Science.gov

Sample records for stimulated cell motility

  1. 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

  2. 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.

  3. 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

  4. 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

  5. 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

  6. 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

  7. Quantitative analysis of signal transduction in motile and phototactic cells by computerized light stimulation and model based tracking.

    PubMed

    Streif, Stefan; Staudinger, Wilfried Franz; Oesterhelt, Dieter; Marwan, Wolfgang

    2009-02-01

    To investigate the responses of Halobacterium salinarum to stimulation with light (phototaxis and photokinesis), we designed an experimental setup consisting of optical devices for automatic video image acquisition and computer-controlled light stimulation, and developed algorithms to analyze physiological responses of the cells. Cells are categorized as motile and nonmotile by a classification scheme based on the square displacement of cell positions. Computerized tracking based on a dynamic model of the stochastic cell movement and a Kalman filter-based algorithm allows smoothed estimates of the cell tracks and the detection of physiological responses to complex stimulus patterns. The setup and algorithms were calibrated which allows quantitative measurements and systematic analysis of cellular sensing and response. Overall, the setup is flexible, extensible, and consists mainly of commercially available products. This facilitates modifications of the setup and algorithms for physiological studies of the motility of cells or microorganisms. PMID:19256655

  8. β-casein-derived peptides, produced by bacteria, stimulate cancer cell invasion and motility

    PubMed Central

    Oliveira, Maria José; Van Damme, Jozef; Lauwaet, Tineke; De Corte, Veerle; De Bruyne, Georges; Verschraegen, Gerda; Vaneechoutte, Mario; Goethals, Marc; Ahmadian, Mohammad Reza; Müller, Oliver; Vandekerckhove, Joël; Mareel, Marc; Leroy, Ancy

    2003-01-01

    In colon cancer, enteric bacteria and dietary factors are major determinants of the microenvironment but their effect on cellular invasion is not known. We therefore incubated human HCT-8/E11 colon cancer cells with bacteria or bacterial conditioned medium on top of collagen type I gels. Listeria monocytogenes stimulate cellular invasion through the formation of a soluble motility-promoting factor, identified as a 13mer β-casein-derived peptide (HKEMPFPKYPVEP). The peptide is formed through the combined action of Mpl, a Listeria thermolysin-like metalloprotease, and a collagen-associated trypsin-like serine protease. The 13mer peptide was also formed by tumour biopsies isolated from colon cancer patients and incubated with a β-casein source. The pro- invasive 13mer peptide-signalling pathway implicates activation of Cdc42 and inactivation of RhoA, linked to each other through the serine/threonine p21- activated kinase 1. Since both changes are necessary but not sufficient, another pathway might branch upstream of Cdc42 at phosphatidylinositol 3-kinase. Delta opioid receptor (δOR) is a candidate receptor for the 13mer peptide since naloxone, an δOR antagonist, blocks both δOR serine phosphorylation and 13mer peptide-mediated invasion. PMID:14609961

  9. Pancreatic Fibroblasts Stimulate the Motility of Pancreatic Cancer Cells through IGF1/IGF1R Signaling under Hypoxia

    PubMed Central

    Hirakawa, Toshiki; Yashiro, Masakazu; Doi, Yosuke; Kinoshita, Haruhito; Morisaki, Tamami; Fukuoka, Tatsunari; Hasegawa, Tsuyoshi; Kimura, Kenjiro; Amano, Ryosuke; Hirakawa, Kosei

    2016-01-01

    Pancreatic ductal adenocarcinoma (PDAC) is characterized by its hypovascularity, with an extremely poor prognosis because of its highly invasive nature. PDAC proliferates with abundant stromal cells, suggesting that its invasive activity might be controlled by intercellular interactions between cancer cells and fibroblasts. Using four PDAC cell lines and two pancreas cancer-associated fibroblasts (CAFs), the expression of insulin-like growth factor-1 (IGF1) and IGF1 receptor (IGF1R) was evaluated by RT-PCR, FACScan, western blot, or ELISA. Correlation between IGF1R and the hypoxia marker carbonic anhydrase 9 (CA9) was examined by immunohistochemical staining of 120 pancreatic specimens. The effects of CAFs, IGF1, and IGF1R inhibitors on the motility of cancer cells were examined by wound-healing assay or invasion assay under normoxia (20% O2) and hypoxia (1% O2). IGF1R expression was significantly higher in RWP-1, MiaPaCa-2, and OCUP-AT cells than in Panc-1 cells. Hypoxia increased the expression level of IGF1R in RWP-1, MiaPaCa-2, and OCUP-AT cells. CA9 expression was correlated with IGF1R expression in pancreatic specimens. CAFs produced IGF1 under hypoxia, but PDAC cells did not. A conditioned medium from CAFs, which expressed αSMA, stimulated the migration and invasion ability of MiaPaCa-2, RWP-1, and OCUP-AT cells. The motility of all PDAC cells was greater under hypoxia than under normoxia. The motility-stimulating ability of CAFs was decreased by IGF1R inhibitors. These findings might suggest that pancreas CAFs stimulate the invasion activity of PDAC cells through paracrine IGF1/IGF1R signaling, especially under hypoxia. Therefore the targeting of IGF1R signaling might represent a promising therapeutic approach in IGF1R-dependent PDAC. PMID:27487118

  10. 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

  11. Hepatocyte growth factor stimulates motility, chemotaxis and mitogenesis in ovarian carcinoma cells expressing high levels of c-met.

    PubMed

    Corps, A N; Sowter, H M; Smith, S K

    1997-09-26

    A proportion of ovarian carcinomas markedly overexpress the proto-oncogene c-met, which encodes the receptor for hepatocyte growth factor (HGF). HGF may either stimulate or inhibit the multiplication of its target cells, and may also promote motogenesis and morphogenesis. In this study, we established that the ovarian carcinoma-derived cell-line SK-OV-3 expressed about 20-fold higher levels of c-met protein than are expressed by a second line, CH1. This enabled us to test functional consequences of high-level expression of c-met in ovarian carcinoma cells. The addition of HGF to attached cultures of SK-OV-3 cells caused a change to a motile phenotype, that was evident after 4-6 hr and affected essentially all of the cells by 24 hr. When HGF was placed in the lower compartment of a migration chamber, it induced a 17-fold increase in the migration of SK-OV-3 cells to the lower surface of the filter. Finally, HGF stimulated the incorporation of [3H]-thymidine by cultures of SK-OV-3 cells incubated in medium containing either low (0.2%) or full (10%) FCS. None of these responses were obtained when HGF was added to CH1 cells. We conclude that high levels of c-met expression in ovarian cancer cells may lead to a range of responses to HGF that would promote tumour growth and dissemination. PMID:9334823

  12. Wnt7a stimulates myogenic stem cell motility and engraftment resulting in improved muscle strength.

    PubMed

    Bentzinger, C Florian; von Maltzahn, Julia; Dumont, Nicolas A; Stark, Danny A; Wang, Yu Xin; Nhan, Kevin; Frenette, Jérôme; Cornelison, D D W; Rudnicki, Michael A

    2014-04-14

    Wnt7a/Fzd7 signaling stimulates skeletal muscle growth and repair by inducing the symmetric expansion of satellite stem cells through the planar cell polarity pathway and by activating the Akt/mTOR growth pathway in muscle fibers. Here we describe a third level of activity where Wnt7a/Fzd7 increases the polarity and directional migration of mouse satellite cells and human myogenic progenitors through activation of Dvl2 and the small GTPase Rac1. Importantly, these effects can be exploited to potentiate the outcome of myogenic cell transplantation into dystrophic muscles. We observed that a short Wnt7a treatment markedly stimulated tissue dispersal and engraftment, leading to significantly improved muscle function. Moreover, myofibers at distal sites that fused with Wnt7a-treated cells were hypertrophic, suggesting that the transplanted cells deliver activated Wnt7a/Fzd7 signaling complexes to recipient myofibers. Taken together, we describe a viable and effective ex vivo cell modulation process that profoundly enhances the efficacy of stem cell therapy for skeletal muscle. PMID:24711502

  13. Wnt7a stimulates myogenic stem cell motility and engraftment resulting in improved muscle strength

    PubMed Central

    Bentzinger, C. Florian; von Maltzahn, Julia; Dumont, Nicolas A.; Stark, Danny A.; Wang, Yu Xin; Nhan, Kevin; Frenette, Jérôme; Cornelison, DDW

    2014-01-01

    Wnt7a/Fzd7 signaling stimulates skeletal muscle growth and repair by inducing the symmetric expansion of satellite stem cells through the planar cell polarity pathway and by activating the Akt/mTOR growth pathway in muscle fibers. Here we describe a third level of activity where Wnt7a/Fzd7 increases the polarity and directional migration of mouse satellite cells and human myogenic progenitors through activation of Dvl2 and the small GTPase Rac1. Importantly, these effects can be exploited to potentiate the outcome of myogenic cell transplantation into dystrophic muscles. We observed that a short Wnt7a treatment markedly stimulated tissue dispersal and engraftment, leading to significantly improved muscle function. Moreover, myofibers at distal sites that fused with Wnt7a-treated cells were hypertrophic, suggesting that the transplanted cells deliver activated Wnt7a/Fzd7 signaling complexes to recipient myofibers. Taken together, we describe a viable and effective ex vivo cell modulation process that profoundly enhances the efficacy of stem cell therapy for skeletal muscle. PMID:24711502

  14. 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.

  15. 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.

  16. 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

  17. The human PMR1 endonuclease stimulates cell motility by down regulating miR-200 family microRNAs.

    PubMed

    Gu, Shan-Qing; Gallego-Perez, Daniel; McClory, Sean P; Shi, Junfeng; Han, Joonhee; Lee, L James; Schoenberg, Daniel R

    2016-07-01

    The motility of MCF-7 cells increases following expression of a human PMR1 transgene and the current study sought to identify the molecular basis for this phenotypic change. Ensemble and single cell analyses show increased motility is dependent on the endonuclease activity of hPMR1, and cells expressing active but not inactive hPMR1 invade extracellular matrix. Nanostring profiling identified 14 microRNAs that are downregulated by hPMR1, including all five members of the miR-200 family and others that also regulate invasive growth. miR-200 levels increase following hPMR1 knockdown, and changes in miR-200 family microRNAs were matched by corresponding changes in miR-200 targets and reporter expression. PMR1 preferentially cleaves between UG dinucleotides within a consensus YUGR element when present in the unpaired loop of a stem-loop structure. This motif is present in the apical loop of precursors to most of the downregulated microRNAs, and hPMR1 targeting of pre-miRs was confirmed by their loss following induced expression and increase following hPMR1 knockdown. Introduction of miR-200c into hPMR1-expressing cells reduced motility and miR-200 target gene expression, confirming hPMR1 acts upstream of Dicer processing. These findings identify a new role for hPMR1 in the post-transcriptional regulation of microRNAs in breast cancer cells. PMID:27257068

  18. The human PMR1 endonuclease stimulates cell motility by down regulating miR-200 family microRNAs

    PubMed Central

    Gu, Shan-Qing; Gallego-Perez, Daniel; McClory, Sean P.; Shi, Junfeng; Han, Joonhee; Lee, L. James; Schoenberg, Daniel R.

    2016-01-01

    The motility of MCF-7 cells increases following expression of a human PMR1 transgene and the current study sought to identify the molecular basis for this phenotypic change. Ensemble and single cell analyses show increased motility is dependent on the endonuclease activity of hPMR1, and cells expressing active but not inactive hPMR1 invade extracellular matrix. Nanostring profiling identified 14 microRNAs that are downregulated by hPMR1, including all five members of the miR-200 family and others that also regulate invasive growth. miR-200 levels increase following hPMR1 knockdown, and changes in miR-200 family microRNAs were matched by corresponding changes in miR-200 targets and reporter expression. PMR1 preferentially cleaves between UG dinucleotides within a consensus YUGR element when present in the unpaired loop of a stem–loop structure. This motif is present in the apical loop of precursors to most of the downregulated microRNAs, and hPMR1 targeting of pre-miRs was confirmed by their loss following induced expression and increase following hPMR1 knockdown. Introduction of miR-200c into hPMR1-expressing cells reduced motility and miR-200 target gene expression, confirming hPMR1 acts upstream of Dicer processing. These findings identify a new role for hPMR1 in the post-transcriptional regulation of microRNAs in breast cancer cells. PMID:27257068

  19. Rac regulates vascular endothelial growth factor stimulated motility.

    PubMed

    Soga, N; Connolly, J O; Chellaiah, M; Kawamura, J; Hruska, K A

    2001-01-01

    During angiogenesis endothelial cells migrate towards a chemotactic stimulus. Understanding the mechanism of endothelial cell migration is critical to the therapeutic manipulation of angiogenesis and ultimately cancer prevention. Vascular endothelial growth factor (VEGF) is a potent chemotactic stimulus of endothelial cells during angiogenesis. The endothelial cell signal transduction pathway of VEGF represents a potential target for cancer therapy, but the mechanisms of post-receptor signal transduction including the roles of rho family GTPases in regulating the cytoskeletal effects of VEGF in endothelial cells are not understood. Here we analyze the mechanisms of cell migration in the mouse brain endothelial cell line (bEND3). Stable transfectants containing a tetracycline repressible expression vector were used to induce expression of Rac mutants. Endothelial cell haptotaxis was stimulated by constitutively active V12Rac on collagen and vitronectin coated supports, and chemotaxis was further stimulated by VEGF. Osteopontin coated supports were the most stimulatory to bEND3 haptotaxis, but VEGF was not effective in further increasing migration on osteopontin coated supports. Haptotaxis on support coated with collagen, vitronectin, and to a lesser degree osteopontin was inhibited by N17 Rac. N17 Rac expression blocked stimulation of endothelial cell chemotaxis by VEGF. As part of the chemotactic stimulation, VEGF caused a loss of actin organization at areas of cell-cell contact and increased stress fiber expression in endothelial cells which were directed towards pores in the transwell membrane. N17 Rac prevented the stimulation of cell-cell contact disruption and the stress fiber stimulation by VEGF. These data demonstrate two pathways of regulating endothelial cell motility, one in which Rac is activated by matrix/integrin stimulation and is a crucial modulator of endothelial cell haptotaxis. The other pathway, in the presence of osteopontin, is Rac independent

  20. 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.

  1. 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

  2. Comparison of motility stimulants for cryopreserved human semen.

    PubMed

    Hammitt, D G; Bedia, E; Rogers, P R; Syrop, C H; Donovan, J F; Williamson, R A

    1989-09-01

    Caffeine, pentoxifylline, 2-deoxyadenosine, cyclic adenosine monophosphate (cAMP), relaxin, adenosine, kallikrein, and calcium were compared for their ability to stimulate motility of cryopreserved sperm. Caffeine, pentoxifylline, and 2-deoxyadenosine significantly increased the percentage of motile sperm at 15, 30, 45, and 60 minutes after administration. Sperm velocity was significantly increased by caffeine at 0, 15, 30, and 45 minutes, and by pentoxifylline at 0, 45, and 60 minutes. Consistent stimulation was not observed for other chemicals. Caffeine, pentoxifylline, and 2-deoxyadenosine were then examined for their ability to provide motility stimulation after removal with washing. With the exception of caffeine, percent motility and velocity for stimulated and untreated sperm were similar after washing. A significant reduction in motility was observed at 48 hours after washing for caffeine. The percentage of hamster oocytes penetrated at 24 hours after washing was significantly reduced for caffeine, 2-deoxyadenosine, and pentoxifylline combined with 2-deoxyadenosine. Pentoxifylline-treated sperm showed no reduction in fertilizing capacity. These results indicate that, of the chemicals examined, pentoxifylline is superior for motility stimulation of cryopreserved sperm. PMID:2550282

  3. 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.

  4. 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

  5. Galectin-1 stimulates motility of human umbilical cord blood-derived mesenchymal stem cells by downregulation of smad2/3-dependent collagen 3/5 and upregulation of NF-κB-dependent fibronectin/laminin 5 expression.

    PubMed

    Yun, S P; Lee, S-J; Jung, Y H; Han, H J

    2014-01-01

    Galectin-1 (Gal-1) belongs to a family of endogenous lectins with conserved carbohydrate recognition domains binding β-galactosidase sugars and plays a vital role in regulating stem cell functions including determination of cell fate. However, our understanding of the functional roles of Gal-1 in human umbilical cord blood-derived mesenchymal stem cells (UCB-MSCs) is still fragmentary and incomplete. Gal-1 significantly increased motility after a 24-h incubation, and this effect was inhibited by β-lactose. We analyzed 17 extracellular matrix (ECM) genes in UCB-MSCs. Gal-1 decreased the expression of collagen genes COL3A1 (COL-3) and COL5A1 (COL-5) but increased the expression of fibronectin (FN) and laminin 5 (LM-5), that were reversed by β-lactose. Gal-1 increased protein kinase C (PKC), c-Src, and caveolin-1 (Cav-1) phosphorylation that was attenuated by β-lactose and the Src inhibitor PP2. In addition, pretreatment with the lipid raft disruptor Mβ-CD and the PKC inhibitors inhibited Gal-1-induced UCB-MSC motility. In addition, Gal-1 reduced smad2/3 phosphorylation and induced nuclear factor (NF)-κB phosphorylation. Pretreatment with Mβ-CD attenuated Gal-1-reduced smad2/3 phosphorylation, COL-3, and COL-5 expression but did not affect NF-κB phosphorylation, FN, or LM-5 expression. In contrast, PKC inhibitors only attenuated NF-κB phosphorylation, FN, and LM-5 expression. Reconstructing Gal-1-induced genetic changes by replacing it with siRNA specific for COL-3 or COL-5, or treatment of the cells with FN and LM-5 proteins, increased motility and its related proteins such as focal adhesion kinase, Akt, Erk, integrins, and matrix metalloproteinase-2. A combined treatment with COL-3/COL-5 siRNA or FN/LM-5 compared with that of single treatments was synergistic. However, a single Gal-1 treatment maximally stimulated motility and related protein phosphorylation/expression. These results demonstrate that Gal-1 stimulated human UCB-MSC motility by decreasing COL

  6. 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

  7. 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

  8. The cleaved FAS ligand activates the Na+/H+ exchanger NHE1 through Akt/ROCK1 to stimulate cell motility

    PubMed Central

    Monet, Michael; Poët, Mallorie; Tauzin, Sébastien; Fouqué, Amélie; Cophignon, Auréa; Lagadic-Gossmann, Dominique; Vacher, Pierre; Legembre, Patrick; Counillon, Laurent

    2016-01-01

    Transmembrane CD95L (Fas ligand) can be cleaved to release a promigratory soluble ligand, cl-CD95L, which can contribute to chronic inflammation and cancer cell dissemination. The motility signaling pathway elicited by cl-CD95L remains poorly defined. Here, we show that in the presence of cl-CD95L, CD95 activates the Akt and RhoA signaling pathways, which together orchestrate an allosteric activation of the Na+/H+ exchanger NHE1. Pharmacologic inhibition of Akt or ROCK1 independently blocks the cl-CD95L-induced migration. Confirming these pharmacologic data, disruption of the Akt and ROCK1 phosphorylation sites on NHE1 decreases cell migration in cells exposed to cl-CD95L. Together, these findings demonstrate that NHE1 is a novel molecular actor in the CD95 signaling pathway that drives the cl-CD95L-induced cell migration through both the Akt and RhoA signaling pathways. PMID:27302366

  9. Extracellular Regulation of Sperm Transmembrane Adenylyl Cyclase by a Forward Motility Stimulating Protein

    PubMed Central

    Dey, Souvik; Roy, Debarun; Majumder, Gopal C.; Bhattacharyya, Debdas

    2014-01-01

    Forward motility stimulating factor (FMSF), a glycoprotein isolated from buffalo serum, binds to the surface of the mature sperm cells to promote their progressive motility. This article reports the mode of signal transduction of this extracellular factor in goat sperm. The mechanism was investigated by assaying intracellular second messenger level and forward motility in presence of different pharmacological modulators. Mg++-dependent Forskolin responsive form of transmembrane adenylyl cyclase (tmAC) of goat spermatozoa was probed for its involvement in FMSF action. Dideoxyadenosine, a selective inhibitor of tmACs, was used to identify the role of this enzyme in the scheme of FMSF-signaling. Involvement of the α-subunit of G-protein in this regard has been inspected using GTPγS. Participation of protein kinase A (PKA) and tyrosine kinase was checked using IP20 and genistein, respectively. FMSF promotes tmAC activity in a dose-dependent manner through receptor/G-protein activation to enhance intracellular cAMP and forward motility. Motility boosting effects of this glycoprotein are almost lost in presence of dideoxyadenosine. But, FMSF displayed substantial motility promoting activity when movement of spermatozoa was inhibited with KH7, the specific inhibitor of soluble adenylyl cyclase indicating tmAC to be the primary target of FMSF action. Involvement of cAMP in mediating FMSF action was confirmed by the application of dibutyryl cAMP. Observed motility regulatory effects with IP20 and genistein indicate contribution of PKA and tyrosine kinase in FMSF activity; enhanced phosphorylation of a tyrosine containing ≈50 kDa protein was detected in this regard. FMSF initiates a novel signaling cascade to stimulate tmAC activity that augments intracellular cAMP, which through downstream crosstalk of phosphokinases leads to enhanced forward motility in mature spermatozoa. Thus, this article for the first time describes conventional tmAC-dependent profound activation

  10. 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

  11. 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

  12. 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

  13. 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.

  14. 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.

  15. 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.

  16. 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

  17. 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

  18. Contact- and Protein Transfer-Dependent Stimulation of Assembly of the Gliding Motility Machinery in Myxococcus xanthus

    PubMed Central

    Jakobczak, Beata; Keilberg, Daniela; Wuichet, Kristin; Søgaard-Andersen, Lotte

    2015-01-01

    Bacteria engage in contact-dependent activities to coordinate cellular activities that aid their survival. Cells of Myxococcus xanthus move over surfaces by means of type IV pili and gliding motility. Upon direct contact, cells physically exchange outer membrane (OM) lipoproteins, and this transfer can rescue motility in mutants lacking lipoproteins required for motility. The mechanism of gliding motility and its stimulation by transferred OM lipoproteins remain poorly characterized. We investigated the function of CglC, GltB, GltA and GltC, all of which are required for gliding. We demonstrate that CglC is an OM lipoprotein, GltB and GltA are integral OM β-barrel proteins, and GltC is a soluble periplasmic protein. GltB and GltA are mutually stabilizing, and both are required to stabilize GltC, whereas CglC accumulate independently of GltB, GltA and GltC. Consistently, purified GltB, GltA and GltC proteins interact in all pair-wise combinations. Using active fluorescently-tagged fusion proteins, we demonstrate that GltB, GltA and GltC are integral components of the gliding motility complex. Incorporation of GltB and GltA into this complex depends on CglC and GltC as well as on the cytoplasmic AglZ protein and the inner membrane protein AglQ, both of which are components of the gliding motility complex. Conversely, incorporation of AglZ and AglQ into the gliding motility complex depends on CglC, GltB, GltA and GltC. Remarkably, physical transfer of the OM lipoprotein CglC to a ΔcglC recipient stimulates assembly of the gliding motility complex in the recipient likely by facilitating the OM integration of GltB and GltA. These data provide evidence that the gliding motility complex in M. xanthus includes OM proteins and suggest that this complex extends from the cytoplasm across the cell envelope to the OM. These data add assembly of gliding motility complexes in M. xanthus to the growing list of contact-dependent activities in bacteria. PMID:26132848

  19. 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

  20. 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

  1. 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

  2. Effect of electroacupuncture stimulation at Zusanli acupoint (ST36) on gastric motility: possible through PKC and MAPK signal transduction pathways

    PubMed Central

    2014-01-01

    Background Electroacupuncture (EA) stimulation has been shown to have a great therapeutic potential for treating gastrointestinal motility disorders. However, no evidence has clarified the mechanisms contributing to the effects of EA stimulation at the Zusanli acupoint (ST.36). This study was designed to investigate the regulative effect of EA stimulation at the ST.36 on gastric motility and to explore its possible mechanisms. Methods Thirty Sprague-Dawley rats were randomly divided into three groups: the ST.36 group, the non-acupoint group, and the control group. EA stimulation was set at 2 Hz, continuous mode, and 1 V for 30 min. The frequency and average peak amplitude of gastric motility were measured by electrogastrography. The protein kinase C (PKC) and mitogen-activated protein kinase (MAPK) signaling pathways were assessed using real-time polymerase chain reactions. Caldesmon (CaD) and calponin (CaP) protein expression in the gastric antrum were detected on Western blots. A Computed Video Processing System was used to evaluate morphological changes in smooth muscle cells (SMCs) from the gastric antrum. Results EA stimulation at ST.36 had a dual effect on the frequency and average peak amplitude. Additionally, EA stimulation at ST.36 regulated the expression of some genes in the PKC and MAPK signaling pathways, and it regulated the expression of the CaD and CaP proteins. EA serum induced SMC contractility. Promotion of gastric motility may correlate with up-regulation of MAPK6 (ERK3), MAPK13, and Prostaglandin-endoperoxide synthase 2 (PTGS2) gene expression, and the down-regulation of the collagen, type I, alpha 1 (COL1A1) gene and CaD and CaP protein expression. Inhibition of gastric motility may correlate with down-regulation of the Interleukin-1 receptor type 2 (IL1R2) and Matrix metalloproteinase-9 (MMP9) genes, and up-regulation of CaD and CaP protein expression. Conclusions EA stimulation at ST.36 regulated gastric motility, and the effects were

  3. 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

  4. 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

  5. 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

  6. Intragastric monosodium L-glutamate stimulates motility of upper gut via vagus nerve in conscious dogs.

    PubMed

    Toyomasu, Yoshitaka; Mochiki, Erito; Yanai, Mitsuhiro; Ogata, Kyoichi; Tabe, Yuichi; Ando, Hiroyuki; Ohno, Tetsuro; Aihara, Ryuusuke; Zai, Hiroaki; Kuwano, Hiroyuki

    2010-04-01

    Monosodium l-glutamate (MSG) is a substance known to produce the umami taste. Recent studies indicate that MSG also stimulates a variety of activities in the gastrointestinal tract through its receptor in the gut, but no study has reported the activity in conscious large experimental animals. The aim of our study was to investigate whether direct intragastric MSG stimulates gut motility and to identify the mechanism in conscious dogs. Contractile response to intraluminal injection of MSG was studied in the fed and fasted states by means of chronically implanted force transducers. MSG (5, 15, 45, and 90 mM/kg) dissolved in water was injected into the stomach and duodenum in normal and vagotomized dogs. MSG solution was administered into the stomach before feeding, and gastric emptying was evaluated. Several inhibitors of gastrointestinal motility (atropine, hexamethonium, and granisetron) were injected intravenously before MSG administration to the stomach. The effect of MSG was investigated in Pavlov (vagally innervated corpus pouch), Heidenhain (vagally denervated corpus pouch), and antral pouch (vagally innervated) dogs. Upper gut motility was significantly increased by intragastric MSG but not significantly stimulated by intraduodenal MSG. Intragastric MSG (45 mM/kg) stimulated postprandial motility and accelerated gastric emptying. MSG-induced contractions were inhibited by truncal vagotomy, atropine, hexamethonium, and granisetron. Gut motility was increased by intrapouch injection of MSG in the Pavlov pouch, but it was not affected in the Heidenhain or antral pouch dogs. We conclude that intragastric MSG stimulates upper gut motility and accelerates gastric emptying. The sensory structure of MSG is present in the gastric corpus, and the signal is mediated by the vagus nerve. PMID:20071606

  7. 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.

