect measurements such as flow chamber experiments, but data is lacking at the single cell level. Here, we present measurements on the dextran-induced aggregation of red blood cells using atomic force microscopy-based single cell force spectroscopy. The effects of dextran concentration and molecular weight on the interaction energy of adhering RBCs were determined. The results on adhesion energy are in excellent agreement with a model based on the depletion effect and previous experimental studies. Furthermore, our method allowed to determine the adhesion force, a quantity that is needed in theoretical investigations on blood flow. PMID:23383842

  1. Vimentin and post-translational modifications in cell motility during cancer - a review.

    PubMed

    Shi, A-M; Tao, Z-Q; Li, R; Wang, Y-Q; Wang, X; Zhao, J

    2016-07-01

    The post-translational modifications (PTMs) are defined as the covalent modification or enzymatic modification of proteins during or after protein biosynthesis. Proteins are synthesized by ribosomes translating mRNA into polypeptide chains, which may then undergo PTM to form the mature protein product. PTMs are important components in cell signaling. Moreover, it is a known fact that PTM regulation offers an immense array and depth of regulatory possibilities. The present review article will focus on their possible role in cancer cell motility with special reference to vimentin, an intermediate filament (IF), as the later is an important process responsible for life-threatening state viz. cancer metastasis. PMID:27383311

  2. Non-Cell-Adhesive Substrates for Printing of Arrayed Biomaterials

    PubMed Central

    Appel, Eric A.; Larson, Benjamin L.; Luly, Kathryn M.; Kim, Jinseong D.

    2015-01-01

    Cellular microarrays have become extremely useful in expediting the investigation of large libraries of (bio)materials for both in vitro and in vivo biomedical applications. We have developed an exceedingly simple strategy for the fabrication of non-cell-adhesive substrates supporting the immobilization of diverse (bio)material features, including both monomeric and polymeric adhesion molecules (e.g. RGD and polylysine), hydrogels, and polymers. PMID:25430948

  3. Focal Adhesion Kinase regulates cell-cell contact formation in epithelial cells via modulation of Rho

    SciTech Connect

    Playford, Martin P.; Vadali, Kavita; Cai Xinming; Burridge, Keith; Schaller, Michael D.

    2008-10-15

    Focal Adhesion Kinase (FAK) is a non-receptor tyrosine kinase that plays a key role in cellular processes such as cell adhesion, migration, proliferation and survival. Recent studies have also implicated FAK in the regulation of cell-cell adhesion. Here, evidence is presented showing that siRNA-mediated suppression of FAK levels in NBT-II cells and expression of dominant negative mutants of FAK caused loss of epithelial cell morphology and inhibited the formation of cell-cell adhesions. Rac and Rho have been implicated in the regulation of cell-cell adhesions and can be regulated by FAK signaling. Expression of active Rac or Rho in NBT-II cells disrupted formation of cell-cell contacts, thus promoting a phenotype similar to FAK-depleted cells. The loss of intercellular contacts in FAK-depleted cells is prevented upon expression of a dominant negative Rho mutant, but not a dominant negative Rac mutant. Inhibition of FAK decreased tyrosine phosphorylation of p190RhoGAP and elevated the level of GTP-bound Rho. This suggests that FAK regulates cell-cell contact formation by regulation of Rho.

  4. Dynamic interplay between adhesion surfaces in carcinomas: Cell-cell and cell-matrix crosstalk

    PubMed Central

    Smith, Yvonne E; Vellanki, Sri HariKrishna; Hopkins, Ann M

    2016-01-01

    Cell-cell and cell-matrix signaling and communication between adhesion sites involve mechanisms which are required for cellular functions during normal development and homeostasis; however these cellular functions and mechanisms are often deregulated in cancer. Aberrant signaling at cell-cell and cell-matrix adhesion sites often involves downstream mediators including Rho GTPases and tyrosine kinases. This review discusses these molecules as putative mediators of cellular crosstalk between cell-cell and cell-matrix adhesion sites, in addition to their attractiveness as therapeutic targets in cancer. Interestingly, inter-junctional crosstalk mechanisms are frequently typified by the way in which bacterial and viral pathogens opportunistically infect or intoxicate mammalian cells. This review therefore also discusses the concept of learning from pathogen-host interaction studies to better understand coordinated communication between cell-cell and cell-matrix adhesion sites, in addition to highlighting the potential therapeutic usefulness of exploiting pathogens or their products to tap into inter-junctional crosstalk. Taken together, we feel that increased knowledge around mechanisms of cell-cell and cell-matrix adhesion site crosstalk and consequently a greater understanding of their therapeutic targeting offers a unique opportunity to contribute to the emerging molecular revolution in cancer biology. PMID:26981196

  5. Dynamic interplay between adhesion surfaces in carcinomas: Cell-cell and cell-matrix crosstalk.

    PubMed

    Smith, Yvonne E; Vellanki, Sri HariKrishna; Hopkins, Ann M

    2016-02-26

    Cell-cell and cell-matrix signaling and communication between adhesion sites involve mechanisms which are required for cellular functions during normal development and homeostasis; however these cellular functions and mechanisms are often deregulated in cancer. Aberrant signaling at cell-cell and cell-matrix adhesion sites often involves downstream mediators including Rho GTPases and tyrosine kinases. This review discusses these molecules as putative mediators of cellular crosstalk between cell-cell and cell-matrix adhesion sites, in addition to their attractiveness as therapeutic targets in cancer. Interestingly, inter-junctional crosstalk mechanisms are frequently typified by the way in which bacterial and viral pathogens opportunistically infect or intoxicate mammalian cells. This review therefore also discusses the concept of learning from pathogen-host interaction studies to better understand coordinated communication between cell-cell and cell-matrix adhesion sites, in addition to highlighting the potential therapeutic usefulness of exploiting pathogens or their products to tap into inter-junctional crosstalk. Taken together, we feel that increased knowledge around mechanisms of cell-cell and cell-matrix adhesion site crosstalk and consequently a greater understanding of their therapeutic targeting offers a unique opportunity to contribute to the emerging molecular revolution in cancer biology. PMID:26981196

  6. Second-harmonic generation scattering directionality predicts tumor cell motility in collagen gels

    NASA Astrophysics Data System (ADS)

    Burke, Kathleen A.; Dawes, Ryan P.; Cheema, Mehar K.; Van Hove, Amy; Benoit, Danielle S. W.; Perry, Seth W.; Brown, Edward

    2015-05-01

    Second-harmonic generation (SHG) allows for the analysis of tumor collagen structural changes throughout metastatic progression. SHG directionality, measured through the ratio of the forward-propagating to backward-propagating signal (F/B ratio), is affected by collagen fibril diameter, spacing, and disorder of fibril packing within a fiber. As tumors progress, these parameters evolve, producing concurrent changes in F/B. It has been recently shown that the F/B of highly metastatic invasive ductal carcinoma (IDC) breast tumors is significantly different from less metastatic tumors. This suggests a possible relationship between the microstructure of collagen, as measured by the F/B, and the ability of tumor cells to locomote through that collagen. Utilizing in vitro collagen gels of different F/B ratios, we explored the relationship between collagen microstructure and motility of tumor cells in a "clean" environment, free of the myriad cells, and signals found in in vivo. We found a significant relationship between F/B and the total distance traveled by the tumor cell, as well as both the average and maximum velocities of the cells. Consequently, one possible mechanism underlying the observed relationship between tumor F/B and metastatic output in IDC patient samples is a direct influence of collagen structure on tumor cell motility.

  7. Second-harmonic generation scattering directionality predicts tumor cell motility in collagen gels.

    PubMed

    Burke, Kathleen A; Dawes, Ryan P; Cheema, Mehar K; Van Hove, Amy; Benoit, Danielle S W; Perry, Seth W; Brown, Edward

    2015-05-01

    Second-harmonic generation (SHG) allows for the analysis of tumor collagen structural changes throughout metastatic progression. SHG directionality, measured through the ratio of the forward-propagating to backward-propagating signal (F/B ratio), is affected by collagen fibril diameter, spacing, and disorder of fibril packing within a fiber. As tumors progress, these parameters evolve, producing concurrent changes in F/B. It has been recently shown that the F/B of highly metastatic invasive ductal carcinoma (IDC) breast tumors is significantly different from less metastatic tumors. This suggests a possible relationship between the microstructure of collagen, as measured by the F/B, and the ability of tumor cells to locomote through that collagen. Utilizing in vitro collagen gels of different F/B ratios, we explored the relationship between collagen microstructure and motility of tumor cells in a “clean” environment, free of the myriad cells, and signals found in in vivo. We found a significant relationship between F/B and the total distance traveled by the tumor cell, as well as both the average and maximum velocities of the cells. Consequently, one possible mechanism underlying the observed relationship between tumor F/B and metastatic output in IDC patient samples is a direct influence of collagen structure on tumor cell motility. PMID:25625899

  8. Adhesion and Fusion of Muscle Cells Are Promoted by Filopodia.

    PubMed

    Segal, Dagan; Dhanyasi, Nagaraju; Schejter, Eyal D; Shilo, Ben-Zion

    2016-08-01

    Indirect flight muscles (IFMs) in Drosophila are generated during pupariation by fusion of hundreds of myoblasts with larval muscle templates (myotubes). Live observation of these muscles during the fusion process revealed multiple long actin-based protrusions that emanate from the myotube surface and require Enabled and IRSp53 for their generation and maintenance. Fusion is blocked when formation of these filopodia is compromised. While filopodia are not required for the signaling process underlying critical myoblast cell-fate changes prior to fusion, myotube-myoblast adhesion appears to be filopodia dependent. Without filopodia, close apposition between the cell membranes is not achieved, the cell-adhesion molecule Duf is not recruited to the myotube surface, and adhesion-dependent actin foci do not form. We therefore propose that the filopodia are necessary to prime the heterotypic adhesion process between the two cell types, possibly by recruiting the cell-adhesion molecule Sns to discrete patches on the myoblast cell surface. PMID:27505416

  9. Mechanisms of lymphocyte adhesion to endothelial cells: studies using a LFA-1-deficient cell line.

    PubMed Central

    Haskard, D O; Strobel, S; Thornhill, M; Pitzalis, C; Levinsky, R J

    1989-01-01

    In order to investigate the role of lymphocyte function-associated antigen 1 (LFA-1) in lymphocyte adhesion to endothelial cells (EC), we have studied the adhesion of a LFA-1-deficient lymphoblastoid cell line, ICH-KM, which has < 10% of the cell surface LFA-1 expressed on a normal lymphoblastoid cell line, ICH-BJ. The adhesion of ICH-KM cells to unstimulated EC was 49.9 +/- 8.6% (mean +/- SD) that of ICH-BJ cells. Moreover, phorbol ester-stimulated ICH-KM cells showed a considerably weaker increase in adhesion to unstimulated EC compared with ICH-BJ cells (mean +/- SD increase in percentage adhesion, 3.8 +/- 2.3 compared with 18.5 +/- 8.0; P<0.025). In contrast, there was no significant difference between the enhanced adhesion of ICH-KM cells and ICH-BJ cells to interleukin-1 (IL-1)-stimulated EC. Thus ICH-KM cells showed a 22.7 +/- 11.0 (mean +/- SD) increase in percentage adhesion to IL-1-stimulated EC compared with the 24.8 +/- 8.5 increase in percentage adhesion of ICH-BJ cells. Anti-LFA-1 monoclonal antibodies had no effect on the enhanced adhesion of ICH-KM and ICH-BJ cells to IL-1-stimulated EC but abolished the differences in adhesion between the two cell lines. The study therefore indicates that although a major part of unstimulated and phorbol ester-stimulated lymphocyte-EC adhesion is dependent upon LFA-1, the enhanced adhesion due to stimulation of EC with IL-1 is not dependent upon this molecule. The data therefore supports the existence of cytokine-inducible LFA-1-independent adhesion molecules for lymphocytes on EC. PMID:15493272

  10. Eph/ephrin interactions modulate muscle satellite cell motility and patterning.

    PubMed

    Stark, Danny A; Karvas, Rowan M; Siegel, Ashley L; Cornelison, D D W

    2011-12-01

    During development and regeneration, directed migration of cells, including neural crest cells, endothelial cells, axonal growth cones and many types of adult stem cells, to specific areas distant from their origin is necessary for their function. We have recently shown that adult skeletal muscle stem cells (satellite cells), once activated by isolation or injury, are a highly motile population with the potential to respond to multiple guidance cues, based on their expression of classical guidance receptors. We show here that, in vivo, differentiated and regenerating myofibers dynamically express a subset of ephrin guidance ligands, as well as Eph receptors. This expression has previously only been examined in the context of muscle-nerve interactions; however, we propose that it might also play a role in satellite cell-mediated muscle repair. Therefore, we investigated whether Eph-ephrin signaling would produce changes in satellite cell directional motility. Using a classical ephrin 'stripe' assay, we found that satellite cells respond to a subset of ephrins with repulsive behavior in vitro; patterning of differentiating myotubes is also parallel to ephrin stripes. This behavior can be replicated in a heterologous in vivo system, the hindbrain of the developing quail, in which neural crest cells are directed in streams to the branchial arches and to the forelimb of the developing quail, where presumptive limb myoblasts emigrate from the somite. We hypothesize that guidance signaling might impact multiple steps in muscle regeneration, including escape from the niche, directed migration to sites of injury, cell-cell interactions among satellite cell progeny, and differentiation and patterning of regenerated muscle. PMID:22071104

  11. Eph/ephrin interactions modulate muscle satellite cell motility and patterning

    PubMed Central

    Stark, Danny A.; Karvas, Rowan M.; Siegel, Ashley L.; Cornelison, D. D. W.

    2011-01-01

    During development and regeneration, directed migration of cells, including neural crest cells, endothelial cells, axonal growth cones and many types of adult stem cells, to specific areas distant from their origin is necessary for their function. We have recently shown that adult skeletal muscle stem cells (satellite cells), once activated by isolation or injury, are a highly motile population with the potential to respond to multiple guidance cues, based on their expression of classical guidance receptors. We show here that, in vivo, differentiated and regenerating myofibers dynamically express a subset of ephrin guidance ligands, as well as Eph receptors. This expression has previously only been examined in the context of muscle-nerve interactions; however, we propose that it might also play a role in satellite cell-mediated muscle repair. Therefore, we investigated whether Eph-ephrin signaling would produce changes in satellite cell directional motility. Using a classical ephrin ‘stripe’ assay, we found that satellite cells respond to a subset of ephrins with repulsive behavior in vitro; patterning of differentiating myotubes is also parallel to ephrin stripes. This behavior can be replicated in a heterologous in vivo system, the hindbrain of the developing quail, in which neural crest cells are directed in streams to the branchial arches and to the forelimb of the developing quail, where presumptive limb myoblasts emigrate from the somite. We hypothesize that guidance signaling might impact multiple steps in muscle regeneration, including escape from the niche, directed migration to sites of injury, cell-cell interactions among satellite cell progeny, and differentiation and patterning of regenerated muscle. PMID:22071104

  12. Differential Adhesion of Tumor Cells to Capillary Endothelial Cells in vitro

    NASA Astrophysics Data System (ADS)

    Alby, Laverna; Auerbach, Robert

    1984-09-01

    Adhesion studies were carried out to determine the relative ability of glioma cells and ovary-derived teratoma cells to adhere to endothelial cells obtained from mouse brain capillaries (designated MBE cell line) or mouse ovaries (designated MOE cell line). The teratoma cells showed preferential adhesion to MOE cells, whereas the glioma cells showed preferential adhesion to the MBE cell line. In contrast, the glioma and teratoma cells adhered equally to L929 and 3T3 fibroblasts. A testicular teratoma with ovary-seeking properties in vivo also adhered preferentially to MOE cells, while the preference for MBE cells was shared by glioma cells with an endothelioma and a bladder tumor line. The endothelioma, interestingly, showed a marked preferential adhesion to 3T3 cells, thus distinguishing it from the glioma. The experiments demonstrate that capillary endothelial cells derived from different sources are not alike and that differences expressed at the cell surface of these cells can be distinguished by tumor cells.

  13. A microfluidic perfusion platform for cultivation and screening study of motile microalgal cells

    PubMed Central

    Eu, Young-Jae; Park, Hye-Sun; Kim, Dong-Pyo; Wook Hong, Jong

    2014-01-01

    Systematic screening of algal cells is getting huge interest due to their capability of producing lipid-based biodiesel. Here, we introduce a new microfluidic platform composed of an array of perfusion chambers designed for long-term cultivation and preliminary screening of motile microalgal cells through loading and releasing of cells to and from the chambers. The chemical environment in each perfusion chamber was independently controlled for 5 days. The effect of nitrogen-depletion on the lipid production, phototaxis behavior in the absence of Ca2+, and cytotoxic effect of herbicide on microalgal cells was successfully monitored and compared with simultaneous control experiments on the platform. The present methodology could be extended to effective screening of algal cells and various cell lines for the production of biodiesel and other useful chemicals. PMID:24803962

  14. Liprin-α1 is a regulator of vimentin intermediate filament network in the cancer cell adhesion machinery

    PubMed Central

    Pehkonen, Henna; von Nandelstadh, Pernilla; Karhemo, Piia-Riitta; Lepikhova, Tatiana; Grenman, Reidar; Lehti, Kaisa; Monni, Outi

    2016-01-01

    PPFIA1 is located at the 11q13 region, which is one of the most commonly amplified regions in several epithelial cancers including head and neck squamous cell carcinoma and breast carcinoma. Considering the location of PPFIA1 in this amplicon, we examined whether protein encoded by PPFIA1, liprin-α1, possesses oncogenic properties in relevant carcinoma cell lines. Our results indicate that liprin-α1 localizes to different adhesion and cytoskeletal structures to regulate vimentin intermediate filament network, thereby altering the invasion and growth properties of the cancer cells. In non-invasive cells liprin-α1 promotes expansive growth behavior with limited invasive capacity, whereas in invasive cells liprin-α1 has significant impact on mesenchymal cancer cell invasion in three-dimensional collagen. Current results identify liprin-α1 as a novel regulator of the tumor cell intermediate filaments with differential oncogenic properties in actively proliferating or motile cells. PMID:27075696

  15. Cell Adhesion Molecules and Ubiquitination—Functions and Significance

    PubMed Central

    Homrich, Mirka; Gotthard, Ingo; Wobst, Hilke; Diestel, Simone

    2015-01-01

    Cell adhesion molecules of the immunoglobulin (Ig) superfamily represent the biggest group of cell adhesion molecules. They have been analyzed since approximately 40 years ago and most of them have been shown to play a role in tumor progression and in the nervous system. All members of the Ig superfamily are intensively posttranslationally modified. However, many aspects of their cellular functions are not yet known. Since a few years ago it is known that some of the Ig superfamily members are modified by ubiquitin. Ubiquitination has classically been described as a proteasomal degradation signal but during the last years it became obvious that it can regulate many other processes including internalization of cell surface molecules and lysosomal sorting. The purpose of this review is to summarize the current knowledge about the ubiquitination of cell adhesion molecules of the Ig superfamily and to discuss its potential physiological roles in tumorigenesis and in the nervous system. PMID:26703751

  16. A genome-wide RNAi screen for microtubule bundle formation and lysosome motility regulation in Drosophila S2 cells

    PubMed Central

    Jolly, Amber L.; Luan, Chi-Hao; Dusel, Brendon E.; Dunne, Sara Fernandez; Winding, Michael; Dixit, Vishrut J.; Robins, Chloe; Saluk, Jennifer L.; Logan, David J.; Carpenter, Anne E.; Sharma, Manu; Dean, Deborah; Cohen, Andrew R.; Gelfand, Vladimir I.

    2016-01-01

    Summary Long-distance intracellular transport of organelles, mRNA, and proteins (“cargo”) occurs along the microtubule cytoskeleton by the action of kinesin and dynein motor proteins; the vast network of factors involved in regulating intracellular cargo transport are still unknown. We capitalize on the Drosophila melanogaster S2 model cell system to monitor lysosome transport along microtubule bundles, which require enzymatically active kinesin-1 motor protein for their formation. We use an automated tracking program and a naïve Bayesian classifier for the multivariate motility data to analyze 15,683 gene phenotypes, and find 98 proteins involved in regulating lysosome motility along microtubules and 48 involved in the formation of microtubule filled processes in S2 cells. We identify innate immunity genes, ion channels and signaling proteins having a role in lysosome motility regulation, and find an unexpected relationship between the dynein motor, Rab7a and lysosome motility regulation. PMID:26774481

  17. Superdiffusive cell motility on 2D substrates modeled as a persistent Lévy walk

    NASA Astrophysics Data System (ADS)

    Passucci, Giuseppe; Brasch, Megan E.; Deakin, Nicholas O.; Turner, Christopher E.; Henderson, James H.; Manning, M. Lisa

    Cell motility is an essential part of many biological processes such as morphogenesis, wound healing and tumorigenesis. We quantified cell motility by tracking mouse fibroblast and human breast carcinoma nuclei to construct cell trajectories. The mean-squared displacement of these trajectories reveals that cell motion is super diffusive, where displacements scale faster than t 1 / 2 in all directions. Existing self-propelled particle (SPP) models that do not explicitly incorporate ensemble heterogeneity are unable to predict this super-diffusive behavior. Therefore we developed a run-and-tumble SPP model with Levy distributed run times that captures observed super-diffusive behavior in the mean-squared displacement as well as scaling collapse exponents of displacement probability distributions which match those of mouse fibroblast and human breast carcinoma cell trajectories. We additionally introduced small fluctuations in particle orientation during runs, which generates a crossover from super-diffusive to diffusive dynamics at a very long times. This timescale can be extracted in experiments from the velocity auto-correlation function, allowing us to explicitly test this model prediction.

  18. A20 inhibits the motility of HCC cells induced by TNF-α

    PubMed Central

    Xiao, Ying; Li, Na; Guo, Chun; Zhang, Lining; Shi, Yongyu

    2016-01-01

    Metastasis of hepatocellular carcinoma (HCC) can be facilitated by TNF-α, a prototypical inflammatory cytokine in the HCC microenvironment. A20 is a negative regulator of NF-κB signaling pathway. In the present study we ask whether A20 plays a role in HCC metastasis. We found that A20 expression was downregulated in the invasive cells of microvascular invasions (MVI) compared with the noninvasive cells in 89 tissue samples from patients with HCC by immunochemistry methods. Overexpression of A20 in HCC cell lines inhibited their motility induced by TNF-α. Furthermore, the overexpression of A20 inhibited epithelial-mesenchymal transition (EMT), FAK activation and RAC1 activity. By contrast, knockdown of A20 in one HCC cell line results in the converse. In addition, the overexpression of A20 restrained the formation of MVI in HCC xenograft in nude mice treated with TNF-α. All the results suggested that A20 functioned as a negative regulator in motility of HCC cells induced by TNF-α. PMID:26909601

  19. A20 inhibits the motility of HCC cells induced by TNF-α.

    PubMed

    Wang, Xianteng; Ma, Chao; Zong, Zhaoyun; Xiao, Ying; Li, Na; Guo, Chun; Zhang, Lining; Shi, Yongyu

    2016-03-22

    Metastasis of hepatocellular carcinoma (HCC) can be facilitated by TNF-α, a prototypical inflammatory cytokine in the HCC microenvironment. A20 is a negative regulator of NF-κB signaling pathway. In the present study we ask whether A20 plays a role in HCC metastasis. We found that A20 expression was downregulated in the invasive cells of microvascular invasions (MVI) compared with the noninvasive cells in 89 tissue samples from patients with HCC by immunochemistry methods. Overexpression of A20 in HCC cell lines inhibited their motility induced by TNF-α. Furthermore, the overexpression of A20 inhibited epithelial-mesenchymal transition (EMT), FAK activation and RAC1 activity. By contrast, knockdown of A20 in one HCC cell line results in the converse. In addition, the overexpression of A20 restrained the formation of MVI in HCC xenograft in nude mice treated with TNF-α. All the results suggested that A20 functioned as a negative regulator in motility of HCC cells induced by TNF-α. PMID:26909601

  20. Apicobasal polarity controls lymphocyte adhesion to hepatic epithelial cells.

    PubMed

    Reglero-Real, Natalia; Alvarez-Varela, Adrián; Cernuda-Morollón, Eva; Feito, Jorge; Marcos-Ramiro, Beatriz; Fernández-Martín, Laura; Gómez-Lechón, Maria José; Muntané, Jordi; Sandoval, Pilar; Majano, Pedro L; Correas, Isabel; Alonso, Miguel A; Millán, Jaime

    2014-09-25

    Loss of apicobasal polarity is a hallmark of epithelial pathologies. Leukocyte infiltration and crosstalk with dysfunctional epithelial barriers are crucial for the inflammatory response. Here, we show that apicobasal architecture regulates the adhesion between hepatic epithelial cells and lymphocytes. Polarized hepatocytes and epithelium from bile ducts segregate the intercellular adhesion molecule 1 (ICAM-1) adhesion receptor onto their apical, microvilli-rich membranes, which are less accessible by circulating immune cells. Upon cell depolarization, hepatic ICAM-1 becomes exposed and increases lymphocyte binding. Polarized hepatic cells prevent ICAM-1 exposure to lymphocytes by redirecting basolateral ICAM-1 to apical domains. Loss of ICAM-1 polarity occurs in human inflammatory liver diseases and can be induced by the inflammatory cytokine tumor necrosis factor alpha (TNF-α). We propose that adhesion receptor polarization is a parenchymal immune checkpoint that allows functional epithelium to hamper leukocyte binding. This contributes to the haptotactic guidance of leukocytes toward neighboring damaged or chronically inflamed epithelial cells that expose their adhesion machinery. PMID:25242329

  1. Osteoblast Adhesion of Breast Cancer Cells with Scanning Acoustic Microscopy

    NASA Astrophysics Data System (ADS)

    Miyasaka, C.; Mercer, R. R.; Mastro, A. M.

    Conditioned medium was collected from a bone-metastatic breast cancer cell line, MDA-MB-231, and cultured with an immature osteoblast cell line, MC3T3-E1. Under these conditions the osteoblasts acquired a changed morphology and appeared to adhere in a different way to the substrate and to each other. To characterize cellular adhesion, MC3T3-E1 osteoblasts were cultured with or without MDA-MB-231 conditioned medium for two days. With mechanical scanning acoustic reflection microscopy, we were able to detect a change in the adhesive condition of the interface between the cell and the substrate, but not with optical microscopy

  2. The Aeromonas caviae AHA0618 gene modulates cell length and influences swimming and swarming motility

    PubMed Central

    Lowry, Rebecca C; Parker, Jennifer L; Kumbhar, Ramhari; Mesnage, Stephane; Shaw, Jonathan G; Stafford, Graham P

    2015-01-01

    Aeromonas caviae is motile via a polar flagellum in liquid culture, with a lateral flagella system used for swarming on solid surfaces. The polar flagellum also has a role in cellular adherence and biofilm formation. The two subunits of the polar flagellum, FlaA and FlaB, are posttranslationally modified by O-linked glycosylation with pseudaminic acid on 6–8 serine and threonine residues within the central region of these proteins. This modification is essential for the formation of the flagellum. Aeromonas caviae possesses the simplest set of genes required for bacterial glycosylation currently known, with the putative glycosyltransferase, Maf1, being described recently. Here, we investigated the role of the AHA0618 gene, which shares homology (37% at the amino acid level) with the central region of a putative deglycosylation enzyme (HP0518) from the human pathogen Helicobacter pylori, which also glycosylates its flagellin and is proposed to be part of a flagellin deglycosylation pathway. Phenotypic analysis of an AHA0618 A. caviae mutant revealed increased swimming and swarming motility compared to the wild-type strain but without any detectable effects on the glycosylation status of the polar flagellins when analyzed by western blot analysis or mass spectroscopy. Bioinformatic analysis of the protein AHA0618, demonstrated homology to a family of l,d-transpeptidases involved in cell wall biology and peptidoglycan cross-linking (YkuD-like). Scanning electron microscopy (SEM) and fluorescence microscopy analysis of the wild-type and AHA0618-mutant A. caviae strains revealed the mutant to be subtly but significantly shorter than wild-type cells; a phenomenon that could be recovered when either AHA0618 or H. pylori HP0518 were introduced. We can therefore conclude that AHA0618 does not affect A. caviae behavior by altering polar flagellin glycosylation levels but is likely to have a role in peptidoglycan processing at the bacterial cell wall, consequently altering

  3. A Novel Laser Vaccine Adjuvant Increases the Motility of Antigen Presenting Cells

    PubMed Central

    Chen, Xinyuan; Kim, Pilhan; Farinelli, Bill; Doukas, Apostolos; Yun, Seok-Hyun; Gelfand, Jeffrey A.; Anderson, Richard R.; Wu, Mei X.

    2010-01-01

    Background Development of a potent vaccine adjuvant without introduction of any side effects remains an unmet challenge in the field of the vaccine research. Methodology/Principal Findings We found that laser at a specific setting increased the motility of antigen presenting cells (APCs) and immune responses, with few local or systemic side effects. This laser vaccine adjuvant (LVA) effect was induced by brief illumination of a small area of the skin or muscle with a nondestructive, 532 nm green laser prior to intradermal (i.d.) or intramuscular (i.m.) administration of vaccines at the site of laser illumination. The pre-illumination accelerated the motility of APCs as shown by intravital confocal microscopy, leading to sufficient antigen (Ag)-uptake at the site of vaccine injection and transportation of the Ag-captured APCs to the draining lymph nodes. As a result, the number of Ag+ dendritic cells (DCs) in draining lymph nodes was significantly higher in both the 1° and 2° draining lymph nodes in the presence than in the absence of LVA. Laser-mediated increases in the motility and lymphatic transportation of APCs augmented significantly humoral immune responses directed against a model vaccine ovalbumin (OVA) or influenza vaccine i.d. injected in both primary and booster vaccinations as compared to the vaccine itself. Strikingly, when the laser was delivered by a hair-like diffusing optical fiber into muscle, laser illumination greatly boosted not only humoral but also cell-mediated immune responses provoked by i.m. immunization with OVA relative to OVA alone. Conclusion/Significance The results demonstrate the ability of this safe LVA to augment both humoral and cell-mediated immune responses. In comparison with all current vaccine adjuvants that are either chemical compounds or biological agents, LVA is novel in both its form and mechanism; it is risk-free and has distinct advantages over traditional vaccine adjuvants. PMID:21048884

  4. The manipulation of miRNA-gene regulatory networks by KSHV induces endothelial cell motility.

    PubMed

    Wu, Yu-Hsuan; Hu, Tzu-Fang; Chen, Yu-Chieh; Tsai, Ya-Ni; Tsai, Yuan-Hau; Cheng, Cheng-Chung; Wang, Hsei-Wei

    2011-09-01

    miRNAs have emerged as master regulators of cancer-related events. miRNA dysregulation also occurs in Kaposi sarcoma (KS). Exploring the roles of KS-associated miRNAs should help to identify novel angiogenesis and lymphangiogenesis pathways. In the present study, we show that Kaposi sarcoma-associated herpesvirus (KSHV), the etiological agent of KS, induces global miRNA changes in lymphatic endothelial cells (LECs). Specifically, the miR-221/miR-222 cluster is down-regulated, whereas miR-31 is up-regulated. Both latent nuclear antigen (LANA) and Kaposin B repress the expression of the miR-221/miR-222 cluster, which results in an increase of endothelial cell (EC) migration. In contrast, miR-31 stimulates EC migration, so depletion of miR-31 in KSHV-transformed ECs reduces cell motility. Analysis of the putative miRNA targets among KSHV-affected genes showed that ETS2 and ETS1 are the downstream targets of miR-221 and miR-222, respectively. FAT4 is one of the direct targets of miR-31. Overexpression of ETS1 or ETS2 alone is sufficient to induce EC migration, whereas a reduction in FAT4 enhances EC motility. Our results show that KSHV regulates multiple miRNA-mRNA networks to enhance EC motility, which eventually contributes to KS progression by promoting the spread of malignant KS progenitor cells. Targeting KSHV-regulated miRNAs or genes might allow the development of novel therapeutic strategies that induce angiogenesis or allow the treatment of pathogenic (lymph)angiogenesis. PMID:21715310

  5. The Effects of Cell Compressibility, Motility and Contact Inhibition on the Growth of Tumor Cell Clusters using the Cellular Potts Model

    PubMed Central

    Li, Jonathan F.; Lowengrub, John

    2014-01-01

    There are numerous biological examples where genes associated with migratory ability of cells also confer the cells with an increased fitness even though these genes may not have any known effect on the cell mitosis rates. Here, we provide insight into these observations by analyzing the effects of cell migration, compression, and contact inhibition on the growth of tumor cell clusters using the Cellular Potts Model (CPM) in a monolayer geometry. This is a follow-up of a previous study (Thalhauser et al., Biol. Direct, 2010, 5:21) in which a Moran-type model was used to study the interaction of cell proliferation, migratory potential and death on the emergence of invasive phenotypes. Here, we extend the study to include the effects of cell size and shape. In particular, we investigate the interplay between cell motility and compressibility within the CPM and find that the CPM predicts that increased cell motility leads to smaller cells. This is an artifact in the CPM. An analysis of the CPM reveals an explicit inverse-relationship between the cell stiffness and motility parameters. We use this relationship to compensate for motility-induced changes in cell size in the CPM so that in the corrected CPM, cell size is independent of the cell motility. We find that subject to comparable levels of compression, clusters of motile cells grow faster than clusters of less motile cells, in qualitative agreement with biological observations and our previous study. Increasing compression tends to reduce growth rates. Contact inhibition penalizes clumped cells by halting their growth and gives motile cells an even greater advantage. Finally, our model predicts cell size distributions that are consistent with those observed in clusters of neuroblastoma cells cultured in low and high density conditions. PMID:24211749

  6. BAG-1 enhances cell-cell adhesion, reduces proliferation and induces chaperone-independent suppression of hepatocyte growth factor-induced epidermal keratinocyte migration

    SciTech Connect

    Hinitt, C.A.M.; Wood, J.; Lee, S.S.; Williams, A.C.; Howarth, J.L.; Glover, C.P.; Uney, J.B.; Hague, A.

    2010-08-01

    Cell motility is important in maintaining tissue homeostasis, facilitating epithelial wound repair and in tumour formation and progression. The aim of this study was to determine whether BAG-1 isoforms regulate epidermal cell migration in in vitro models of wound healing. In the human epidermal cell line HaCaT, endogenous BAG-1 is primarily nuclear and increases with confluence. Both transient and stable p36-Bag-1 overexpression resulted in increased cellular cohesion. Stable transfection of either of the three human BAG-1 isoforms p36-Bag-1 (BAG-1S), p46-Bag-1 (BAG-1M) and p50-Bag-1 (BAG-1L) inhibited growth and wound closure in serum-containing medium. However, in response to hepatocyte growth factor (HGF) in serum-free medium, BAG-1S/M reduced communal motility and colony scattering, but BAG-1L did not. In the presence of HGF, p36-Bag-1 transfectants retained proliferative response to HGF with no change in ERK1/2 activation. However, the cells retained E-cadherin localisation at cell-cell junctions and exhibited pronounced cortical actin. Point mutations in the BAG domain showed that BAG-1 inhibition of motility is independent of its function as a chaperone regulator. These findings are the first to suggest that BAG-1 plays a role in regulating cell-cell adhesion and suggest an important function in epidermal cohesion.

  7. Differential effects on cell motility, embryonic stem cell self-renewal and senescence by diverse Src kinase family inhibitors

    SciTech Connect

    Tamm, Christoffer Galito, Sara Pijuan Anneren, Cecilia

    2012-02-15

    The Src family of non-receptor tyrosine kinases (SFKs) has been shown to play an intricate role in embryonic stem (ES) cell maintenance. In the present study we have focused on the underlying molecular mechanisms responsible for the vastly different effects induced by various commonly used SFK inhibitors. We show that several diverse cell types, including fibroblasts completely lacking SFKs, cannot undergo mitosis in response to SU6656 and that this is caused by an unselective inhibition of Aurora kinases. In contrast, PP2 and PD173952 block motility immediately upon exposure and forces cells to grow in dense colonies. The subsequent halt in proliferation of fibroblast and epithelial cells in the center of the colonies approximately 24 h post-treatment appears to be caused by cell-to-cell contact inhibition rather than a direct effect of SFK kinase inhibition. Interestingly, in addition to generating more homogenous and dense ES cell cultures, without any diverse effect on proliferation, PP2 and PD173652 also promote ES cell self-renewal by reducing the small amount of spontaneous differentiation typically observed under standard ES cell culture conditions. These effects could not be mirrored by the use of Gleevec, a potent inhibitor of c-Abl and PDGFR kinases that are also inhibited by PP2. -- Highlights: Black-Right-Pointing-Pointer SFK inhibitor SU6656 induces senescence in mouse ES cells. Black-Right-Pointing-Pointer SU6656 inhibits mitosis in a SFK-independent manner via cross-selectivity for Aurora kinases. Black-Right-Pointing-Pointer SFK inhibitor PP2 impairs cell motility in various cell lines, including mouse ES cells. Black-Right-Pointing-Pointer Ensuing impeded motility, PP2 inhibits proliferation of various cells lines except for mouse ES cells. Black-Right-Pointing-Pointer SFK inhibitors PP2 and PD173952 impede spontaneous differentiation in standard mouse ES culture maintenance.

  8. Fibroblasts Lead the Way: A Unified View of 3D Cell Motility.

    PubMed

    Petrie, Ryan J; Yamada, Kenneth M

    2015-11-01

    Primary human fibroblasts are remarkably adaptable, able to migrate in differing types of physiological 3D tissue and on rigid 2D tissue culture surfaces. The crawling behavior of these and other vertebrate cells has been studied intensively, which has helped generate the concept of the cell motility cycle as a comprehensive model of 2D cell migration. However, this model fails to explain how cells force their large nuclei through the confines of a 3D matrix environment and why primary fibroblasts can use more than one mechanism to move in 3D. Recent work shows that the intracellular localization of myosin II activity is governed by cell-matrix interactions to both force the nucleus through the extracellular matrix (ECM) and dictate the type of protrusions used to migrate in 3D. PMID:26437597

  9. Hybrid inverse opals for regulating cell adhesion and orientation.

    PubMed

    Lu, Jie; Zheng, Fuyin; Cheng, Yao; Ding, Haibo; Zhao, Yuanjin; Gu, Zhongze

    2014-09-21

    Cell adhesion and alignment are two important considerations in tissue engineering applications as they can regulate the subsequent cell proliferation activity and differentiation program. Although many effects have been applied to regulate the adhesion or alignment of cells by using physical and chemical methods, it is still a challenge to regulate these cell behaviors simultaneously. Here, we present novel substrates with tunable nanoscale patterned structures for regulating the adhesion and alignment of cells. The substrates with different degrees of pattern orientation were achieved by customizing the amount of stretching applied to polymer inverse opal films. Cells cultured on these substrates showed an adjustable morphology and alignment. Moreover, soft hydrogels, which have poor plasticity and are difficult to cast into patterned structures, were applied to infiltrate the inverse opal structure. We demonstrated that the adhesion ratio of cells could be regulated by these hybrid substrates, as well as adjusting the cell morphology and alignment. These features of functional inverse opal substrates make them suitable for important applications in tissue engineering. PMID:25088946

  10. Hybrid inverse opals for regulating cell adhesion and orientation

    NASA Astrophysics Data System (ADS)

    Lu, Jie; Zheng, Fuyin; Cheng, Yao; Ding, Haibo; Zhao, Yuanjin; Gu, Zhongze

    2014-08-01

    Cell adhesion and alignment are two important considerations in tissue engineering applications as they can regulate the subsequent cell proliferation activity and differentiation program. Although many effects have been applied to regulate the adhesion or alignment of cells by using physical and chemical methods, it is still a challenge to regulate these cell behaviors simultaneously. Here, we present novel substrates with tunable nanoscale patterned structures for regulating the adhesion and alignment of cells. The substrates with different degrees of pattern orientation were achieved by customizing the amount of stretching applied to polymer inverse opal films. Cells cultured on these substrates showed an adjustable morphology and alignment. Moreover, soft hydrogels, which have poor plasticity and are difficult to cast into patterned structures, were applied to infiltrate the inverse opal structure. We demonstrated that the adhesion ratio of cells could be regulated by these hybrid substrates, as well as adjusting the cell morphology and alignment. These features of functional inverse opal substrates make them suitable for important applications in tissue engineering.