  8. 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.

  9. 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

  10. 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.

  11. 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

  12. 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

  13. 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

  14. 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

  15. 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

  16. [Effect of stimulation of the tooth pulp on gastrointestinal motility in rabbits].

    PubMed

    Nando, R

    1983-04-01

    Effects of electrical stimulation of the inciser tooth pulp on the gastrointestinal motility were investigated in the rabbit anesthetized with urethane and chloralose. Pulpal Stimulation caused an excitatory or an inhibitory effect in the gastric body and antrum and the ducodenum. After bilateral splanchnicotomy the excitatory response to the pulpal stimulation was reinforced or the inhibitory response converted to the excitatory response. An additional cervical vagotomy abolished the excitatory and inhibitory response. Atropine diminished the spontaneous efferent discharges of vagal gastric branch (VGB) and abolished the excitatory and inhibitory response to stimulation of the pulp and the inferior alveolar nerve. This agent also blocked the potentials of the VGB evoked by afferent stimulation of the inferior aveolar nerve. Hexamethonium bromide abolished the excitatory and inhibitory responses to the pulpal stimulation but did not affect spontaneous discharges and increased discharges of the VGB to pulpal stimulation. Morphine produced decreased rate of the spontaneous discharge of the VGB and abolished increased rate of discharges of the VGB as well as the gastrointestinal responses to pulpal stimulation. It is concluded from these results that the afferent impulses caused by pulpal stimulation and the inferior alveolar nerve 'reflex'ly activate the vagal motor nuclei in the medulla oblongata and the sympathetic splanchnic nuclei in the thoracic segments through the trigeminal nerve: The vagus nerves produced the excitatory response in the gastrointestinal motility, while the splanchnic nerves caused the inhibitory response. It was supposed that sites of action of atropine and morphine is not in peripheral site, but in the central nerves site. PMID:6663937

  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. Human Axonal Survival of Motor Neuron (a-SMN) Protein Stimulates Axon Growth, Cell Motility, C-C Motif Ligand 2 (CCL2), and Insulin-like Growth Factor-1 (IGF1) Production*

    PubMed Central

    Locatelli, Denise; Terao, Mineko; Fratelli, Maddalena; Zanetti, Adriana; Kurosaki, Mami; Lupi, Monica; Barzago, Maria Monica; Uggetti, Andrea; Capra, Silvia; D'Errico, Paolo; Battaglia, Giorgio S.; Garattini, Enrico

    2012-01-01

    Spinal muscular atrophy is a fatal genetic disease of motoneurons due to loss of full-length survival of motor neuron protein, the main product of the disease gene SMN1. Axonal SMN (a-SMN) is an alternatively spliced isoform of SMN1, generated by retention of intron 3. To study a-SMN function, we generated cellular clones for the expression of the protein in mouse motoneuron-like NSC34 cells. The model was instrumental in providing evidence that a-SMN decreases cell growth and plays an important role in the processes of axon growth and cellular motility. In our conditions, low levels of a-SMN expression were sufficient to trigger the observed biological effects, which were not modified by further increasing the amounts of the expressed protein. Differential transcriptome analysis led to the identification of novel a-SMN-regulated factors, i.e. the transcripts coding for the two chemokines, C-C motif ligands 2 and 7 (CCL2 and CCL7), as well as the neuronal and myotrophic factor, insulin-like growth factor-1 (IGF1). a-SMN-dependent induction of CCL2 and IGF1 mRNAs resulted in increased intracellular levels and secretion of the respective protein products. Induction of CCL2 contributes to the a-SMN effects, mediating part of the action on axon growth and random cell motility, as indicated by chemokine knockdown and re-addition studies. Our results shed new light on a-SMN function and the underlying molecular mechanisms. The data provide a rational framework to understand the role of a-SMN deficiency in the etiopathogenesis of spinal muscular atrophy. PMID:22669976

  19. 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

  20. Speract, a sea urchin egg peptide that regulates sperm motility, also stimulates sperm mitochondrial metabolism.

    PubMed

    García-Rincón, Juan; Darszon, Alberto; Beltrán, Carmen

    2016-04-01

    Sea urchin sperm have only one mitochondrion, that in addition to being the main source of energy, may modulate intracellular Ca(2+) concentration ([Ca(2+)]i) to regulate their motility and possibly the acrosome reaction. Speract is a decapeptide from the outer jelly layer of the Strongylocentrotus purpuratus egg that upon binding to its receptor in the sperm, stimulates sperm motility, respiration and ion fluxes, among other physiological events. Altering the sea urchin sperm mitochondrial function with specific inhibitors of this organelle, increases [Ca(2+)]i in an external Ca(2+) concentration ([Ca(2+)]ext)-dependent manner (Ardón, et al., 2009. BBActa 1787: 15), suggesting that the mitochondrion is involved in sperm [Ca(2+)]i homeostasis. To further understand the interrelationship between the mitochondrion and the speract responses, we measured mitochondrial membrane potential (ΔΨ) and NADH levels. We found that the stimulation of sperm with speract depolarizes the mitochondrion and increases the levels of NADH. Surprisingly, these responses are independent of external Ca(2+) and are due to the increase in intracellular pH (pHi) induced by speract. Our findings indicate that speract, by regulating pHi, in addition to [Ca(2+)]i, may finely modulate mitochondrial metabolism to control motility and ensure that sperm reach the egg and fertilize it. PMID:26772728

  1. 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.

  2. 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

  3. A novel tachykinin NK2 receptor antagonist prevents motility-stimulating effects of neurokinin A in small intestine

    PubMed Central

    Lördal, Mikael; Navalesi, Giovanni; Theodorsson, Elvar; Maggi, Carlo A; Hellström, Per M

    2001-01-01

    MEN 11420 (nepadutant) is a potent, selective and competitive antagonist of tachykinin NK2 receptors. The objective of the present study was to assess the capability of the drug to antagonize the stimulatory effects of neurokinin A (NKA) on gastrointestinal motility, as well as to change the fasting migrating motor complex (MMC). Thirty-four male volunteers were randomized to treatment with either placebo or MEN 11420 in a double-blinded manner. Effects of MEN 11420 (8 mg intravenously) were evaluated as changes in phases I, II and III of MMC, as well as contraction frequency, amplitude and motility index during baseline conditions and during stimulation of motility using NKA (25 pmol kg−1 min−1 intravenously). NKA preceded by placebo increased the fraction of time occupied by phase II, increased contraction frequency, amplitude and motility index. MEN 11420 effectively antagonized the motility-stimulating effects of NKA. MEN 11420 reduced the phase II-stimulating effect of NKA. In addition, the stimulatory effect of NKA on contraction frequency and amplitude, as well as motility index were inhibited by MEN 11420. MEN 11420 did not affect the characteristics of MMC during saline infusion. Plasma levels of MEN 11420 peaked during the first hour after infusion and decreased to less than half during the first 2 h. In conclusion, intravenous MEN 11420 effectively inhibited NKA-stimulated, but not basal gastrointestinal motility, and was well tolerated by all subjects. PMID:11522614

  4. 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

  5. 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

  6. Effective regularity in modulation on gastric motility induced by different acupoint stimulation

    PubMed Central

    Li, Yu-Qing; Zhu, Bing; Rong, Pei-Jing; Ben, Hui; Li, Yan-Hua

    2006-01-01

    AIM: To investigate whether manual acupuncture at representative acupoints in different parts of the body can modulate responses of gastric motility in rats and regular effects in different acupoint stimulation. METHODS: The gastric motor activity of rats was recorded by the intrapyloric balloon. The changes of gastric motility induced by the stimulation were compared with the background activity in intragastric pressure and/or waves of gastric contraction recorded before any stimulation. Morphological study was also conducted by observing the Evans dye extravasation in the skin after mustard oil injection into the intragastric mucous membrane to certify cutaneous innervations of blue dots related to gastric segmental innervations. RESULTS: In all six rats that received mustard oil injections into intragastric mucosa, small blue dots appeared in the skin over the whole abdomen, but mainly in peri-midline upper- and middle- abdomen and middle-back, a few in thigh and groin. It may speculate that cutaneous innervations of blue dots have the same distribution as gastric segmental innervations. Acu-stimulation in acupoints of head-neck, four limbs, upper chest-dorsum and lower-dorsum induced markedly augmentation of gastric motility (acupoints on head-neck such as St-2: n = 16, 105.19 ± 1.36 vs 112.25 ± 2.02 and St-3: n = 14, 101.5 ± 1.75 vs 109.36 ± 1.8; acupoints on limbs such as Sp-6: n = 19, 100.74 ± 1.54 vs 110.26 ± 3.88; St-32: n = 17, 103.59 ± 1.64 vs 108.24 ± 2.41; St-36: n = 16, 104.81 ± 1.72 vs 110.81 ± 2.74 and Li-11: n = 17, 106.47 ± 2.61 vs 114.77 ± 3.77, P < 0.05-0.001). Vigorous inhibitory regulations of gastric motility induced by acu-stimulation applied in acupoints on whole abdomen and middle-dorsum were significantly different as compared with the controls before acu-stimulation (abdomen acupoints such as Cv-12: n = 11, 109.36 ± 2.09 vs 101 ± 2.21; Cv-6: n = 18, 104.39 ± 1.42 vs 91.83 ± 3.22 and St-21: n = 12, 107 ± 2.97 vs 98.58

  7. ATP and related purines stimulate motility, spatial congregation, and coalescence in red algal spores.

    PubMed

    Huidobro-Toro, Juan P; Donoso, Verónica; Flores, Verónica; Santelices, Bernabé

    2015-04-01

    Adenosine 5'-triphosphate (ATP) is a versatile extracellular signal along the tree of life, whereas cAMP plays a major role in vertebrates as an intracellular messenger for hormones, transmitters, tastants, and odorants. Since red algal spore coalescence may be considered analogous to the congregation process of social amoeba, which is stimulated by cAMP, we ascertained whether exogenous applications of ATP, cAMP, adenine, or adenosine modified spore survival and motility, spore settlement and coalescence. Concentration-response studies were performed with carpospores of Mazzaella laminarioides (Gigartinales), incubated with and without added purines. Stirring of algal blades released ADP/ATP to the cell media in a time-dependent manner. 10-300 μM ATP significantly increased spore survival; however, 1,500 μM ATP, cAMP or adenine induced 100% mortality within less than 24 h; the exception was adenosine, which up to 3,000 μM, did not alter spore survival. ATP exposure elicited spore movement with speeds of 2.2-2.5 μm · s(-1) . 14 d after 1,000 μM ATP addition, spore abundance in the central zone of the plaques was increased 2.7-fold as compared with parallel controls. Likewise, 1-10 μM cAMP or 30-100 μM adenine also increased central zone spore abundance, albeit these purines were less efficacious than ATP; adenosine up to 3,000 μM did not influence settlement. Moreover, 1,000 μM ATP markedly accelerated coalescence, the other purines caused a variable effect. We conclude that exogenous cAMP, adenine, but particularly ATP, markedly influence red algal spore physiology; effects are compatible with the expression of one or more membrane purinoceptor(s), discarding adenosine receptor participation. PMID:26986520

  8. 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.

  9. 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.

  10. 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

  11. 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

  12. 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

  13. 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

  14. 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

  15. 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.

  16. 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.

  17. 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

  18. 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

  19. 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.

  20. 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

  1. 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

  2. Antigen-induced regulation of T-cell motility, interaction with antigen-presenting cells and activation through endogenous thrombospondin-1 and its receptors

    PubMed Central

    Bergström, Sten-Erik; Uzunel, Mehmet; Talme, Toomas; Bergdahl, Eva; Sundqvist, Karl-Gösta

    2015-01-01

    Antigen recognition reduces T-cell motility, and induces prolonged contact with antigen-presenting cells and activation through mechanisms that remain unclear. Here we show that the T-cell receptor (TCR) and CD28 regulate T-cell motility, contact with antigen-presenting cells and activation through endogenous thrombospondin-1 (TSP-1) and its receptors low-density lipoprotein receptor-related protein 1 (LRP1), calreticulin and CD47. Antigen stimulation induced a prominent up-regulation of TSP-1 expression, and transiently increased and subsequently decreased LRP1 expression whereas calreticulin was unaffected. This antigen-induced TSP-1/LRP1 response down-regulated a motogenic mechanism directed by LRP1-mediated processing of TSP-1 in cis within the same plasma membrane while promoting contact with antigen-presenting cells and activation through cis interaction of the C-terminal domain of TSP-1 with CD47 in response to N-terminal TSP-1 triggering by calreticulin. The antigen-induced TSP-1/LRP1 response maintained a reduced but significant motility level in activated cells. Blocking CD28 co-stimulation abrogated LRP1 and TSP-1 expression and motility. TCR/CD3 ligation alone enhanced TSP-1 expression whereas CD28 ligation alone enhanced LRP1 expression. Silencing of TSP-1 inhibited T-cell conjugation to antigen-presenting cells and T helper type 1 (Th1) and Th2 cytokine responses. The Th1 response enhanced motility and increased TSP-1 expression through interleukin-2, whereas the Th2 response weakened motility and reduced LRP1 expression through interleukin-4. Ligation of the TCR and CD28 therefore elicits a TSP-1/LRP1 response that stimulates prolonged contact with antigen-presenting cells and, although down-regulating motility, maintains a significant motility level to allow serial contacts and activation. Th1 and Th2 cytokine responses differentially regulate T-cell expression of TSP-1 and LRP1 and motility. PMID:25393517

  3. Stimulation of colonic motility by oral PEG electrolyte bowel preparation assessed by MRI: comparison of split vs single dose

    PubMed Central

    Marciani, L; Garsed, K C; Hoad, C L; Fields, A; Fordham, I; Pritchard, S E; Placidi, E; Murray, K; Chaddock, G; Costigan, C; Lam, C; Jalanka-Tuovinen, J; De Vos, W M; Gowland, P A; Spiller, R C

    2014-01-01

    Background Most methods of assessing colonic motility are poorly acceptable to patients. Magnetic resonance imaging (MRI) can monitor gastrointestinal motility and fluid distributions. We predicted that a dose of oral polyethylene glycol (PEG) and electrolyte solution would increase ileo-colonic inflow and stimulate colonic motility. We aimed to investigate the colonic response to distension by oral PEG electrolyte in healthy volunteers (HVs) and to evaluate the effect of single 2 L vs split (2 × 1 L) dosing. Methods Twelve HVs received a split dose (1 L the evening before and 1 L on the study day) and another 12 HVs a single dose (2 L on the main study day) of PEG electrolyte. They underwent MRI scans, completed symptom questionnaires, and provided stool samples. Outcomes included small bowel water content, ascending colon motility index, and regional colonic volumes. Key Results Small bowel water content increased fourfold from baseline after ingesting both split (p = 0.0010) and single dose (p = 0.0005). The total colonic volume increase from baseline was smaller for the split dose at 35 ± 8% than for the single dose at 102 ± 27%, p = 0.0332. The ascending colon motility index after treatment was twofold higher for the single dose group (p = 0.0103). Conclusions & Inferences Ingestion of 1 and 2 L PEG electrolyte solution caused a rapid increase in the small bowel and colonic volumes and a robust rise in colonic motility. The increase in both volumes and motility was dose dependent. Such a challenge, being well-tolerated, could be a useful way of assessing colonic motility in future studies. PMID:25060551

  4. 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

  5. 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

  6. 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

  7. 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

  8. 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.

  9. Therapeutic potential of synchronized gastric electrical stimulation for gastroparesis: enhanced gastric motility in dogs.

    PubMed

    Zhu, Hongbing; Sallam, Hanaa; Chen, Dennis D; Chen, Jiande D Z

    2007-11-01

    The aim of this study was to determine the effects and mechanism of synchronized gastric electrical stimulation (SGES) on gastric contractions and gastric emptying. The first experiment was designed to study the effects of SGES on antral contractions in four randomized sessions. Sessions 1 (control) and 2 (atropine) were performed in the fasting state, composed of three 30-min periods (baseline, stimulation, and recovery). Sessions 3 (control) and 4 (SGES performed during 2nd 20-min period) were performed in the fed state, consisting of two 20-min periods; glucagon was injected after the first 20-min recording. The second experiment was designed to study the effect of SGES on gastric emptying and consisted of two sessions (control and SGES). SGES was delivered with train duration of 0.5-0.8s, pulse frequency of 40 Hz, width of 2 ms, and amplitude of 4 mA. We found that 1) SGES induced gastric antral contractions in the fasting state. The motility index was 1.3 +/- 0.5 at baseline and 6.1 +/- 0.7 (P = 0.001) during SGES. This excitatory effect was completely blocked by atropine. 2) SGES enhanced postprandial antral contractions impaired by glucagon. 3) SGES significantly accelerated glucagon-induced delayed gastric emptying. Gastric emptying was 25.5 +/- 11.3% without SGES and 38.3 +/- 10.7% with SGES (P = 0.006 vs. control). This novel method of SGES induces gastric antral contractions in the fasting state, enhances glucagon-induced antral hypomotility in the fed state, and accelerates glucagon-induced delayed gastric emptying. The effect of SGES on antral contractions is mediated via the cholinergic pathway. PMID:17881615

  10. 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

  11. 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

  12. 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

  13. RhoA mediates cyclooxygenase-2 signaling to disrupt the formation of adherens junctions and increase cell motility.

    PubMed

    Chang, Yu-Wen E; Marlin, Jerry W; Chance, Terry W; Jakobi, Rolf

    2006-12-15

    Cyclooxygenase-2 (COX-2) represents an important target for treatment and prevention of colorectal cancer. Although COX-2 signaling is implicated in promoting tumor cell growth and invasion, the molecular mechanisms that mediate these processes are largely unknown. In this study, we show that the RhoA pathway mediates COX-2 signaling to disrupt the formation of adherens junctions and increase cell motility. Disruption of adherens junctions promotes tumor cell invasion and metastasis and is often associated with tumor progression. We detected high levels of RhoA activity in HCA-7 colon carcinoma cells that constitutively express COX-2. Inhibition of COX-2 significantly reduced the levels of RhoA activity in HCA-7 cells, suggesting that constitutive expression of COX-2 stimulates RhoA activity. Interestingly, inhibition of COX-2 or silencing of COX-2 expression with small interfering RNA (siRNA) stimulated the formation of adherens junctions, concomitant with increased protein levels of E-cadherin and alpha-catenin. Furthermore, inhibition of RhoA or silencing of RhoA expression with siRNA increased the levels of E-cadherin and alpha-catenin. Inhibition of Rho kinases (ROCK), the RhoA effector proteins, also increased levels of E-cadherin and alpha-catenin and stimulated formation of adherens junctions. The motility of HCA-7 cells was significantly decreased when COX-2 or RhoA was inhibited. Therefore, our data reveal a novel molecular mechanism that links COX-2 signaling to disrupt the formation of adherens junctions; COX-2 stimulates the RhoA/ROCK pathway, which reduces levels of E-cadherin and alpha-catenin leading to disruption of adherens junction formation and increased motility. Understanding of COX-2 downstream signaling pathways that promote tumor progression is crucial for the development of novel therapeutic strategies. PMID:17178865

  14. Scapinin, the Protein Phosphatase 1 Binding Protein, Enhances Cell Spreading and Motility by Interacting with the Actin Cytoskeleton

    PubMed Central

    Sagara, Junji; Arata, Toshiaki; Taniguchi, Shunichiro

    2009-01-01

    Scapinin, also named phactr3, is an actin and protein phosphatase 1 (PP1) binding protein, which is expressed in the adult brain and some tumor cells. At present, the role(s) of scapinin in the brain and tumors are poorly understood. We show that the RPEL-repeat domain of scapinin, which is responsible for its direct interaction with actin, inhibits actin polymerization in vitro. Next, we established a Hela cell line, where scapinin expression was induced by tetracycline. In these cells, expression of scapinin stimulated cell spreading and motility. Scapinin was colocalized with actin at the edge of spreading cells. To explore the roles of the RPEL-repeat and PP1-binding domains, we expressed wild-type and mutant scapinins as fusion proteins with green fluorescence protein (GFP) in Cos7 cells. Expression of GFP-scapinin (wild type) also stimulated cell spreading, but mutation in the RPEL-repeat domain abolished both the actin binding and the cell spreading activity. PP1-binding deficient mutants strongly induced cell retraction. Long and branched cytoplasmic processes were developed during the cell retraction. These results suggest that scapinin enhances cell spreading and motility through direct interaction with actin and that PP1 plays a regulatory role in scapinin-induced morphological changes. PMID:19158953

  15. 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

  16. 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.