  11. Gene expression profiles in mouse embryo fibroblasts lacking stathmin, a microtubule regulatory protein, reveal changes in the expression of genes contributing to cell motility

    PubMed Central

    Ringhoff, Danielle N; Cassimeris, Lynne

    2009-01-01

    Background Stathmin (STMN1) protein functions to regulate assembly of the microtubule cytoskeleton by destabilizing microtubule polymers. Stathmin over-expression has been correlated with cancer stage progression, while stathmin depletion leads to death of some cancer cell lines in culture. In contrast, stathmin-null mice are viable with minor axonopathies and loss of innate fear response. Several stathmin binding partners, in addition to tubulin, have been shown to affect cell motility in culture. To expand our understanding of stathmin function in normal cells, we compared gene expression profiles, measured by microarray and qRT-PCR, of mouse embryo fibroblasts isolated from STMN1+/+ and STMN1-/- mice to determine the transcriptome level changes present in the genetic knock-out of stathmin. Results Microarray analysis of STMN1 loss at a fold change threshold of ≥ 2.0 revealed expression changes for 437 genes, of which 269 were up-regulated and 168 were down-regulated. Microarray data and qRT-PCR analysis of mRNA expression demonstrated changes in the message levels for STMN4, encoding RB3, a protein related to stathmin, and in alterations to many tubulin isotype mRNAs. KEGG Pathway analysis of the microarray data indicated changes to cell motility-related genes, and qRT-PCR plates specific for focal adhesion and ECM proteins generally confirmed the microarray data. Several microtubule assembly regulators and motors were also differentially regulated in STMN1-/- cells, but these changes should not compensate for loss of stathmin. Conclusion Approximately 50% of genes up or down regulated (at a fold change of ≥ 2) in STMN1-/- mouse embryo fibroblasts function broadly in cell adhesion and motility. These results support models indicating a role for stathmin in regulating cell locomotion, but also suggest that this functional activity may involve changes to the cohort of proteins expressed in the cell, rather than as a direct consequence of stathmin

  12. Nodal signaling regulates endodermal cell motility and actin dynamics via Rac1 and Prex1

    PubMed Central

    Housley, Michael P.; Weiner, Orion D.

    2012-01-01

    Embryo morphogenesis is driven by dynamic cell behaviors, including migration, that are coordinated with fate specification and differentiation, but how such coordination is achieved remains poorly understood. During zebrafish gastrulation, endodermal cells sequentially exhibit first random, nonpersistent migration followed by oriented, persistent migration and finally collective migration. Using a novel transgenic line that labels the endodermal actin cytoskeleton, we found that these stage-dependent changes in migratory behavior correlated with changes in actin dynamics. The dynamic actin and random motility exhibited during early gastrulation were dependent on both Nodal and Rac1 signaling. We further identified the Rac-specific guanine nucleotide exchange factor Prex1 as a Nodal target and showed that it mediated Nodal-dependent random motility. Reducing Rac1 activity in endodermal cells caused them to bypass the random migration phase and aberrantly contribute to mesodermal tissues. Together, our results reveal a novel role for Nodal signaling in regulating actin dynamics and migration behavior, which are crucial for endodermal morphogenesis and cell fate decisions. PMID:22945937

  13. Epithelial cell adhesion and gastrointestinal colonization of Lactobacillus in poultry.

    PubMed

    Spivey, Megan A; Dunn-Horrocks, Sadie L; Duong, Tri

    2014-11-01

    Administration of probiotic Lactobacillus cultures is an important alternative to the use of antibiotic growth promoters and has been demonstrated to improve animal health, growth performance, and preharvest food safety in poultry production. Whereas gastrointestinal colonization is thought to be critical to their probiotic functionality, factors important to Lactobacillus colonization in chickens are not well understood. In this study we investigate epithelial cell adhesion in vitro and colonization of Lactobacillusin vivo in broiler chickens. Adhesion of Lactobacillus cultures to epithelial cells was evaluated using the chicken LMH cell line. Lactobacillus cultures were able adhere effectively to LMH cells relative to Bacillus subtilis and Salmonella Typhimurium. Epithelial cell adhesion was similar for Lactobacillus crispatus TDCC 75, L. cristpatus TDCC 76, and Lactobacillus gallinarum TDCC 77, and all 3 were more adherent than L. gallinarum TDCC 78. However, when colonization was evaluated in the ileum and cecum of broiler chicks, L. crispatus TDCC 75 and L. gallinarum TDCC 77 were more persistent than L. crispatus TDCC 76 and L. gallinarum TDCC 78. The reduction of growth in medium supplemented with oxgal was greater for L. gallinarum TDCC 78 than L. gallinarum TDCC 77, suggesting that whereas adhesion was similar for the 2 strains, the difference in colonization between L. gallinarum strains may be due in part to their bile sensitivity. This study demonstrates that whereas adhesion to epithelial cells may be important in predicting gastrointestinal colonization, other factors including bile tolerance may also contribute to the colonization of Lactobacillus in poultry. Additionally, the chicken LMH cell line is expected to provide a platform for investigating mechanisms of Lactobacillus adhesion to epithelial tissue and evaluating the probiotic potential Lactobacillus in poultry. PMID:25239531

  14. Human Schlafen 5 (SLFN5) Is a Regulator of Motility and Invasiveness of Renal Cell Carcinoma Cells

    PubMed Central

    Sassano, Antonella; Mavrommatis, Evangelos; Arslan, Ahmet Dirim; Kroczynska, Barbara; Beauchamp, Elspeth M.; Khuon, Satya; Chew, Ten-Leong; Green, Kathleen J.; Munshi, Hidayatullah G.; Verma, Amit K.

    2015-01-01

    We provide evidence that human SLFN5, an interferon (IFN)-inducible member of the Schlafen (SLFN) family of proteins, exhibits key roles in controlling motility and invasiveness of renal cell carcinoma (RCC) cells. Our studies define the mechanism by which this occurs, demonstrating that SLFN5 negatively controls expression of the matrix metalloproteinase 1 gene (MMP-1), MMP-13, and several other genes involved in the control of malignant cell motility. Importantly, our data establish that SLFN5 expression correlates with a better overall survival in a large cohort of patients with RCC. The inverse relationship between SLFN5 expression and RCC aggressiveness raises the possibility of developing unique therapeutic approaches in the treatment of RCC, by modulating SLFN5 expression. PMID:26012550

  15. MYBPH inhibits NM IIA assembly via direct interaction with NMHC IIA and reduces cell motility

    SciTech Connect

    Hosono, Yasuyuki; Usukura, Jiro; Yamaguchi, Tomoya; Yanagisawa, Kiyoshi; Suzuki, Motoshi; Takahashi, Takashi

    2012-11-09

    Highlights: Black-Right-Pointing-Pointer MYBPH inhibits NMHC IIA assembly and cell motility. Black-Right-Pointing-Pointer MYBPH interacts to assembly-competent NM IIA. Black-Right-Pointing-Pointer MYBPH inhibits RLC and NMHC IIA, independent components of NM IIA. -- Abstract: Actomyosin filament assembly is a critical step in tumor cell migration. We previously found that myosin binding protein H (MYBPH) is directly transactivated by the TTF-1 lineage-survival oncogene in lung adenocarcinomas and inhibits phosphorylation of the myosin regulatory light chain (RLC) of non-muscle myosin IIA (NM IIA) via direct interaction with Rho kinase 1 (ROCK1). Here, we report that MYBPH also directly interacts with an additional molecule, non-muscle myosin heavy chain IIA (NMHC IIA), which was found to occur between MYBPH and the rod portion of NMHC IIA. MYBPH inhibited NMHC IIA assembly and reduced cell motility. Conversely, siMYBPH-induced increased motility was partially, yet significantly, suppressed by blebbistatin, a non-muscle myosin II inhibitor, while more profound effects were attained by combined treatment with siROCK1 and blebbistatin. Electron microscopy observations showed well-ordered paracrystals of NMHC IIA reflecting an assembled state, which were significantly less frequently observed in the presence of MYBPH. Furthermore, an in vitro sedimentation assay showed that a greater amount of NMHC IIA was in an unassembled state in the presence of MYBPH. Interestingly, treatment with a ROCK inhibitor that impairs transition of NM IIA from an assembly-incompetent to assembly-competent state reduced the interaction between MYBPH and NMHC IIA, suggesting that MYBPH has higher affinity to assembly-competent NM IIA. These results suggest that MYBPH inhibits RLC and NMHC IIA, independent components of NM IIA, and negatively regulates actomyosin organization at 2 distinct steps, resulting in firm inhibition of NM IIA assembly.

  16. C-terminal Src kinase-mediated EPIYA phosphorylation of Pragmin creates a feed-forward C-terminal Src kinase activation loop that promotes cell motility.

    PubMed

    Senda, Yoshie; Murata-Kamiya, Naoko; Hatakeyama, Masanori

    2016-07-01

    Pragmin is one of the few mammalian proteins containing the Glu-Pro-Ile-Tyr-Ala (EPIYA) tyrosine-phosphorylation motif that was originally discovered in the Helicobacter pylori CagA oncoprotein. Following delivery into gastric epithelial cells by type IV secretion and subsequent tyrosine phosphorylation at the EPIYA motifs, CagA serves as an oncogenic scaffold/adaptor that promiscuously interacts with SH2 domain-containing mammalian proteins such as the Src homology 2 (SH2) domain-containing protein tyrosine phosphatase-2 (SHP2) and the C-terminal Src kinase (Csk), a negative regulator of Src family kinases. Like CagA, Pragmin also forms a physical complex with Csk. In the present study, we found that Pragmin directly binds to Csk by the tyrosine-phosphorylated EPIYA motif. The complex formation potentiates kinase activity of Csk, which in turn phosphorylates Pragmin on tyrosine-238 (Y238), Y343, and Y391. As Y391 of Pragmin comprises the EPIYA motif, Pragmin-Csk interaction creates a feed-forward regulatory loop of Csk activation. Together with the finding that Pragmin and Csk are colocalized to focal adhesions, these observations indicate that the Pragmin-Csk interaction, triggered by Pragmin EPIYA phosphorylation, robustly stimulates the kinase activity of Csk at focal adhesions, which direct cell-matrix adhesion that regulates cell morphology and cell motility. As a consequence, expression of Pragmin and/or Csk in epithelial cells induces an elongated cell shape with elevated cell scattering in a manner that is mutually dependent on Pragmin and Csk. Deregulation of the Pragmin-Csk axis may therefore induce aberrant cell migration that contributes to tumor invasion and metastasis. PMID:27116701

  17. Fluid-flow-induced mesenchymal stem cell migration: role of focal adhesion kinase and RhoA kinase sensors.

    PubMed

    Riehl, Brandon D; Lee, Jeong Soon; Ha, Ligyeom; Lim, Jung Yul

    2015-03-01

    The study of mesenchymal stem cell (MSC) migration under flow conditions with investigation of the underlying molecular mechanism could lead to a better understanding and outcome in stem-cell-based cell therapy and regenerative medicine. We used peer-reviewed open source software to develop methods for efficiently and accurately tracking, measuring and processing cell migration as well as morphology. Using these tools, we investigated MSC migration under flow-induced shear and tested the molecular mechanism with stable knockdown of focal adhesion kinase (FAK) and RhoA kinase (ROCK). Under steady flow, MSCs migrated following the flow direction in a shear stress magnitude-dependent manner, as assessed by root mean square displacement and mean square displacement, motility coefficient and confinement ratio. Silencing FAK in MSCs suppressed morphology adaptation capability and reduced cellular motility for both static and flow conditions. Interestingly, ROCK silencing significantly increased migration tendency especially under flow. Blocking ROCK, which is known to reduce cytoskeletal tension, may lower the resistance to skeletal remodelling during the flow-induced migration. Our data thus propose a potentially differential role of focal adhesion and cytoskeletal tension signalling elements in MSC migration under flow shear. PMID:25589570

  18. Fluid-flow-induced mesenchymal stem cell migration: role of focal adhesion kinase and RhoA kinase sensors

    PubMed Central

    Riehl, Brandon D.; Lee, Jeong Soon; Ha, Ligyeom; Lim, Jung Yul

    2015-01-01

    The study of mesenchymal stem cell (MSC) migration under flow conditions with investigation of the underlying molecular mechanism could lead to a better understanding and outcome in stem-cell-based cell therapy and regenerative medicine. We used peer-reviewed open source software to develop methods for efficiently and accurately tracking, measuring and processing cell migration as well as morphology. Using these tools, we investigated MSC migration under flow-induced shear and tested the molecular mechanism with stable knockdown of focal adhesion kinase (FAK) and RhoA kinase (ROCK). Under steady flow, MSCs migrated following the flow direction in a shear stress magnitude-dependent manner, as assessed by root mean square displacement and mean square displacement, motility coefficient and confinement ratio. Silencing FAK in MSCs suppressed morphology adaptation capability and reduced cellular motility for both static and flow conditions. Interestingly, ROCK silencing significantly increased migration tendency especially under flow. Blocking ROCK, which is known to reduce cytoskeletal tension, may lower the resistance to skeletal remodelling during the flow-induced migration. Our data thus propose a potentially differential role of focal adhesion and cytoskeletal tension signalling elements in MSC migration under flow shear. PMID:25589570

  19. Neisseria meningitidis Differentially Controls Host Cell Motility through PilC1 and PilC2 Components of Type IV Pili

    PubMed Central

    Morand, Philippe C.; Drab, Marek; Rajalingam, Krishnaraj; Nassif, Xavier; Meyer, Thomas F.

    2009-01-01

    Neisseria meningitidis is a strictly human pathogen that has two facets since asymptomatic carriage can unpredictably turn into fulminant forms of infection. Meningococcal pathogenesis relies on the ability of the bacteria to break host epithelial or endothelial cellular barriers. Highly restrictive, yet poorly understood, mechanisms allow meningococcal adhesion to cells of only human origin. Adhesion of encapsulated and virulent meningococci to human cells relies on the expression of bacterial type four pili (T4P) that trigger intense host cell signalling. Among the components of the meningococcal T4P, the concomitantly expressed PilC1 and PilC2 proteins regulate pili exposure at the bacterial surface, and until now, PilC1 was believed to be specifically responsible for T4P-mediated meningococcal adhesion to human cells. Contrary to previous reports, we show that, like PilC1, the meningococcal PilC2 component is capable of mediating adhesion to human ME180 epithelial cells, with cortical plaque formation and F-actin condensation. However, PilC1 and PilC2 promote different effects on infected cells. Cellular tracking analysis revealed that PilC1-expressing meningococci caused a severe reduction in the motility of infected cells, which was not the case when cells were infected with PilC2-expressing strains. The amount of both total and phosphorylated forms of EGFR was dramatically reduced in cells upon PilC1-mediated infection. In contrast, PilC2-mediated infection did not notably affect the EGFR pathway, and these specificities were shared among unrelated meningococcal strains. These results suggest that meningococci have evolved a highly discriminative tool for differential adhesion in specific microenvironments where different cell types are present. Moreover, the fine-tuning of cellular control through the combined action of two concomitantly expressed, but distinctly regulated, T4P-associated variants of the same molecule (i.e. PilC1 and PilC2) brings a new

  20. Dictyostelium Dock180-related RacGEFs regulate the actin cytoskeleton during cell motility.

    PubMed

    Para, Alessia; Krischke, Miriam; Merlot, Sylvain; Shen, Zhouxin; Oberholzer, Michael; Lee, Susan; Briggs, Steven; Firtel, Richard A

    2009-01-01

    Cell motility of amoeboid cells is mediated by localized F-actin polymerization that drives the extension of membrane protrusions to promote forward movements. We show that deletion of either of two members of the Dictyostelium Dock180 family of RacGEFs, DockA and DockD, causes decreased speed of chemotaxing cells. The phenotype is enhanced in the double mutant and expression of DockA or DockD complements the reduced speed of randomly moving DockD null cells' phenotype, suggesting that DockA and DockD are likely to act redundantly and to have similar functions in regulating cell movement. In this regard, we find that overexpressing DockD causes increased cell speed by enhancing F-actin polymerization at the sites of pseudopod extension. DockD localizes to the cell cortex upon chemoattractant stimulation and at the leading edge of migrating cells and this localization is dependent on PI3K activity, suggesting that DockD might be part of the pathway that links PtdIns(3,4,5)P(3) production to F-actin polymerization. Using a proteomic approach, we found that DdELMO1 is associated with DockD and that Rac1A and RacC are possible in vivo DockD substrates. In conclusion, our work provides a further understanding of how cell motility is controlled and provides evidence that the molecular mechanism underlying Dock180-related protein function is evolutionarily conserved. PMID:19037099

  1. A genetically-encoded photoactivatable Rac controls the motility of living cells

    PubMed Central

    Wu, Yi I.; Frey, Daniel; Lungu, Oana I.; Jaehrig, Angelika; Schlichting, Ilme; Kuhlman, Brian; Hahn, Klaus M.

    2009-01-01

    The precise spatio-temporal dynamics of protein activity are often critical in determining cell behaviour, yet for most proteins they remain poorly understood; it remains difficult to manipulate protein activity at precise times and places within living cells. Protein activity has been controlled by light, through protein derivatization with photocleavable moieties1 or using photoreactive small molecule ligands2. However, this requires use of toxic UV wavelengths, activation is irreversible, and/or cell loading is accomplished via disruption of the cell membrane (i.e. through microinjection). We have developed a new approach to produce genetically-encoded photo-activatable derivatives of Rac1, a key GTPase regulating actin cytoskeletal dynamics3,4. Rac1 mutants were fused to the photoreactive LOV (light oxygen voltage) domain from phototropin5,6, sterically blocking Rac1 interactions until irradiation unwound a helix linking LOV to Rac1. Photoactivatable Rac1 (PA-Rac1) could be reversibly and repeatedly activated using 458 or 473 nm light to generate precisely localized cell protrusions and ruffling. Localized Rac activation or inactivation was sufficient to produce cell motility and control the direction of cell movement. Myosin was involved in Rac control of directionality but not in Rac-induced protrusion, while PAK was required for Rac-induced protrusion. PA-Rac1 was used to elucidate Rac regulation of RhoA in cell motility. Rac and Rho coordinate cytoskeletal behaviours with seconds and submicron precision7,8. Their mutual regulation remains controversial9, with data indicating that Rac inhibits and/or activates Rho10,11. Rac was shown to inhibit RhoA in living cells, with inhibition modulated at protrusions and ruffles. A PA-Rac crystal structure and modelling revealed LOV-Rac interactions that will facilitate extension of this photoactivation approach to other proteins. PMID:19693014

  2. Three-dimensional hMSC Motility within Peptide-Functionalized PEG-Based Hydrogel of Varying Adhesivity and Crosslinking Density

    PubMed Central

    Kyburz, Kyle A; Anseth, Kristi S

    2013-01-01

    Human mesenchymal stem cell (hMSC) migration and recruitment play a critical role during bone fracture healing. Within the complex 3D in vivo microenvironment, hMSC migration is regulated through a myriad of extracellular cues. Here, we use a thiol-ene photopolymerized hydrogel to recapitulate structural and bioactive inputs in a tunable manner to understand their role in regulating 3D hMSC migration. Specifically, peptide-functionalized poly(ethylene glycol) hydrogels were used to encapsulate hMSC while varying the crosslinking density, 0.18 ± 0.02 - 1.60 ± 0.04 mM, and the adhesive ligand density, 0.001 to 1.0 mM. Using live cell videomicroscopy migratory cell paths were tracked and fit to a persistent random walk model. It was shown that hMSC migrating through the lowest crosslinking density and highest adhesivity had more sustained polarization, higher migrating speeds (17.6 ± 0.9 μm/hr), and higher cell spreading (Elliptical Form Factor = 3.9 ± 0.2). However, manipulation of these material properties did not significantly affect migration persistence. Further, there was a monotonic increase in cell speed and spreading with increasing adhesivity showing a lack of the biphasic trend seen in two dimensional cell migration. Immunohistochemistry showed well-formed actin fibers and β1 integrin staining at the ends of stress fibers. This thiol-ene platform provides a highly tunable substrate to characterize 3D hMSC migration with application as an implantable cell carrier platform or for the recruitment of endogenous hMSC in vivo. PMID:23376239

  3. Adhesion between peptides/antibodies and breast cancer cells

    NASA Astrophysics Data System (ADS)

    Meng, J.; Paetzell, E.; Bogorad, A.; Soboyejo, W. O.

    2010-06-01

    Atomic force microscopy (AFM) techniques were used to measure the adhesion forces between the receptors on breast cancer cells specific to human luteinizing hormone-releasing hormone (LHRH) peptides and antibodies specific to the EphA2 receptor. The adhesion forces between LHRH-coated AFM tips and human MDA-MB-231 cells (breast cancer cells) were shown to be about five times greater than those between LHRH-coated AFM tips and normal Hs578Bst breast cells. Similarly, those between EphA2 antibody-coated AFM tips and breast cancer cells were over five times greater than those between EphA2 antibody-coated AFM tips and normal breast cells. The results suggest that AFM can be used for the detection of breast cancer cells in biopsies. The implications of the results are also discussed for the early detection and localized treatment of cancer.

  4. Variant antigenic peptide promotes cytotoxic T lymphocyte adhesion to target cells without cytotoxicity

    PubMed Central

    Shotton, David M.; Attaran, Amir

    1998-01-01

    Timelapse video microscopy has been used to record the motility and dynamic interactions between an H-2Db-restricted murine cytotoxic T lymphocyte clone (F5) and Db-transfected L929 mouse fibroblasts (LDb) presenting normal or variant antigenic peptides from human influenza nucleoprotein. F5 cells will kill LDb target cells presenting specific antigen (peptide NP68: ASNENMDAM) after “browsing” their surfaces for between 8 min and many hours. Cell death is characterized by abrupt cellular rounding followed by zeiosis (vigorous “boiling” of the cytoplasm and blebbing of the plasma membrane) for 10–20 min, with subsequent cessation of all activity. Departure of cytotoxic T lymphocytes from unkilled target cells is rare, whereas serial killing is sometimes observed. In the absence of antigenic peptide, cytotoxic T lymphocytes browse target cells for much shorter periods, and readily leave to encounter other targets, while never causing target cell death. Two variant antigenic peptides, differing in nonamer position 7 or 8, also act as antigens, albeit with lower efficiency. A third variant peptide NP34 (ASNENMETM), which differs from NP68 in both positions and yet still binds Db, does not stimulate F5 cytotoxicity. Nevertheless, timelapse video analysis shows that NP34 leads to a significant modification of cell behavior, by up-regulating F5–LDb adhesive interactions. These data extend recent studies showing that partial agonists may elicit a subset of the T cell responses associated with full antigen stimulation, by demonstrating that TCR interaction with variant peptide antigens can trigger target cell adhesion and surface exploration without activating the signaling pathway that results in cytotoxicity. PMID:9861010

  5. The neural cell adhesion molecule (NCAM) heparin binding domain binds to cell surface heparan sulfate proteoglycans.

    PubMed

    Kallapur, S G; Akeson, R A

    1992-12-01

    The neural cell adhesion molecule (NCAM) has been strongly implicated in several aspects of neural development. NCAM mediated adhesion has been proposed to involve a homophilic interaction between NCAMs on adjacent cells. The heparin binding domain (HBD) is an amino acid sequence within NCAM and has been shown to be involved in NCAM mediated adhesion but the relationship of this domain to NCAM segments mediating homophilic adhesion has not been defined. In the present study, a synthetic peptide corresponding to the HBD has been used as a substrate to determine its role in NCAM mediated adhesion. A neural cell line expressing NCAM (B35) and its derived clone which does not express NCAM (B35 clone 3) adhered similarly to plates coated with HBD peptide. A polyclonal antiserum to NCAM inhibited B35 cell-HBD peptide adhesion by only 10%, a value not statistically different from inhibition caused by preimmune serum. Both these experiments suggested no direct NCAM-HBD interactions. To test whether the HBD peptide bound to cell surface heparan sulfate proteoglycans (HSPG), HSPG synthesis was inhibited using beta-D-xyloside. After treatment, B35 cell adhesion to the HBD peptide, but not to control substrates, was significantly decreased. B35 cell adhesion to the HBD peptide could be inhibited by 10(-7) M heparin but not chondroitin sulfate. Preincubation of the substrate (HBD peptide) with heparin caused dramatic reduction of B35 cell-HBD peptide adhesion whereas preincubation of B35 cells with heparin caused only modest reductions in cell-HBD adhesion. Furthermore, inhibition of HSPG sulfation with sodium chlorate also decreased the adhesion of B35 cells to the HBD peptide. These results strongly suggest that, within the assay system, the NCAM HBD does not participate in homophilic interactions but binds to cell surface heparan sulfate proteoglycan. This interaction potentially represents an important mechanism of NCAM adhesion and further supports the view that NCAM has

  6. Epstein–Barr virus LMP1 induces focal adhesions and epithelial cell migration through effects on integrin-α5 and N-cadherin

    PubMed Central

    Wasil, L R; Shair, K H Y

    2015-01-01

    Epstein–Barr virus (EBV) is a γ-herpesvirus associated with human epithelial and B-cell malignancies. The EBV latent membrane protein (LMP) 1 is expressed in nasopharyngeal carcinoma (NPC) and promotes oncogenic intracellular signaling mechanisms. LMP1 also promotes a pro-migratory phenotype through potential effects on cell surface proteins, as expression of LMP1 induces an epithelial–mesenchymal transition (EMT) in epithelial cell lines. In this study, LMP1 was examined for potential effects on cadherin and integrin surface interactions, and assessed for biological effects on adhesion and motility to fibronectin. Expression of LMP1 in the non-tumorigenic epithelial cell line MCF10a induced an EMT-associated cadherin switch. The induced N-cadherin was ligated and localized to the cell surface as determined by triton-solubility and immunofluorescence assays. In addition, LMP1 induced the assembly of focal adhesions (FAs) with increased production of fibronectin in MCF10a and NP460hTERT-immortalized nasopharyngeal cells. Biochemical enrichment of fibronectin-associated proteins indicated that LMP1 selectively promoted the recruitment of integrin-α5 and Src family kinase proteins to FA complexes. Neutralizing antibodies to N-cadherin and integrin-α5, but not integrin-αV, blocked the adhesion and transwell motility of MCF10a cells to fibronectin induced by LMP1. LMP1-induced transwell motility was also decreased by Src inhibition with the PP2 kinase inhibitor and short hairpin RNAs. These studies reveal that LMP1 has multiple mechanisms to promote the adhesive and migratory properties of epithelial cells through induction of fibronectin and modulation of cell surface interactions involving integrin-α5 and N-cadherin, which may contribute to the metastatic potential of NPC. PMID:26479443

  7. Acetylcholinesterase-R increases germ cell apoptosis but enhances sperm motility

    PubMed Central

    Mor, I; Sklan, EH; Podoly, E; Pick, M; Kirschner, M; Yogev, L; Bar-Sheshet Itach, S; Schreiber, L; Geyer, B; Mor, T; Grisaru, D; Soreq, H

    2008-01-01

    Abstract Changes in protein subdomains through alternative splicing often modify protein-protein interactions, altering biological processes. A relevant example is that of the stress-induced up-regulation of the acetylcholinesterase (AChE-R) splice variant, a common response in various tissues. In germ cells of male transgenic TgR mice, AChE-R excess associates with reduced sperm differentiation and sperm counts. To explore the mechanism(s) by which AChE-R up-regulation affects spermatogenesis, we identified AChE-R's protein partners through a yeast two-hybrid screen. In meiotic spermatocytes from TgR mice, we detected AChE-R interaction with the scaffold protein RACK1 and elevated apoptosis. This correlated with reduced scavenging by RACK1 of the pro-apoptotic TAp73, an outcome compatible with the increased apoptosis. In contrast, at later stages in sperm development, AChE-R's interaction with the glycolytic enzyme enolase-α elevates enolase activity. In transfected cells, enforced AChE-R excess increased glucose uptake and adenosine tri-phosphate (ATP) levels. Correspondingly, TgR sperm cells display elevated ATP levels, mitochondrial hyperactivity and increased motility. In human donors' sperm, we found direct association of sperm motility with AChE-R expression. Interchanging interactions with RACK1 and enolase-α may hence enable AChE-R to affect both sperm differentiation and function by participating in independent cellular pathways. PMID:18194455

  8. Investigating differential cell-matrix adhesion by directly comparative single-cell force spectroscopy.

    PubMed

    Dao, Lu; Gonnermann, Carina; Franz, Clemens M

    2013-11-01

    Tissue-embedded cells are often exposed to a complex mixture of extracellular matrix (ECM) molecules, to which they bind with different cell adhesion receptors and affinities. Differential cell adhesion to ECM components is believed to regulate many aspects of tissue function, such as the sorting of specific cell types into different tissue compartments or ECM niches. In turn, aberrant switches in cell adhesion preferences may contribute to cell misplacement, tissue invasion, and metastasis. Methods to determine differential adhesion profiles of single cells are therefore desirable, but established bulk assays usually only test cell population adhesion to a single type of ECM molecule. We have recently demonstrated that atomic force microscopy-based single-cell force spectroscopy (SCFS), performed on bifunctional, microstructured adhesion substrates, provides a useful tool for accurately quantitating differential matrix adhesion of single Chinese hamster ovary cells to laminin and collagen I. Here, we have extended this approach to include additional ECM substrates, such as bifunctional collagen I/collagen IV surfaces, as well as adhesion-passivated control surfaces. We investigate differential single cell adhesion to these substrates and analyze in detail suitable experimental conditions for comparative SCFS, including optimal cell-substrate contact times and the impact of force cycle repetitions on single cell adhesion force statistics. Insight gained through these experiments may help in adapting this technique to other ECM molecules and cell systems, making directly comparative SCFS a versatile tool for comparing receptor-mediated cell adhesion to different matrix molecules in a wide range of biological contexts. PMID:24089365

  9. Polycomb group gene BMI1 controls invasion of medulloblastoma cells and inhibits BMP-regulated cell adhesion

    PubMed Central

    2014-01-01

    Background Medulloblastoma is the most common intracranial childhood malignancy and a genetically heterogeneous disease. Despite recent advances, current therapeutic approaches are still associated with high morbidity and mortality. Recent molecular profiling has suggested the stratification of medulloblastoma from one single disease into four distinct subgroups namely: WNT Group (best prognosis), SHH Group (intermediate prognosis), Group 3 (worst prognosis) and Group 4 (intermediate prognosis). BMI1 is a Polycomb group repressor complex gene overexpressed across medulloblastoma subgroups but most significantly in Group 4 tumours. Bone morphogenetic proteins are morphogens belonging to TGF-β superfamily of growth factors, known to inhibit medulloblastoma cell proliferation and induce apoptosis. Results Here we demonstrate that human medulloblastoma of Group 4 characterised by the greatest overexpression of BMI1, also display deregulation of cell adhesion molecules. We show that BMI1 controls intraparenchymal invasion in a novel xenograft model of human MB of Group 4, while in vitro assays highlight that cell adhesion and motility are controlled by BMI1 in a BMP dependent manner. Conclusions BMI1 controls MB cell migration and invasion through repression of the BMP pathway, raising the possibility that BMI1 could be used as a biomarker to identify groups of patients who may benefit from a treatment with BMP agonists. PMID:24460684

  10. Microfluidic shear devices for quantitative analysis of cell adhesion.

    PubMed

    Lu, Hang; Koo, Lily Y; Wang, Wechung M; Lauffenburger, Douglas A; Griffith, Linda G; Jensen, Klavs F

    2004-09-15

    We describe the design, construction, and characterization of microfluidic devices for studying cell adhesion and cell mechanics. The method offers multiple advantages over previous approaches, including a wide range of distractive forces, high-throughput performance, simplicity in experimental setup and control, and potential for integration with other microanalytic modules. By manipulating the geometry and surface chemistry of the microdevices, we are able to vary the shear force and the biochemistry during an experiment. The dynamics of cell detachment under different conditions can be captured simultaneously using time-lapse videomicroscopy. We demonstrate assessment of cell adhesion to fibronectin-coated substrates as a function of the shear stress or fibronectin concentration in microchannels. Furthermore, a combined perfusion-shear device is designed to maintain cell viability for long-term culture as well as to introduce exogenous reagents for biochemical studies of cell adhesion regulation. In agreement with established literature, we show that fibroblasts cultured in the combined device reduced their adhesion strength to the substrate in response to epidermal growth factor stimulation. PMID:15362881

  11. Motility efficiency and spatiotemporal synchronization in non-metastatic vs. metastatic breast cancer cells

    PubMed Central

    Hermans, Thomas M.; Pilans, Didzis; Huda, Sabil; Fuller, Patrick; Kandere-Grzybowska, Kristiana; Grzybowski, Bartosz A.

    2014-01-01

    Metastatic breast cancer cells move not only more rapidly and persistently than their non-metastatic variants but in doing so use the mechanical work of the cytoskeleton more efficiently. The efficiency of the cell motions is defined for entire cells (rather than parts of the cell membrane) and is related to the work expended in forming membrane protrusions and retractions. This work, in turn, is estimated by integrating the protruded and retracted areas along the entire cell perimeter and is standardized with respect to the net translocation of the cell. A combination of cross-correlation, Granger causality, and morphodynamic profiling analyses is then used to relate the efficiency to the cell membrane dynamics. In metastatic cells, the protrusions and retractions are highly “synchronized” both in space and in time and these cells move efficiently. In contrast, protrusions and retractions formed by non-metastatic cells are not “synchronized” corresponding to low motility efficiencies. Our work provides a link between the kinematics of cell motions and their energetics. It also suggests that spatiotemporal synchronization might be one of the hallmarks of invasiveness of cancerous cells. PMID:24136177

  12. Evidence for heterophilic adhesion of embryonic retinal cells and neuroblastoma cells to substratum-adsorbed NCAM.

    PubMed

    Murray, B A; Jensen, J J

    1992-06-01

    The adhesion of embryonic chicken retinal cells and mouse N2A neuroblastoma cells to purified embryonic chicken retinal NCAM adsorbed on a solid substratum was examined using a quantitative centrifugal adhesion assay. Both cell types adhered to NCAM and the adhesion was specifically inhibited by monovalent anti-NCAM antibody fragments. N2A cell adhesion depended on the amount of NCAM applied to the substratum, was cation independent, and was insensitive to treatment with the cytoskeletal perturbing drugs colchicine and cytochalasin D. These results indicated that the tubulin and actin cytoskeletons were not critically required for adhesion to NCAM and make it unlikely that the cell surface ligand for NCAM is an integrin. Adhesion was however temperature dependent, strengthening greatly after a brief incubation at 37 degrees C. CHO cells transfected with NCAM cDNAs did not adhere specifically to substratum-bound NCAM and pretreatment of N2A cells and retinal cells with anti-NCAM antibodies did not inhibit adhesion to substratum-bound NCAM. These results suggest that a heterophilic interaction between substratum-adsorbed NCAM and a non-NCAM ligand on the surface of the probe cells affects adhesion in this system and support the possibility that heterophilic adhesion may be a function of NCAM in vivo. PMID:1607391

  13. Expression and cell distribution of the intercellular adhesion molecule, vascular cell adhesion molecule, endothelial leukocyte adhesion molecule, and endothelial cell adhesion molecule (CD31) in reactive human lymph nodes and in Hodgkin's disease.

    PubMed Central

    Ruco, L. P.; Pomponi, D.; Pigott, R.; Gearing, A. J.; Baiocchini, A.; Baroni, C. D.

    1992-01-01

    The immunocytochemical expression of intercellular adhesion molecule (ICAM-1), vascular cell adhesion molecule (VCAM-1), endothelial leukocyte adhesion molecule (ELAM-1), endothelial cell adhesion molecule (EndoCAM CD31), and HLA-DR antigens was investigated in sections of 24 reactive lymph nodes and in 15 cases of Hodgkin's disease. ICAM-1 was detected in sinus macrophages, follicular dendritic reticulum cells (FDRCs), interdigitating reticulum cells (IDRCs), epithelioid macrophages, Hodgkin's cells (HCs), and vascular endothelium. ICAM-1 expression was often associated with that of HLA-DR antigens. VCAM-1 was detected in FDRCs, in fibroblast reticulum cells (FRCs), in macrophages, and in rare blood vessels. EndoCAM (CD31) was constitutively expressed in all types of endothelial cells, sinus macrophages, and in epithelioid granulomas. ELAM-1 was selectively expressed by activated endothelial cells of high endothelium venules (HEVs). When expression of the inducible adhesion molecules ICAM-1, VCAM-1 and ELAM-1 was comparatively evaluated in HEVs, it was found that ICAM-1 + HEVs were present in all reactive and HD nodes, whereas ELAM-1 and/or VCAM-1 were expressed only in those pathologic conditions characterized by high levels of interleukin-1/tumor necrosis factor (IL-1/TNF) production, such as granulomatosis and Hodgkin's disease. In Hodgkin's disease, the expression of ELAM-1/VCAM-1 was more pronounced in cases of nodular sclerosis and was associated with a significantly higher content of perivascular neutrophils. Images Figure 1 Figure 2 PMID:1605306

  14. One isoform of Arg/Abl2 tyrosine kinase is nuclear and the other seven cytosolic isoforms differently modulate cell morphology, motility and the cytoskeleton

    SciTech Connect

    Bianchi, Cristina; Torsello, Barbara; Di Stefano, Vitalba; Zipeto, Maria A.; Facchetti, Rita; Bombelli, Silvia; Perego, Roberto A.

    2013-08-01

    The non-receptor tyrosine kinase Abelson related gene (Arg/Abl2) regulates cell migration and morphogenesis by modulating the cytoskeleton. Arg promotes actin-based cell protrusions and spreading, and inhibits cell migration by attenuating stress fiber formation and contractility via activation of the RhoA inhibitor, p190RhoGAP, and by regulating focal adhesion dynamics also via CrkII phosphorylation. Eight full-length Arg isoforms with different N- and C-termini are endogenously expressed in human cells. In this paper, the eight Arg isoforms, subcloned in the pFLAG-CMV2 vector, were transfected in COS-7 cells in order to study their subcellular distribution and role in cell morphology, migration and cytoskeletal modulation. The transfected 1BSCTS Arg isoform has a nuclear distribution and phosphorylates CrkII in the nucleus, whilst the other isoforms are detected in the cytoplasm. The 1BLCTL, 1BSCTL, 1ASCTS isoforms were able to significantly decrease stress fibers, induce cell shrinkage and filopodia-like protrusions with a significant increase in p190RhoGAP phosphorylation. In contrast, 1ALCTL, 1ALCTS, 1ASCTL and 1BLCTS isoforms do not significantly decrease stress fibers and induce the formation of retraction tail-like protrusions. The 1BLCTL and 1ALCTL isoforms have different effects on cell migration and focal adhesions. All these data may open new perspectives to study the mechanisms of cell invasiveness. -Highlights: • Each of the eight Arg isoforms was transfected in COS-7 cells. • Only the 1BSCTS Arg isoform has a nuclear distribution in transfected cells. • The cytoplasmic isoforms and F-actin colocalize cortically and in cell protrusions. • Arg isoforms differently phosphorylate p190RhoGAP and CrkII. • Arg isoforms differently modulate stress fibers, cell protrusions and motility.