  17. 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

  18. 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

  19. Brain-derived neurotrophic factor regulates cell motility in human colon cancer.

    PubMed

    Huang, Ssu-Ming; Lin, Chingju; Lin, Hsiao-Yun; Chiu, Chien-Ming; Fang, Chia-Wei; Liao, Kuan-Fu; Chen, Dar-Ren; Yeh, Wei-Lan

    2015-06-01

    Brain-derived neurotrophic factor (BDNF) is a potent neurotrophic factor that has been shown to affect cancer cell metastasis and migration. In the present study, we investigated the mechanisms of BDNF-induced cell migration in colon cancer cells. The migratory activities of two colon cancer cell lines, HCT116 and SW480, were found to be increased in the presence of human BDNF. Heme oxygenase-1 (HO)-1 is known to be involved in the development and progression of tumors. However, the molecular mechanisms that underlie HO-1 in the regulation of colon cancer cell migration remain unclear. Expression of HO-1 protein and mRNA increased in response to BDNF stimulation. The BDNF-induced increase in cell migration was antagonized by a HO-1 inhibitor and HO-1 siRNA. Furthermore, the expression of vascular endothelial growth factor (VEGF) also increased in response to BDNF stimulation, as did VEGF mRNA expression and transcriptional activity. The increase in BDNF-induced cancer cell migration was antagonized by a VEGF-neutralizing antibody. Moreover, transfection with HO-1 siRNA effectively reduced the increased VEGF expression induced by BDNF. The BDNF-induced cell migration was regulated by the ERK, p38, and Akt signaling pathways. Furthermore, BDNF-increased HO-1 and VEGF promoter transcriptional activity were inhibited by ERK, p38, and AKT pharmacological inhibitors and dominant-negative mutants in colon cancer cells. These results indicate that BDNF increases the migration of colon cancer cells by regulating VEGF/HO-1 activation through the ERK, p38, and PI3K/Akt signaling pathways. The results of this study may provide a relevant contribution to our understanding of the molecular mechanisms by which BDNF promotes colon cancer cell motility. PMID:25876647

  20. 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

  1. Diffused and Sustained Inhibitory Effects of Intestinal Electrical Stimulation on Intestinal Motility Mediated via Sympathetic Pathway

    PubMed Central

    Zhao, Xiaotuan; Yin, Jieyun; Wang, Lijie; Chen, J D Z

    2013-01-01

    Objective The aims was to investigate the energy-dose response effect of IES on small bowel motility, to compare the effect of forward and backward IES; to explore the possibility of using intermittent IES and mechanism of IES on intestinal motility. Material and Methods Five dogs implanted with a duodenal cannula and one pair of intestinal serosal electrodes were studied in 5 sessions: 1) energy-dose response study; 2) forward IES; 3) backward IES; 4) intermittent IES vs. continuous IES; 5) administration of guanethidine. The contractile activity and tonic pressure of the small intestine were recorded. The duration of sustained effect after turning off IES was manually calculated. Results 1) IES with long pulses energy-dose dependently inhibited contractile activity and tonic pressure of the small intestine (p < 0.001). 2) The duration of sustained inhibitory effect of IES on the small intestine depended on the energy of IES delivered (p < 0.001). 3) The potency of the inhibitory effect was the same between forward and backward IES. 4) The efficacy of intermittent IES was the same as continuous IES in inhibiting motility of the small intestine. 5) Guanethidine blocked the inhibitory effect of IES on intestinal motility. Conclusions IES with long pulses inhibits small intestinal motility; the effect is energy-dose dependent, diffused and sustained. Intermittent IES has the same efficacy as the continuous IES in inhibiting small intestinal motility. Forward and backward IES have similar inhibitory effects on small bowel motility. This IES-induced inhibitory effect is mediated via the sympathetic pathway. PMID:23924055

  2. 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

  3. 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

  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. 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.

  6. 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

  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. 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

  9. 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

  10. Electrolysis cell stimulation

    NASA Technical Reports Server (NTRS)

    Gordon, L. H.; Phillips, B. R.; Evangelista, J.

    1978-01-01

    Computer program represents attempt to understand and model characteristics of electrolysis cells. It allows user to determine how cell efficiency is affected by temperature, pressure, current density, electrolyte concentration, characteristic dimensions, membrane resistance, and electrolyte circulation rate. It also calculates ratio of bubble velocity to electrolyte velocity for anode and cathode chambers.

  11. 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.

  12. 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

  13. Are Primo Vessels (PVs) on the Surface of Gastrointestine Involved in Regulation of Gastric Motility Induced by Stimulating Acupoints ST36 or CV12?

    PubMed Central

    Wang, Xiaoyu; Shi, Hong; Shang, Hongyan; Su, Yangshuai; Xin, Juanjuan; He, Wei; Jing, Xianghong; Zhu, Bing

    2012-01-01

    Previous studies showed primo vessels (PVs), which were referred to as Bonhan ducts (BHDs) and a part of circulatory system by Kim, located in different places of the body. The BHDs system was once considered as the anatomical basis of classical acupuncture meridian but not clearly identified by other investigators. In the present study, we tried to address the relationship between PVs and meridians through detecting the modulation of gastric motility by stimulating the PVs on the surface of stomach or intestine, as well as acupoints Zusanli (ST36) and Zhongwan (CV12). The results showed electric stimulation of the PVs had no effect on the gastric motility. While stimulating CV12 inhibited gastric motility significantly in PVs-intact and PVs-cut rats, there is no significant difference between the inhibition rate of the PVS-intact and the PVS-cut rats. Stimulating at ST36 increased gastric motility significantly in both the PVs-intact and the PVs-cut rats, yet there was no significant difference between the facilitation rate of the both groups. Taken together, the PVs on the surface of stomach or intestine did not mediate the regulation of gastric motility induced by stimulating at the acupoints ST36 or CV12. PMID:23091558

  14. 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

  15. 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.

  16. 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.

  17. 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

  18. 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

  19. 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

  20. 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

  1. Ulcerogenic and intestinal motility/transit stimulating actions of nevirapine in albino Wistar rats.

    PubMed

    Umoren, Elizabeth Bassey; Obembe, Agona Odeh; Osim, Eme Effiom

    2013-09-01

    The antiretroviral is a non-nucleoside reverse transcriptase inhibitor of human immunodeficiency virus type 1. This study was undertaken to investigate the effect of nevirapine (NVP) administration on gastric acid secretion, pepsin secretion, mucosal secretion, intestinal motility, and transit using apparently healthy albino Wistar rats. Eighty albino Wistar rats (50-125 g body weight) from the start of the experiment were used for the study. Rats in the control group were fed normal rodent chow, while the NVP group was fed by gavage NVP (0.4 mg/kg body weight) two times daily (07:00 and 18:00 hours) in addition to normal rodent chow for 12 weeks. All animals were allowed free access to clean drinking water. Mean basal gastric output and peak acid output following histamine administration in the NVP-treated group were significantly higher (p < 0.001, respectively) compared to the control. Following cimetidine administration, there was significant decrease (p < 0.001) in peak acid output in the NVP-treated group compared to the control. The concentration of gastric pepsin, adherent mucus secretion, and mean value for ulcer score were significantly higher (p < 0.001) compared to their control group, respectively. There were significant increases (p < 0.05, respectively) in intestinal motility and basal contraction (p < 0.05) and increase in intestinal transit of the ileum of NVP-treated rats compared to their control, respectively. Results of the study suggest that NVP administration might provoke gastric ulceration in rats which may be caused by high pepsin, high basal acid output, and increased intestinal motility and transit. PMID:23536414

  2. 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

  3. 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

  4. 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

  5. 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

  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. 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

  8. The RET/PTC-RAS-BRAF linear signaling cascade mediates the motile and mitogenic phenotype of thyroid cancer cells

    PubMed Central

    Melillo, Rosa Marina; Castellone, Maria Domenica; Guarino, Valentina; De Falco, Valentina; Cirafici, Anna Maria; Salvatore, Giuliana; Caiazzo, Fiorina; Basolo, Fulvio; Giannini, Riccardo; Kruhoffer, Mogens; Orntoft, Torben; Fusco, Alfredo; Santoro, Massimo

    2005-01-01

    In papillary thyroid carcinomas (PTCs), rearrangements of the RET receptor (RET/PTC) and activating mutations in the BRAF or RAS oncogenes are mutually exclusive. Here we show that the 3 proteins function along a linear oncogenic signaling cascade in which RET/PTC induces RAS-dependent BRAF activation and RAS- and BRAF-dependent ERK activation. Adoptive activation of the RET/PTC-RAS-BRAF axis induced cell proliferation and Matrigel invasion of thyroid follicular cells. Gene expression profiling revealed that the 3 oncogenes activate a common transcriptional program in thyroid cells that includes upregulation of the CXCL1 and CXCL10 chemokines, which in turn stimulate proliferation and invasion. Thus, motile and mitogenic properties are intrinsic to transformed thyroid cells and are governed by an epistatic oncogenic signaling cascade. PMID:15761501

  9. 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

  10. 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

  11. Platelet-activating factor promotes motility in breast cancer cells and disrupts non-transformed breast acinar structures.

    PubMed

    Anandi, V Libi; Ashiq, K A; Nitheesh, K; Lahiri, M

    2016-01-01

    A plethora of studies have demonstrated that chronic inflammatory microenvironment influences the genesis and progression of tumors. Such microenvironments are enriched with various lipid mediators. Platelet activating factor (PAF, 1-alkyl-2-acetyl-sn-glycero-3-phosphocholine) is one such lipid mediator that is secreted by different immune cell types during inflammation and by breast cancer cells upon stimulation with growth factors. Overexpression of PAF-receptor has also been observed in many other cancers. Here we report the possible roles of PAF in tumor initiation and progression. MCF10A, a non-transformed and non-malignant mammary epithelial cell line, when grown as 3D 'on-top' cultures form spheroids that have a distinct hollow lumen surrounded by a monolayer of epithelial cells. Exposure of these spheroids to PAF resulted in the formation of large deformed acinar structures with disrupted lumen, implying transformation. We then examined the response of transformed cells such as MDA-MB 231 to stimulation with PAF. We observed collective cell migration as well as motility at the single cell level on PAF induction, suggesting its role during metastasis. This increase in collective cell migration is mediated via PI3-kinase and/or JNK pathway and is independent of the MAP-kinase pathway. Taken together this study signifies a novel role of PAF in inducing transformation of non-tumorigenic cells and the vital role in promotion of breast cancer cell migration. PMID:26531049

  12. 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.

  13. 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

  14. 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.

  15. 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

  16. 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

  17. 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

  18. 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

  19. RanBPM Protein Acts as a Negative Regulator of BLT2 Receptor to Attenuate BLT2-mediated Cell Motility*

    PubMed Central

    Wei, Jun-Dong; Kim, Joo-Young; Kim, Ae-Kyoung; Jang, Sung Key; Kim, Jae-Hong

    2013-01-01

    BLT2, a low affinity receptor for leukotriene B4 (LTB4), is a member of the G protein-coupled receptor family and is involved in many signal transduction pathways associated with various cellular phenotypes, including chemotactic motility. However, the regulatory mechanism for BLT2 has not yet been demonstrated. To understand the regulatory mechanism of BLT2, we screened and identified the proteins that bind to BLT2. Using a yeast two-hybrid assay with the BLT2 C-terminal domain as bait, we found that RanBPM, a previously proposed scaffold protein, interacts with BLT2. We demonstrated the specific interaction between BLT2 and RanBPM by GST pulldown assay and co-immunoprecipitation assay. To elucidate the biological function of the RanBPM-BLT2 interaction, we evaluated the effects of RanBPM overexpression or knockdown. We found that BLT2-mediated motility was severely attenuated by RanBPM overexpression and that knockdown of endogenous RanBPM by shRNA strongly promoted BLT2-mediated motility, suggesting a negative regulatory function of RanBPM toward BLT2. Furthermore, we observed that the addition of BLT2 ligands caused the dissociation of BLT2 and RanBPM, thus releasing the negative regulatory effect of RanBPM. Finally, we propose that Akt-induced BLT2 phosphorylation at residue Thr355, which occurs after the addition of BLT2 ligands, is a potential mechanism by which BLT2 dissociates from RanBPM, resulting in stimulation of BLT2 signaling. Taken together, our results suggest that RanBPM acts as a negative regulator of BLT2 signaling to attenuate BLT2-mediated cell motility. PMID:23928309

  20. 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

  1. 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

  2. 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

  3. 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.

  4. 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

  5. General pharmacology of the four gastrointestinal motility stimulants bethanechol, metoclopramide, trimebutine, and cisapride.

    PubMed

    Megens, A A; Awouters, F H; Niemegeers, C J

    1991-06-01

    The pharmacological profile of bethanechol (CAS 674-38-4), metoclopramide (CAS 364-62-5), trimebutine (CAS 39133-31-8) and cisapride (CAS 81098-60-4) was studied in a series of simple pharmacological tests in rats and dogs. Bethanechol stimulated both gastric emptying and intestinal propulsion but displayed also the well-known behavioral effects of a direct muscarinic acetylcholine receptor agonist. Metoclopramide showed the profile of a centrally active dopamine D2 antagonist. In addition, metoclopramide displayed a stimulant effect on spontaneous gastric emptying in rats, an effect that could not be related to dopamine D2 antagonism. The only effect observed with trimebutine was protection from castor oil diarrhea, probably due to its reported interaction with peripheral opiate receptors. Cisapride was a potent stimulant of gastric emptying in rats, 7 times more potent than metoclopramide. Cisapride was also a very specific gastrokinetic, over a large dose range (specificity ratio: greater than or equal to 20) devoid of effects indicative for direct interaction with dopamine or acetylcholine receptors. The relationship between the differential activity profiles of the compounds in the present study and differences in their mechanism of action and side-effect liability is discussed. PMID:1930352

  6. 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

  7. 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

  8. 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

  9. 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

  10. 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

  11. 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

  12. Expression of E1AF/PEA3, an Ets-related transcription factor in human non-small-cell lung cancers: its relevance in cell motility and invasion.

    PubMed

    Hiroumi, H; Dosaka-Akita, H; Yoshida, K; Shindoh, M; Ohbuchi, T; Fujinaga, K; Nishimura, M

    2001-09-01

    Cell invasion and metastasis characterize the malignant potential of non-small-cell lung cancers (NSCLCs). We have previously reported that E1AF, a member of the Ets-related transcription factor family, confers invasive phenotype on breast cancer and oral squamous-cell carcinoma cell lines. In our study, we analyzed the E1AF expression in cell lines and resected tumors of NSCLCs by Northern blot and in situ hybridization analyses and found that 15 of 17 cell lines and 12 of 19 tumors expressed E1AF mRNA while normal lung tissue and concomitant normal cells within tumors did not. To examine the biologic importance of E1AF in NSCLCs, we introduced the E1AF gene into VMRC-LCD and NCI-H226, NSCLC cell lines lacking E1AF expression, and examined cell motility and invasion activities. E1AF-transfected VMRC-LCD cells showed increased cell motility that was 2-fold that of parental and vector-transfected control cells (p < 0.01), and both cell motility and invasion were increased 1.6-fold in NCI-H226 (p < 0.01). Furthermore, hepatocyte growth factor (HGF), which is one of the most effective cell-scattering factors, stimulated the motile and invasive activities in E1AF-transfected VMRC-LCD and NCI-H226 cells but not in their parental or vector-transfected control cells. Ets-1 mRNA expression was found in E1AF-transfected VMRC-LCD cells but not in parental or vector-transfected cells. HGF further induced expression of the Ets-1 and urokinase-type plasminogen activator (uPA) genes specifically in E1AF-transfected cells. These findings suggest that E1AF plays a substantial role in the cell motility and invasion of NSCLCs. PMID:11519038

  13. 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

  14. 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

  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. 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

  17. 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

  18. 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

  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. 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

  1. 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

  2. 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

  3. Tensile stress stimulates microtubule outgrowth in living cells

    NASA Technical Reports Server (NTRS)

    Kaverina, Irina; Krylyshkina, Olga; Beningo, Karen; Anderson, Kurt; Wang, Yu-Li; Small, J. Victor

    2002-01-01

    Cell motility is driven by the sum of asymmetric traction forces exerted on the substrate through adhesion foci that interface with the actin cytoskeleton. Establishment of this asymmetry involves microtubules, which exert a destabilising effect on adhesion foci via targeting events. Here, we demonstrate the existence of a mechano-sensing mechanism that signals microtubule polymerisation and guidance of the microtubules towards adhesion sites under increased stress. Stress was applied either by manipulating the body of cells moving on glass with a microneedle or by stretching a flexible substrate that cells were migrating on. We propose a model for this mechano-sensing phenomenon whereby microtubule polymerisation is stimulated and guided through the interaction of a microtubule tip complex with actin filaments under tension.

  4. 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

  5. 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

  6. 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

  7. 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

  8. 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

  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. 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

  13. 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

  14. 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

  15. 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

  16. Polo-like kinase 1 induces epithelial-to-mesenchymal transition and promotes epithelial cell motility by activating CRAF/ERK signaling

    PubMed Central

    Wu, Jianguo; Ivanov, Andrei I; Fisher, Paul B; Fu, Zheng

    2016-01-01

    Polo-like kinase 1 (PLK1) is a key cell cycle regulator implicated in the development of various cancers, including prostate cancer. However, the functions of PLK1 beyond cell cycle regulation remain poorly characterized. Here, we report that PLK1 overexpression in prostate epithelial cells triggers oncogenic transformation. It also results in dramatic transcriptional reprogramming of the cells, leading to epithelial-to-mesenchymal transition (EMT) and stimulation of cell migration and invasion. Consistently, PLK1 downregulation in metastatic prostate cancer cells enhances epithelial characteristics and inhibits cell motility. The signaling mechanisms underlying the observed cellular effects of PLK1 involve direct PLK1-dependent phosphorylation of CRAF with subsequent stimulation of the MEK1/2-ERK1/2-Fra1-ZEB1/2 signaling pathway. Our findings highlight novel non-canonical functions of PLK1 as a key regulator of EMT and cell motility in normal prostate epithelium and prostate cancer. This study also uncovers a previously unanticipated role of PLK1 as a potent activator of MAPK signaling. DOI: http://dx.doi.org/10.7554/eLife.10734.001 PMID:27003818

  17. 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

  18. 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

  19. 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.

  20. 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.

  1. Intraocular BDNF Promotes Ectopic Branching, Alters Motility and Stimulates Abnormal Collaterals in Regenerating Optic Fibers

    PubMed Central

    Dawson, Amy J.; Miotke, Jill A.; Meyer, Ronald L.

    2015-01-01

    A great deal of effort has been invested in using trophic factors and other bioactive molecules to promote cell survival and axonal regeneration in the adult central nervous system. Far less attention has been paid to investigating potential effects that trophic factors may have that might interfere with recovery. In the visual system, BDNF has been previously reported to prevent regeneration. To test if BDNF is inherently incompatible with regeneration, BDNF was given intraocularly during optic nerve regeneration in the adult goldfish. In vivo imaging and anatomical analysis of selectively labeled axons were used as a sensitive assay for effects on regeneration within the tectum. BDNF had no detectable inhibitory effect on the ability of axons to regenerate. Normal numbers of axons regenerated into the tectum, exhibited dynamic growth and retractions similar to controls, and were able to navigate to their correct target zone in the tectum. However, BDNF was found to have additional effects that adversely affected the quality of regeneration. It promoted premature branching at ectopic locations, diminished the growth rate of axons through the tectum, and resulted in the formation of ectopic collaterals. Thus, although BDNF has robust effects on axonal behavior, it is, nevertheless, compatible with axonal regeneration, axon navigation and the formation of terminal arbors. PMID:25847715

  2. 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.

  3. 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

  4. The motile and invasive capacity of human endometrial stromal cells: implications for normal and impaired reproductive function.

    PubMed

    Weimar, Charlotte H E; Macklon, Nick S; Post Uiterweer, Emiel D; Brosens, Jan J; Gellersen, Birgit

    2013-01-01

    BACKGROUND Mechanisms underlying early reproductive loss in the human are beginning to be elucidated. The migratory and invasive capacity of human endometrial stromal cells (ESCs) is increasingly recognized to contribute to the intense tissue remodelling associated with embryo implantation, trophoblast invasion and endometrial regeneration. In this review, we examine the signals and mechanisms that control ESC migration and invasion and assess how deregulation of these cell functions contributes to common reproductive disorders. METHODS The PubMed database was searched for publications on motility and invasiveness of human ESCs in normal endometrial function and in reproductive disorders including implantation failure, recurrent pregnancy loss (RPL), endometriosis and adenomyosis, covering the period 2000-2012. RESULTS Increasing evidence suggests that implantation failure and RPL involve abnormal migratory responses of decidualizing ESCs to embryo and trophoblast signals. Numerous reports indicate that endometriosis, as well as adenomyosis, is associated with increased basal and stimulated invasiveness of ESCs and their progenitor cells, suggesting a link between a heightened menstrual repair response and the formation of ectopic implants. Migration and invasiveness of ESCs are controlled by a complex array of hormones, growth factors, chemokines and inflammatory mediators, and involve signalling through Rho GTPases, phosphatidylinositol-3-kinase and mitogen-activated protein kinase pathways. CONCLUSIONS Novel concepts are extending our understanding of the key functions of ESCs in effecting tissue repair imposed by cyclic menstruation and parturition. Migration of decidualizing ESCs also serves to support blastocyst implantation and embryo selection through discriminate motile responses directed by embryo quality. Targeting regulatory molecules holds promise for developing new strategies for the treatment of reproductive disorders such as endometriosis and

  5. 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

  6. 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.

  7. 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

  8. 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

  9. 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

  10. 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

  11. 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.

  12. 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.

  13. 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

  14. 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

  15. 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

  16. Different effects of GPR120 and GPR40 on cellular functions stimulated by 12-O-tetradecanoylphorbol-13-acetate in melanoma cells.

    PubMed

    Fukushima, Kaori; Takahashi, Kaede; Fukushima, Nobuyuki; Honoki, Kanya; Tsujiuchi, Toshifumi

    2016-06-17

    G-protein-coupled receptor 120 (GPR120) and GPR40 exhibit a variety of biological responses by the binding of free fatty acids. 12-O-Tetradecanoylphorbol-13-acetate (TPA) is a tumor promoting agent of skin carcinogenesis. It is known that TPA treatment stimulates cell motile activity of cancer cells, including melanoma cells. In the present study, we investigated whether GRP120 and GPR40 are involved in regulation of cell motile activity induced by TPA in two melanoma cell lines. A375 and G361 cells were treated with TPA at a concentration of 10 nM for 24 h. The cell motile activity of A375 cells was significantly increased by TPA, correlating with GPR40 expression. In contrast, TPA suppressed the cell motile activity of G361 cells, while GPR120 and GPR40 expressions were increased. The cell motile activity of A375 cells treated with TPA was markedly increased by GPR120 knockdown. In addition, to assess roles of GPR120 and GPR40 in cellular functions of A375 cells by the long-term TPA treatment, cells were treated with TPA (1 nM) for at least 3 months. The long-term TPA treatment induced the high cell motile activity and elevated GPR120 and GPR40 expressions. The high cell motile activity of A375 cells stimulated by the long-term TPA treatment was enhanced by GPR120 knockdown. These results suggest that GPR120 negatively and GPR40 positively regulate cell motile activities induce by TPA in melanoma cells. PMID:27163640

  17. 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

  18. Motile Cilia of Human Airway Epithelia Are Chemosensory

    PubMed Central

    Shah, Alok S; Ben-Shahar, Yehuda; Moninger, Thomas O; Kline, Joel N; Welsh, Michael J

    2010-01-01

    Cilia are microscopic projections that extend from eukaryotic cells. There are two general types of cilia; primary cilia serve as sensory organelles, whereas motile cilia exert mechanical force. The motile cilia emerging from human airway epithelial cells propel harmful inhaled material out of the lung. We found that these cells express sensory bitter taste receptors, which localized on motile cilia. Bitter compounds increased the intracellular Ca2+ concentration and stimulated ciliary beat frequency. Thus, airway epithelia contain a cell-autonomous system in which motile cilia both sense noxious substances entering airways and initiate a defensive mechanical mechanism to eliminate the offending compound. Hence, like primary cilia, classical motile cilia also contain sensors to detect the external environment. PMID:19628819

  19. Ovarian stimulation and granulosa-cell tumour.

    PubMed

    Willemsen, W; Kruitwagen, R; Bastiaans, B; Hanselaar, T; Rolland, R

    1993-04-17

    Ovarian stimulation in the treatment of infertility is far from physiological because patients and their ovaries are exposed to high concentrations of gonadotropins. Many studies have focused on the two most common side-effects of ovarian stimulation--ie, hyperstimulation and multiple pregnancy. We describe 12 patients in whom granulosa-cell tumour was discovered after ovarian stimulation treatment with clomiphene citrate and/or gonadotropins. Although we cannot prove a causal link between the tumour and the medication, investigations in animals have shown a relation between gonadotropin exposition and the development of granulosa-cell tumours. The possible relation of ovarian stimulation and granulosa-cell tumours in human beings has not been published before. We postulate three explanations for this finding; first, the granulosa-cell tumour is present in the ovary, waiting for a hormonal trigger; second, increased follicle stimulating hormone concentrations are oncogenic to granulosa cell; and third, the onset of the granulosa-cell tumour during ovarian stimulation is coincidental. We recommend that ovarian stimulation is done only if there is a valid indication after proper assessment of the ovaries, and that women who have had ovarian stimulation are followed for longer than at present. PMID:8096944

  20. Toll-like Receptor 2 (TLR2), Transforming Growth Factor-β, Hyaluronan (HA), and Receptor for HA-mediated Motility (RHAMM) Are Required for Surfactant Protein A-stimulated Macrophage Chemotaxis*

    PubMed Central

    Foley, Joseph P.; Lam, David; Jiang, Hongmei; Liao, Jie; Cheong, Naeun; McDevitt, Theresa M.; Zaman, Aisha; Wright, Jo Rae; Savani, Rashmin C.