  15. Tyrosine kinase activity, cytoskeletal organization, and motility in human vascular endothelial cells.

    PubMed Central

    Romer, L H; McLean, N; Turner, C E; Burridge, K

    1994-01-01

    Tyrosine phosphorylation of cytoskeletal proteins occurs during integrin-mediated cell adhesion to extracellular matrix proteins. We have investigated the role of tyrosine phosphorylation in the migration and initial spreading of human umbilical vein endothelial cells (HUVEC). Elevated phosphotyrosine concentrations were noted in the focal adhesions of HUVEC migrating into wounds. Anti-phosphotyrosine Western blots of extracts of wounded HUVEC monolayers demonstrated increased phosphorylation at 120-130 kDa when compared with extracts of intact monolayers. The pp125FAK immunoprecipitated from wounded monolayers exhibited increased kinase activity as compared to pp125FAK from intact monolayers. The time to wound closure in HUVEC monolayers was doubled by tyrphostin AG 213 treatment. The same concentration of AG 213 interfered with HUVEC focal adhesion and stress fiber formation. AG 213 inhibited adhesion-associated tyrosine phosphorylation of pp125FAK in HUVEC. Tyrphostins AG 213 and AG 808 inhibited pp125FAK activity in in vitro kinase assays. pp125FAK immunoprecipitates from HUVEC treated with both of these inhibitors also had kinase activity in vitro that was below levels seen in untreated HUVEC. These findings suggest that tyrosine phosphorylation of cytoskeletal proteins may be important in HUVEC spreading and migration and that pp125FAK may mediate phosphotyrosine formation during these processes. Images PMID:8049526

  16. Structural requirements for neural cell adhesion molecule-heparin interaction.

    PubMed Central

    Reyes, A A; Akeson, R; Brezina, L; Cole, G J

    1990-01-01

    Two biological domains have been identified in the amino terminal region of the neural cell adhesion molecule (NCAM): a homophilic-binding domain, responsible for NCAM-NCAM interactions, and a heparin-binding domain (HBD). It is not known whether these two domains exist as distinct structural entities in the NCAM molecule. To approach this question, we have further defined the relationship between NCAM-heparin binding and cell adhesion. A putative HBD consisting of two clusters of basic amino acid residues located close to each other in the linear amino acid sequence of NCAM has previously been identified. Synthetic peptides corresponding to this domain were shown to bind both heparin and retinal cells. Here we report the construction of NCAM cDNAs with targeted mutations in the HBD. Mouse fibroblast cells transfected with the mutant cDNAs express NCAM polypeptides with altered HBD (NCAM-102 and NCAM-104) or deleted HBD (HBD-) at levels similar to those of wild-type NCAM. Mutant NCAM polypeptides purified from transfected cell lines have substantially reduced binding to heparin and fail to promote chick retinal cell attachment. Furthermore, whereas a synthetic peptide that contains both basic amino acid clusters inhibits retinal-cell adhesion to NCAM-coated dishes, synthetic peptides in which either one of the two basic regions is altered to contain only neutral amino acids do not inhibit this adhesion. These results confirm that this region of the NCAM polypeptide does indeed mediate not only the large majority of NCAM's affinity for heparin but also a significant portion of the cell-adhesion-mediating capability of NCAM. Images PMID:2078567

  17. Cell adhesion: The effect of a surprising cohesive force

    NASA Astrophysics Data System (ADS)

    Vasseur, H.

    2009-10-01

    When an experimentalist or a biological mechanism applies an external force onto a cell chemically sticking to its substrate, a reacting “suction” force, due to the slow penetration of the surrounding fluid between the cell and the substrate, opposes to the dissociation. This force can overcome other known adhesive forces when the process is sufficiently violent (typically 105pN ). Its maximal contribution to the total adhesive energy of the cell can then be estimated to 2×10-3J/m2 . The physical origin of this effect is quite simple and it may be compared to that leaning a “suction cup” against a bathroom wall. We address the consequences of this effect on (i) the separation energy, (ii) the motion of the fluid surrounding the cell, and more especially on the pumping of the fluid by moving cells, and (iii) the inhibition of cell motion.

  18. Bacterial adhesion to uroepithelial cells: a morphologic study.

    PubMed

    Marrie, T J; Lam, J; Costerton, J W

    1980-08-01

    Urethral and midstream urine samples from healthy women and from patients with urinary tract infections (UTI) were examined by electron microscopy. Urethral urine samples from healthy subjects contained sparsely and densely colonized uroepithelial cells. The latter had morphologically heterogeneous bacteria adherent to each other and to the epithelial cell by a ruthenium red-positive fibrous matrix, which was present on the surface of all bacteria examined. Urethral urine samples from patients with UTI often had two distinct microcolonies of morphologically similar bacteria adherent to the same uroepithelial cell. Midstream urine samples from these patients contained large microcolonies of morphologically identical bacteria. Urine from patients with catheter-associated infections contained few uroepithelial cells and two distinct varieties of bacterial microcolonies--one of intact homogeneous cells and another of a mixture of damaged and intact bacteria. These in vivo observations indicate that the bacterial surface matrix participates in bacterial adhesion to uroepithelial cells and in bacteria-bacteria adhesion. PMID:6774033

  19. Cucurbitacin I Inhibits Cell Motility by Indirectly Interfering with Actin Dynamics

    PubMed Central

    Knecht, David A.; LaFleur, Rebecca A.; Kahsai, Alem W.; Argueta, Christian E.; Beshir, Anwar B.; Fenteany, Gabriel

    2010-01-01

    Background Cucurbitacins are plant natural products that inhibit activation of the Janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) pathway by an unknown mechanism. They are also known to cause changes in the organization of the actin cytoskeleton. Methodology/Principal Findings We show that cucurbitacin I potently inhibits the migration of Madin-Darby canine kidney (MDCK) cell sheets during wound closure, as well as the random motility of B16-F1 mouse melanoma cells, but has no effect on movement of Dictyostelium discoideum amoebae. Upon treatment of MDCK or B16-F1 cells with cucurbitacin I, there is a very rapid cessation of motility and gradual accumulation of filamentous actin aggregates. The cellular effect of the compound is similar to that observed when cells are treated with the actin filament-stabilizing agent jasplakinolide. However, we found that, unlike jasplakinolide or phallacidin, cucurbitacin I does not directly stabilize actin filaments. In in vitro actin depolymerization experiments, cucurbitacin I had no effect on the rate of actin filament disassembly at the nanomolar concentrations that inhibit cell migration. At elevated concentrations, the depolymerization rate was also unaffected, although there was a delay in the initiation of depolymerization. Therefore, cucurbitacin I targets some factor involved in cellular actin dynamics other than actin itself. Two candidate proteins that play roles in actin depolymerization are the actin-severing proteins cofilin and gelsolin. Cucurbitacin I possesses electrophilic reactivity that may lead to chemical modification of its target protein, as suggested by structure-activity relationship data. However, mass spectrometry revealed no evidence for modification of purified cofilin or gelsolin by cucurbitacin I. Conclusions/Significance Cucurbitacin I results in accumulation of actin filaments in cells by a unique indirect mechanism. Furthermore, the proximal target of

  20. CD151-α3β1 integrin complexes are prognostic markers of glioblastoma and cooperate with EGFR to drive tumor cell motility and invasion.

    PubMed

    Zhou, Pengcheng; Erfani, Sonia; Liu, Zeyi; Jia, Changhe; Chen, Yecang; Xu, Bingwei; Deng, Xinyu; Alfáro, Jose E; Chen, Li; Napier, Dana; Lu, Michael; Huang, Jian-An; Liu, Chunming; Thibault, Olivier; Segal, Rosalind; Zhou, Binhua P; Kyprianou, Natasha; Horbinski, Craig; Yang, Xiuwei H

    2015-10-01

    Glioblastoma, one of the most aggressive forms of brain cancer, is featured by high tumor cell motility and invasiveness, which not only fuel tumor infiltration, but also enable escape from surgical or other clinical interventions. Thus, better understanding of how these malignant traits are controlled will be key to the discovery of novel biomarkers and therapies against this deadly disease. Tetraspanin CD151 and its associated α3β1 integrin have been implicated in facilitating tumor progression across multiple cancer types. How these adhesion molecules are involved in the progression of glioblastoma, however, remains largely unclear. Here, we examined an in-house tissue microarray-based cohort of 96 patient biopsies and TCGA dataset to evaluate the clinical significance of CD151 and α3β1 integrin. Functional and signaling analyses were also conducted to understand how these molecules promote the aggressiveness of glioblastoma at molecular and cellular levels. Results from our analyses showed that CD151 and α3 integrin were significantly elevated in glioblastomas at both protein and mRNA levels, and exhibited strong inverse correlation with patient survival (p < 0.006). These adhesion molecules also formed tight protein complexes and synergized with EGF/EGFR to accelerate tumor cell motility and invasion. Furthermore, disruption of such complexes enhanced the survival of tumor-bearing mice in a xenograft model, and impaired activation of FAK and small GTPases. Also, knockdown- or pharmacological agent-based attenuation of EGFR, FAK or Graf (ARHGAP26)/small GTPase-mediated pathways markedly mitigated the aggressiveness of glioblastoma cells. Collectively, our findings provide clinical, molecular and cellular evidence of CD151-α3β1 integrin complexes as promising prognostic biomarkers and therapeutic targets for glioblastoma. PMID:26377974

  1. CD151-α3β1 integrin complexes are prognostic markers of glioblastoma and cooperate with EGFR to drive tumor cell motility and invasion

    PubMed Central

    Xu, Bingwei; Deng, Xinyu; Alfáro, Jose E.; Chen, Li; Napier, Dana; Lu, Michael; Huang, Jian-An; Liu, Chunming; Thibault, Olivier; Segal, Rosalind; Zhou, Binhua P.; Kyprianou, Natasha; Horbinski, Craig; Yang, Xiuwei H.

    2015-01-01

    Glioblastoma, one of the most aggressive forms of brain cancer, is featured by high tumor cell motility and invasiveness, which not only fuel tumor infiltration, but also enable escape from surgical or other clinical interventions. Thus, better understanding of how these malignant traits are controlled will be key to the discovery of novel biomarkers and therapies against this deadly disease. Tetraspanin CD151 and its associated α3β1 integrin have been implicated in facilitating tumor progression across multiple cancer types. How these adhesion molecules are involved in the progression of glioblastoma, however, remains largely unclear. Here, we examined an in-house tissue microarray-based cohort of 96 patient biopsies and TCGA dataset to evaluate the clinical significance of CD151 and α3β1 integrin. Functional and signaling analyses were also conducted to understand how these molecules promote the aggressiveness of glioblastoma at molecular and cellular levels. Results from our analyses showed that CD151 and α3 integrin were significantly elevated in glioblastomas at both protein and mRNA levels, and exhibited strong inverse correlation with patient survival (p < 0.006). These adhesion molecules also formed tight protein complexes and synergized with EGF/EGFR to accelerate tumor cell motility and invasion. Furthermore, disruption of such complexes enhanced the survival of tumor-bearing mice in a xenograft model, and impaired activation of FAK and small GTPases. Also, knockdown- or pharmacological agent-based attenuation of EGFR, FAK or Graf (ARHGAP26)/small GTPase-mediated pathways markedly mitigated the aggressiveness of glioblastoma cells. Collectively, our findings provide clinical, molecular and cellular evidence of CD151-α3β1 integrin complexes as promising prognostic biomarkers and therapeutic targets for glioblastoma. PMID:26377974

  2. BRE facilitates skeletal muscle regeneration by promoting satellite cell motility and differentiation

    PubMed Central

    Xiao, Lihai; Lee, Kenneth Ka Ho

    2016-01-01

    ABSTRACT The function of the Bre gene in satellite cells was investigated during skeletal muscle regeneration. The tibialis anterior leg muscle was experimentally injured in Bre knockout mutant (BRE-KO) mice. It was established that the accompanying muscle regeneration was impaired as compared with their normal wild-type counterparts (BRE-WT). There were significantly fewer pax7+ satellite cells and smaller newly formed myofibers present in the injury sites of BRE-KO mice. Bre was required for satellite cell fusion and myofiber formation. The cell fusion index and average length of newly-formed BRE-KO myofibers were found to be significantly reduced as compared with BRE-WT myofibers. It is well established that satellite cells are highly invasive which confers on them the homing ability to reach the muscle injury sites. Hence, we tracked the migratory behavior of these cells using time-lapse microscopy. Image analysis revealed no difference in directionality of movement between BRE-KO and BRE-WT satellite cells but there was a significant decrease in the velocity of BRE-KO cell movement. Moreover, chemotactic migration assays indicated that BRE-KO satellite cells were significantly less responsive to chemoattractant SDF-1α than BRE-WT satellite cells. We also established that BRE normally protects CXCR4 from SDF-1α-induced degradation. In sum, BRE facilitates skeletal muscle regeneration by enhancing satellite cell motility, homing and fusion. PMID:26740569

  3. Cytoplasmic Tail Regulates the Intercellular Adhesion Function of the Epithelial Cell Adhesion Molecule

    PubMed Central

    Balzar, Maarten; Bakker, Hellen A. M.; Briaire-de-Bruijn, Inge H.; Fleuren, Gert Jan; Warnaar, Sven O.; Litvinov, Sergey V.

    1998-01-01

    Ep-CAM, an epithelium-specific cell-cell adhesion molecule (CAM) not structurally related to the major families of CAMs, contains a cytoplasmic domain of 26 amino acids. The chemical disruption of the actin microfilaments, but not of the microtubuli or intermediate filaments, affected the localization of Ep-CAM at the cell-cell boundaries, suggesting that the molecule interacts with the actin-based cytoskeleton. Mutated forms of Ep-CAM were generated with the cytoplasmic domain truncated at various lengths. All of the mutants were transported to the cell surface in the transfectants; however, the mutant lacking the complete cytoplasmic domain was not able to localize to the cell-cell boundaries, in contrast to mutants with partial deletions. Both the disruption of the actin microfilaments and a complete truncation of the cytoplasmic tail strongly affected the ability of Ep-CAM to mediate aggregation of L cells. The capability of direct aggregation was reduced for the partially truncated mutants but remained cytochalasin D sensitive. The tail truncation did not affect the ability of the transfectants to adhere to solid-phase-adsorbed Ep-CAM, suggesting that the ability to form stable adhesions and not the ligand specificity of the molecule was affected by the truncation. The formation of intercellular adhesions mediated by Ep-CAM induced a redistribution to the cell-cell boundaries of α-actinin, but not of vinculin, talin, filamin, spectrin, or catenins. Coprecipitation demonstrated direct association of Ep-CAM with α-actinin. Binding of α-actinin to purified mutated and wild-type Ep-CAMs and to peptides representing different domains of the cytoplasmic tail of Ep-CAM demonstrates two binding sites for α-actinin at positions 289 to 296 and 304 to 314 of the amino acid sequence. The results demonstrate that the cytoplasmic domain of Ep-CAM regulates the adhesion function of the molecule through interaction with the actin cytoskeleton via α-actinin. PMID:9671492

  4. Cytoplasmic tail regulates the intercellular adhesion function of the epithelial cell adhesion molecule.

    PubMed

    Balzar, M; Bakker, H A; Briaire-de-Bruijn, I H; Fleuren, G J; Warnaar, S O; Litvinov, S V

    1998-08-01

    Ep-CAM, an epithelium-specific cell-cell adhesion molecule (CAM) not structurally related to the major families of CAMs, contains a cytoplasmic domain of 26 amino acids. The chemical disruption of the actin microfilaments, but not of the microtubuli or intermediate filaments, affected the localization of Ep-CAM at the cell-cell boundaries, suggesting that the molecule interacts with the actin-based cytoskeleton. Mutated forms of Ep-CAM were generated with the cytoplasmic domain truncated at various lengths. All of the mutants were transported to the cell surface in the transfectants; however, the mutant lacking the complete cytoplasmic domain was not able to localize to the cell-cell boundaries, in contrast to mutants with partial deletions. Both the disruption of the actin microfilaments and a complete truncation of the cytoplasmic tail strongly affected the ability of Ep-CAM to mediate aggregation of L cells. The capability of direct aggregation was reduced for the partially truncated mutants but remained cytochalasin D sensitive. The tail truncation did not affect the ability of the transfectants to adhere to solid-phase-adsorbed Ep-CAM, suggesting that the ability to form stable adhesions and not the ligand specificity of the molecule was affected by the truncation. The formation of intercellular adhesions mediated by Ep-CAM induced a redistribution to the cell-cell boundaries of alpha-actinin, but not of vinculin, talin, filamin, spectrin, or catenins. Coprecipitation demonstrated direct association of Ep-CAM with alpha-actinin. Binding of alpha-actinin to purified mutated and wild-type Ep-CAMs and to peptides representing different domains of the cytoplasmic tail of Ep-CAM demonstrates two binding sites for alpha-actinin at positions 289 to 296 and 304 to 314 of the amino acid sequence. The results demonstrate that the cytoplasmic domain of Ep-CAM regulates the adhesion function of the molecule through interaction with the actin cytoskeleton via alpha

  5. Epac Activation Regulates Human Mesenchymal Stem Cells Migration and Adhesion.

    PubMed

    Yu, Jiao-Le; Deng, Ruixia; Chung, Sookja K; Chan, Godfrey Chi-Fung

    2016-04-01

    How to enhance the homing of human mesenchymal stem cells (hMSCs) to the target tissues remains a clinical challenge nowadays. To overcome this barrier, the mechanism responsible for the hMSCs migration and engraftment has to be defined. Currently, the exact mechanism involved in migration and adhesion of hMSCs remains unknown. Exchange protein directly activated by cAMP (Epac), a novel protein discovered in cAMP signaling pathway, may have a potential role in regulating cells adhesion and migration by triggering the downstream Rap family signaling cascades. However, the exact role of Epac in cells homing is elusive. Our study evaluated the role of Epac in the homing of hMSCs. We confirmed that hMSCs expressed functional Epac and its activation enhanced the migration and adhesion of hMSCs significantly. The Epac activation was further found to be contributed directly to the chemotactic responses induced by stromal cell derived factor-1 (SDF-1) which is a known chemokine in regulating hMSCs homing. These findings suggested Epac is connected to the SDF-1 signaling cascades. In conclusion, our study revealed that Epac plays a role in hMSCs homing by promoting adhesion and migration. Appropriate manipulation of Epac may enhance the homing of hMSCs and facilitate their future clinical applications. Stem Cells 2016;34:948-959. PMID:26727165

  6. Tumor metastatic promoter ABCE1 interacts with the cytoskeleton protein actin and increases cell motility.

    PubMed

    Han, Xu; Tian, Ye; Tian, Dali

    2016-06-01

    ABCE1, a member of the ATP-binding cassette (ABC) family, is a candidate tumor metastatic promoter in lung cancer. Overexpression of ABCE1 is correlated with aggressive growth and metastasis in lung cancer cells. However, the exact mechanism remains unclear. In the present study, GST pull-down assay provided evidence of the possible interaction between ABCE1 and β-actin using GST-ABCE1 as a bait protein. Co-immunoprecipitation manifested ABCE1 formed complexes with β-actin in vivo. ABCE1 overexpression significantly increased the migration of lung cancer cells which may be attributed to the promotion of F-actin rearrangements. Taken together, these data suggest that overexpression of ABCE1 produces an obvious effect on the motility of lung cancer cells through cytoskeleton rearrangement. PMID:27109616

  7. Four-dimensional motility tracking of biological cells by digital holographic microscopy

    PubMed Central

    Yu, Xiao; Hong, Jisoo; Liu, Changgeng; Cross, Michael; Haynie, Donald T.; Kim, Myung K.