    2012-01-01

    The innate immune system protects the host from bacterial and viral invasion. Surfactant protein A (SPA), a lung-specific collectin, stimulates macrophage chemotaxis. However, the mechanisms regulating this function are unknown. Hyaluronan (HA) and its receptors RHAMM (receptor for HA- mediated motility, CD168) and CD44 also regulate cell migration and inflammation. We therefore examined the role of HA, RHAMM, and CD44 in SPA-stimulated macrophage chemotaxis. Using antibody blockade and murine macrophages, SPA-stimulated macrophage chemotaxis was dependent on TLR2 but not the other SPA receptors examined. Anti-TLR2 blocked SPA-induced production of TGFβ. In turn, TGFβ1-stimulated chemotaxis was inhibited by HA-binding peptide and anti-RHAMM antibody but not anti-TLR2 antibody. Macrophages from TLR2−/− mice failed to migrate in response to SPA but responded normally to TGFβ1 and HA, effects that were blocked by anti-RHAMM antibody. Macrophages from WT and CD44−/− mice had similar responses to SPA, whereas those from RHAMM−/− mice had decreased chemotaxis to SPA, TGFβ1, and HA. In primary macrophages, SPA-stimulated TGFβ production was dependent on TLR2, JNK, and ERK but not p38. Pam3Cys, a specific TLR2 agonist, stimulated phosphorylation of JNK, ERK, and p38, but only JNK and ERK inhibition blocked Pam3Cys-stimulated chemotaxis. We have uncovered a novel pathway for SPA-stimulated macrophage chemotaxis where SPA stimulation via TLR2 drives JNK- and ERK-dependent TGFβ production. TGFβ1, in turn, stimulates macrophage chemotaxis in a RHAMM and HA-dependent manner. These findings are highly relevant to the regulation of innate immune responses by SPA with key roles for specific components of the extracellular matrix. PMID:22948158

  1. 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

  2. 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

  3. 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

  4. 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

  5. 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

  6. 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

  7. 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

  8. 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.

  9. 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

  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. [Effect of drugs on granulocyte motility].

    PubMed

    Schmidt, D; Morenz, J

    1985-01-01

    The in-vitro influence of drugs on the chemokinesis and chemotaxis of neutrophils was investigated in order to prevent additional drug-induced motility impairment of cells in cases of already existing host defense disorders and for an eventual specific treatment of motility defects. Granulocyte motility is unimpaired by penicillin, ampicillin, carbenicillin, streptomycin, nystatin, and cyclophosphamide. The chemokinesis and chemotaxis of neutrophils are inhibited by erythromycin, oxytetracycline, doxycycline, chloramphenicol, hydrocortisone, g-strophanthin, digoxin, and digitoxin and in higher concentrations also by sulfonamides, gentamycin, prednisolone, methylprednisolone, dexamethasone, and phenylbutazone. Chemotaxis is selectively or rather more inhibited than chemokinesis by amphotericin B, griseofulvin, vinblastine++, trifluoperazine, and promethazine. Granulocyte motility is, however, stimulated by ascorbic acid, potassium thiocyanate, levamisole, lithium, and metofenazate. PMID:3161313

  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. 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

  15. 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.

  16. 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

  17. 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

  18. 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

  19. 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

  20. 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

  1. 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.

  2. 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

  3. 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.

  4. 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

  5. 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

  6. 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

  7. 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.

  8. 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

  9. 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

  10. Murine epidermal growth factor (EGF) fragment (33-42) inhibits both EGF- and laminin-dependent endothelial cell motility and angiogenesis.

    PubMed

    Nelson, J; Allen, W E; Scott, W N; Bailie, J R; Walker, B; McFerran, N V; Wilson, D J

    1995-09-01

    Laminin, murine epidermal growth factor (mEGF), and the synthetic laminin peptide Lam.B1(925-933) (a linear peptide from the B1 chain of murine laminin, CDPGY1GSR-amide) all stimulate endothelial cell motility above basal rates, whereas a synthetic mEGF fragment, mEGF33-42 (a linear peptide from the C-loop of mEGF, acetyl-C-[S-Acm]-VIGYSGDR-C-[S-Acm]-amide), inhibits motility. In both human SK HEP-1 and embryonic chick endothelial cells, mEGF33-42 blocks both EGF- and laminin-stimulated locomotion of endothelial cells. In vivo, mEGF33-42 also blocks both laminin- and mEGF-induced angiogenesis in the chick. In the human cell line. Lam.B1(925-933) has an additive effect in coincubation with either laminin or mEGF, but it blocks their effects in the chick cells. Lam.B1(925-933) alone stimulates angiogenesis in the chick but blocks laminin-induced angiogenesis. Thus, mEGF33-42 acts as a general laminin antagonist, whereas Lam.B1(925-933) acts as a laminin agonist in human cells, but in chick cells it acts as a partial antagonist. We propose that the presence of an anionic group at the eighth residue of mEGF33-42 may be the source of the antagonistic effects seen with this peptide as compared with the laminin fragment. These findings have important implications in the design of human antiangiogenic agents, and also in the use of chick models in the study of human disease. PMID:7543818

  11. 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

  12. 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

  13. 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

  14. 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.

  15. 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

  16. Reconstitution of Actin-based Motility by Vasodilator-stimulated Phosphoprotein (VASP) Depends on the Recruitment of F-actin Seeds from the Solution Produced by Cofilin*

    PubMed Central

    Siton, Orit; Bernheim-Groswasser, Anne

    2014-01-01

    Vasodilator-stimulated phosphoprotein (VASP) is active in many filopodium-based and cytoskeleton reorganization processes. It is not fully understood how VASP directly functions in actin-based motility and how regulatory proteins affect its function. Here, we combine bead motility assay and single filament experiments. In the presence of a bundling component, actin bundles that grow from the surface of WT-VASP-coated beads induced movement of the beads. VASP promotes actin-based movement alone, in the absence of other actin nucleators. We propose that at physiological salt conditions VASP nucleation activity is too weak to promote motility and bundle formation. Rather, VASP recruits F-actin seeds from the solution and promotes their elongation. Cofilin has a crucial role in the nucleation of these F-actin seeds, notably under conditions of unfavorable spontaneous actin nucleation. We explored the role of multiple VASP variants. We found that the VASP-F-actin binding domain is required for the recruitment of F-actin seeds from the solution. We also found that the interaction of profilin-actin complexes with the VASP-proline-rich domain and the binding of the VASP-F-actin binding domain to the side of growing filaments is critical for transforming actin polymerization into motion. At the single filament level, profilin mediates both filament elongation rate and VASP anti-capping activity. Binding of profilin-actin complexes increases the polymerization efficiency by VASP but decreases its efficiency as an anti-capper; binding of free profilin creates the opposite effect. Finally, we found that an additional component such as methylcellulose or fascin is required for actin bundle formation and motility mediated by VASP. PMID:25246528

  17. 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

  18. Interaction of urokinase with specific receptors stimulates mobilization of bovine adrenal capillary endothelial cells

    SciTech Connect

    Fibbi, G.; Ziche, M.; Morbidelli, L. ); Magnelli, L.; Del Rosso, M. )

    1988-12-01

    On the basis of {sup 125}I-labeled plasminogen activator binding analysis the authors have found that bovine adrenal capillary endothelial cells have specific receptors for human urinary-type plasminogen activator on the cell membrane. Each cell exposes about 37,000 free receptors with a K{sub d} of 0.8958{times}10{sup {minus}12} M. A monoclonal antibody against the 17,500 proteolytic fragment of the A chain of the plasminogen activator, not containing the catalytic site of the enzyme, impaired the specific binding, thus suggesting the involvement of a sequence present on the A chain in the interaction with the receptor, as previously shown in other cell model systems. Both the native molecule and the A chain are able to stimulate endothelial cell motility in the Boyden chamber, when used at nanomolar concentrations. The use of the same monoclonal antibody that can inhibit ligand-receptor interaction can impair the plasminogen activator and A-chain-induced endothelial cell motility, suggesting that under the conditions used in this in vitro model system, the motility of bovine adrenal capillary endothelial cells depends on the specific interaction of the ligand with free receptors on the surface of endothelial cells.

  19. 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

  20. 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

  1. 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

  2. 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

  3. 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

  4. 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.

  5. 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

  6. 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

  7. 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

  8. 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

  9. 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.

  10. Reactive oxygen species induce MMP12-dependent degradation of collagen 5 and fibronectin to promote the motility of human umbilical cord-derived mesenchymal stem cells

    PubMed Central

    Yun, Seung Pil; Lee, Sei-Jung; Oh, Sang Yub; Jung, Young Hyun; Ryu, Jung Min; Suh, Han Na; Kim, Mi Ok; Oh, Keon Bong; Han, Ho Jae

    2014-01-01

    BACKGROUND AND PURPOSE Reactive oxygen species (ROS) are potent regulators of stem cell behaviour; however, their physiological significance as regards MMP-mediated regulation of the motility of human umbilical cord blood-derived mesenchymal stem cells (UCB-MSCs) has not been characterized. In the present study, we investigated the role of hydrogen peroxide (H2O2) and associated signalling pathways in promoting UCB-MSCs motility. EXPERIMENTAL APPROACH The regulatory effects of H2O2 on the activation of PKC, MAPKs, NF-κB and β-catenin were determined. The expressions of MMP and extracellular matrix proteins were examined. Pharmacological inhibitors and gene-specific siRNA were used to identify the signalling pathways of H2O2 that affect UCB-MSCs motility. An experimental skin wound-healing model was used to confirm the functional role of UCB-MSCs treated with H2O2 in ICR mice. KEY RESULTS H2O2 increased the motility of UCB-MSCs by activating PKCα via a calcium influx mechanism. H2O2 activated ERK and p38 MAPK, which are responsible for the distinct activation of transcription factors NF-κB and β-catenin. UCB-MSCs expressed eight MMP genes, but only MMP12 expression was uniquely regulated by NF-κB and β-catenin activation. H2O2 increased the MMP12-dependent degradation of collagen 5 (COL-5) and fibronectin (FN) associated with UCB-MSCs motility. Finally, topical transplantation of UCB-MSCs treated with H2O2 enhanced skin wound healing in mice. CONCLUSIONS AND IMPLICATIONS H2O2 stimulated UCB-MSCs motility by increasing MMP12-dependent degradation of COL-5 and FN through the activation of NF-κB and glycogen synthase kinase-3β/β-catenin, which is critical for providing a suitable microenvironment for MSCs transplantation and re-epithelialization of skin wounds in mice. PMID:24627968

  11. 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

  12. 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

  13. 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

  14. 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

  15. 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

  16. 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

  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. 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

  19. 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

  20. 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

  1. 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

  2. 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

  3. 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

  4. 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

  5. Glass Probe Stimulation of Hair Cell Stereocilia.

    PubMed

    Peng, Anthony W; Ricci, Anthony J

    2016-01-01

    Hair cells are designed to sense mechanical stimuli of sound using their apical stereocilia hair bundles. Mechanical deflection of this hair bundle is converted into an electrical signal through gating of mechano-electric transduction channels. Stiff probe stimulation of hair bundles is an invaluable tool for studying the transduction channel and its associated processes because of the speed and ability to precisely control hair bundle position. Proper construction of these devices is critical to their ultimate performance as is appropriate placement of the probe onto the hair bundle. Here we describe the construction and use of a glass probe coupled to a piezo-electric actuator for stimulating hair bundles, including the basic technique for positioning of the stimulating probe onto the hair bundle. These piezo-electric stimulators can be adapted to other mechanically sensitive systems. PMID:27259944

  6. Type III TGFβ receptor and Src direct hyaluronan-mediated invasive cell motility.

    PubMed

    Allison, Patrick; Espiritu, Daniella; Barnett, Joey V; Camenisch, Todd D

    2015-03-01

    During embryogenesis, the epicardium undergoes proliferation, migration, and differentiation into several cardiac cell types which contribute to the coronary vessels. This process requires epithelial to mesenchymal transition (EMT) and directed cellular invasion. The Type III Transforming Growth Factor-beta Receptor (TGFβR3) is required for epicardial cell invasion and coronary vessel development. Using primary epicardial cells derived from Tgfbr3(+/+) and Tgfbr3(-/-) mouse embryos, high-molecular weight hyaluronan (HMWHA) stimulated cellular invasion and filamentous (f-actin) polymerization are detected in Tgfbr3(+/+) cells, but not in Tgfbr3(-/-) cells. Furthermore, HMWHA-stimulated cellular invasion and f-actin polymerization in Tgfbr3(+/+) epicardial cells are dependent on Src kinase. Src activation in HMWHA-stimulated Tgfbr3(-/-) epicardial cells is not detected in response to HMWHA. RhoA and Rac1 also fail to activate in response to HMWHA in Tgfbr3(-/-) cells. These events coincide with defective f-actin formation and deficient cellular invasion. Finally, a T841A activating substitution in TGFβR3 drives ligand-independent Src activation. Collectively, these data define a TGFβR3-Src-RhoA/Rac1 pathway that is essential for hyaluronan-directed cell invasion in epicardial cells. PMID:25499979

  7. 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

  8. Stimulation of incretin secreting cells.

    PubMed

    Pais, Ramona; Gribble, Fiona M; Reimann, Frank

    2016-02-01

    The incretin hormones glucose-dependent insulinotropic polypeptide (GIP) and glucagon like peptide-1 (GLP-1) are secreted from enteroendocrine cells in the gut and regulate physiological and homeostatic functions related to glucose control, metabolism and food intake. This review provides a systematic summary of the molecular mechanisms underlying secretion from incretin cells, and an understanding of how they sense and interact with lumen and vascular factors and the enteric nervous system through transporters and G-protein coupled receptors (GPCRs) present on their surface to ultimately culminate in hormone release. Some of the molecules described below such as sodium coupled glucose transporter 1 (SGLT1), G-protein coupled receptor (GPR) 119 and GPR40 are targets of novel therapeutics designed to enhance endogenous gut hormone release. Synthetic ligands at these receptors aimed at treating obesity and type 2 diabetes are currently under investigation. PMID:26885360

  9. Stimulation of incretin secreting cells

    PubMed Central

    Pais, Ramona; Gribble, Fiona M.; Reimann, Frank

    2016-01-01

    The incretin hormones glucose-dependent insulinotropic polypeptide (GIP) and glucagon like peptide-1 (GLP-1) are secreted from enteroendocrine cells in the gut and regulate physiological and homeostatic functions related to glucose control, metabolism and food intake. This review provides a systematic summary of the molecular mechanisms underlying secretion from incretin cells, and an understanding of how they sense and interact with lumen and vascular factors and the enteric nervous system through transporters and G-protein coupled receptors (GPCRs) present on their surface to ultimately culminate in hormone release. Some of the molecules described below such as sodium coupled glucose transporter 1 (SGLT1), G-protein coupled receptor (GPR) 119 and GPR40 are targets of novel therapeutics designed to enhance endogenous gut hormone release. Synthetic ligands at these receptors aimed at treating obesity and type 2 diabetes are currently under investigation. PMID:26885360

  10. 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

  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 colonic motility has been influenced by the specific motility pattern(s) studied, the stimulus used to initiate the motility (spontaneous vs induced), and the route of administration of drugs. All of these considerations contribute to the understanding and the controversy that continues to surround the role of serotonin in the gut. PMID:26095115

  12. URI promotes gastric cancer cell motility, survival, and resistance to adriamycin in vitro

    PubMed Central

    Hu, Xiaoxia; Zhang, Fei; Luo, Dongwei; Li, Na; Wang, Qian; Xu, Zhonghai; Bian, Huiqin; Liang, Yuting; Lu, Yaojuan; Zheng, Qiping; Gu, Junxia

    2016-01-01

    Unconventional prefoldin RPB5 interactor (URI), a RNA polymerase II Subunit 5-Interacting protein, is known to participate in the regulation of nutrient-sensitive mTOR-dependent transcription programs. Multiple studies have recently demonstrated that URI functions as an oncoprotein, possibly through the mTOR pathway, and regulates tumor cell motility, invasion, and metastasis. However, whether and how URI plays a role in gastric oncogenesis has not been elucidated. Due to drug resistance, recurrence and metastasis, the prognosis of gastric cancer remains poor. This study aims to explore the effects of URI on gastric cancer cells by focusing on their migratory ability and resistance to adriamycin. URI was over-expressed or knocked-down in MGC-803 and HGC-27 gastric cancer cells using URI plasmid or siRNA transfection approach. The cell viability, apoptosis, and migration ability were then examined by the CCK-8 assay, flow cytometer Annexin V/PI staining, and the Transwell cell migration assay respectively. The protein levels of apoptosis and EMT related genes were detected by western blot. The results showed that overexpression of URI promoted while knock-down of URI inhibited gastric cancer cell proliferation. URI overexpression resulted in increased Bcl-2 expression but decreased levels of Bax, cleaved PARP-1 and cleaved caspase-3. Conversely, cells treated with URI siRNA showed increased adriamycin induced apoptosis, along with reduced Bcl-2, but increased Bax, cleaved PARP-1 and cleaved caspase-3 expression. We have also shown that overexpression of URI enhanced cancer cell proliferation and migration with higher levels of Snail and Vimentin, whereas knockdown of URI in MGC-803 and HGC-27 cells inhibited proliferation and migration with decreased Snail and Vimentin expression. Together, our results support that URI promotes cell survival and mobility and acts as a chemotherapeutics resistant protein in MGC-803 and HGC-27 cells. URI might be a potential biomarker

  13. Exposure to Music Alters Cell Viability and Cell Motility of Human Nonauditory Cells in Culture

    PubMed Central

    Lestard, Nathalia R.

    2016-01-01

    Although music is part of virtually all cultures in the world, little is known about how it affects us. Since the beginning of this century several studies suggested that the response to music, and to sound in general, is complex and might not be exclusively due to emotion, given that cell types other than auditory hair cells can also directly react to audible sound. The present study was designed to better understand the direct effects of acoustic vibrations, in the form of music, in human cells in culture. Our results suggest that the mechanisms of cell growth arrest and/or cell death induced by acoustic vibrations are similar for auditory and nonauditory cells. PMID:27478480

  14. Exposure to Music Alters Cell Viability and Cell Motility of Human Nonauditory Cells in Culture.

    PubMed

    Lestard, Nathalia R; Capella, Marcia A M

    2016-01-01

    Although music is part of virtually all cultures in the world, little is known about how it affects us. Since the beginning of this century several studies suggested that the response to music, and to sound in general, is complex and might not be exclusively due to emotion, given that cell types other than auditory hair cells can also directly react to audible sound. The present study was designed to better understand the direct effects of acoustic vibrations, in the form of music, in human cells in culture. Our results suggest that the mechanisms of cell growth arrest and/or cell death induced by acoustic vibrations are similar for auditory and nonauditory cells. PMID:27478480

  15. 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

  16. 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

  17. Orientational order of the lamellipodial actin network as demonstrated in living motile cells.

    PubMed

    Verkhovsky, Alexander B; Chaga, Oleg Y; Schaub, Sébastien; Svitkina, Tatyana M; Meister, Jean-Jacques; Borisy, Gary G

    2003-11-01

    Lamellipodia of crawling cells represent both the motor for cell advance and the primary building site for the actin cytoskeleton. The organization of actin in the lamellipodium reflects actin dynamics and is of critical importance for the mechanism of cell motility. In previous structural studies, the lamellipodial actin network was analyzed primarily by electron microscopy (EM). An understanding of lamellipodial organization would benefit significantly if the EM data were complemented and put into a kinetic context by establishing correspondence with structural features observable at the light microscopic level in living cells. Here, we use an enhanced phase contrast microscopy technique to visualize an apparent long-range diagonal actin meshwork in the advancing lamellipodia of living cells. Visualization of this meshwork permitted a correlative light and electron microscopic approach that validated the underlying organization of lamellipodia. The linear features in the light microscopic meshwork corresponded to regions of greater actin filament density. Orientation of features was analyzed quantitatively and compared with the orientation of actin filaments at the EM level. We infer that the light microscopic meshwork reflects the orientational order of actin filaments which, in turn, is related to their branching angle. PMID:13679520

  18. Orientational Order of the Lamellipodial Actin Network as Demonstrated in Living Motile CellsV⃞

    PubMed Central

    Verkhovsky, Alexander B.; Chaga, Oleg Y.; Schaub, Sébastien; Svitkina, Tatyana M.; Meister, Jean-Jacques; Borisy, Gary G.

    2003-01-01

    Lamellipodia of crawling cells represent both the motor for cell advance and the primary building site for the actin cytoskeleton. The organization of actin in the lamellipodium reflects actin dynamics and is of critical importance for the mechanism of cell motility. In previous structural studies, the lamellipodial actin network was analyzed primarily by electron microscopy (EM). An understanding of lamellipodial organization would benefit significantly if the EM data were complemented and put into a kinetic context by establishing correspondence with structural features observable at the light microscopic level in living cells. Here, we use an enhanced phase contrast microscopy technique to visualize an apparent long-range diagonal actin meshwork in the advancing lamellipodia of living cells. Visualization of this meshwork permitted a correlative light and electron microscopic approach that validated the underlying organization of lamellipodia. The linear features in the light microscopic meshwork corresponded to regions of greater actin filament density. Orientation of features was analyzed quantitatively and compared with the orientation of actin filaments at the EM level. We infer that the light microscopic meshwork reflects the orientational order of actin filaments which, in turn, is related to their branching angle. PMID:13679520

  19. Interaction of Motility, Directional Sensing, and Polarity Modules Recreates the Behaviors of Chemotaxing Cells

    PubMed Central

    Shi, Changji; Huang, Chuan-Hsiang; Devreotes, Peter N.; Iglesias, Pablo A.

    2013-01-01

    Chemotaxis involves the coordinated action of separable but interrelated processes: motility, gradient sensing, and polarization. We have hypothesized that these are mediated by separate modules that account for these processes individually and that, when combined, recreate most of the behaviors of chemotactic cells. Here, we describe a mathematical model where the modules are implemented in terms of reaction-diffusion equations. Migration and the accompanying changes in cellular morphology are demonstrated in simulations using a mechanical model of the cell cortex implemented in the level set framework. The central module is an excitable network that accounts for random migration. The response to combinations of uniform stimuli and gradients is mediated by a local excitation, global inhibition module that biases the direction in which excitability is directed. A polarization module linked to the excitable network through the cytoskeleton allows unstimulated cells to move persistently and, for cells in gradients, to gradually acquire distinct sensitivity between front and back. Finally, by varying the strengths of various feedback loops in the model we obtain cellular behaviors that mirror those of genetically altered cell lines. PMID:23861660

  20. 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

  1. 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

  2. 4D Tumorigenesis Model for Quantitating Coalescence, Directed Cell Motility and Chemotaxis, Identifying Unique Cell Behaviors, and Testing Anticancer Drugs.