    2014-01-01

    Abstract. Three-dimensional profiling and tracking by digital holography microscopy (DHM) provide label-free and quantitative analysis of the characteristics and dynamic processes of objects, since DHM can record real-time data for microscale objects and produce a single hologram containing all the information about their three-dimensional structures. Here, we have utilized DHM to visualize suspended microspheres and microfibers in three dimensions, and record the four-dimensional trajectories of free-swimming cells in the absence of mechanical focus adjustment. The displacement of microfibers due to interactions with cells in three spatial dimensions has been measured as a function of time at subsecond and micrometer levels in a direct and straightforward manner. It has thus been shown that DHM is a highly efficient and versatile means for quantitative tracking and analysis of cell motility. PMID:24699632

  8. Wnt Signaling in Cell Motility and Invasion: Drawing Parallels between Development and Cancer.

    PubMed

    Sedgwick, Alanna E; D'Souza-Schorey, Crislyn

    2016-01-01

    The importance of canonical and non-canonical Wnt signal transduction cascades in embryonic development and tissue homeostasis is well recognized. The aberrant activation of these pathways in the adult leads to abnormal cellular behaviors, and tumor progression is frequently a consequence. Here we discuss recent findings and analogies between Wnt signaling in developmental processes and tumor progression, with a particular focus on cell motility and matrix invasion and highlight the roles of the ARF (ADP-Ribosylation Factor) and Rho-family small GTP-binding proteins. Wnt-regulated signal transduction from cell surface receptors, signaling endosomes and/or extracellular vesicles has the potential to profoundly influence cell movement, matrix degradation and paracrine signaling in both development and disease. PMID:27589803

  9. Calmodulin-dependent protein kinases mediate calcium-induced slow motility of mammalian outer hair cells.

    PubMed

    Puschner, B; Schacht, J

    1997-08-01

    Cochlear outer hair cells in vitro respond to elevation of intracellular calcium with slow shape changes over seconds to minutes ('slow motility'). This process is blocked by general calmodulin antagonists suggesting the participation of calcium/calmodulin-dependent enzymatic reactions. The present study proposes a mechanism for these reactions. Length changes of outer hair cells isolated from the guinea pig cochlea were induced by exposure to the calcium ionophore ionomycin. ATP levels remained unaffected by this treatment ruling out depletion of ATP (by activation of calcium-dependent ATPases) as a cause of the observed shape changes. Involvement of protein kinases was suggested by the inhibition of shape changes by K252a, a broad-spectrum inhibitor of protein kinase activity. Furthermore, the inhibitors ML-7 and ML-9 blocked the shape changes at concentrations compatible with inhibition of myosin light chain kinase (MLCK). KN-62, an inhibitor of Ca2+/calmodulin-dependent protein kinase II (CaMKII), also attenuated the length changes. Inhibitors with selectivity for cyclic nucleotide-dependent protein kinases (H-89, staurosporine) were tested to assess potential additional contributions by such enzymes. The dose dependence of their action supported the notion that the most likely mechanism of slow motility involves phosphorylation reactions catalyzed by MLCK or CaMKII or both. PMID:9282907

  10. No Correlates for Somatic Motility in Freeze-Fractured Hair-Cell Membranes of Lizards and Birds

    NASA Astrophysics Data System (ADS)

    Köppl, C.; Forge, A.; Manley, G. A.

    2003-02-01

    It is not known whether active processes in mammals and non-mammals are due to the same underlying mechanism. To address this, we studied the size and density of particles in hair-cell membranes in mammals, in a lizard, the Tokay gecko, and in a bird, the barn owl. We surmised that if the prominent particles described in mammalian outer-hair-cell membranes are responsible for cochlear motility, a similar occurrence in non-mammalian hair cells would argue for similar mechanisms. Particle densities differed, however, substantially from those of mammals, suggesting that non-mammals have no membrane-based motility.

  11. Adhesion of Annexin 7 Deficient Erythrocytes to Endothelial Cells

    PubMed Central

    Abed, Majed; Balasaheb, Siraskar; Towhid, Syeda Tasneem; Daniel, Christoph; Amann, Kerstin; Lang, Florian

    2013-01-01

    Annexin 7 deficiency has previously been shown to foster suicidal death of erythrocytes or eryptosis, which is triggered by increase of intracellular Ca2+ concentration ([Ca2+]i) and characterized by cell shrinkage and cell membrane scrambling with subsequent phosphatidylserine exposure at the cell surface. Eryptosis following increase of [Ca2+]i by Ca2+ ionophore ionomycin, osmotic shock or energy depletion was more pronounced in erythrocytes from annexinA7-deficient mice (anxA7−/−) than in erythrocytes from wild type mice (anxA7+/+). As phosphatidylserine exposure is considered to mediate adhesion of erythrocytes to the vascular wall, the present study explored adhesion of erythrocytes from anx7−/− and anx7+/+-mice following increase of [Ca2+]i by Ca2+ ionophore ionomycin (1 µM for 30 min), hyperosmotic shock (addition of 550 mM sucrose for 2 hours) or energy depletion (removal of glucose for 12 hours). Phosphatidylserine exposing erythrocytes were identified by annexin V binding, cell volume estimated from forward scatter in FACS analysis and adhesion to human umbilical vein endothelial cells (HUVEC) utilizing a flow chamber. As a result, ionomycin, sucrose addition and glucose removal all triggered phosphatidylserine-exposure, decreased forward scatter and enhanced adhesion of erythrocytes to human umbilical vein endothelial cells (HUVEC), effects significantly more pronounced in anx7−/− than in anx7+/+-erythrocytes. Following ischemia, morphological renal injury was significantly higher in anx7−/− than in anx7+/+-mice. The present observations demonstrate that enhanced eryptosis of annexin7 deficient cells is paralleled by increased adhesion of erythrocytes to the vascular wall, an effect, which may impact on microcirculation during ischemia. PMID:23437197

  12. Piperine inhibits the growth and motility of triple-negative breast cancer cells.

    PubMed

    Greenshields, Anna L; Doucette, Carolyn D; Sutton, Kimberly M; Madera, Laurence; Annan, Henry; Yaffe, Paul B; Knickle, Allison F; Dong, Zhongmin; Hoskin, David W

    2015-02-01

    Piperine, an alkaloid from black pepper, is reported to have anticancer activities. In this study, we investigated the effect of piperine on the growth and motility of triple-negative breast cancer (TNBC) cells. Piperine inhibited the in vitro growth of TNBC cells, as well as hormone-dependent breast cancer cells, without affecting normal mammary epithelial cell growth. Exposure to piperine decreased the percentage of TNBC cells in the G2 phase of the cell cycle. In addition, G1- and G2-associated protein expression was decreased and p21(Waf1/Cip1) expression was increased in piperine-treated TNBC cells. Piperine also inhibited survival-promoting Akt activation in TNBC cells and caused caspase-dependent apoptosis via the mitochondrial pathway. Interestingly, combined treatment with piperine and γ radiation was more cytotoxic for TNBC cells than γ radiation alone. The in vitro migration of piperine-treated TNBC cells was impaired and expression of matrix metalloproteinase-2 and -9 mRNA was decreased, suggesting an antimetastatic effect by piperine. Finally, intratumoral administration of piperine inhibited the growth of TNBC xenografts in immune-deficient mice. Taken together, these findings suggest that piperine may be useful in the treatment of TNBC. PMID:25444919

  13. CD34 promotes satellite cell motility and entry into proliferation to facilitate efficient skeletal muscle regeneration.

    PubMed

    Alfaro, Leslie Ann So; Dick, Sarah A; Siegel, Ashley L; Anonuevo, Adam S; McNagny, Kelly M; Megeney, Lynn A; Cornelison, D D W; Rossi, Fabio M V

    2011-12-01

    Expression of the cell surface sialomucin CD34 is common to many adult stem cell types, including muscle satellite cells. However, no clear stem cell or regeneration-related phenotype has ever been reported in mice lacking CD34, and its function on these cells remains poorly understood. Here, we assess the functional role of CD34 on satellite cell-mediated muscle regeneration. We show that Cd34(-/-) mice, which have no obvious developmental phenotype, display a defect in muscle regeneration when challenged with either acute or chronic muscle injury. This regenerative defect is caused by impaired entry into proliferation and delayed myogenic progression. Consistent with the reported antiadhesive function of CD34, knockout satellite cells also show decreased motility along their host myofiber. Altogether, our results identify a role for CD34 in the poorly understood early steps of satellite cell activation and provide the first evidence that beyond being a stem cell marker, CD34 may play an important function in modulating stem cell activity. PMID:21997891

  14. Approaches to myosin modelling in a two-phase flow model for cell motility

    NASA Astrophysics Data System (ADS)

    Kimpton, L. S.; Whiteley, J. P.; Waters, S. L.; Oliver, J. M.

    2016-04-01

    A wide range of biological processes rely on the ability of cells to move through their environment. Mathematical models have been developed to improve our understanding of how cells achieve motion. Here we develop models that explicitly track the cell's distribution of myosin within a two-phase flow framework. Myosin is a small motor protein which is important for contracting the cell's actin cytoskeleton and enabling cell motion. The two phases represent the actin network and the cytosol in the cell. We start from a fairly general description of myosin kinetics, advection and diffusion in the two-phase flow framework, then identify a number of sub-limits of the model that may be relevant in practice, two of which we investigate further via linear stability analyses and numerical simulations. We demonstrate that myosin-driven contraction of the actin network destabilizes a stationary steady state leading to cell motion, but that rapid diffusion of myosin and rapid unbinding of myosin from the actin network are stabilizing. We use numerical simulation to investigate travelling-wave solutions relevant to a steadily gliding cell and we consider a reduction of the model in which the cell adheres strongly to the substrate on which it is crawling. This work demonstrates that a number of existing models for the effect of myosin on cell motility can be understood as different sub-limits of our two-phase flow model.

  15. Effects of zinc oxide nanoparticles on Kupffer cell phagosomal motility, bacterial clearance, and liver function

    PubMed Central

    Watson, Christa Y; Molina, Ramon M; Louzada, Andressa; Murdaugh, Kimberly M; Donaghey, Thomas C; Brain, Joseph D

    2015-01-01

    Background Zinc oxide engineered nanoparticles (ZnO ENPs) have potential as nanomedicines due to their inherent properties. Studies have described their pulmonary impact, but less is known about the consequences of ZnO ENP interactions with the liver. This study was designed to describe the effects of ZnO ENPs on the liver and Kupffer cells after intravenous (IV) administration. Materials and methods First, pharmacokinetic studies were conducted to determine the tissue distribution of neutron-activated 65ZnO ENPs post-IV injection in Wistar Han rats. Then, a noninvasive in vivo method to assess Kupffer cell phagosomal motility was employed using ferromagnetic iron particles and magnetometry. We also examined whether prior IV injection of ZnO ENPs altered Kupffer cell bactericidal activity on circulating Pseudomonas aeruginosa. Serum and liver tissues were collected to assess liver-injury biomarkers and histological changes, respectively. Results We found that the liver was the major site of initial uptake of 65ZnO ENPs. There was a time-dependent decrease in tissue levels of 65Zn in all organs examined, refecting particle dissolution. In vivo magnetometry showed a time-dependent and transient reduction in Kupffer cell phagosomal motility. Animals challenged with P. aeruginosa 24 hours post-ZnO ENP injection showed an initial (30 minutes) delay in vascular bacterial clearance. However, by 4 hours, IV-injected bacteria were cleared from the blood, liver, spleen, lungs, and kidneys. Seven days post-ZnO ENP injection, creatine phosphokinase and aspartate aminotransferase levels in serum were significantly increased. Histological evidence of hepatocyte damage and marginated neutrophils were observed in the liver. Conclusion Administration of ZnO ENPs transiently inhibited Kupffer cell phagosomal motility and later induced hepatocyte injury, but did not alter bacterial clearance from the blood or killing in the liver, spleen, lungs, or kidneys. Our data show that

  16. CD146 expression is associated with a poor prognosis in human breast tumors and with enhanced motility in breast cancer cell lines

    PubMed Central

    Zabouo, Gwladys; Imbert, Anne-Marie; Jacquemier, Jocelyne; Finetti, Pascal; Moreau, Thomas; Esterni, Benjamin; Birnbaum, Daniel; Bertucci, François; Chabannon, Christian

    2009-01-01

    Introduction Metastasis is a complex process involving loss of adhesion, migration, invasion and proliferation of cancer cells. Cell adhesion molecules play a pivotal role in this phenomenon by regulating cell–cell and cell–matrix interactions. CD146 (MCAM) is associated with an advanced tumor stage in melanoma, prostate cancer and ovarian cancer. Studies of CD146 expression and function in breast cancer remain scarce except for a report concluding that CD146 could act as a tumor suppressor in breast carcinogenesis. Methods To resolve these apparent discrepancies in the role of CD146 in tumor cells, we looked at the association of CD146 expression with histoclinical features in human primary breast cancers using DNA and tissue microarrays. By flow cytometry, we characterized CD146 expression on different breast cancer cell lines. Using siRNA or shRNA technology, we studied functional consequences of CD146 downmodulation of MDA-MB-231 cells in migration assays. Wild-type, mock-transfected and downmodulated transfected cells were profiled using whole-genome DNA microarrays to identify genes whose expression was modified by CD146 downregulation. Results Microarray studies revealed the association of higher levels of CD146 with histoclinical features that belong to the basal cluster of human tumors. Expression of CD146 protein on epithelial cells was detected in a small subset of cancers with histoclinical features of basal tumors. CD146+ cell lines displayed a mesenchymal phenotype. Downmodulation of CD146 expression in the MDA-MB-231 cell line resulted in downmodulation of vimentin, as well as of a set of genes that include both genes associated with a poor prognosis in a variety of cancers and genes known to promote cell motility. In vitro functional assays revealed decreased migration abilities associated with decreased CD146 expression. Conclusions In addition to its expression in the vascular compartment, CD146 is expressed on a subset of epithelial cells in

  17. Understanding dynamic changes in live cell adhesion with neutron reflectometry

    DOE PAGESBeta

    Junghans, Ann; Waltman, Mary Jo; Smith, Hillary L.; Pocivavsek, Luka; Zebda, Noureddine; Birukov, Konstantin; Viapiano, Mariano; Majewski, Jaroslaw

    2014-12-10

    In this study, neutron reflectometry (NR) was used to examine various live cells' adhesion to quartz substrates under different environmental conditions, including flow stress. To the best of our knowledge, these measurements represent the first successful visualization and quantization of the interface between live cells and a substrate with sub-nanometer resolution. In our first experiments, we examined live mouse fibroblast cells as opposed to past experiments using supported lipids, proteins, or peptide layers with no associated cells. We continued the NR studies of cell adhesion by investigating endothelial monolayers and glioblastoma cells under dynamic flow conditions. We demonstrated that neutronmore » reflectometry is a powerful tool to study the strength of cellular layer adhesion in living tissues, which is a key factor in understanding the physiology of cell interactions and conditions leading to abnormal or disease circumstances. Continuative measurements, such as investigating changes in tumor cell — surface contact of various glioblastomas, could impact advancements in tumor treatments. In principle, this can help us to identify changes that correlate with tumor invasiveness. Pursuit of these studies can have significant medical impact on the understanding of complex biological problems and their effective treatment, e.g. for the development of targeted anti-invasive therapies.« less

  18. Understanding dynamic changes in live cell adhesion with neutron reflectometry

    NASA Astrophysics Data System (ADS)

    Junghans, Ann; Waltman, Mary Jo; Smith, Hillary L.; Pocivavsek, Luka; Zebda, Noureddine; Birukov, Konstantin; Viapiano, Mariano; Majewski, Jaroslaw

    2014-12-01

    Neutron reflectometry (NR) was used to examine various live cells' adhesion to quartz substrates under different environmental conditions, including flow stress. To the best of our knowledge, these measurements represent the first successful visualization and quantization of the interface between live cells and a substrate with sub-nanometer resolution. In our first experiments, we examined live mouse fibroblast cells as opposed to past experiments using supported lipids, proteins, or peptide layers with no associated cells. We continued the NR studies of cell adhesion by investigating endothelial monolayers and glioblastoma cells under dynamic flow conditions. We demonstrated that neutron reflectometry is a powerful tool to study the strength of cellular layer adhesion in living tissues, which is a key factor in understanding the physiology of cell interactions and conditions leading to abnormal or disease circumstances. Continuative measurements, such as investigating changes in tumor cell — surface contact of various glioblastomas, could impact advancements in tumor treatments. In principle, this can help us to identify changes that correlate with tumor invasiveness. Pursuit of these studies can have significant medical impact on the understanding of complex biological problems and their effective treatment, e.g. for the development of targeted anti-invasive therapies.

  19. Understanding dynamic changes in live cell adhesion with neutron reflectometry

    SciTech Connect

    Junghans, Ann; Waltman, Mary Jo; Smith, Hillary L.; Pocivavsek, Luka; Zebda, Noureddine; Birukov, Konstantin; Viapiano, Mariano; Majewski, Jaroslaw

    2014-12-10

    In this study, neutron reflectometry (NR) was used to examine various live cells' adhesion to quartz substrates under different environmental conditions, including flow stress. To the best of our knowledge, these measurements represent the first successful visualization and quantization of the interface between live cells and a substrate with sub-nanometer resolution. In our first experiments, we examined live mouse fibroblast cells as opposed to past experiments using supported lipids, proteins, or peptide layers with no associated cells. We continued the NR studies of cell adhesion by investigating endothelial monolayers and glioblastoma cells under dynamic flow conditions. We demonstrated that neutron reflectometry is a powerful tool to study the strength of cellular layer adhesion in living tissues, which is a key factor in understanding the physiology of cell interactions and conditions leading to abnormal or disease circumstances. Continuative measurements, such as investigating changes in tumor cell — surface contact of various glioblastomas, could impact advancements in tumor treatments. In principle, this can help us to identify changes that correlate with tumor invasiveness. Pursuit of these studies can have significant medical impact on the understanding of complex biological problems and their effective treatment, e.g. for the development of targeted anti-invasive therapies.

  20. How to let go: pectin and plant cell adhesion

    PubMed Central

    Daher, Firas Bou; Braybrook, Siobhan A.