    PubMed

    Kuhl, Spencer; Voss, Edward; Scherer, Amanda; Lusche, Daniel F; Wessels, Deborah; Soll, David R

    2016-01-01

    A 4D high-resolution computer-assisted reconstruction and motion analysis system has been developed and applied to the long-term (14-30 days) analysis of cancer cells migrating and aggregating within a 3D matrix. 4D tumorigenesis models more closely approximate the tumor microenvironment than 2D substrates and, therefore, are improved tools for elucidating the interactions within the tumor microenvironment that promote growth and metastasis. The model we describe here can be used to analyze the growth of tumor cells, aggregate coalescence, directed cell motility and chemotaxis, matrix degradation, the effects of anticancer drugs, and the behavior of immune and endothelial cells mixed with cancer cells. The information given in this chapter is also intended to acquaint the reader with computer-assisted methods and algorithms that can be used for high-resolution 3D reconstruction and quantitative motion analysis. PMID:27271907

  3. Biaxial cell stimulation: A mechanical validation.

    PubMed

    Bieler, F H; Ott, C E; Thompson, M S; Seidel, R; Ahrens, S; Epari, D R; Wilkening, U; Schaser, K D; Mundlos, S; Duda, G N

    2009-08-01

    To analyse mechanotransduction resulting from tensile loading under defined conditions, various devices for in vitro cell stimulation have been developed. This work aimed to determine the strain distribution on the membrane of a commercially available device and its consistency with rising cycle numbers, as well as the amount of strain transferred to adherent cells. The strains and their behaviour within the stimulation device were determined using digital image correlation (DIC). The strain transferred to cells was measured on eGFP-transfected bone marrow-derived cells imaged with a fluorescence microscope. The analysis was performed by determining the coordinates of prominent positions on the cells, calculating vectors between the coordinates and their length changes with increasing applied tensile strain. The stimulation device was found to apply homogeneous (mean of standard deviations approx. 2% of mean strain) and reproducible strains in the central well area. However, on average, only half of the applied strain was transferred to the bone marrow-derived cells. Furthermore, the strain measured within the device increased significantly with an increasing number of cycles while the membrane's Young's modulus decreased, indicating permanent changes in the material during extended use. Thus, strain magnitudes do not match the system readout and results require careful interpretation, especially at high cycle numbers. PMID:19446815

  4. Cell motility and biofilm formation in Bacillus subtilis are affected by the ribosomal proteins, S11 and S21.

    PubMed

    Takada, Hiraku; Morita, Masato; Shiwa, Yuh; Sugimoto, Ryoma; Suzuki, Shota; Kawamura, Fujio; Yoshikawa, Hirofumi

    2014-01-01

    Bacillus subtilis differentiates into various cellular states in response to environmental changes. It exists in two states during the exponential growth phase: motile cells and connected chains of sessile cells. Here, we identified new regulators of cell motility and chaining, the ribosomal proteins S21 (rpsU) and S11 (rpsK). Their mutants showed impaired cell motility (observed in a laboratory strain) and robust biofilm formation (observed in an undomesticated strain). The two major operons for biofilm formation, tapA-sipW-tasA and epsA-O, were strongly expressed in the rpsU mutant, whereas the flagellin-encoding hag gene and other SigD-dependent motility regulons were not. Genetic analysis revealed that the mutation of remA, the transcriptional activator of the eps operon, is epistatic to that of rpsU, whereas the mutation of antagonistic regulators of SinR is not. Our studies demonstrate that S11 and S21 participate in the regulation of bistability via the RemA/RemB pathway. PMID:25035996

  5. 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

  6. The role of hair cells, cilia and ciliary motility in otolith formation in the zebrafish otic vesicle.

    PubMed

    Stooke-Vaughan, Georgina A; Huang, Peng; Hammond, Katherine L; Schier, Alexander F; Whitfield, Tanya T

    2012-05-01

    Otoliths are biomineralised structures required for the sensation of gravity, linear acceleration and sound in the zebrafish ear. Otolith precursor particles, initially distributed throughout the otic vesicle lumen, become tethered to the tips of hair cell kinocilia (tether cilia) at the otic vesicle poles, forming two otoliths. We have used high-speed video microscopy to investigate the role of cilia and ciliary motility in otolith formation. In wild-type ears, groups of motile cilia are present at the otic vesicle poles, surrounding the immotile tether cilia. A few motile cilia are also found on the medial wall, but most cilia (92-98%) in the otic vesicle are immotile. In mutants with defective cilia (iguana) or ciliary motility (lrrc50), otoliths are frequently ectopic, untethered or fused. Nevertheless, neither cilia nor ciliary motility are absolutely required for otolith tethering: a mutant that lacks cilia completely (MZovl) is still capable of tethering otoliths at the otic vesicle poles. In embryos with attenuated Notch signalling [mindbomb mutant or Su(H) morphant], supernumerary hair cells develop and otolith precursor particles bind to the tips of all kinocilia, or bind directly to the hair cells' apical surface if cilia are absent [MZovl injected with a Su(H)1+2 morpholino]. However, if the first hair cells are missing (atoh1b morphant), otolith formation is severely disrupted and delayed. Our data support a model in which hair cells produce an otolith precursor-binding factor, normally localised to tether cell kinocilia. We also show that embryonic movement plays a minor role in the formation of normal otoliths. PMID:22461562

  7. Graphene electrodes for stimulation of neuronal cells

    NASA Astrophysics Data System (ADS)

    Koerbitzer, Berit; Krauss, Peter; Nick, Christoph; Yadav, Sandeep; Schneider, Joerg J.; Thielemann, Christiane

    2016-06-01

    Graphene has the ability to improve the electrical interface between neuronal cells and electrodes used for recording and stimulation purposes. It provides a biocompatible coating for common electrode materials such as gold and improves the electrode properties. Graphene electrodes are also prepared on SiO2 substrate to benefit from its optical properties like transparency. We perform electrochemical and Raman characterization of gold electrodes with graphene coating and compare them with graphene on SiO2 substrate. It was found that the substrate plays an important role in the performance of graphene and show that graphene on SiO2 substrate is a very promising material combination for stimulation electrodes.

  8. Hyaluronidase Hyal1 Increases Tumor Cell Proliferation and Motility through Accelerated Vesicle Trafficking*

    PubMed Central

    McAtee, Caitlin O.; Berkebile, Abigail R.; Elowsky, Christian G.; Fangman, Teresa; Barycki, Joseph J.; Wahl, James K.; Khalimonchuk, Oleh; Naslavsky, Naava; Caplan, Steve; Simpson, Melanie A.

    2015-01-01

    Hyaluronan (HA) turnover accelerates metastatic progression of prostate cancer in part by increasing rates of tumor cell proliferation and motility. To determine the mechanism, we overexpressed hyaluronidase 1 (Hyal1) as a fluorescent fusion protein and examined its impact on endocytosis and vesicular trafficking. Overexpression of Hyal1 led to increased rates of internalization of HA and the endocytic recycling marker transferrin. Live imaging of Hyal1, sucrose gradient centrifugation, and specific colocalization of Rab GTPases defined the subcellular distribution of Hyal1 as early and late endosomes, lysosomes, and recycling vesicles. Manipulation of vesicular trafficking by chemical inhibitors or with constitutively active and dominant negative Rab expression constructs caused atypical localization of Hyal1. Using the catalytically inactive point mutant Hyal1-E131Q, we found that enzymatic activity of Hyal1 was necessary for normal localization within the cell as Hyal1-E131Q was mainly detected within the endoplasmic reticulum. Expression of a HA-binding point mutant, Hyal1-Y202F, revealed that secretion of Hyal1 and concurrent reuptake from the extracellular space are critical for rapid HA internalization and cell proliferation. Overall, excess Hyal1 secretion accelerates endocytic vesicle trafficking in a substrate-dependent manner, promoting aggressive tumor cell behavior. PMID:25855794

  9. Simulating the Complex Cell Design of Trypanosoma brucei and Its Motility

    PubMed Central

    Alizadehrad, Davod; Krüger, Timothy; Engstler, Markus; Stark, Holger

    2015-01-01

    The flagellate Trypanosoma brucei, which causes the sleeping sickness when infecting a mammalian host, goes through an intricate life cycle. It has a rather complex propulsion mechanism and swims in diverse microenvironments. These continuously exert selective pressure, to which the trypanosome adjusts with its architecture and behavior. As a result, the trypanosome assumes a diversity of complex morphotypes during its life cycle. However, although cell biology has detailed form and function of most of them, experimental data on the dynamic behavior and development of most morphotypes is lacking. Here we show that simulation science can predict intermediate cell designs by conducting specific and controlled modifications of an accurate, nature-inspired cell model, which we developed using information from live cell analyses. The cell models account for several important characteristics of the real trypanosomal morphotypes, such as the geometry and elastic properties of the cell body, and their swimming mechanism using an eukaryotic flagellum. We introduce an elastic network model for the cell body, including bending rigidity and simulate swimming in a fluid environment, using the mesoscale simulation technique called multi-particle collision dynamics. The in silico trypanosome of the bloodstream form displays the characteristic in vivo rotational and translational motility pattern that is crucial for survival and virulence in the vertebrate host. Moreover, our model accurately simulates the trypanosome's tumbling and backward motion. We show that the distinctive course of the attached flagellum around the cell body is one important aspect to produce the observed swimming behavior in a viscous fluid, and also required to reach the maximal swimming velocity. Changing details of the flagellar attachment generates less efficient swimmers. We also simulate different morphotypes that occur during the parasite's development in the tsetse fly, and predict a flagellar

  10. Role of HER-2 activity in the regulation of malignant meningioma cell proliferation and motility.

    PubMed

    Wang, Weijia; Tu, Yi; Wang, Shanshan; Xu, Shan; Xu, Linlin; Xiong, Yifeng; Mei, Jinhong; Wang, Chunliang

    2015-09-01

    Meningiomas are common types of intracranial tumor. Invasive and malignant meningiomas present a significant therapeutic challenge due to high rates of recurrence and invasion. Understanding the molecular mechanism of invasion may assist in designing novel therapeutic approaches and improving patient survival rates. The HER‑2 gene has been demonstrated to be a useful predictor of tumor aggression, which promotes the survival and growth of cancer cells through the mitogen‑activated protein kinase and/or phosphatidylinositol 3‑kinase (PI3K)/AKT pathway. Until now, few studies have investigated the associateion between meningiomas and the expression of HER‑2, and the significance of HER‑2 in meningiomas remains to be elucidated. The present study aimed to investigate the effects of the HER‑2 gene on the biological behaviors of human malignant meningioma cells. The results demonstrated that downregulation of the expression of HER‑2 by small interfering RNA in human meningioma cells significantly inhibited cell motility and proliferation, led to cell cycle arrest at the G0/G1‑phase and increased early apoptosis. By contrast, the overexpression of HER‑2 group resulted in meningioma cell invasion, migration and proliferation being significantly enhanced, cell cycle was promoted at the G1/S‑phase and early apoptosis was decreased. Accordingly, the inhibition of HER‑2 also prevented the protein expression of PI3K and phosphorylated AKT. The results demonstrated that regulation of the HER‑2 gene can affect the proliferation, apoptosis, invasion and metastasis abilities of human meningioma cells in vitro. Furthermore, PI3K/AKT may contribute to the carcinogenesis and development of human meningiomas in combination with HER-2. PMID:25998419

  11. 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.

  12. Special type of morphological reorganization induced by phorbol ester: reversible partition of cell into motile and stable domains

    SciTech Connect

    Dugina, V.B.; Svitkina, T.M.; Vasiliev, J.M.; Gelfand, I.M.

    1987-06-01

    The phorbol ester phorbol 12-myristate 13-acetate (PMA) induced reversible alteration of the shape of fibroblastic cells of certain transformed lines-namely, partition of the cells into two types of domains: motile body actively extending large lamellas and stable narrow cytoplasmic processes. Dynamic observations have shown that stable processes are formed from partially retracted lamellas and from contracted tail parts of cell bodies. Immunofluorescence microscopy and electron microscopy of platinum replicas of cytoskeleton have shown that PMA-induced narrow processes are rich in microtubules and intermediate filaments but relatively poor in actin microfilaments; in contrast, lamellas and cell bodies contained numerous microfilaments. Colcemid-induced depolymerization of microtubules led to contraction of PMA-induced processes; cytochalasin B prevented this contraction. It is suggested that PMA-induced separation of cell into motile and stable parts is due to directional movement of actin structures along the microtubular framework. Similar movements may play an important role in various normal morphogenetic processes.

  13. Individual motile CD4+ T cells can participate in efficient multi-killing through conjugation to multiple tumor cells

    PubMed Central

    Liadi, Ivan; Singh, Harjeet; Romain, Gabrielle; Rey-Villamizar, Nicolas; Merouane, Amine; Adolacion, Jay R T.; Kebriaei, Partow; Huls, Helen; Qiu, Peng; Roysam, Badrinath; Cooper, Laurence J.N.; Varadarajan, Navin

    2015-01-01

    T cells genetically modified to express a CD19-specific chimeric antigen receptor (CAR) for the investigational treatment of B-cell malignancies comprise a heterogeneous population, and their ability to persist and participate in serial killing of tumor cells is a predictor of therapeutic success. We implemented Timelapse Imaging Microscopy In Nanowell Grids (TIMING) to provide direct evidence that CD4+CAR+ T cells (CAR4 cells) can engage in multi-killing via simultaneous conjugation to multiple tumor cells. Comparisons of the CAR4 cells and CD8+CAR+ T cells (CAR8 cells) demonstrate that while CAR4 cells can participate in killing and multi-killing, they do so at slower rates, likely due to the lower Granzyme B content. Significantly, in both sets of T cells, a minor sub-population of individual T cells identified by their high motility, demonstrated efficient killing of single tumor cells. By comparing both the multi-killer and single killer CAR+ T cells it appears that the propensity and kinetics of T-cell apoptosis was modulated by the number of functional conjugations. T cells underwent rapid apoptosis, and at higher frequencies, when conjugated to single tumor cells in isolation and this effect was more pronounced on CAR8 cells. Our results suggest that the ability of CAR+ T cells to participate in multi-killing should be evaluated in the context of their ability to resist activation induced cell death (AICD). We anticipate that TIMING may be utilized to rapidly determine the potency of T-cell populations and may facilitate the design and manufacture of next-generation CAR+ T cells with improved efficacy. PMID:25711538

  14. Seizure-Induced Motility of Differentiated Dentate Granule Cells Is Prevented by the Central Reelin Fragment

    PubMed Central

    Orcinha, Catarina; Münzner, Gert; Gerlach, Johannes; Kilias, Antje; Follo, Marie; Egert, Ulrich; Haas, Carola A.

    2016-01-01

    Granule cell dispersion (GCD) represents a pathological widening of the granule cell layer in the dentate gyrus and it is frequently observed in patients with mesial temporal lobe epilepsy (MTLE). Recent studies in human MTLE specimens and in animal epilepsy models have shown that a decreased expression and functional inactivation of the extracellular matrix protein Reelin correlates with GCD formation, but causal evidence is still lacking. Here, we used unilateral kainate (KA) injection into the mouse hippocampus, an established MTLE animal model, to precisely map the loss of reelin mRNA-synthesizing neurons in relation to GCD along the septotemporal axis of the epileptic hippocampus. We show that reelin mRNA-producing neurons are mainly lost in the hilus and that this loss precisely correlates with the occurrence of GCD. To monitor GCD formation in real time, we used organotypic hippocampal slice cultures (OHSCs) prepared from mice which express enhanced green fluorescent protein (eGFP) primarily in differentiated dentate granule cells. Using life cell microscopy we observed that increasing doses of KA resulted in an enhanced motility of eGFP-positive granule cells. Moreover, KA treatment of OHSC resulted in a rapid loss of Reelin-producing interneurons mainly in the hilus, as observed in vivo. A detailed analysis of the migration behavior of individual eGFP-positive granule cells revealed that the majority of these neurons actively migrate toward the hilar region, where Reelin-producing neurons are lost. Treatment with KA and subsequent addition of the recombinant R3–6 Reelin fragment significantly prevented the movement of eGFP-positive granule cells. Together, these findings suggest that GCD formation is indeed triggered by a loss of Reelin in hilar interneurons. PMID:27516734

  15. Seizure-Induced Motility of Differentiated Dentate Granule Cells Is Prevented by the Central Reelin Fragment.

    PubMed

    Orcinha, Catarina; Münzner, Gert; Gerlach, Johannes; Kilias, Antje; Follo, Marie; Egert, Ulrich; Haas, Carola A

    2016-01-01

    Granule cell dispersion (GCD) represents a pathological widening of the granule cell layer in the dentate gyrus and it is frequently observed in patients with mesial temporal lobe epilepsy (MTLE). Recent studies in human MTLE specimens and in animal epilepsy models have shown that a decreased expression and functional inactivation of the extracellular matrix protein Reelin correlates with GCD formation, but causal evidence is still lacking. Here, we used unilateral kainate (KA) injection into the mouse hippocampus, an established MTLE animal model, to precisely map the loss of reelin mRNA-synthesizing neurons in relation to GCD along the septotemporal axis of the epileptic hippocampus. We show that reelin mRNA-producing neurons are mainly lost in the hilus and that this loss precisely correlates with the occurrence of GCD. To monitor GCD formation in real time, we used organotypic hippocampal slice cultures (OHSCs) prepared from mice which express enhanced green fluorescent protein (eGFP) primarily in differentiated dentate granule cells. Using life cell microscopy we observed that increasing doses of KA resulted in an enhanced motility of eGFP-positive granule cells. Moreover, KA treatment of OHSC resulted in a rapid loss of Reelin-producing interneurons mainly in the hilus, as observed in vivo. A detailed analysis of the migration behavior of individual eGFP-positive granule cells revealed that the majority of these neurons actively migrate toward the hilar region, where Reelin-producing neurons are lost. Treatment with KA and subsequent addition of the recombinant R3-6 Reelin fragment significantly prevented the movement of eGFP-positive granule cells. Together, these findings suggest that GCD formation is indeed triggered by a loss of Reelin in hilar interneurons. PMID:27516734

  16. Transplantation stimulates interstitial cell migration in hydra

    SciTech Connect

    Fujisawa, T.; David, C.N.; Bosch, T.C. )

    1990-04-01

    Migration of interstitial cells and nerve cell precursors was analyzed in Hydra magnipapillata and Hydra vulgaris (formerly Hydra attenuata). Axial grafts were made between ({sup 3}H)thymidine-labeled donor and unlabeled host tissue. Migration of labeled cells into the unlabeled half was followed for 4 days. The results indicate that the rate of migration was initially high and then slowed on Days 2-4. Regrafting fresh donor tissue on Days 2-4 maintained high levels of migration. Thus, migration appears to be stimulated by the grafting procedure itself.

  17. Crucial roles of RSK in cell motility by catalysing serine phosphorylation of EphA2.

    PubMed

    Zhou, Yue; Yamada, Naoki; Tanaka, Tomohiro; Hori, Takashi; Yokoyama, Satoru; Hayakawa, Yoshihiro; Yano, Seiji; Fukuoka, Junya; Koizumi, Keiichi; Saiki, Ikuo; Sakurai, Hiroaki

    2015-01-01

    Crosstalk between inflammatory signalling pathways and receptor tyrosine kinases has been revealed as an indicator of cancer malignant progression. In the present study, we focus on EphA2 receptor tyrosine kinase, which is overexpressed in many human cancers. It has been reported that ligand-independent phosphorylation of EphA2 at Ser-897 is induced by Akt. We show that inflammatory cytokines promote RSK-, not Akt-, dependent phosphorylation of EphA2 at Ser-897. In addition, the RSK-EphA2 signalling pathway controls cell migration and invasion of metastatic breast cancer cells. Moreover, Ser-897-phosphorylated EphA2 co-localizes with phosphorylated active form of RSK in various human tumour specimens, and this double positivity is related to poor survival in lung cancer patients, especially those with a smoking history. Taken together, these results indicate that the phosphorylation of EphA2 at Ser-897 is controlled by RSK and the RSK-EphA2 axis might contribute to cell motility and promote tumour malignant progression. PMID:26158630

  18. Cell Motility in Carcinoma Metastasis as Modulated by Switching between Epithelial and Mesenchymal Phenotypes

    PubMed Central

    Wells, Alan; Chao, Yvonne L; Grahovac, Jelena; Wu, Qian; Lauffenburger, Douglas A

    2014-01-01

    The most ominous stage of cancer progression is the dissemination of carcinomas from their primary site into adjacent tissues, invasion, or distant ectopic organs, metastasis. These steps renders current extirpative therapies paliative at best and heralds the use of systemic therapies that are curative in only a small subset of patients even using the newest biological agents. This calls for a greater understanding of the tumor biology of tumor progression integrating the carcinoma intrinsic properties with the tissue environmental modulators of behavior. In no aspect of progression is this more evident that the critical step of tumor cell motility that is critical for both escape from the primary mass and seeding into ectopic organs and tissues. In this overview, we discuss how this behavior is modified by carcinoma cell phenotypic plasticity that is evidenced by reversible switching between epithelial and mesenchymal phenotypes. The intercellular linkages or absence thereof dictate the receptivity towards signals from the extracellular milieu. A number of clearly implicated such signals, soluble growth factors and cytokines and extracellular matrix components with embedded matrikines and matricryptines, will be discussed in depth. Finally, we will describe a new mode of discerning the balance between movement as an epithelioid cell and as a mesenchymal-like counterpart. PMID:21196205

  19. Crucial roles of RSK in cell motility by catalysing serine phosphorylation of EphA2

    PubMed Central

    Zhou, Yue; Yamada, Naoki; Tanaka, Tomohiro; Hori, Takashi; Yokoyama, Satoru; Hayakawa, Yoshihiro; Yano, Seiji; Fukuoka, Junya; Koizumi, Keiichi; Saiki, Ikuo; Sakurai, Hiroaki

    2015-01-01

    Crosstalk between inflammatory signalling pathways and receptor tyrosine kinases has been revealed as an indicator of cancer malignant progression. In the present study, we focus on EphA2 receptor tyrosine kinase, which is overexpressed in many human cancers. It has been reported that ligand-independent phosphorylation of EphA2 at Ser-897 is induced by Akt. We show that inflammatory cytokines promote RSK-, not Akt-, dependent phosphorylation of EphA2 at Ser-897. In addition, the RSK–EphA2 signalling pathway controls cell migration and invasion of metastatic breast cancer cells. Moreover, Ser-897-phosphorylated EphA2 co-localizes with phosphorylated active form of RSK in various human tumour specimens, and this double positivity is related to poor survival in lung cancer patients, especially those with a smoking history. Taken together, these results indicate that the phosphorylation of EphA2 at Ser-897 is controlled by RSK and the RSK–EphA2 axis might contribute to cell motility and promote tumour malignant progression. PMID:26158630

  20. The anti-motility signaling mechanism of TGFβ3 that controls cell traffic during skin wound healing.

    PubMed

    Han, Arum; Bandyopadhyay, Balaji; Jayaprakash, Priyamvada; Lua, Ingrid; Sahu, Divya; Chen, Mei; Woodley, David T; Li, Wei

    2012-12-15

    When skin is wounded, migration of epidermal keratinocytes at the wound edge initiates within hours, whereas migration of dermal fibroblasts toward the wounded area remains undetectable until several days later. This "cell type traffic" regulation ensures proper healing of the wound, as disruptions of the regulation could either cause delay of wound healing or result in hypertrophic scars. TGFβ3 is the critical traffic controller that selectively halts migration of the dermal, but not epidermal, cells to ensure completion of wound re-epithelialization prior to wound remodeling. However, the mechanism of TGFβ3's anti-motility signaling has never been investigated. We report here that activated TβRII transmits the anti-motility signal of TGFβ3 in full to TβRI, since expression of the constitutively activated TβRI-TD mutant was sufficient to replace TGFβ3 to block PDGF-bb-induced dermal fibroblast migration. Second, the three components of R-Smad complex are all required. Individual downregulation of Smad2, Smad3 or Smad4 prevented TGFβ3 from inhibiting dermal fibroblast migration. Third, Protein Kinase Array allowed us to identify the protein kinase A (PKA) as a specific downstream effector of R-Smads in dermal fibroblasts. Activation of PKA alone blocked PDGF-bb-induced dermal fibroblast migration, just like TGFβ3. Downregulation of PKA's catalytic subunit nullified the anti-motility signaling of TGFβ3. This is the first report on anti-motility signaling mechanism by TGFβ family cytokines. Significance of this finding is not only limited to wound healing but also to other human disorders, such as heart attack and cancer, where the diseased cells have often managed to avoid the anti-motility effect of TGFβ. PMID:23259050

  1. Altering the motility of Trypanosoma cruzi with rabbit polyclonal anti-peptide antibodies reduces infection to susceptible mammalian cells.

    PubMed

    Finkelsztein, Eli J; Diaz-Soto, Juan C; Vargas-Zambrano, Juan C; Suesca, Elizabeth; Guzmán, Fanny; López, Manuel C; Thomas, M Carmen; Forero-Shelton, Manu; Cuellar, Adriana; Puerta, Concepción J; González, John M

    2015-03-01

    Trypanosoma cruzi's trypomastigotes are highly active and their incessant motility seems to be important for mammalian host cell infection. The kinetoplastid membrane protein-11 (KMP-11) is a protein expressed in all parasite stages, which induces a cellular and humoral immune response in the infected host, and is hypothesized to participate in the parasite's motility. An N-terminal peptide from KMP-11, termed K1 or TcTLE, induced polyclonal antibodies that inhibit parasitic invasion of Vero cells. The goal of this study was to evaluate the motility and infectivity of T. cruzi when exposed to polyclonal anti-TcTLE antibodies. Rabbits were immunized with TcTLE peptide along with FIS peptide as an immunomodulator. ELISA assay results showed that post-immunization sera contained high titers of polyclonal anti-TcTLE antibodies, which were also reactive against the native KMP-11 protein and live parasites as detected by immunofluorescence and flow cytometry assays. Trypomastigotes of T. cruzi were incubated with pre- or post-immunization sera, and infectivity to human astrocytes was assessed by Giemsa staining/light microscope and flow cytometry using carboxyfluorescein diacetate succinimidyl ester (CFSE) labeled parasites. T. cruzi infection in astrocytes decreased approximately by 30% upon incubation with post-immunization sera compared with pre-immunization sera. Furthermore, trypomastigotes were recorded by video microscopy and the parasite's flagellar speed was calculated by tracking the flagella. Trypomastigotes exposed to post-immunization sera had qualitative alterations in motility and significantly slower flagella (45.5 µm/s), compared with those exposed to pre-immunization sera (69.2 µm/s). In summary, polyclonal anti-TcTLE serum significantly reduced the parasite's flagellar speed and cell infectivity. These findings support that KMP-11 could be important for parasite motility, and that by targeting its N-terminal peptide infectivity can be reduced

  2. Daydreamer, a Ras effector and GSK-3 substrate, is important for directional sensing and cell motility

    PubMed Central

    Kölsch, Verena; Shen, Zhouxin; Lee, Susan; Plak, Katarzyna; Lotfi, Pouya; Chang, Jessica; Charest, Pascale G.; Romero, Jesus Lacal; Jeon, Taeck J.; Kortholt, Arjan; Briggs, Steven P.; Firtel, Richard A.

    2013-01-01

    How independent signaling pathways are integrated to holistically control a biological process is not well understood. We have identified Daydreamer (DydA), a new member of the Mig10/RIAM/lamellipodin (MRL) family of adaptor proteins that localizes to the leading edge of the cell. DydA is a putative Ras effector that is required for cell polarization and directional movement during chemotaxis. dydA− cells exhibit elevated F-actin and assembled myosin II (MyoII), increased and extended phosphoinositide-3-kinase (PI3K) activity, and extended phosphorylation of the activation loop of PKB and PKBR1, suggesting that DydA is involved in the negative regulation of these pathways. DydA is phosphorylated by glycogen synthase kinase-3 (GSK-3), which is required for some, but not all, of DydA's functions, including the proper regulation of PKB and PKBR1 and MyoII assembly. gskA− cells exhibit very strong chemotactic phenotypes, as previously described, but exhibit an increased rate of random motility. gskA− cells have a reduced MyoII response and a reduced level of phosphatidylinositol (3,4,5)-triphosphate production, but a highly extended recruitment of PI3K to the plasma membrane and highly extended kinetics of PKB and PKBR1 activation. Our results demonstrate that GSK-3 function is essential for chemotaxis, regulating multiple substrates, and that one of these effectors, DydA, plays a key function in the dynamic regulation of chemotaxis. PMID:23135995

  3. Live-Cell Imaging of Phagosome Motility in Primary Mouse RPE Cells.

    PubMed

    Hazim, Roni; Jiang, Mei; Esteve-Rudd, Julian; Diemer, Tanja; Lopes, Vanda S; Williams, David S

    2016-01-01

    The retinal pigment epithelium (RPE) is a post-mitotic epithelial monolayer situated between the light-sensitive photoreceptors and the choriocapillaris. Given its vital functions for healthy vision, the RPE is a primary target for insults that result in blinding diseases, including age-related macular degeneration (AMD). One such function is the phagocytosis and digestion of shed photoreceptor outer segments. In the present study, we examined the process of trafficking of outer segment disk membranes in live cultures of primary mouse RPE, using high speed spinning disk confocal microscopy. This approach has enabled us to track phagosomes, and determine parameters of their motility, which are important for their efficient degradation. PMID:26427485

  4. Cross-talk between LPA1 and Epidermal Growth Factor Receptors Mediates Up-regulation of Sphingosine Kinase 1 to Promote Gastric Cancer Cell Motility and Invasion

    PubMed Central

    Shida, Dai; Fang, Xianjun; Kordula, Tomasz; Takabe, Kazuaki; Lépine, Sandrine; Alvarez, Sergio E.; Milstien, Sheldon; Spiegel, Sarah

    2009-01-01

    Lysophosphatidic acid (LPA) and sphingosine-1-phosphate (S1P) are lysophospholipid mediators of diverse cellular processes important for cancer progression. S1P is produced by two sphingosine kinases, SphK1 and SphK2. Expression of SphK1 is elevated in many cancers. Here, we report that LPA markedly enhanced SphK1 mRNA and protein in gastric cancer MKN1 cells but had no effect on SphK2. LPA also up-regulated SphK1 expression in other human cancer cells that endogenously express the LPA1 receptor, such as DLD1 colon cancer cells and MDA-MB-231 breast cancer cells, but not in HT29 colon cancer cells or MDA-MB-453 breast cancer cells, which do not express the LPA1 receptor. An LPA1 receptor antagonist or down-regulation of its expression prevented SphK1 and S1P3 receptor up-regulation by LPA. LPA transactivated the epidermal growth factor receptor (EGFR) in these cells, and the EGFR inhibitor AG1478 attenuated the increased SphK1 and S1P3 expression induced by LPA. Moreover, down-regulation of SphK1 attenuated LPA-stimulated migration and invasion of MNK1 cells yet had no effect on expression of neovascularizing factors, such as interleukin (IL)-8, IL-6, urokinase-type plasminogen activator (uPA), or uPA receptor induced by LPA. Finally, down-regulation of S1P3, but not S1P1, also reduced LPA-stimulated migration and invasion of MKN1 cells. Collectively, our results suggest that SphK1 is a convergence point of multiple cell surface receptors for three different ligands, LPA, EGF, and S1P, which have all been implicated in regulation of motility and invasiveness of cancer cells. PMID:18701480

  5. Suppressive effects on cell proliferation and motility in gastric cancer SGC-7901 cells by introducing ulinastatin in vitro.

    PubMed

    Wang, Junqing; Chen, Xuehua; Su, Liping; Zhu, Zhenggang; Wu, Weize; Zhou, Yunyun

    2016-08-01

    Ulinastatin (UTI) is a kind of urinary trypsin inhibitor regulating broad-spectrum proteases and is used widely in the treatment of inflammatory diseases. Some evidence has suggested that UTI has antitumor functions in human carcinomas, but its function in gastric cancer (GC) has not been discussed extensively. In this study, we investigated the effects of UTI on GC SGC-7901 cells in vitro by preincubating cells with the UTI. The expression of the related molecules, urokinase-type plasminogen activator (uPA), was investigated at both the mRNA and the protein stages. Activation of uPA was analyzed and the phosphorylation of ERK1/2 downstream uPA was detected. According to the results, UTI downregulated uPA expression and significantly suppressed the activation of uPA and the phosphorylation of ERK1/2. Furthermore, the SGC-7901 cells treated by UTI showed a significant decrease in cell proliferation and impairment of invasion and migration. However, no significant influence was observed on cell apoptosis. By ectopically expressing uPA in SGC-7901 cells, suppression effects of UTI were rescued. We suggest that UTI suppresses GC cell proliferation, motility, and at least partly conducted through uPA. Although the effects of UTI in GC cells need to be validated further, UTI represents a strong therapeutic strategy that is worth following up in GC treatment. PMID:27187019

  6. Dendritic Cells Stimulated by Cationic Liposomes.

    PubMed

    Vitor, Micaela Tamara; Bergami-Santos, Patrícia Cruz; Cruz, Karen Steponavicius Piedade; Pinho, Mariana Pereira; Barbuto, José Alexandre Marzagão; De La Torre, Lucimara Gaziola

    2016-01-01

    Immunotherapy of cancer aims to harness the immune system to detect and destroy cancer cells. To induce an immune response against cancer, activated dendritic cells (DCs) must present tumor antigens to T lymphocytes of patients. However, cancer patients' DCs are frequently defective, therefore, they are prone to induce rather tolerance than immune responses. In this context, loading tumor antigens into DCs and, at the same time, activating these cells, is a tempting goal within the field. Thus, we investigated the effects of cationic liposomes on the DCs differentiation/maturation, evaluating their surface phenotype and ability to stimulate T lymphocytes proliferation in vitro. The cationic liposomes composed by egg phosphatidylcholine, 1,2-dioleoyl-3-trimethylammonium propane and 1,2-dioleoylphosphatidylethanolamine (50/25/25% molar) were prepared by the thin film method followed by extrusion (65 nm, polydispersity of 0.13) and by the dehydration-rehydration method (95% of the population 107 nm, polydispersity of 0.52). The phenotypic analysis of dendritic cells and the analysis of T lymphocyte proliferation were performed by flow cytometry and showed that both cationic liposomes were incorporated and activated dendritic cells. Extruded liposomes were better incorporated and induced higher CD86 expression for dendritic cells than dehydrated-rehydrated vesicles. Furthermore, dendritic cells which internalized extruded liposomes also provided stronger T lymphocyte stimulation. Thus, cationic liposomes with a smaller size and polydispersity seem to be better incorporated by dendritic cells. Hence, these cationic liposomes could be used as a potential tool in further cancer immunotherapy strategies and contribute to new strategies in immunotherapy. PMID:27398454

  7. Ketotifen, a mast cell blocker improves sperm motility in asthenospermic infertile men

    PubMed Central

    Saharkhiz, Nasrin; Nikbakht, Roshan; Hemadi, Masoud

    2013-01-01

    AIM: This study aimed to evaluate the efficacy of ketotifen on sperm motility of asthenospermic infertile men. SETTING AND DESIGN: It is a prospective study designed in vivo. MATERIALS AND METHODS: In this interventional experimental study, a total of 40 infertile couples with asthenospermic infertility factor undergoing assisted reproductive technology (ART) cycles were enrolled. The couples were randomly assigned to one of two groups at the starting of the cycle. In control group (n = 20), the men did not receive Ketotifen, while in experiment group (n = 20), the men received oraly ketotifen (1 mg Bid) for 2 months. Semen analysis, under optimal circumferences, was obtained prior to initiation of treatment. The second semen analysis was done 2-3 weeks after stopped ketotifen treatment and sperm motility was defined. Clinical pregnancy was identified as the presence of a fetal sac by vaginal ultrasound examination. STATISTICAL ANALYSIS USED: All data are expressed as the mean ± standard error of mean (SEM). t test was used for comparing the data of the control and treated groups. RESULTS: The mean sperm motility increased significantly (from 16.7% to 21.4%) after ketotifen treatment (P < 0.001). This sperm motility improvement was more pronounced in the primary infertility cases (P < 0.003). The rate of pregnancy was 12.5% in infertile couples that their men receiving 1 mg/twice a day ketotifen. In 52% of infertile men's semen, the percentage of sperm motility was increased from 5% to 35% and this sperm motility improvement was also observed in 33% of necrospermia (0% motility) cases. CONCLUSION: These results suggest that ketotifen may represent as a novel therapeutic approach to improve sperm motility in the infertile men with cause of asthenospermia or necrospermia. PMID:23869145

  8. Acute effects of morphine and opioid peptides on the motility and responses of rat colon to electrical stimulation.

    PubMed Central

    Gillan, M. G.; Pollock, D.

    1980-01-01

    1 Morphine and leucine- and methionine-enkephalins inhibited the contractile response of the pithed rat colon to electrical stimulation of the spinal motor outflows and inhibited motor responses of the isolated colon to field stimulation. 2 Morphine and the opioid peptides also had an excitatory action in the colon. In the pithed rat, opiates caused regular fluctuations in intracolonic pressure and in the isolated colon, caused regular waves of contraction. This excitatory response was produced by low concentrations of the enkephalins (2 X 10(-8) M, 2 X 10(-9) M), was stereospecific and was antagonized by naloxone. 3 Opiate-induced contractions in the isolated colon were inhibited by catecholamines, adenine nucleotides and by phosphodiesterase inhibitors. These contractions were unaffected by ergotamine and tolazoline, or by propranolol. 4 The excitatory action of opiates in the isolated colon was not antagonized and usually was potentiated by atropine, (+)-tubocurarine and hexamethonium. In the absence of opiates, these drugs also produced similar waves of contraction, which were unaffected by naloxone. 5 Opiate-induced contractions occurred in colon rendered unresponsive to 5-hydroxytryptamine (5-HT) and these contractions were potentiated by the 5-HT antagonist, lysergic acid diethylamide, which, when administered alone, caused similar contractions. The 5-HT antagonist, cyproheptadine, inhibited opiate-induced contractions but was non-specific, since it also inhibited responses of the colon to carbachol and KC1. 6 Opiate-induced contractions were unaffected by procaine and were potentiated by tetrodotoxin. Both of these drugs, when administered alone, produced waves of contractions, which were similar to those produced by opiates but were unaffected by naloxone. 7 Contractions produced in the isolated colon either by opiates, atropine or (+)-tubocurarine, or any combination of these drugs, were inhibited by field stimulation applied at the peak of a wave of

  9. SWAP-70 Identifies a Transitional Subset of Actin Filaments in Motile CellsV⃞

    PubMed Central

    Hilpelä, Pirta; Oberbanscheidt, Pia; Hahne, Penelope; Hund, Martin; Kalhammer, Georg; Small, J. Victor; Bähler, Martin

    2003-01-01

    Functionally different subsets of actin filament arrays contribute to cellular organization and motility. We report the identification of a novel subset of loose actin filament arrays through regulated association with the widely expressed protein SWAP-70. These loose actin filament arrays were commonly located behind protruding lamellipodia and membrane ruffles. Visualization of these loose actin filament arrays was dependent on lamellipodial protrusion and the binding of the SWAP-70 PH-domain to a 3′-phosphoinositide. SWAP-70 with a functional pleckstrin homology-domain lacking the C-terminal 60 residues was targeted to the area of the loose actin filament arrays, but it did not associate with actin filaments. The C-terminal 60 residues were sufficient for actin filament association, but they provided no specificity for the subset of loose actin filament arrays. These results identify SWAP-70 as a phosphoinositide 3-kinase signaling-dependent marker for a distinct, hitherto unrecognized, array of actin filaments. Overexpression of SWAP-70 altered the actin organization and lamellipodial morphology. These alterations were dependent on a proper subcellular targeting of SWAP-70. We propose that SWAP-70 regulates the actincytoskeletonasaneffectororadaptorproteininresponsetoagoniststimulatedphosphatidylinositol (3,4)-bisphosphate production and cell protrusion. PMID:12925760

  10. Small molecule targeting Cdc42-intersectin interaction disrupts Golgi organization and suppresses cell motility.

    PubMed

    Friesland, Amy; Zhao, Yaxue; Chen, Yan-Hua; Wang, Lie; Zhou, Huchen; Lu, Qun

    2013-01-22

    Signaling through the Rho family of small GTPases has been intensely investigated for its crucial roles in a wide variety of human diseases. Although RhoA and Rac1 signaling pathways are frequently exploited with the aid of effective small molecule modulators, studies of the Cdc42 subclass have lagged because of a lack of such means. We have applied high-throughput in silico screening and identified compounds that are able to fit into the surface groove of Cdc42, which is critical for guanine nucleotide exchange factor binding. Based on the interaction between Cdc42 and intersectin (ITSN), a specific Cdc42 guanine nucleotide exchange factor, we discovered compounds that rendered ITSN-like interactions in the binding pocket. By using in vitro binding and imaging as well as biochemical and cell-based assays, we demonstrated that ZCL278 has emerged as a selective Cdc42 small molecule modulator that directly binds to Cdc42 and inhibits its functions. In Swiss 3T3 fibroblast cultures, ZCL278 abolished microspike formation and disrupted GM130-docked Golgi structures, two of the most prominent Cdc42-mediated subcellular events. ZCL278 reduces the perinuclear accumulation of active Cdc42 in contrast to NSC23766, a selective Rac inhibitor. ZCL278 suppresses Cdc42-mediated neuronal branching and growth cone dynamics as well as actin-based motility and migration in a metastatic prostate cancer cell line (i.e., PC-3) without disrupting cell viability. Thus, ZCL278 is a small molecule that specifically targets Cdc42-ITSN interaction and inhibits Cdc42-mediated cellular processes, thus providing a powerful tool for research of Cdc42 subclass of Rho GTPases in human pathogenesis, such as those of cancer and neurological disorders. PMID:23284167

  11. Stem Cell Stimulation of Endogenous Myocyte Regeneration

    PubMed Central

    Weil, Brian R.; Canty, John M.

    2015-01-01

    Cell-based therapy has emerged as a promising approach to combat the myocyte loss and cardiac remodeling that characterize the progression of left ventricular dysfunction to heart failure. Several clinical trials conducted during the past decade have shown that a variety of autologous bone marrow- and peripheral blood-derived stem and progenitor cell populations can be safely administered to patients with ischemic heart disease and yield modest improvements in cardiac function. Concurrently, rapid progress has been made at the preclinical level to identify novel therapeutic cell populations, delineate the mechanisms underlying cell-mediated cardiac repair, and optimize cell-based approaches for clinical use. The following review summarizes the progress that has been made in this rapidly evolving field over the past decade and examines how our current understanding of the mechanisms involved in successful cardiac regeneration should direct future investigation in this area. Particular emphasis is placed on discussion of the general hypothesis that the benefits of cell therapy primarily result from stimulation of endogenous cardiac repair processes that have only recently been identified in the adult mammalian heart, rather than direct differentiation of exogenous cells. Continued scientific investigation in this area will guide the optimization of cell-based approaches for myocardial regeneration, with the ultimate goal of clinical implementation and substantial improvement in our ability to restore cardiac function in ischemic heart disease patients. PMID:23577634

  12. Silibinin inhibits fibronectin induced motility, invasiveness and survival in human prostate carcinoma PC3 cells via targeting integrin signaling.

    PubMed

    Deep, Gagan; Kumar, Rahul; Jain, Anil K; Agarwal, Chapla; Agarwal, Rajesh

    2014-10-01

    Prostate cancer (PCA) is the 2nd leading cause of cancer-related deaths among men in the United States. Preventing or inhibiting metastasis-related events through non-toxic agents could be a useful approach for lowering high mortality among PCA patients. We have earlier reported that natural flavonoid silibinin possesses strong anti-metastatic efficacy against PCA however, mechanism/s of its action still remains largely unknown. One of the major events during metastasis is the replacement of cell-cell interaction with integrins-based cell-matrix interaction that controls motility, invasiveness and survival of cancer cells. Accordingly, here we examined silibinin effect on advanced human PCA PC3 cells' interaction with extracellular matrix component fibronectin. Silibinin (50-200 μM) treatment significantly decreased the fibronectin (5 μg/ml)-induced motile morphology via targeting actin cytoskeleton organization in PC3 cells. Silibinin also decreased the fibronectin-induced cell proliferation and motility but significantly increased cell death in PC3 cells. Silibinin also inhibited the PC3 cells invasiveness in Transwell invasion assays with fibronectin or cancer associated fibroblasts (CAFs) serving as chemoattractant. Importantly, PC3-luc cells cultured on fibronectin showed rapid dissemination and localized in lungs following tail vein injection in athymic male nude mice; however, in silibinin-treated PC3-luc cells, dissemination and lung localization was largely compromised. Molecular analyses revealed that silibinin treatment modulated the fibronectin-induced expression of integrins (α5, αV, β1 and β3), actin-remodeling (FAK, Src, GTPases, ARP2 and cortactin), apoptosis (cPARP and cleaved caspase 3), EMT (E-cadherin and β-catenin), and cell survival (survivin and Akt) related signaling molecules in PC3 cells. Furthermore, PC3-xenograft tissue analyses confirmed the inhibitory effect of silibinin on fibronectin and integrins expression. Together, these

  13. GDNF increases cell motility in human colon cancer through VEGF-VEGFR1 interaction.

    PubMed

    Huang, Ssu-Ming; Chen, Tzu-Sheng; Chiu, Chien-Ming; Chang, Leang-Kai; Liao, Kuan-Fu; Tan, Hsiao-Ming; Yeh, Wei-Lan; Chang, Gary Ro-Lin; Wang, Min-Ying; Lu, Dah-Yuu

    2014-02-01

    Glial cell line-derived neurotrophic factor (GDNF), a potent neurotrophic factor, has been shown to affect cancer cell metastasis and invasion. However, the molecular mechanisms underlying GDNF-induced colon cancer cell migration remain unclear. GDNF is found to be positively correlated with malignancy in human colon cancer patients. The migratory activities of two human colon cancer cell lines, HCT116 and SW480, were found to be enhanced in the presence of human GDNF. The expression of vascular endothelial growth factor (VEGF) was also increased in response to GDNF stimulation, along with VEGF mRNA expression and transcriptional activity. The enhancement of GDNF-induced cancer cell migration was antagonized by a VEGF-neutralizing antibody. Our results also showed that the expression of VEGF receptor 1 (VEGFR1) was increased in response to GDNF stimulation, whereas GDNF-induced cancer cell migration was reduced by a VEGFR inhibitor. The GDNF-induced VEGF expression was regulated by the p38 and PI3K/Akt signaling pathways. Treatment with GDNF increased nuclear hypoxia-inducible factor 1 α (HIF1α) accumulation and its transcriptional activity in a time-dependent manner. Moreover, GDNF increased hypoxia responsive element (HRE)-containing VEGF promoter transcriptional activity but not that of the HRE-deletion VEGF promoter construct. Inhibition of HIF1α by a pharmacological inhibitor or dominant-negative mutant reduced the GDNF-induced migratory activity in human colon cancer cells. These results indicate that GDNF enhances the migration of colon cancer cells by increasing VEGF-VEGFR interaction, which is mainly regulated by the p38, PI3K/Akt, and HIF1α signaling pathways. PMID:24165321

  14. Gonadotropin-releasing hormone type II (GnRH-II) agonist regulates the motility of human decidual endometrial stromal cells: possible effect on embryo implantation and pregnancy.

    PubMed

    Wu, Hsien-Ming; Huang, Hong-Yuan; Lee, Chyi-Long; Soong, Yung-Kuei; Leung, Peter C K; Wang, Hsin-Shih

    2015-04-01

    Invasion of the maternal decidua by extravillous trophoblast is an important process for embryo implantation and placentation in humans. Motile behavior of decidual endometrial stromal cells has been considered of critical importance for embryo implantation and programming of human pregnancy. The gonadotropin-releasing hormone (GnRH) effects in endometrium have raised concerns in reproduction. In the present study, we examined the action of GnRH-II agonist-promoted motility of human decidual endometrial stromal cells and the mechanisms of the action, indicating the role of GnRH-II agonist in embryo implantation and early pregnancy. Human decidual endometrial stromal cells were isolated from the decidual tissue from healthy women undergoing elective pregnancy termination of a normal pregnancy at 6- to 12-wk gestation, after informed consent. Cell motility was estimated by invasion and migration assay. Zymography and immunoblot analysis were performed to investigate the mechanisms of the GnRH-II action. The GnRH-I receptor (GnRH-IR) was expressed in human decidual tissue and endometrial stromal cells. The GnRH-II agonist promoted cell motility. Mitogen-activated protein kinase inhibitors abolished GnRH-II agonist-induced cell motility and activation of MMP-2 and MMP-9. GnRH-II agonist-mediated cell motility was suppressed by knockdown of endogenous GnRH-IR, MMP (matrix metalloproteinase)-2, and MMP-9 with small interfering RNA and MMP inhibitors. Our study demonstrates that the GnRH-II agonist promoted the cell motility of human decidual endometrial stromal cells through the GnRH-IR and the phosphorylation of extracellular signal-regulated protein kinase 1/2 and JNK-dependent activation of MMP-2 and MMP-9. Our findings represent a new concept regarding the mechanisms of GnRH-II-promoted cell motility, suggesting that GnRH-II agonist has strong effects on embryo implantation and decidual programming of human pregnancy. PMID:25761596

  15. [Obesity and gastrointestinal motility].

    PubMed

    Lee, Joon Seong

    2006-08-01

    Gastrointestinal (GI) motility has a crucial role in the food consumption, digestion and absorption, and also controls the appetite and satiety. In obese patients, various alterations of GI motility have been investigated. The prevalence of GERD and esophageal motor disorders in obese patients are higher than those of general population. Gastric emptying of solid food is generally accelerated and fasting gastric volume especially in distal stomach is larger in obese patients without change in accommodation. Contractile activity of small intestine in fasting period is more prominent, but orocecal transit is delayed. Autonomic dysfunction is frequently demonstrated in obese patients. These findings correspond with increased appetite and delayed satiety in obese patients, but causes or results have not been confirmed. Therapeutic interventions of these altered GI motility have been developed using botulinum toxin, gastric electrical stimulation in obese patients. Novel agents targeted for GI hormone modulation (such as ghrelin and leptin) need to be developed in the near future. PMID:16929152

  16. Reticulate Structures Reveal the Significance of Cell Motility in the Morphogenesis of Complex Microbial Structures in Pavilion Lake, British Columbia

    NASA Astrophysics Data System (ADS)

    Shepard, R.