    2015-01-01

    Plant cells do not, in general, migrate. They maintain a fixed position relative to their neighbors, intimately linked through growth and differentiation. The mediator of this connection, the pectin-rich middle lamella, is deposited during cell division and maintained throughout the cell’s life to protect tissue integrity. The maintenance of adhesion requires cell wall modification and is dependent on the actin cytoskeleton. There are developmental processes that require cell separation, such as organ abscission, dehiscence, and ripening. In these instances, the pectin-rich middle lamella must be actively altered to allow cell separation, a process which also requires cell wall modification. In this review, we will focus on the role of pectin and its modification in cell adhesion and separation. Recent insights gained in pectin gel mechanics will be discussed in relation to existing knowledge of pectin chemistry as it relates to cell adhesion. As a whole, we hope to begin defining the physical mechanisms behind a cells’ ability to hang on, and how it lets go. PMID:26236321

  1. Epidermal Growth Factor-Induced Tumor Cell Invasion and Metastasis Initiated by Dephosphorylation and Downregulation of Focal Adhesion Kinase

    PubMed Central

    Lu, Zhimin; Jiang, Guoqiang; Blume-Jensen, Peter; Hunter, Tony

    2001-01-01

    Upregulated epidermal growth factor (EGF) receptor (EGFR) expression and EGFR-induced signaling have been correlated with progression to invasion and metastasis in a wide variety of carcinomas, but the mechanism behind this is not well understood. We show here that, in various human carcinoma cells that overexpress EGFR, EGF treatment induced rapid tyrosine dephosphorylation of focal adhesion kinase (FAK) associated with downregulation of its kinase activity. The downregulation of FAK activity was both required and sufficient for EGF-induced refractile morphological changes, detachment of cells from the extracellular matrix, and increased tumor cell motility, invasion, and metastasis. Tumor cells with downregulated FAK activity became less adherent to the extracellular matrix. However, once cells started reattaching, FAK activity was restored by activated integrin signaling. Moreover, this process of readhesion and spreading could not be abrogated by further EGF stimulation. Interruption of transforming growth factor alpha-EGFR autocrine regulation with an EGFR tyrosine kinase inhibitor led to a substantial increase in FAK tyrosine phosphorylation and inhibition of tumor cell invasion in vitro. Consistent with this, FAK tyrosine phosphorylation was reduced in cells from tumors growing in transplanted, athymic, nude mice, which have an intact autocrine regulation of the EGFR. We suggest that the dynamic regulation of FAK activity, initiated by EGF-induced downregulation of FAK leading to cell detachment and increased motility and invasion, followed by integrin-dependent reactivation during readhesion, plays a role in EGF-associated tumor invasion and metastasis. PMID:11359909

  2. The Evolutionary Origin of Epithelial Cell-Cell Adhesion Mechanisms

    PubMed Central

    Miller, Phillip W.; Clarke, Donald N.; Weis, William I.; Lowe, Christopher J.; Nelson, W. James

    2014-01-01

    SUMMARY A simple epithelium forms a barrier between the outside and the inside of an organism, and is the first organized multicellular tissue found in evolution. We examine the relationship between the evolution of epithelia and specialized cell-cell adhesion proteins comprising the classical cadherin/β-catenin/α-catenin complex (CCC). A review of the divergent functional properties of the CCC in metazoans and non-metazoans, and an updated phylogenetic coverage of the CCC using recent genomic data reveal: 1) The core CCC likely originated before the last common ancestor of unikonts and their closest bikont sister taxa. 2) Formation of the CCC may have constrained sequence evolution of the classical cadherin cytoplasmic domain and β-catenin in metazoa. 3) The α-catenin binding domain in β-catenin appears to be the favored mutation site for disrupting β-catenin function in the CCC. 4) The ancestral function of the α/β-catenin heterodimer appears to be an actin-binding module. In some metazoan groups, more complex functions of α-catenin were gained by sequence divergence in the non-actin binding (N-, M-) domains. 5) Allosteric regulation of α-catenin, rather than loss of function mutations, may have evolved for more complex regulation of the actin cytoskeleton. PMID:24210433

  3. Involvement of S100-related calcium-binding protein pEL98 (or mts1) in cell motility and tumor cell invasion.

    PubMed

    Takenaga, K; Nakamura, Y; Endo, H; Sakiyama, S

    1994-08-01

    We examined the relationship between cell motility and the expressions of pEL98 (mts1) mRNA and protein in various murine normal and transformed cells. The expression of pEL98 (mts1) in v-Ha-ras-transformed NIH3T3 cells and in normal rat kidney cells transformed by either v-Ha-ras or v-src was increased over that in the corresponding parental cells at both mRNA and protein levels. The expression in normal rat fibroblasts (3Y1) transformed by v-Ha-ras was also increased compared with that in 3Y1 cells. However, the expression of pEL98 (mts1) in 3Y1 cells transformed by v-src was increased in one clone (src 3Y1-K), but decreased in another clone (src 3Y1-H). The expression level of pEL98 (mts1) correlated well with cell motility, which was examined by measuring cell tracks by phagokinesis. In order to test direct involvement of the pEL98 (mts1) protein in cell motility, src 3Y1-H cells that showed low cell motility were transfected with pEL98 cDNA. The transfectants expressing large amounts of the pEL98 protein showed significantly higher cell motility than src 3Y1-H cells. The expression of pEL98 (mts1) was also found to be correlated with motile and invasive abilities in various clones derived from Lewis lung carcinoma. These results suggest that the pEL98 (mts1) protein plays a role in regulating cell motility and tumor cell invasiveness. PMID:7928629

  4. Computational Estimates of Membrane Flow and Tension Gradient in Motile Cells

    PubMed Central

    Fogelson, Ben; Mogilner, Alex

    2014-01-01

    All parts of motile cells, including the plasma membrane, have to translocate in the direction of locomotion. Both directed intracellular membrane transport coupled with polarized endo- and exocytosis and fluid flow in the plane of the plasma membrane can contribute to this overall plasma membrane translocation. It remains unclear how strong a force is required to generate this flow. We numerically solve Stokes equations for the viscous membrane flow across a flat plasma membrane surface in the presence of transmembrane proteins attached to the cytoskeleton and find the membrane tension gradient associated with this flow. This gradient is sensitive to the size and density of the transmembrane proteins attached to the cytoskeleton and can become significant enough to slow down cell movement. We estimate the influence of intracellular membrane transport and actin growth and contraction on the tension gradient, and discuss possible ‘tank tread’ flow at ventral and dorsal surfaces. PMID:24465414

  5. Microgel Film Dynamics Modulate Cell Adhesion Behavior

    PubMed Central

    Saxena, Shalini; Spears, Mark W.; Yoshida, Hiroaki; Gaulding, Jeffrey C.; García, Andrés J.; Lyon, L. Andrew

    2014-01-01

    A material’s mechanical properties greatly control cell behavior at the cell-substrate interface. In this work, we demonstrate that microgel multilayers have unique elastic and viscoelastic-like properties that can be modulated to produce morphological changes in fibroblasts cultured on the film. Protein adsorption is also examined and the data are contrasted with the number of cells adhered. The dynamic interaction of cell and substrate is only partially explained by conventional understanding of surface-receptor interactions and substrate elasticity. Viscoelasticity, a mechanical property not often considered, plays a significant role at cellular length and time scales for microgel films. PMID:24634694

  6. Endoglin regulates mural cell adhesion in the circulatory system.

    PubMed

    Rossi, Elisa; Smadja, David M; Boscolo, Elisa; Langa, Carmen; Arevalo, Miguel A; Pericacho, Miguel; Gamella-Pozuelo, Luis; Kauskot, Alexandre; Botella, Luisa M; Gaussem, Pascale; Bischoff, Joyce; Lopez-Novoa, José M; Bernabeu, Carmelo

    2016-04-01

    The circulatory system is walled off by different cell types, including vascular mural cells and podocytes. The interaction and interplay between endothelial cells (ECs) and mural cells, such as vascular smooth muscle cells or pericytes, play a pivotal role in vascular biology. Endoglin is an RGD-containing counter-receptor for β1 integrins and is highly expressed by ECs during angiogenesis. We find that the adhesion between vascular ECs and mural cells is enhanced by integrin activators and inhibited upon suppression of membrane endoglin or β1-integrin, as well as by addition of soluble endoglin (SolEng), anti-integrin α5β1 antibody or an RGD peptide. Analysis of different endoglin mutants, allowed the mapping of the endoglin RGD motif as involved in the adhesion process. In Eng (+/-) mice, a model for hereditary hemorrhagic telangectasia type 1, endoglin haploinsufficiency induces a pericyte-dependent increase in vascular permeability. Also, transgenic mice overexpressing SolEng, an animal model for preeclampsia, show podocyturia, suggesting that SolEng is responsible for podocytes detachment from glomerular capillaries. These results suggest a critical role for endoglin in integrin-mediated adhesion of mural cells and provide a better understanding on the mechanisms of vessel maturation in normal physiology as well as in pathologies such as preeclampsia or hereditary hemorrhagic telangiectasia. PMID:26646071

  7. Intracellular photoactivation of caged cGMP induces myosin II and actin responses in motile cells.

    PubMed

    Pfannes, Eva K B; Anielski, Alexander; Gerhardt, Matthias; Beta, Carsten

    2013-12-01

    Cyclic GMP (cGMP) is a ubiquitous second messenger in eukaryotic cells. It is assumed to regulate the association of myosin II with the cytoskeleton of motile cells. When cells of the social amoeba Dictyostelium discoideum are exposed to chemoattractants or to increased osmotic stress, intracellular cGMP levels rise, preceding the accumulation of myosin II in the cell cortex. To directly investigate the impact of intracellular cGMP on cytoskeletal dynamics in a living cell, we released cGMP inside the cell by laser-induced photo-cleavage of a caged precursor. With this approach, we could directly show in a live cell experiment that an increase in intracellular cGMP indeed induces myosin II to accumulate in the cortex. Unexpectedly, we observed for the first time that also the amount of filamentous actin in the cell cortex increases upon a rise in the cGMP concentration, independently of cAMP receptor activation and signaling. We discuss our results in the light of recent work on the cGMP signaling pathway and suggest possible links between cGMP signaling and the actin system. PMID:24136144

  8. Heparanase promotes myeloma progression by inducing mesenchymal features and motility of myeloma cells

    PubMed Central

    Trotter, Timothy N.; Peker, Deniz; Regal, Kellie M.; Javed, Amjad; Suva, Larry J.; Yang, Yang

    2016-01-01

    Bone dissemination and bone disease occur in approximately 80% of patients with multiple myeloma (MM) and are a major cause of patient mortality. We previously demonstrated that MM cell-derived heparanase (HPSE) is a major driver of MM dissemination to and progression in new bone sites. However the mechanism(s) by which HPSE promotes MM progression remains unclear. In the present study, we investigated the involvement of mesenchymal features in HPSE-promoted MM progression in bone. Using a combination of molecular, biochemical, cellular, and in vivo approaches, we demonstrated that (1) HPSE enhanced the expression of mesenchymal markers in both MM and vascular endothelial cells; (2) HPSE expression in patient myeloma cells positively correlated with the expression of the mesenchymal markers vimentin and fibronectin. Additional mechanistic studies revealed that the enhanced mesenchymal-like phenotype induced by HPSE in MM cells is due, at least in part, to the stimulation of the ERK signaling pathway. Finally, knockdown of vimentin in HPSE expressing MM cells resulted in significantly attenuated MM cell dissemination and tumor growth in vivo. Collectively, these data demonstrate that the mesenchymal features induced by HPSE in MM cells contribute to enhanced tumor cell motility and bone-dissemination. PMID:26849235

  9. Targeting the MAP kinase pathway in astrocytoma cells using a recombinant anthrax lethal toxin as a way to inhibit cell motility and invasion.

    PubMed

    Al-Dimassi, Saleh; Salloum, Gilbert; Saykali, Bechara; Khoury, Oula; Liu, Shihui; Leppla, Stephen H; Abi-Habib, Ralph; El-Sibai, Mirvat

    2016-05-01

    Malignant astrocytomas are highly invasive into adjacent and distant regions of the normal brain. Understanding and targeting cancer cell invasion is an important therapeutic approach. Cell invasion is a complex process that replies on many signaling pathways including the mitogen-activated protein (MAP) kinase (MAPK). In many cell lines, the use of MAPK-targeted drugs proved to be a potential method to inhibit cancer cell motility. In the present study, we use a recombinant anthrax lethal toxin (LeTx), which selectively inhibits the MAPK pathway, in order to target invasion. LeTx proved ineffective on cell survival in astrocytoma (as well as normal cells). However, astrocytoma cells that were treated with LeTx showed a significant decrease in cell motility as seen by wound healing as well as random 2D motility in serum. The cells also showed a decrease in invasion across a collagen matrix. The effect of LeTx on cell migration was mediated though the deregulation of Rho GTPases, which play a role in cell motility. Finally, the effect of LeTx on cell migration and Rho GTPases was mimicked by the inhibition of the MAPK pathway. In this study, we describe for the first time the effect of the LeTx on cancer cell motility and invasion not cell survival making it a potentially selective brain tumor invasion inhibitor. PMID:26984023

  10. Cell adhesion defines the topology of endocytosis and signaling

    PubMed Central

    Grossier, Jean-Philippe; Xouri, Georgia; Goud, Bruno; Schauer, Kristine

    2014-01-01

    Preferred sites of endocytosis have been observed in various cell types, but whether they occur randomly or are linked to cellular cues is debated. Here, we quantified the sites of endocytosis of transferrin (Tfn) and epidermal growth factor (EGF) in cells whose adhesion geometry was defined by micropatterns. 3D probabilistic density maps revealed that Tfn was enriched in adhesive sites during uptake, whereas EGF endocytosis was restricted to the dorsal cellular surface. This spatial separation was not due to distributions of corresponding receptors but was regulated by uptake mechanisms. Asymmetric uptake of Tfn resulted from the enrichment of clathrin and adaptor protein 2 at adhesive areas. Asymmetry in EGF uptake was strongly dependent on the actin cytoskeleton and led to asymmetry in EGF receptor activation. Mild alteration of actin dynamics abolished asymmetry in EGF uptake and decreased EGF-induced downstream signaling, suggesting that cellular adhesion cues influence signal propagation. We propose that restriction of endocytosis at distinct sites allows cells to sense their environment in an “outside-in” mechanism. PMID:24366944

  11. Topographic cell instructive patterns to control cell adhesion, polarization and migration

    PubMed Central

    Ventre, Maurizio; Natale, Carlo Fortunato; Rianna, Carmela; Netti, Paolo Antonio

    2014-01-01

    Topographic patterns are known to affect cellular processes such as adhesion, migration and differentiation. However, the optimal way to deliver topographic signals to provide cells with precise instructions has not been defined yet. In this work, we hypothesize that topographic patterns may be able to control the sensing and adhesion machinery of cells when their interval features are tuned on the characteristic lengths of filopodial probing and focal adhesions (FAs). Features separated by distance beyond the length of filopodia cannot be readily perceived; therefore, the formation of new adhesions is discouraged. If, however, topographic features are separated by a distance within the reach of filopodia extension, cells can establish contact between adjacent topographic islands. In the latter case, cell adhesion and polarization rely upon the growth of FAs occurring on a specific length scale that depends on the chemical properties of the surface. Topographic patterns and chemical properties may interfere with the growth of FAs, thus making adhesions unstable. To test this hypothesis, we fabricated different micropatterned surfaces displaying feature dimensions and adhesive properties able to interfere with the filopodial sensing and the adhesion maturation, selectively. Our data demonstrate that it is possible to exert a potent control on cell adhesion, elongation and migration by tuning topographic features’ dimensions and surface chemistry. PMID:25253035

  12. A Review of Cell Adhesion Studies for Biomedical and Biological Applications.

    PubMed

    Khalili, Amelia Ahmad; Ahmad, Mohd Ridzuan

    2015-01-01

    Cell adhesion is essential in cell communication and regulation, and is of fundamental importance in the development and maintenance of tissues. The mechanical interactions between a cell and its extracellular matrix (ECM) can influence and control cell behavior and function. The essential function of cell adhesion has created tremendous interests in developing methods for measuring and studying cell adhesion properties. The study of cell adhesion could be categorized into cell adhesion attachment and detachment events. The study of cell adhesion has been widely explored via both events for many important purposes in cellular biology, biomedical, and engineering fields. Cell adhesion attachment and detachment events could be further grouped into the cell population and single cell approach. Various techniques to measure cell adhesion have been applied to many fields of study in order to gain understanding of cell signaling pathways, biomaterial studies for implantable sensors, artificial bone and tooth replacement, the development of tissue-on-a-chip and organ-on-a-chip in tissue engineering, the effects of biochemical treatments and environmental stimuli to the cell adhesion, the potential of drug treatments, cancer metastasis study, and the determination of the adhesion properties of normal and cancerous cells. This review discussed the overview of the available methods to study cell adhesion through attachment and detachment events. PMID:26251901

  13. A Review of Cell Adhesion Studies for Biomedical and Biological Applications

    PubMed Central

    Ahmad Khalili, Amelia; Ahmad, Mohd Ridzuan

    2015-01-01

    Cell adhesion is essential in cell communication and regulation, and is of fundamental importance in the development and maintenance of tissues. The mechanical interactions between a cell and its extracellular matrix (ECM) can influence and control cell behavior and function. The essential function of cell adhesion has created tremendous interests in developing methods for measuring and studying cell adhesion properties. The study of cell adhesion could be categorized into cell adhesion attachment and detachment events. The study of cell adhesion has been widely explored via both events for many important purposes in cellular biology, biomedical, and engineering fields. Cell adhesion attachment and detachment events could be further grouped into the cell population and single cell approach. Various techniques to measure cell adhesion have been applied to many fields of study in order to gain understanding of cell signaling pathways, biomaterial studies for implantable sensors, artificial bone and tooth replacement, the development of tissue-on-a-chip and organ-on-a-chip in tissue engineering, the effects of biochemical treatments and environmental stimuli to the cell adhesion, the potential of drug treatments, cancer metastasis study, and the determination of the adhesion properties of normal and cancerous cells. This review discussed the overview of the available methods to study cell adhesion through attachment and detachment events. PMID:26251901

  14. Dose Dependent Side Effect of Superparamagnetic Iron Oxide Nanoparticle Labeling on Cell Motility in Two Fetal Stem Cell Populations

    PubMed Central

    Diana, Valentina; Bossolasco, Patrizia; Moscatelli, Davide; Silani, Vincenzo; Cova, Lidia

    2013-01-01

    Multipotent stem cells (SCs) could substitute damaged cells and also rescue degeneration through the secretion of trophic factors able to activate the endogenous SC compartment. Therefore, fetal SCs, characterized by high proliferation rate and devoid of ethical concern, appear promising candidate, particularly for the treatment of neurodegenerative diseases. Super Paramagnetic Iron Oxide nanoparticles (SPIOn), routinely used for pre-clinical cell imaging and already approved for clinical practice, allow tracking of transplanted SCs and characterization of their fate within the host tissue, when combined with Magnetic Resonance Imaging (MRI). In this work we investigated how SPIOn could influence cell migration after internalization in two fetal SC populations: human amniotic fluid and chorial villi SCs were labeled with SPIOn and their motility was evaluated. We found that SPIOn loading significantly reduced SC movements without increasing production of Reactive Oxygen Species (ROS). Moreover, motility impairment was directly proportional to the amount of loaded SPIOn while a chemoattractant-induced recovery was obtained by increasing serum levels. Interestingly, the migration rate of SPIOn labeled cells was also significantly influenced by a degenerative surrounding. In conclusion, this work highlights how SPIOn labeling affects SC motility in vitro in a dose-dependent manner, shedding the light on an important parameter for the creation of clinical protocols. Establishment of an optimal SPIOn dose that enables both a good visualization of grafted cells by MRI and the physiological migration rate is a main step in order to maximize the effects of SC therapy in both animal models of neurodegeneration and clinical studies. PMID:24244310

  15. Structural and functional analysis of cell adhesion and nuclear envelope nano-topography in cell death

    PubMed Central

    Kwon, Hyuk-Kwon; Lee, Jae-Hyeok; Shin, Hyeon-Jun; Kim, Jae-Ho; Choi, Sangdun

    2015-01-01

    The cell death mechanisms of necrosis and apoptosis generate biochemical and morphological changes in different manners. However, the changes that occur in cell adhesion and nuclear envelope (NE) topography, during necrosis and apoptosis, are not yet fully understood. Here, we show the different alterations in cell adhesion function, as well as the topographical changes occurring to the NE, during the necrotic and apoptotic cell death process, using the xCELLigence system and atomic force microscopy (AFM). Studies using xCELLigence technology and AFM have shown that necrotic cell death induced the expansion of the cell adhesion area, but did not affect the speed of cell adhesion. Necrotic nuclei showed a round shape and presence of nuclear pore complexes (NPCs). Moreover, we found that the process of necrosis in combination with apoptosis (termed nepoptosis here) resulted in the reduction of the cell adhesion area and cell adhesion speed through the activation of caspases. Our findings showed, for the first time, a successful characterization of NE topography and cell adhesion during necrosis and apoptosis, which may be of importance for the understanding of cell death and might aid the design of future drug delivery methods for anti-cancer therapies. PMID:26490051

  16. Structural and functional analysis of cell adhesion and nuclear envelope nano-topography in cell death.

    PubMed

    Kwon, Hyuk-Kwon; Lee, Jae-Hyeok; Shin, Hyeon-Jun; Kim, Jae-Ho; Choi, Sangdun

    2015-01-01

    The cell death mechanisms of necrosis and apoptosis generate biochemical and morphological changes in different manners. However, the changes that occur in cell adhesion and nuclear envelope (NE) topography, during necrosis and apoptosis, are not yet fully understood. Here, we show the different alterations in cell adhesion function, as well as the topographical changes occurring to the NE, during the necrotic and apoptotic cell death process, using the xCELLigence system and atomic force microscopy (AFM). Studies using xCELLigence technology and AFM have shown that necrotic cell death induced the expansion of the cell adhesion area, but did not affect the speed of cell adhesion. Necrotic nuclei showed a round shape and presence of nuclear pore complexes (NPCs). Moreover, we found that the process of necrosis in combination with apoptosis (termed nepoptosis here) resulted in the reduction of the cell adhesion area and cell adhesion speed through the activation of caspases. Our findings showed, for the first time, a successful characterization of NE topography and cell adhesion during necrosis and apoptosis, which may be of importance for the understanding of cell death and might aid the design of future drug delivery methods for anti-cancer therapies. PMID:26490051

  17. Regulation of T cell motility in vitro and in vivo by LPA and LPA2.

    PubMed

    Knowlden, Sara A; Capece, Tara; Popovic, Milan; Chapman, Timothy J; Rezaee, Fariba; Kim, Minsoo; Georas, Steve N