    2008-12-01

    Microbial communities are architects of incredibly complex and diverse morphological structures. Each morphology is a snapshot that reflects the complex interactions within the microbial community and between the community and its environment. Characterizing morphology as an emergent property of microbial communities is thus relevant to understanding the evolution of multicellularity and complexity in developmental systems, to the identification of biosignatures, and to furthering our understanding of modern and ancient microbial ecology. Recently discovered cyanobacterial mats in Pavilion Lake, British Columbia construct unusual complex architecture on the scale of decimeters that incorporates significant void space. Fundamental mesoscale morphological elements include terraces, arches, bridges, depressions, domes, and pillars. The mats themselves also exhibit several microscale morphologies, with reticulate structures being the dominant example. The reticulate structures exhibit a diverse spectrum of morphologies with endmembers characterized by either angular or curvilinear ridges. In laboratory studies, aggregation into reticulate structures occurs as a result of the random gliding and colliding among motile cyanobacterial filaments. Likewise, when Pavilion reticulate mats were sampled and brought to the surface, cyanobacteria invariably migrated out of the mat onto surrounding surfaces. Filaments were observed to move rapidly in clumps, preferentially following paths of previous filaments. The migrating filaments organized into new angular and ropey reticulate biofilms within hours of sampling, demonstrating that cell motility is responsible for the reticulate patterns. Because the morphogenesis of reticulate structures can be linked to motility behaviors of filamentous cyanobacteria, the Willow Point mats provide a unique natural laboratory in which to elucidate the connections between a specific microbial behavior and the construction of complex microbial

  17. Collagen degradation and platelet-derived growth factor stimulate the migration of vascular smooth muscle cells.

    PubMed

    Stringa, E; Knäuper, V; Murphy, G; Gavrilovic, J

    2000-06-01

    Cell migration is a key event in many biological processes and depends on signals from both extracellular matrix and soluble motogenic factors. During atherosclerotic plaque development, vascular smooth muscle cells migrate from the tunica media to the intima through a basement membrane and interstitial collagenous matrix and proliferate to form a neointima. Matrix metalloproteinases have previously been implicated in neointimal formation and in this study smooth muscle cell adhesion and migration on degraded collagen have been evaluated. Vascular smooth muscle cells adhered to native intact collagen type I and to its first degradation by-product, 3/4 fragment (generated by collagenase-3 cleavage), unwound at 35 degrees C to mimic physiological conditions. PDGF-BB pre-treatment induced a fourfold stimulation of smooth muscle cell motility on the collagen 3/4 fragment whereas no increase in smooth muscle cell motility on collagen type I was observed. Cell migration on collagen type I was mediated by alpha2 integrin, whereas PDGF-BB-stimulated migration on the 3/4 collagen fragment was dependent on alphavbeta3 integrin. alphavbeta3 integrin was organised in clusters concentrated at the leading and trailing edges of the cells and was only expressed when cells were exposed to the 3/4 collagen fragment. Tyrphostin A9, an inhibitor of PDGF receptor-beta tyrosine kinase activity, resulted in complete abolition of migration of PDGF-BB treated cells on collagen type I and 3/4 fragment. These results strongly support the hypothesis that the cellular migratory response to soluble motogens can be regulated by proteolytic modification of the extracellular matrix. PMID:10806116

  18. Pediatric intestinal motility disorders

    PubMed Central

    Gfroerer, Stefan; Rolle, Udo

    2015-01-01

    Pediatric intestinal motility disorders affect many children and thus not only impose a significant impact on pediatric health care in general but also on the quality of life of the affected patient. Furthermore, some of these conditions might also have implications for adulthood. Pediatric intestinal motility disorders frequently present as chronic constipation in toddler age children. Most of these conditions are functional, meaning that constipation does not have an organic etiology, but in 5% of the cases, an underlying, clearly organic disorder can be identified. Patients with organic causes for intestinal motility disorders usually present in early infancy or even right after birth. The most striking clinical feature of children with severe intestinal motility disorders is the delayed passage of meconium in the newborn period. This sign is highly indicative of the presence of Hirschsprung disease (HD), which is the most frequent congenital disorder of intestinal motility. HD is a rare but important congenital disease and the most significant entity of pediatric intestinal motility disorders. The etiology and pathogenesis of HD have been extensively studied over the last several decades. A defect in neural crest derived cell migration has been proven as an underlying cause of HD, leading to an aganglionic distal end of the gut. Numerous basic science and clinical research related studies have been conducted to better diagnose and treat HD. Resection of the aganglionic bowel remains the gold standard for treatment of HD. Most recent studies show, at least experimentally, the possibility of a stem cell based therapy for HD. This editorial also includes rare causes of pediatric intestinal motility disorders such as hypoganglionosis, dysganglionosis, chronic intestinal pseudo-obstruction and ganglioneuromatosis in multiple endocrine metaplasia. Underlying organic pathologies are rare in pediatric intestinal motility disorders but must be recognized as early as

  19. Pediatric intestinal motility disorders.

    PubMed

    Gfroerer, Stefan; Rolle, Udo

    2015-09-01

    Pediatric intestinal motility disorders affect many children and thus not only impose a significant impact on pediatric health care in general but also on the quality of life of the affected patient. Furthermore, some of these conditions might also have implications for adulthood. Pediatric intestinal motility disorders frequently present as chronic constipation in toddler age children. Most of these conditions are functional, meaning that constipation does not have an organic etiology, but in 5% of the cases, an underlying, clearly organic disorder can be identified. Patients with organic causes for intestinal motility disorders usually present in early infancy or even right after birth. The most striking clinical feature of children with severe intestinal motility disorders is the delayed passage of meconium in the newborn period. This sign is highly indicative of the presence of Hirschsprung disease (HD), which is the most frequent congenital disorder of intestinal motility. HD is a rare but important congenital disease and the most significant entity of pediatric intestinal motility disorders. The etiology and pathogenesis of HD have been extensively studied over the last several decades. A defect in neural crest derived cell migration has been proven as an underlying cause of HD, leading to an aganglionic distal end of the gut. Numerous basic science and clinical research related studies have been conducted to better diagnose and treat HD. Resection of the aganglionic bowel remains the gold standard for treatment of HD. Most recent studies show, at least experimentally, the possibility of a stem cell based therapy for HD. This editorial also includes rare causes of pediatric intestinal motility disorders such as hypoganglionosis, dysganglionosis, chronic intestinal pseudo-obstruction and ganglioneuromatosis in multiple endocrine metaplasia. Underlying organic pathologies are rare in pediatric intestinal motility disorders but must be recognized as early as

  20. The Stem Cell Marker CD133 Associates with Enhanced Colony Formation and Cell Motility in Colorectal Cancer

    PubMed Central

    Elsaba, Tarek M. A.; Martinez-Pomares, Luisa; Robins, Adrian R.; Crook, Simon; Seth, Rashmi; Jackson, Darryl; McCart, Amy; Silver, Andrew R.; Tomlinson, Ian P. M.; Ilyas, Mohammad

    2010-01-01

    CD133 is a membrane molecule that has been, controversially, reported as a CSC marker in colorectal cancer (CRC). In this study, we sought to clarify the expression and role of CD133 in CRC. Initially the size of the CD133−expressing (CD133+) population in eight well-described CRC cell lines was measured by flow cytometry and was found to range from 0% to >95%. The cell line HT29 has a CD133+ population of >95% and was chosen for functional evaluation of CD133 after gene knockdown by RNA interference. A time course assay showed that CD133 inhibition had no significant effect on cell proliferation or apoptosis. However, CD133 knockdown did result in greater susceptibility to staurosporine-induced apoptosis (p = 0.01) and reduction in cell motility (p<0.04). Since gene knockdown may cause “off-target” effects, the cell line SW480 (which has a CD133+ population of 40%) was sorted into pure CD133+ and CD133− populations to allow functional comparison of isogenic populations separated only by CD133 expression. In concordance with the knockdown experiments, a time course assay showed no significant proliferative differences between the CD133+/CD133− populations. Also greater resistance to staurosporine-induced apoptosis (p = 0.008), greater cell motility (p = 0.03) and greater colony forming efficiency was seen in the CD133+ population than the CD133− population in both 2D and 3D culture (p<0.0001 and p<0.003 respectively). Finally, the plasticity of CD133 expression in tumour cells was tested. Quantitative PCR analysis showed there was transcriptional repression in the CD133− population of SW480. Prolonged culture of a pure CD133− population resulted in re-emergence of CD133+ cells. We conclude that CD133 expression in CRCs is associated with some features attributable to stemness and that there is plasticity of CD133 expression. Further studies are necessary to delineate the mechanistic basis of these features. PMID:20502714

  1. Secreted or nonsecreted forms of acidic fibroblast growth factor produced by transfected epithelial cells influence cell morphology, motility, and invasive potential.

    PubMed Central

    Jouanneau, J; Gavrilovic, J; Caruelle, D; Jaye, M; Moens, G; Caruelle, J P; Thiery, J P

    1991-01-01

    Addition of exogenous acidic fibroblast growth factor (aFGF) to NBT-II epithelial carcinoma cells results in fibroblastic transformation and cell motility. We have generated aFGF-producing NBT-II cells by transfection with recombinant expression vectors containing human aFGF cDNA, or the human aFGF cDNA coupled to a signal peptide (SP) sequence. The effects of the nonsecreted and the secreted 16-kDa growth factor on the morphology, motility, and cell invasive potential (gelatinase activity) were compared. aFGF coupled to a SP was actively secreted out of the producing cells. The secretion of aFGF was not necessary for induction of gelatinase activity, as this was observed in NBT-II cells producing aFGF with or without SP. Production of aFGF, whether secreted or not secreted, resulted in increased in vitro motility of most isolated clones; however, there was no correlation between aFGF level and motility rate. The data suggest that expression of aFGF in NBT-II cells induces metastatic potential through an autocrine or intracrine mechanism. Images PMID:1707175

  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. MT1-MMP dependent repression of the tumor suppressor SPRY4 contributes to MT1-MMP driven melanoma cell motility

    PubMed Central

    Shaverdashvili, Khvaramze; Zhang, Keman; Osman, Iman; Honda, Kord; Jobava, Rauli; Bedogni, Barbara

    2015-01-01

    Metastatic melanoma is the deadliest of all skin cancers. Despite progress in diagnostics and treatment of melanoma, the prognosis for metastatic patients remains poor. We previously showed that Membrane-type 1 Matrix Metalloproteinase (MT1-MMP) is one of the drivers of melanoma metastasis. Classically, MT1-MMP regulates a verity of cellular functions including cell-to-cell interaction and cell-to-matrix communication. Recently, MT1-MMP has been found to also modulate gene expression. To specifically assess MT1-MMP dependent gene regulation in melanoma, microarray gene expression analysis was performed in a melanoma cell line whose metastatic properties depend on the activity of MT1-MMP. We identified the tumor suppressor gene SPRY4 as a new transcriptional target of MT1-MMP that is negatively regulated by the protease. Knockdown of MT1-MMP enhances SPRY4 expression at the mRNA and protein level. SPRY4 expression inversely correlates with that of MT1-MMP in melanoma samples and importantly, correlates with melanoma patient survival. SPRY4 modulates MT1-MMP dependent cell migration such that inhibition of SPRY4 rescues cell migration that has been impaired by MT1-MMP knock down. MT1-MMP decreases SPRY4 in part through an MMP2/RAC1 axis we previously show promotes cell motility downstream of MT1-MMP. These results identify the tumor suppressor SPRY4 as a novel molecular effector of MT1-MMP affecting melanoma cell motility. PMID:26392417

  4. Eukaryotic Translation Initiation Factor 3a (eIF3a) Promotes Cell Proliferation and Motility in Pancreatic Cancer.

    PubMed

    Wang, Shu Qian; Liu, Yu; Yao, Min Ya; Jin, Jing

    2016-10-01

    Identifying a target molecule that is crucially involved in pancreatic tumor growth and metastasis is necessary in developing an effective treatment. The study aimed to investigate the role of the eukaryotic translation initiation factor 3a (eIF3a) in the cell proliferation and motility in pancreatic cancer. Our data showed that the expression of eIF3a was upregulated in pancreatic ductal adenocarcinoma as compared with its expression in normal pancreatic tissues. Knockdown of eIF3a by a specific shRNA caused significant decreases in cell proliferation and clonogenic abilities in pancreatic cancer SW1990 and Capan-1 cells. Consistently, the pancreatic cancer cell growth rates were also impaired in xenotransplanted mice. Moreover, wound-healing assay showed that depletion of eIF3a significantly slowed down the wound recovery processes in SW1990 and Capan-1 cells. Transwell migration and invasion assays further showed that cell migration and invasion abilities were significantly inhibited by knockdown of eIF3a in SW1990 and Capan-1 cells. Statistical analysis of eIF3a expression in 140 cases of pancreatic ductal adenocarcinoma samples revealed that eIF3a expression was significantly associated with tumor metastasis and TNM staging. These analyses suggest that eIF3a contributes to cell proliferation and motility in pancreatic ductal adenocarcinoma. PMID:27550487

  5. Claudin-18 inhibits cell proliferation and motility mediated by inhibition of phosphorylation of PDK1 and Akt in human lung adenocarcinoma A549 cells.

    PubMed

    Shimobaba, Shun; Taga, Saeko; Akizuki, Risa; Hichino, Asami; Endo, Satoshi; Matsunaga, Toshiyuki; Watanabe, Ryo; Yamaguchi, Masahiko; Yamazaki, Yasuhiro; Sugatani, Junko; Ikari, Akira

    2016-06-01

    Abnormal expression of claudin subtypes has been reported in various cancers. However, the pathological role of each claudin has not been clarified in detail. Claudin-18 was absent in human non-small cell and small cell lung cancers, although it is expressed in normal lung tissues. Here, we examined the effect of claudin-18 expression on the expression of junctional proteins, cell proliferation, and cell motility using human lung adenocarcinoma A549 cells. Real-time PCR and western blotting showed that exogenous expression of claudin-18 had no effect on the expression of junctional proteins including claudin-1, zonula occludens-1 (ZO-1), occludin, and E-cadherin. Claudin-18 was mainly distributed in cell-cell contact areas concomitant with ZO-1. Cell proliferation was significantly decreased at 48 and 72h after seeding of claudin 18-expressing cells. Claudin-18 suppressed cell motility, whereas it increased cell death in anoikis. Claudin-18 decreased phosphorylated (p)-3-phosphoinositide-dependent protein kinase-1 (PDK1) and p-Akt levels without affecting p-epidermal growth factor receptor and p-phosphatidylinositol-3 kinase (PI3K) levels. Furthermore, claudin-18 was bound with PDK1 and suppressed the nuclear localization of PDK1. We suggest that claudin-18 suppresses the abnormal proliferation and motility of lung epithelial cells mediated by inhibition of the PI3K/PDK1/Akt signaling pathway. PMID:26919807

  6. In Vitro Effect of Cell Phone Radiation on Motility, DNA Fragmentation and Clusterin Gene Expression in Human Sperm

    PubMed Central

    Zalata, Adel; El-Samanoudy, Ayman Z; Shaalan, Dalia; El-Baiomy, Youssef; Mostafa, Taymour

    2015-01-01

    Background Use of cellular phones emitting radiofrequency electromagnetic field (RF-EMF) has been increased exponentially and become a part of everyday life. This study aimed to investigate the effects of in vitro RF-EMF exposure emitted from cellular phones on sperm motility index, sperm DNA fragmentation and seminal clusterin (CLU) gene expression. Materials and Methods In this prospective study, a total of 124 semen samples were grouped into the following main categories: i. normozoospermia (N, n=26), ii. asthenozoospermia (A, n=32), iii. asthenoteratozoospermia (AT, n=31) and iv. oligoasthenoteratozoospermia (OAT, n=35). The same semen samples were then divided into two portions non-exposed and exposed samples to cell phone radiation for 1 hour. Before and immediately after exposure, both aliquots were subjected to different assessments for sperm motility, acrosin activity, sperm DNA fragmentation and CLU gene expression. Statistical differences were analyzed using paired t student test for comparisons between two sub-groups where p<0.05 was set as significant. Results There was a significant decrease in sperm motility, sperm linear velocity, sperm linearity index, and sperm acrosin activity, whereas there was a significant increase in sperm DNA fragmentation percent, CLU gene expression and CLU protein levels in the exposed semen samples to RF-EMF compared with non-exposed samples in OAT>AT>A>N groups, respectively (p<0.05). Conclusion Cell phone emissions have a negative impact on exposed sperm motility index, sperm acrosin activity, sperm DNA fragmentation and seminal CLU gene expression, especially in OAT cases. PMID:25918601

  7. Down-regulation of UDP-glucose dehydrogenase affects glycosaminoglycans synthesis and motility in HCT-8 colorectal carcinoma cells

    SciTech Connect

    Wang, Tsung-Pao; Pan, Yun-Ru; Fu, Chien-Yu; Chang, Hwan-You

    2010-10-15

    UDP-glucose dehydrogenase (UGDH) catalyzes oxidation of UDP-glucose to yield UDP-glucuronic acid, a precursor of hyaluronic acid (HA) and other glycosaminoglycans (GAGs) in extracellular matrix. Although association of extracellular matrix with cell proliferation and migration has been well documented, the importance of UGDH in these behaviors is not clear. Using UGDH-specific small interference RNA to treat HCT-8 colorectal carcinoma cells, a decrease in both mRNA and protein levels of UGDH, as well as the cellular UDP-glucuronic acid and GAG production was observed. Treatment of HCT-8 cells with either UGDH-specific siRNA or HA synthesis inhibitor 4-methylumbelliferone effectively delayed cell aggregation into multicellular spheroids and impaired cell motility in both three-dimensional collagen gel and transwell migration assays. The reduction in cell aggregation and migration rates could be restored by addition of exogenous HA. These results indicate that UGDH can regulate cell motility through the production of GAG. The enzyme may be a potential target for therapeutic intervention of colorectal cancers.

  8. Lamellipodin Is Important for Cell-to-Cell Spread and Actin-Based Motility in Listeria monocytogenes.

    PubMed

    Wang, Jiahui; King, Jane E; Goldrick, Marie; Lowe, Martin; Gertler, Frank B; Roberts, Ian S

    2015-09-01

    Listeria monocytogenes is a foodborne pathogen capable of invading a broad range of cell types and replicating within the host cell cytoplasm. This paper describes the colocalization of host cell lamellipodin (Lpd) with intracellular L. monocytogenes detectable 6 h postinfection of epithelial cells. The association was mediated via interactions between both the peckstrin homology (PH) domain in Lpd and phosphatidylinositol (3,4)-bisphosphate [PI(3,4)P2] on the bacterial surface and by interactions between the C-terminal EVH1 (Ena/VASP [vasodilator-stimulated phosphoprotein] homology domain 1) binding domains of Lpd and the host VASP (vasodilator-stimulated phosphoprotein) recruited to the bacterial cell surface by the listerial ActA protein. Depletion of Lpd by short interfering RNA (siRNA) resulted in reduced plaque size and number, indicating a role for Lpd in cell-to-cell spread. In contrast, overexpression of Lpd resulted in an increase in the number of L. monocytogenes-containing protrusions (listeriopods). Manipulation of the levels of Lpd within the cell also affected the intracellular velocity of L. monocytogenes, with a reduction in Lpd corresponding to an increase in intracellular velocity. These data, together with the observation that Lpd accumulated at the interface between the bacteria and the developing actin tail at the initiation of actin-based movement, indicate a possible role for Lpd in the actin-based movement and the cell-to-cell spread of L. monocytogenes. PMID:26169271

  9. α-TEA inhibits the growth and motility of human colon cancer cells via targeting RhoA/ROCK signaling

    PubMed Central

    Yao, Jialin; Gao, Peng; Xu, Yang; Li, Zhaozhu

    2016-01-01

    Colon or colorectal cancer is a common type of human cancer, which originates in the intestine crassum or the rectum. In the United States, colorectal cancer has one of the highest rates of cancer-related mortality. Investigating novel chemotherapeutic approaches is significant in the treatment of cancers, such as colorectal cancer. α-tocopherol ether-linked acetic acid (α-TEA) is a potent anticancer agent in multiple types of human cancer. However, its effect remains to be determined in colon cancer. In this study, HCT116 and SW480 human colon cancer cells were used to investigate the anticancer role of α-TEA. It was demonstrated that α-TEA inhibited cell proliferation, migration and invasion in colon cancer cells. Furthermore, it was shown that α-TEA downregulated the activity of RhoA and phosphorylated Rho-associated protein kinase (ROCK) substrate myosin light chain (MLC) using a pull-down assay and western blotting, respectively, implying that the RhoA/ROCK pathway is involved in α-TEA-mediated cell growth and motility inhibition. In order to confirm this hypothesis a RhoA inhibitor (clostridium botulinum C3 exoenzyme), a ROCK inhibitor (Y27632) and RhoA small interfering (si)RNA were applied to block RhoA/ROCK signaling. This resulted in the attenuation of MLC phosphorylation, and augmentation of α-TEA-mediated growth and motility inhibition in colon cancer cells. In conclusion, these results indicate that α-TEA inhibits growth and motility in colon cancer cells possibly by targeting RhoA/ROCK signaling. Moreover, combined with RhoA or ROCK inhibitors, α-TEA may exhibit a more effective inhibitory role in colon cancer. PMID:27432222

  10. α-TEA inhibits the growth and motility of human colon cancer cells via targeting RhoA/ROCK signaling.

    PubMed

    Yao, Jialin; Gao, Peng; Xu, Yang; Li, Zhaozhu

    2016-09-01

    Colon or colorectal cancer is a common type of human cancer, which originates in the intestine crassum or the rectum. In the United States, colorectal cancer has one of the highest rates of cancer‑related mortality. Investigating novel chemotherapeutic approaches is significant in the treatment of cancers, such as colorectal cancer. α-tocopherol ether-linked acetic acid (α-TEA) is a potent anticancer agent in multiple types of human cancer. However, its effect remains to be determined in colon cancer. In this study, HCT116 and SW480 human colon cancer cells were used to investigate the anticancer role of α-TEA. It was demonstrated that α-TEA inhibited cell proliferation, migration and invasion in colon cancer cells. Furthermore, it was shown that α-TEA downregulated the activity of RhoA and phosphorylated Rho-associated protein kinase (ROCK) substrate myosin light chain (MLC) using a pull-down assay and western blotting, respectively, implying that the RhoA/ROCK pathway is involved in α-TEA-mediated cell growth and motility inhibition. In order to confirm this hypothesis a RhoA inhibitor (clostridium botulinum C3 exoenzyme), a ROCK inhibitor (Y27632) and RhoA small interfering (si)RNA were applied to block RhoA/ROCK signaling. This resulted in the attenuation of MLC phosphorylation, and augmentation of α-TEA-mediated growth and motility inhibition in colon cancer cells. In conclusion, these results indicate that α-TEA inhibits growth and motility in colon cancer cells possibly by targeting RhoA/ROCK signaling. Moreover, combined with RhoA or ROCK inhibitors, α-TEA may exhibit a more effective inhibitory role in colon cancer. PMID:27432222

  11. Acoustic stimulation causes tonotopic alterations in the length of isolated outer hair cells from guinea pig hearing organ.

    PubMed Central

    Canlon, B; Brundin, L; Flock, A

    1988-01-01

    Isolated outer hair cells from the mammalian cochlea exhibit a motile response to electrical or chemical stimulation. Here we show that isolated outer hair cells can also respond to acoustic stimulation, in the form of a tone burst of 200 Hz, by either shortening or lengthening depending on their cochlear location. Cells from the apical region of the cochlea (long cells) responded by increasing their length, whereas those from more basal regions (short cells) responded by decreasing their length. Cells from intermediate positions showed an equal probability for either elongating or shortening. Both the elongating and shortening response was inhibited by 3 microM poly(L-lysine). It is suggested that this tonotopic and bidirectional acoustic response may be one of the active components underlying the specific phase and frequency displacement of the basilar membrane. Images PMID:3413135

  12. The Na+/H+ exchanger NHE1, but not the Na+, HCO3(-) cotransporter NBCn1, regulates motility of MCF7 breast cancer cells expressing constitutively active ErbB2.

    PubMed

    Lauritzen, Gitte; Stock, Christian-Martin; Lemaire, Justine; Lund, Stine F; Jensen, Mie Frid; Damsgaard, Britt; Petersen, Katrine Seide; Wiwel, Maria; Rønnov-Jessen, Lone; Schwab, Albrecht; Pedersen, Stine Falsig

    2012-04-28

    We and others have shown central roles of the Na(+)/H(+) exchanger NHE1 in cell motility. The aim of this study was to determine the roles of NHE1 and of the Na(+), HCO(3)(-) cotransporter NBCn1 in motility of serum-starved MCF-7 breast cancer cells expressing constitutively active ErbB2 (ΔNErbB2). ΔNErbB2 expression elicited NBCn1 upregulation, Ser(703)-phosphorylation of NHE1, and NHE1-inhibitor (EIPA)-sensitive pericellular acidification, in conjunction with increased expression of β1 integrin and ERM proteins. Active ERM proteins and NHE1 colocalized strongly to invadopodial rosettes, the diameter of which was increased by ΔNErbB2. Adhesion and migration on collagen-I were augmented by ΔNErbB2, unaffected by the NBC inhibitor S0859, and further stimulated by EIPA in a manner potentiated by PI3K-Akt-inhibition. These findings demonstrate that NHE1 inhibition can enhance cancer cell motility, adding an important facet to the understanding of NHE1 in cancer. PMID:22120673

  13. Cigarette smoke induces cell motility via platelet-activating factor accumulation in breast cancer cells: a potential mechanism for metastatic disease

    PubMed Central

    Kispert, Shannon; Marentette, John; McHowat, Jane

    2015-01-01

    Most cancer deaths are a result of metastasis rather than the primary tumor. Although cigarette smoking has been determined as a risk factor for several cancers, its role in metastasis has not been studied in detail. We propose that cigarette smoking contributes to metastatic disease via inhibition of breast cancer cell platelet-activating factor acetylhydrolase (PAF-AH), resulting in PAF accumulation and a subsequent increase in cell motility. We studied several breast cell lines, including immortalized mammary epithelial cells (MCF-10A), luminal A hormone positive MCF-7, basal-like triple negative MDA-MB-468, and claudin-low triple-negative highly metastatic MDA-MB-231 breast tumor cells. We exposed cells to cigarette smoke extract (CSE) for up to 48 h. CSE inhibited PAF-AH activity, increased PAF accumulation, and increased cell motility in MDA-MB-231 metastatic triple negative breast cancer cells. The calcium-independent phospholipase A2 (iPLA2) inhibitor, (S) bromoenol lactone ((S)-BEL) was used to prevent the accumulation of PAF and further prevented the increase in cell motility seen previously when cells were exposed to CSE. Thus, iPLA2 or PAF may represent a therapeutic target to manage metastatic disease, particularly in triple-negative breast cancer patients who smoke. PMID:25802360

  14. 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

  15. Acidification Activates Toxoplasma gondii Motility and Egress by Enhancing Protein Secretion and Cytolytic Activity

    PubMed Central

    Roiko, Marijo S.; Svezhova, Nadezhda; Carruthers, Vern B.