    2014-01-01

    Lysophosphatidic acid (LPA) and the LPA-generating enzyme autotaxin (ATX) have been implicated in lymphocyte trafficking and the regulation of lymphocyte entry into lymph nodes. High local concentrations of LPA are thought to be present in lymph node high endothelial venules, suggesting a direct influence of LPA on cell migration. However, little is known about the mechanism of action of LPA, and more work is needed to define the expression and function of the six known G protein-coupled receptors (LPA 1-6) in T cells. We studied the effects of 18∶1 and 16∶0 LPA on naïve CD4+ T cell migration and show that LPA induces CD4+ T cell chemorepulsion in a Transwell system, and also improves the quality of non-directed migration on ICAM-1 and CCL21 coated plates. Using intravital two-photon microscopy, lpa2-/- CD4+ T cells display a striking defect in early migratory behavior at HEVs and in lymph nodes. However, later homeostatic recirculation and LPA-directed migration in vitro were unaffected by loss of lpa2. Taken together, these data highlight a previously unsuspected and non-redundant role for LPA2 in intranodal T cell motility, and suggest that specific functions of LPA may be manipulated by targeting T cell LPA receptors. PMID:25003200

  18. Signaling networks and cell motility: a computational approach using a phase field description.

    PubMed

    Marth, Wieland; Voigt, Axel

    2014-07-01

    The processes of protrusion and retraction during cell movement are driven by the turnover and reorganization of the actin cytoskeleton. Within a reaction-diffusion model which combines processes along the cell membrane with processes within the cytoplasm a Turing type instability is used to form the necessary polarity to distinguish between cell front and rear and to initiate the formation of different organizational arrays within the cytoplasm leading to protrusion and retraction. A simplified biochemical network model for the activation of GTPase which accounts for the different dimensionality of the cell membrane and the cytoplasm is used for this purpose and combined with a classical Helfrich type model to account for bending and stiffness effects of the cell membrane. In addition streaming within the cytoplasm and the extracellular matrix is taken into account. Combining these phenomena allows to simulate the dynamics of cells and to reproduce the primary phenomenology of cell motility. The coupled model is formulated within a phase field approach and solved using adaptive finite elements. PMID:23835784

  19. FAP-α (Fibroblast activation protein-α) is involved in the control of human breast cancer cell line growth and motility via the FAK pathway

    PubMed Central

    2014-01-01

    Background Fibroblast Activation Protein alpha (FAP-α) or seprase is an integral membrane serine peptidase. Previous work has not satisfactorily explained both the suppression and promotion effects that have been observed in cancer. The purpose of this work was to investigate the role of FAP-α in human breast cancer. Expression of FAP-α was characterized in primary tumour samples and in cell lines, along with the effects of FAP-α expression on in vitro growth, invasion, attachment and migration. Furthermore the potential interaction of FAP-α with other signalling pathways was investigated. Results FAP-α was significantly increased in patients with poor outcome and survival. In vitro results showed that breast cancer cells over expressing FAP-α had increased growth ability and impaired migratory ability. The growth of MDA-MB-231 cells and the adhesion and invasion ability of both MCF-7 cells and MDA-MB-231 cells were not dramatically influenced by FAP-α expression. Over-expression of FAP-α resulted in a reduction of phosphorylated focal adhesion kinase (FAK) level in both cells cultured in normal media and serum-free media. An inhibitor to FAK restored the reduced motility ability of both MCF-7exp cells and MDA-MB-231exp cells and prevented the change in phosphorylated FAK levels. However, inhibitors to PI3K, ERK, PLCϒ, NWASP, ARP2/3, and ROCK had no influence this. Conclusions FAP-α in significantly associated with poor outcome in patients with breast cancer. In vitro, FAP-α promotes proliferation and inhibits migration of breast cancer cells, potentially by regulating the FAK pathway. These results suggest FAP-α could be a target for future therapies. PMID:24885257

  20. LINKIN, a new transmembrane protein necessary for cell adhesion

    PubMed Central

    Kato, Mihoko; Chou, Tsui-Fen; Yu, Collin Z; DeModena, John; Sternberg, Paul W

    2014-01-01

    In epithelial collective migration, leader and follower cells migrate while maintaining cell–cell adhesion and tissue polarity. We have identified a conserved protein and interactors required for maintaining cell adhesion during a simple collective migration in the developing C. elegans male gonad. LINKIN is a previously uncharacterized, transmembrane protein conserved throughout Metazoa. We identified seven atypical FG–GAP domains in the extracellular domain, which potentially folds into a β-propeller structure resembling the α-integrin ligand-binding domain. C. elegans LNKN-1 localizes to the plasma membrane of all gonadal cells, with apical and lateral bias. We identified the LINKIN interactors RUVBL1, RUVBL2, and α-tubulin by using SILAC mass spectrometry on human HEK 293T cells and testing candidates for lnkn-1-like function in C. elegans male gonad. We propose that LINKIN promotes adhesion between neighboring cells through its extracellular domain and regulates microtubule dynamics through RUVBL proteins at its intracellular domain. DOI: http://dx.doi.org/10.7554/eLife.04449.001 PMID:25437307

  1. Understanding dynamic changes in live cell adhesion with neutron reflectometry

    NASA Astrophysics Data System (ADS)

    Junghans, Ann

    Understanding the structure and functionality of biological systems on a nanometer-resolution and short temporal scales is important for solving complex biological problems, developing innovative treatment, and advancing the design of highly functionalized biomimetic materials. For example, adhesion of cells to an underlying substrate plays a crucial role in physiology and disease development, and has been investigated with great interest for several decades. In the talk, we would like to highlight recent advances in utilizing neutron scattering to study bio-related structures in dynamic conditions (e . g . under the shear flow) including in-situ investigations of the interfacial properties of living cells. The strength of neutron reflectometry is its non-pertubative nature, the ability to probe buried interfaces with nanometer resolution and its sensitivity to light elements like hydrogen and carbon. That allows us to study details of cell - substrate interfaces that are not accessible with any other standard techniques. We studied the adhesion of human brain tumor cells (U251) to quartz substrates and their responses to the external mechanical forces. Such cells are isolated within the central nervous system which makes them difficult to reach with conventional therapies and therefore making them highly invasive. Our results reveal changes in the thickness and composition of the adhesion layer (a layer between the cell lipid membrane and the quartz substrate), largely composed of hyaluronic acid and associated proteoglycans, when the cells were subjected to shear stress. Further studies will allow us to determine more conditions triggering changes in the composition of the bio-material in the adhesion layer. This, in turn, can help to identify changes that correlate with tumor invasiveness, which can have significant medical impact for the development of targeted anti-invasive therapies.

  2. Interplay between type IV pili activity and exopolysaccharides secretion controls motility patterns in single cells of Myxococcus xanthus

    PubMed Central

    Hu, Wei; Gibiansky, Maxsim L.; Wang, Jing; Wang, Chuandong; Lux, Renate; Li, Yuezhong; Wong, Gerard C. L.; Shi, Wenyuan

    2016-01-01

    Myxococcus xanthus performs coordinated social motility of cell groups through the extension and retraction of type IV pili (TFP) on solid surfaces, which requires both TFP and exopolysaccharides (EPS). By submerging cells in a liquid medium containing 1% methylcellulose, M. xanthus TFP-driven motility was induced in isolated cells and independently of EPS. We measured and analyzed the movements of cells using community tracking algorithms, which combine single-cell resolution with statistics from large sample populations. Cells without significant multi-cellular social interactions have surprisingly complex behaviors: EPS− cells exhibited a pronounced increase in the tendency to stand vertically and moved with qualitatively different characteristics than other cells. A decrease in the EPS secretion of cells correlates with a higher instantaneous velocity, but with lower directional persistence in trajectories. Moreover, EPS− cells do not adhere to the surface as strongly as wild-type and EPS overproducing cells, and display a greater tendency to have large deviations between the direction of movement and the cell axis, with cell velocity showing only minimal dependence on the direction of movement. The emerging picture is that EPS does not simply provide rheological resistance to a single mechanism but rather that the availability of EPS impacts motility pattern. PMID:26821939

  3. Physics of cell adhesion: some lessons from cell-mimetic systems

    PubMed Central

    Sackmann, Erich; Smith, Ana-Sunčana

    2014-01-01

    Cell adhesion is a paradigm of the ubiquitous interplay of cell signalling, modulation of material properties and biological functions of cells. It is controlled by competition of short range attractive forces, medium range repellant forces and the elastic stresses associated with local and global deformation of the composite cell envelopes. We review the basic physical rules governing the physics of cell adhesion learned by studying cell-mimetic systems and demonstrate the importance of these rules in the context of cellular systems. We review how adhesion induced micro-domains couple to the intracellular actin and microtubule networks allowing cells to generate strong forces with a minimum of attractive cell adhesion molecules (CAMs) and to manipulate other cells through filopodia over micrometer distances. The adhesion strength can be adapted to external force fluctuations within seconds by varying the density of attractive and repellant CAMs through exocytosis and endocytosis or protease-mediated dismantling of the CAM–cytoskeleton link. Adhesion domains form local end global biochemical reaction centres enabling the control of enzymes. Actin–microtubule crosstalk at adhesion foci facilitates the mechanical stabilization of polarized cell shapes. Axon growth in tissue is guided by attractive and repulsive clues controlled by antagonistic signalling pathways. PMID:24651316

  4. Vimentin contributes to epithelial-mesenchymal transition cancer cell mechanics by mediating cytoskeletal organization and focal adhesion maturation

    PubMed Central

    Liu, Ching-Yi; Lin, Hsi-Hui; Tang, Ming-Jer; Wang, Yang-Kao

    2015-01-01

    Modulations of cytoskeletal organization and focal adhesion turnover correlate to tumorigenesis and epithelial-mesenchymal transition (EMT), the latter process accompanied by the loss of epithelial markers and the gain of mesenchymal markers (e.g., vimentin). Clinical microarray results demonstrated that increased levels of vimentin mRNA after chemotherapy correlated to a poor prognosis of breast cancer patients. We hypothesized that vimentin mediated the reorganization of cytoskeletons to maintain the mechanical integrity in EMT cancer cells. By using knockdown strategy, the results showed reduced cell proliferation, impaired wound healing, loss of directional migration, and increased large membrane extension in MDA-MB 231 cells. Vimentin depletion also induced reorganization of cytoskeletons and reduced focal adhesions, which resulted in impaired mechanical strength because of reduced cell stiffness and contractile force. In addition, overexpressing vimentin in MCF7 cells increased cell stiffness, elevated cell motility and directional migration, reoriented microtubule polarity, and increased EMT phenotypes due to the increased β1-integrin and the loss of junction protein E-cadherin. The EMT-related transcription factor slug was also mediated by vimentin. The current study demonstrated that vimentin serves as a regulator to maintain intracellular mechanical homeostasis by mediating cytoskeleton architecture and the balance of cell force generation in EMT cancer cells. PMID:25965826

  5. Modeling keratinocyte wound healing dynamics: Cell-cell adhesion promotes sustained collective migration.

    PubMed

    Nardini, John T; Chapnick, Douglas A; Liu, Xuedong; Bortz, David M

    2016-07-01

    The in vitro migration of keratinocyte cell sheets displays behavioral and biochemical similarities to the in vivo wound healing response of keratinocytes in animal model systems. In both cases, ligand-dependent Epidermal Growth Factor Receptor (EGFR) activation is sufficient to elicit collective cell migration into the wound. Previous mathematical modeling studies of in vitro wound healing assays assume that physical connections between cells have a hindering effect on cell migration, but biological literature suggests a more complicated story. By combining mathematical modeling and experimental observations of collectively migrating sheets of keratinocytes, we investigate the role of cell-cell adhesion during in vitro keratinocyte wound healing assays. We develop and compare two nonlinear diffusion models of the wound healing process in which cell-cell adhesion either hinders or promotes migration. Both models can accurately fit the leading edge propagation of cell sheets during wound healing when using a time-dependent rate of cell-cell adhesion strength. The model that assumes a positive role of cell-cell adhesion on migration, however, is robust to changes in the leading edge definition and yields a qualitatively accurate density profile. Using RNAi for the critical adherens junction protein, α-catenin, we demonstrate that cell sheets with wild type cell-cell adhesion expression maintain migration into the wound longer than cell sheets with decreased cell-cell adhesion expression, which fails to exhibit collective migration. Our modeling and experimental data thus suggest that cell-cell adhesion promotes sustained migration as cells pull neighboring cells into the wound during wound healing. PMID:27105673

  6. Mechanotransduction at focal adhesions: integrating cytoskeletal mechanics in migrating cells

    PubMed Central

    Kuo, Jean-Cheng

    2013-01-01

    Focal adhesions (FAs) are complex plasma membrane-associated macromolecular assemblies that serve to physically connect the actin cytoskeleton to integrins that engage with the surrounding extracellular matrix (ECM). FAs undergo maturation wherein they grow and change composition differentially to provide traction and to transduce the signals that drive cell migration, which is crucial to various biological processes, including development, wound healing and cancer metastasis. FA-related signalling networks dynamically modulate the strength of the linkage between integrin and actin and control the organization of the actin cytoskeleton. In this review, we have summarized a number of recent investigations exploring how FA composition is affected by the mechanical forces that transduce signalling networks to modulate cellular function and drive cell migration. Understanding the fundamental mechanisms of how force governs adhesion signalling provides insights that will allow the manipulation of cell migration and help to control migration-related human diseases. PMID:23551528

  7. Slow motility in hair cells of the frog amphibian papilla: Ca2+-dependent shape changes.

    PubMed

    Farahbakhsh, Nasser A; Narins, Peter M

    2006-02-01

    We investigated the process of slow motility in non-mammalian auditory hair cells by recording the time course of shape change in hair cells of the frog amphibian papilla. The tall hair cells in the rostral segment of this organ, reported to be the sole recipients of efferent innervation, were found to shorten in response to an increase in the concentration of the intracellular free calcium. These shortenings are composed of two partially-overlapping phases: an initial rapid iso-volumetric contraction, followed by a slower length decrease accompanied with swelling. It is possible to unmask the iso-volumetric contraction by delaying the cell swelling with the help of K+ or Cl- channel inhibitors, quinine or furosemide. Furthermore, it appears that the longitudinal contraction in these cells is Ca2+-calmodulin-dependent: in the presence of W-7, a calmodulin inhibitor, only a slow, swelling phase could be observed. These findings suggest that amphibian rostral AP hair cells resemble their mammalian counterparts in expressing both a Ca2+-calmodulin-dependent contractile structure and an "osmotic" mechanism capable of mediating length change in response to extracellular stimuli. Such a mechanism might be utilized by the efferent neurotransmitters for adaptive modulation of mechano-electrical transduction, sensitivity enhancement, frequency selectivity, and protection against over-stimulation. PMID:16426781

  8. Microvascular Transport and Tumor Cell Adhesion in the Microcirculation

    PubMed Central

    Fu, Bingmei M.; Liu, Yang

    2016-01-01

    One critical step in tumor metastasis is tumor cell adhesion to the endothelium forming the microvessel wall. Understanding this step may lead to new therapeutic concepts for tumor metastasis. Vascular endothelium forming the microvessel wall and the glycocalyx layer at its surface are the principal barriers to, and regulators of the material exchange between circulating blood and body tissues. The cleft between adjacent ECs (interendothelial cleft) is the principal pathway for water and solutes transport through the microvessel wall in health. It is also suggested to be the pathway for high molecular weight plasma proteins, leukocytes and tumor cells across microvessel walls in disease. Thus the first part of the review introduced the mathematical models for water and solutes transport through the interendothelial cleft. These models, combined with the experimental results from in vivo animal studies and electron microscopic observations, are used to evaluate the role of the endothelial surface glycocalyx, the junction strand geometry in the interendothelial cleft, and the surrounding extracellular matrix and tissue cells, as the determinants of microvascular transport. The second part of the review demonstrated how the microvascular permeability, hydrodynamic factors, microvascular geometry and cell adhesion molecules affect tumor cell adhesion in the microcirculation. PMID:22476895

  9. Fibronectin adsorption, cell adhesion, and proliferation on nanostructured tantalum surfaces.

    PubMed

    Dolatshahi-Pirouz, A; Jensen, T; Kraft, David Christian; Foss, Morten; Kingshott, Peter; Hansen, John Lundsgaard; Larsen, Arne Nylandsted; Chevallier, Jacques; Besenbacher, Flemming

    2010-05-25

    The interaction between dental pulp derived mesenchymal stem cells (DP-MSCs) and three different tantalum nanotopographies with and without a fibronectin coating is examined: sputter-coated tantalum surfaces with low surface roughness <0.2 nm, hut-nanostructured surfaces with a height of 2.9 +/- 0.6 nm and a width of 35 +/- 8 nm, and dome structures with a height of 13 +/- 2 nm and a width of 52 +/- 14 nm. Using ellipsometry, the adsorption and the availability of fibronectin cell-binding domains on the tantalum surfaces were examined, as well as cellular attachment, proliferation, and vinculin focal adhesion spot assembly on the respective surfaces. The results showed the highest fibronectin mass uptake on the hut structures, with a slightly higher availability of cell-binding domains and the most pronounced formation of vinculin focal adhesion spots as compared to the other surfaces. The proliferation of DP-MSCs was found to be significantly higher on dome and hut surfaces coated with fibronectin compared to the uncoated flat tantalum surfaces. Consequently, the results presented in this study indicate that fibronectin-coated nanotopographies with a vertical dimension of less than 5 nm influence cell adhesion. This rather interesting behavior is argued to originate from the more available fibronectin cell-binding domains observed on the hut structures. PMID:20443575

  10. Electrochemically Preadsorbed Collagen Promotes Adult Human Mesenchymal Stem Cell Adhesion.

    PubMed

    Benavidez, Tomás E; Wechsler, Marissa E; Farrer, Madeleine M; Bizios, Rena; Garcia, Carlos D

    2016-01-01

    The present article reports on the effect of electric potential on the adsorption of collagen type I (the most abundant component of the organic phase of bone) onto optically transparent carbon electrodes (OTCE) and its mediation on subsequent adhesion of adult, human, mesenchymal stem cells (hMSCs). For this purpose, adsorption of collagen type I was investigated as a function of the protein concentration (0.01, 0.1, and 0.25 mg/mL) and applied potential (open circuit potential [OCP; control], +400, +800, and +1500 mV). The resulting substrate surfaces were characterized using spectroscopic ellipsometry, atomic force microscopy, and cyclic voltammetry. Adsorption of collagen type I onto OTCE was affected by the potential applied to the sorbent surface and the concentration of protein. The higher the applied potential and protein concentration, the higher the adsorbed amount (Γcollagen). It was also observed that the application of potential values higher than +800 mV resulted in the oxidation of the adsorbed protein. Subsequent adhesion of hMSCs on the OTCEs (precoated with the collagen type I films) under standard cell culture conditions for 2 h was affected by the extent of collagen preadsorbed onto the OTCE substrates. Specifically, enhanced hMSCs adhesion was observed when the Γcollagen was the highest. When the collagen type I was oxidized (under applied potential equal to +1500 mV), however, hMSCs adhesion was decreased. These results provide the first correlation between the effects of electric potential on protein adsorption and subsequent modulation of anchorage-dependent cell adhesion. PMID:26549607

  11. Serotonin and colonic motility.

    PubMed

    Kendig, D M; Grider, J R

    2015-07-01

    The role of serotonin (5-hydroxytryptamine [5-HT]) in gastrointestinal motility has been studied for over 50 years. Most of the 5-HT in the body resides in the gut wall, where it is located in subsets of mucosal cells (enterochromaffin cells) and neurons (descending interneurons). Many studies suggest that 5-HT is important to normal and dysfunctional gut motility and drugs affecting 5-HT receptors, especially 5-HT3 and 5-HT4 receptors, have been used clinically to treat motility disorders; however, cardiovascular side effects have limited the use of these drugs. Recently studies have questioned the importance and necessity of 5-HT in general and mucosal 5-HT in particular for colonic motility. Recent evidence suggests the importance of 5-HT3 and 5-HT4 receptors for initiation and generation of one of the key colonic motility patterns, the colonic migrating motor complex (CMMC), in rat. The findings suggest that 5-HT3 and 5-HT4 receptors are differentially involved in two different types of rat CMMCs: the long distance contraction (LDC) and the rhythmic propulsive motor complex (RPMC). The understanding of the role of serotonin in c