    2014-01-01

    Pathogenic microbes rely on environmental cues to initiate key events during infection such as differentiation, motility, egress and invasion of cells or tissues. Earlier investigations showed that an acidic environment activates motility of the protozoan parasite T. gondii. Conversely, potassium ions, which are abundant in the intracellular milieu that bathes immotile replicating parasites, suppress motility. Since motility is required for efficient parasite cell invasion and egress we sought to better understand its regulation by environmental cues. We found that low pH stimulates motility by triggering Ca2+-dependent secretion of apical micronemes, and that this cue is sufficient to overcome suppression by potassium ions and drive parasite motility, cell invasion and egress. We also discovered that acidification promotes membrane binding and cytolytic activity of perforin-like protein 1 (PLP1), a pore-forming protein required for efficient egress. Agents that neutralize pH reduce the efficiency of PLP1-dependent perforation of host membranes and compromise egress. Finally, although low pH stimulation of microneme secretion promotes cell invasion, it also causes PLP1-dependent damage to host cells, suggesting a mechanism by which neutral extracellular pH subdues PLP1 activity to allow cell invasion without overt damage to the target cell. These findings implicate acidification as a signal to activate microneme secretion and confine cytolytic activity to egress without compromising the viability of the next cell infected. PMID:25375818

  16. 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

  17. Missing-in-Metastasis regulates cell motility and invasion via PTPδ-mediated changes in SRC activity

    PubMed Central

    Chaudhary, Fauzia; Lucito, Robert; Tonks, Nicholas K.

    2014-01-01

    Missing in Metastasis (MIM), also known as MTSS1, is a scaffold protein that is down-regulated in multiple metastatic cancer cell lines compared to non-metastatic counterparts. MIM regulates cytoskeletal dynamics and actin polymerization, and has been implicated in the control of cell motility and invasion. MIM has also been shown to bind to a receptor PTP, PTPδ, an interaction that may provide a link between tyrosine phosphorylation-dependent signaling and metastasis. We used shRNA-mediated gene silencing to investigate the consequences of loss of MIM on the migration and invasion of the MCF10A mammary epithelial cell model of breast cancer. We observed that suppression of MIM by RNAi enhanced migration and invasion of MCF10A cells, effects that were associated with increased levels of PTPδ. Furthermore, analysis of human clinical data indicated that PTPδ was elevated in breast cancer samples when compared to normal tissue. We demonstrated that the SRC protein tyrosine kinase is a direct substrate of PTPδ and, upon suppression of MIM, we observed changes in the phosphorylation status of SRC, in particular the inhibitory site (Tyr 527) was hypophosphorylated, whereas the activating autophosphorylation site (Tyr 416) was hyperphosphorylated. Thus, the absence of MIM led to PTPδ-mediated activation of SRC. Finally, the SRC inhibitor SU6656 counteracted the effects of MIM suppression on cell motility and invasion. This study illustrates that both SRC and PTPδ have the potential to be therapeutic targets for metastatic tumors associated with loss of MIM. PMID:25287652

  18. The extracellular matrix microtopography drives critical changes in cellular motility and Rho A activity in colon cancer cells

    PubMed Central

    2010-01-01

    We have shown that the microtopography (mT) underlying colon cancer changes as a tumor de-differentiates. We distinguish the well-differentiated mT based on the increasing number of "pits" and poorly differentiated mT on the basis of increasing number of "posts." We investigated Rho A as a mechanosensing protein using mT features derived from those observed in the ECM of colon cancer. We evaluated Rho A activity in less-tumorogenic (Caco-2 E) and more tumorigenic (SW620) colon cancer cell-lines on microfabricated pits and posts at 2.5 μm diameter and 200 nm depth/height. In Caco-2 E cells, we observed a decrease in Rho A activity as well as in the ratio of G/F actin on surfaces with either pits or posts but despite this low activity, knockdown of Rho A led to a significant decrease in confined motility suggesting that while Rho A activity is reduced on these surfaces it still plays an important role in controlling cellular response to barriers. In SW620 cells, we observed that Rho A activity was greatest in cells plated on a post microtopography which led to increased cell motility, and an increase in actin cytoskeletal turnover. PMID:20667086

  19. Adenovirus‑mediated overexpression of cystic fibrosis transmembrane conductance regulator enhances invasiveness and motility of serous ovarian cancer cells.

    PubMed

    Xu, Jiao; Lin, Liangbo; Yong, Min; Dong, Xiaojing; Yu, Tinghe; Hu, Lina

    2016-01-01

    The cystic fibrosis transmembrane conductance regulator (CFTR) belongs to the adenosine triphosphate‑binding cassette transporter family, members of which are involved in several types of cancer. Previous studies by our group reported that CFTR was highly expressed in serous ovarian cancer (SOC) tissues, and that knockdown of CFTR suppressed the proliferation of ovarian cancer in vitro and in vivo. Thus, the aim of the present study was to construct a recombinant adenoviral vector for the expression of the human CFTR gene in order to study the role of CFTR overexpression in the malignant invasion and migration of SOC cells in vitro. The present study then focused on the mechanisms of the role of CFTR in the migratory and invasive malignant properties of SOC cells. The CFTR gene was inserted into an adenoviral vector by using the AdEasy system in order to obtain the Ad‑CFTR overexpression vector, which was used to transfect the A2780 SOC cell line. Reverse-transcription polymerase chain reaction, western blot analysis and immunofluorescence were performed to detect the expression and localization of CFTR. Cell invasion and motility of the transfected cells compared with those of control cells were observed using Transwell and wound healing assays. A ~4,700 bp fragment of the CFTR gene was confirmed to be correctly cloned in the adenoviral vector and amplification of Ad‑CFTR was observed in HEK293 cells during package. After 48 h of transfection with Ad‑CFTR, ~90% of A2780 cells were red fluorescence protein‑positive. Immunofluorescence showed that following transfection, CFTR expression was increased and CFTR was located in the cell membrane and cytoplasm. CFTR overexpression was shown to enhance the invasion and motility of A2780 cells in vitro. Furthermore, the effects of CFTR overexpression on the activation c‑Src signaling were observed by western blot analysis. CFTR overexpressing cells showed the lowest activity of phospho‑Src (Tyr530

  20. Genetic deletion and pharmacological inhibition of Akt1 isoform attenuates bladder cancer cell proliferation, motility and invasion.

    PubMed

    Sabbineni, Harika; Alwhaibi, Abdulrahman; Goc, Anna; Gao, Fei; Pruitt, Alanna; Somanath, Payaningal R

    2015-10-01

    Isoform specific expression, intracellular localization and function of Akt in bladder cancer are not known. In the current study, we identified Akt1, followed by Akt2 and Akt3 as the predominant Akt isoform in human T24 and UM-UC-3 metastatic bladder cancer cells. Whereas Akt1 is localized at the membrane, cytoplasm and nucleus, Akt2 is solely cytoplasmic and Akt3 is mostly localized in the nucleus in T24 cells. ShRNA-mediated Akt1 knockdown resulted in impaired T24 cell survival, proliferation, colony formation, migration and microinvasion. Whereas pharmacological inhibition of Akt1 resulted in impaired T24 and UM-UC-3 cell motility, viability and proliferation, effect of pharmacological inhibition by Akt2 inhibitor was limited to proliferation in T24, but not UM-UC-3 cells. Our data provide important clues on the therapeutic benefits of targeting Akt1 for bladder cancer therapy. PMID:26148825

  1. Epidermal growth factor promotes a mesenchymal over an amoeboid motility of MDA-MB-231 cells embedded within a 3D collagen matrix

    NASA Astrophysics Data System (ADS)

    Geum, Dongil T.; Kim, Beum Jun; Chang, Audrey E.; Hall, Matthew S.; Wu, Mingming

    2016-01-01

    The receptor of epidermal growth factor (EGFR) critically regulates tumor cell invasion and is a potent therapeutic target for treatment of many types of cancers, including carcinomas and glioblastomas. It is known that EGF regulates cell motility when tumor cells are embedded within a 3D biomatrix. However, roles of EGF in modulating tumor cell motility phenotype are largely unknown. In this article, we report that EGF promotes a mesenchymal over an amoeboid motility phenotype using a malignant breast tumor cell line, MDA-MB-231, embedded within a 3D collagen matrix. Amoeboid cells are rounded in shape, while mesenchymal cells are elongated, and their migrations are governed by a distinctly different set of biomolecules. Using single cell tracking analysis, we also show that EGF promotes cell dissemination through a significant increase in cell persistence along with a moderate increase of speed. The increase of persistence is correlated with the increase of the percentage of the mesenchymal cells within the population. Our work reveals a novel role of microenvironmental cue, EGF, in modulating heterogeneity and plasticity of tumor cell motility phenotype. In addition, it suggests a potential visual cue for diagnosing invasive states of breast cancer cells. This work can be easily extended beyond breast cancer cells.

  2. Enkephalins stimulate leukemia cell migration and surface expression of CD9.

    PubMed Central

    Heagy, W; Duca, K; Finberg, R W

    1995-01-01

    Opioid peptides have been implicated in the regulation of tumor growth and biology; however, little attention has been given to the mechanisms that are involved. In this study we show that physiological concentrations of the endogenous opioid neuropeptide methionine-enkephalin (MET-ENK) and the synthetic enkephalins D-Ala2, Me-Phe4, Gly(ol)5 and D-Ala2, D-Leu5 are stimulants for the in vitro migration of pre-B acute lymphoblastoid leukemia (ALL) cells. Activation of the human pre-B ALL cell lines NALM 6 and LAZ 221 with MET-ENK resulted in both an increase in their migration and an augmentation in the surface expression of the leukemia cell marker CD9. The opiate receptor antagonist naloxone reversed these enkephalin-induced effects on the leukemia cells. When the pre-B ALL cells were preincubated with an anti-CD9 mAb before challenge with MET-ENK their migration to the enkephalin was markedly reduced. These studies show that endogenous and synthetic opioid peptides are stimulants for pre-B ALL cell migration and suggest that CD9 is important in the regulation of leukemia cell motility. Images PMID:7657811

  3. Regulation of Chlamydomonas flagella and ependymal cell motile cilia by ceramide-mediated translocation of GSK3

    PubMed Central

    Kong, Ji Na; Hardin, Kara; Dinkins, Michael; Wang, Guanghu; He, Qian; Mujadzic, Tarik; Zhu, Gu; Bielawski, Jacek; Spassieva, Stefka; Bieberich, Erhard

    2015-01-01

    Cilia are important organelles formed by cell membrane protrusions; however, little is known about their regulation by membrane lipids. We characterize a novel activation mechanism for glycogen synthase kinase-3 (GSK3) by the sphingolipids phytoceramide and ceramide that is critical for ciliogenesis in Chlamydomonas and murine ependymal cells, respectively. We show for the first time that Chlamydomonas expresses serine palmitoyl transferase (SPT), the first enzyme in (phyto)ceramide biosynthesis. Inhibition of SPT in Chlamydomonas by myriocin led to loss of flagella and reduced tubulin acetylation, which was prevented by supplementation with the precursor dihydrosphingosine. Immunocytochemistry showed that (phyto)ceramide was colocalized with phospho–Tyr-216-GSK3 (pYGSK3) at the base and tip of Chlamydomonas flagella and motile cilia in ependymal cells. The (phyto)ceramide distribution was consistent with that of a bifunctional ceramide analogue UV cross-linked and visualized by click-chemistry–mediated fluorescent labeling. Ceramide depletion, by myriocin or neutral sphingomyelinase deficiency (fro/fro mouse), led to GSK3 dephosphorylation and defective flagella and cilia. Motile cilia were rescued and pYGSK3 localization restored by incubation of fro/fro ependymal cells with exogenous C24:1 ceramide, which directly bound to pYGSK3. Our findings suggest that (phyto)ceramide-mediated translocation of pYGSK into flagella and cilia is an evolutionarily conserved mechanism fundamental to the regulation of ciliogenesis. PMID:26446842

  4. 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.

  5. Pea Broth Enhances the Biocontrol Efficacy of Lysobacter capsici AZ78 by Triggering Cell Motility Associated with Biogenesis of Type IV Pilus.

    PubMed

    Tomada, Selena; Puopolo, Gerardo; Perazzolli, Michele; Musetti, Rita; Loi, Nazia; Pertot, Ilaria

    2016-01-01

    Bacterial cells can display different types of motility, due to the presence of external appendages such as flagella and type IV pili. To date, little information on the mechanisms involved in the motility of the Lysobacter species has been available. Recently, L. capsici AZ78, a biocontrol agent of phytopathogenic oomycetes, showed the ability to move on jellified pea broth. Pea broth medium improved also the biocontrol activity of L. capsici AZ78 against Plasmopara viticola under greenhouse conditions. Noteworthy, the quantity of pea residues remaining on grapevine leaves fostered cell motility in L. capsici AZ78. Based on these results, this unusual motility related to the composition of the growth medium was investigated in bacterial strains belonging to several Lysobacter species. The six L. capsici strains tested developed dendrite-like colonies when grown on jellified pea broth, while the development of dendrite-like colonies was not recorded in the media commonly used in motility assays. To determine the presence of genes responsible for biogenesis of the flagellum and type IV pili, the genome of L. capsici AZ78 was mined. Genes encoding structural components and regulatory factors of type IV pili were upregulated in L. capsici AZ78 cells grown on the above-mentioned medium, as compared with the other tested media. These results provide new insight into the motility mechanism of L. capsici members and the role of type IV pili and pea compounds on the epiphytic fitness and biocontrol features of L. capsici AZ78. PMID:27507963

  6. Pea Broth Enhances the Biocontrol Efficacy of Lysobacter capsici AZ78 by Triggering Cell Motility Associated with Biogenesis of Type IV Pilus

    PubMed Central

    Tomada, Selena; Puopolo, Gerardo; Perazzolli, Michele; Musetti, Rita; Loi, Nazia; Pertot, Ilaria

    2016-01-01

    Bacterial cells can display different types of motility, due to the presence of external appendages such as flagella and type IV pili. To date, little information on the mechanisms involved in the motility of the Lysobacter species has been available. Recently, L. capsici AZ78, a biocontrol agent of phytopathogenic oomycetes, showed the ability to move on jellified pea broth. Pea broth medium improved also the biocontrol activity of L. capsici AZ78 against Plasmopara viticola under greenhouse conditions. Noteworthy, the quantity of pea residues remaining on grapevine leaves fostered cell motility in L. capsici AZ78. Based on these results, this unusual motility related to the composition of the growth medium was investigated in bacterial strains belonging to several Lysobacter species. The six L. capsici strains tested developed dendrite-like colonies when grown on jellified pea broth, while the development of dendrite-like colonies was not recorded in the media commonly used in motility assays. To determine the presence of genes responsible for biogenesis of the flagellum and type IV pili, the genome of L. capsici AZ78 was mined. Genes encoding structural components and regulatory factors of type IV pili were upregulated in L. capsici AZ78 cells grown on the above-mentioned medium, as compared with the other tested media. These results provide new insight into the motility mechanism of L. capsici members and the role of type IV pili and pea compounds on the epiphytic fitness and biocontrol features of L. capsici AZ78. PMID:27507963

  7. Cell motility and ECM proteolysis regulate tumor growth and tumor relapse by altering the fraction of cancer stem cells and their spatial scattering

    NASA Astrophysics Data System (ADS)

    Kumar, Sandeep; Kulkarni, Rahul; Sen, Shamik

    2016-06-01

    Tumors consist of multiple cell sub-populations including cancer stem cells (CSCs), transiently amplifying cells and terminally differentiated cells (TDCs), with the CSC fraction dictating the aggressiveness of the tumor and drug sensitivity. In epithelial cancers, tumor growth is influenced greatly by properties of the extracellular matrix (ECM), with cancer progression associated with an increase in ECM density. However, the extent to which increased ECM confinement induced by an increase in ECM density influences tumor growth and post treatment relapse dynamics remains incompletely understood. In this study, we use a cellular automata-based discrete modeling approach to study the collective influence of ECM density, cell motility and ECM proteolysis on tumor growth, tumor heterogeneity, and tumor relapse after drug treatment. We show that while increased confinement suppresses tumor growth and the spatial scattering of CSCs, this effect can be reversed when cells become more motile and proteolytically active. Our results further suggest that, in addition to the absolute number of CSCs, their spatial positioning also plays an important role in driving tumor growth. In a nutshell, our study suggests that, in confined environments, cell motility and ECM proteolysis are two key factors that regulate tumor growth and tumor relapse dynamics by altering the number and spatial distribution of CSCs.

  8. Cell motility and ECM proteolysis regulate tumor growth and tumor relapse by altering the fraction of cancer stem cells and their spatial scattering.

    PubMed

    Kumar, Sandeep; Kulkarni, Rahul; Sen, Shamik

    2016-01-01

    Tumors consist of multiple cell sub-populations including cancer stem cells (CSCs), transiently amplifying cells and terminally differentiated cells (TDCs), with the CSC fraction dictating the aggressiveness of the tumor and drug sensitivity. In epithelial cancers, tumor growth is influenced greatly by properties of the extracellular matrix (ECM), with cancer progression associated with an increase in ECM density. However, the extent to which increased ECM confinement induced by an increase in ECM density influences tumor growth and post treatment relapse dynamics remains incompletely understood. In this study, we use a cellular automata-based discrete modeling approach to study the collective influence of ECM density, cell motility and ECM proteolysis on tumor growth, tumor heterogeneity, and tumor relapse after drug treatment. We show that while increased confinement suppresses tumor growth and the spatial scattering of CSCs, this effect can be reversed when cells become more motile and proteolytically active. Our results further suggest that, in addition to the absolute number of CSCs, their spatial positioning also plays an important role in driving tumor growth. In a nutshell, our study suggests that, in confined environments, cell motility and ECM proteolysis are two key factors that regulate tumor growth and tumor relapse dynamics by altering the number and spatial distribution of CSCs. PMID:27125980

  9. Effect of salinity and incubation time of planktonic cells on biofilm formation, motility, exoprotease production, and quorum sensing of Aeromonas hydrophila.

    PubMed

    Jahid, Iqbal Kabir; Mizan, Md Furkanur Rahaman; Ha, Angela J; Ha, Sang-Do

    2015-08-01

    The aim of this study was to determine the effect of salinity and age of cultures on quorum sensing, exoprotease production, and biofilm formation by Aeromonas hydrophila on stainless steel (SS) and crab shell as substrates. Biofilm formation was assessed at various salinities, from fresh (0%) to saline water (3.0%). For young and old cultures, planktonic cells were grown at 30 °C for 24 h and 96 h, respectively. Biofilm formation was assessed on SS, glass, and crab shell; viable counts were determined in R2A agar for SS and glass, but Aeromonas-selective media was used for crab shell samples to eliminate bacterial contamination. Exoprotease activity was assessed using a Fluoro™ protease assay kit. Quantification of acyl-homoserine lactone (AHL) was performed using the bioreporter strain Chromobacterium violaceum CV026 and the concentration was confirmed using high-performance liquid chromatography (HPLC). The concentration of autoinducer-2 (AI-2) was determined with Vibrio harveyi BB170. The biofilm structure at various salinities (0-3 %) was assessed using field emission electron microscopy (FESEM). Young cultures of A. hydrophila grown at 0-0.25% salinity showed gradual increasing of biofilm formation on SS, glass and crab shell; swarming and swimming motility; exoproteases production, AHL and AI-2 quorum sensing; while all these phenotypic characters reduced from 0.5 to 3.0% salinity. The FESEM images also showed that from 0 to 0.25% salinity stimulated formation of three-dimensional biofilm structures that also broke through the surface by utilizing the chitin surfaces of crab, while 3% salinity stimulated attachment only for young cultures. However, in marked contrast, salinity (0.1-3%) had no effect on the stimulation of biofilm formation or on phenotypic characters for old cultures. However, all concentrations reduced biofilm formation, motility, protease production and quorum sensing for old culture. Overall, 0-0.25% salinity enhanced biofilm formation

  10. Diatom Cell Size, Coloniality and Motility: Trade-Offs between Temperature, Salinity and Nutrient Supply with Climate Change

    PubMed Central

    Svensson, Filip; Norberg, Jon; Snoeijs, Pauline

    2014-01-01

    Reduction in body size has been proposed as a universal response of organisms, both to warming and to decreased salinity. However, it is still controversial if size reduction is caused by temperature or salinity on their own, or if other factors interfere as well. We used natural benthic diatom communities to explore how “body size” (cells and colonies) and motility change along temperature (2–26°C) and salinity (0.5–7.8) gradients in the brackish Baltic Sea. Fourth-corner analysis confirmed that small cell and colony sizes were associated with high temperature in summer. Average community cell volume decreased linearly with 2.2% per °C. However, cells were larger with artificial warming when nutrient concentrations were high in the cold season. Average community cell volume increased by 5.2% per °C of artificial warming from 0 to 8.5°C and simultaneously there was a selection for motility, which probably helped to optimize growth rates by trade-offs between nutrient supply and irradiation. Along the Baltic Sea salinity gradient cell size decreased with decreasing salinity, apparently mediated by nutrient stoichiometry. Altogether, our results suggest that climate change in this century may polarize seasonality by creating two new niches, with elevated temperature at high nutrient concentrations in the cold season (increasing cell size) and elevated temperature at low nutrient concentrations in the warm season (decreasing cell size). Higher temperature in summer and lower salinity by increased land-runoff are expected to decrease the average cell size of primary producers, which is likely to affect the transfer of energy to higher trophic levels. PMID:25279720

  11. All-trans-retinoic Acid Modulates the Plasticity and Inhibits the Motility of Breast Cancer Cells: ROLE OF NOTCH1 AND TRANSFORMING GROWTH FACTOR (TGFβ).

    PubMed

    Zanetti, Adriana; Affatato, Roberta; Centritto, Floriana; Fratelli, Maddalena; Kurosaki, Mami; Barzago, Maria Monica; Bolis, Marco; Terao, Mineko; Garattini, Enrico; Paroni, Gabriela

    2015-07-17

    All-trans-retinoic acid (ATRA) is a natural compound proposed for the treatment/chemoprevention of breast cancer. Increasing evidence indicates that aberrant regulation of epithelial-to-mesenchymal transition (EMT) is a determinant of the cancer cell invasive and metastatic behavior. The effects of ATRA on EMT are largely unknown. In HER2-positive SKBR3 and UACC812 cells, showing co-amplification of the ERBB2 and RARA genes, ATRA activates a RARα-dependent epithelial differentiation program. In SKBR3 cells, this causes the formation/reorganization of adherens and tight junctions. Epithelial differentiation and augmented cell-cell contacts underlie the anti-migratory action exerted by the retinoid in cells exposed to the EMT-inducing factors EGF and heregulin-β1. Down-regulation of NOTCH1, an emerging EMT modulator, is involved in the inhibition of motility by ATRA. Indeed, the retinoid blocks NOTCH1 up-regulation by EGF and/or heregulin-β1. Pharmacological inhibition of γ-secretase and NOTCH1 processing also abrogates SKBR3 cell migration. Stimulation of TGFβ contributes to the anti-migratory effect of ATRA. The retinoid switches TGFβ from an EMT-inducing and pro-migratory determinant to an anti-migratory mediator. Inhibition of the NOTCH1 pathway not only plays a role in the anti-migratory action of ATRA; it is relevant also for the anti-proliferative activity of the retinoid in HCC1599 breast cancer cells, which are addicted to NOTCH1 for growth/viability. This effect is enhanced by the combination of ATRA and the γ-secretase inhibitor N-(N-(3,5-difluorophenacetyl)-l-alanyl)-S-phenylglycine t-butyl ester, supporting the concept that the two compounds act at the transcriptional and post-translational levels along the NOTCH1 pathway. PMID:26018078

  12. 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

  13. Lipid rafts direct macrophage motility in the tissue microenvironment.

    PubMed

    Previtera, Michelle L; Peterman, Kimberly; Shah, Smit; Luzuriaga, Juan

    2015-04-01

    Infiltrating leukocytes are exposed to a wide range of tissue elasticities. While we know the effects of substrate elasticity on acute inflammation via the study of neutrophil migration, we do not know its effects on leukocytes that direct chronic inflammatory events. Here, we studied morphology and motility of macrophages, the innate immune cells that orchestrate acute and chronic inflammation, on polyacrylamide hydrogels that mimicked a wide range of tissue elasticities. As expected, we found that macrophage spreading area increased as substrate elasticity increased. Unexpectedly, we found that morphology did not inversely correlate with motility. In fact, velocity of steady-state macrophages remained unaffected by substrate elasticity, while velocity of biologically stimulated macrophages was limited on stiff substrates. We also found that the lack of motility on stiff substrates was due to a lack of lipid rafts on the leading edge of the macrophages. This study implicates lipid rafts in the mechanosensory mechanism of innate immune cell infiltration. PMID:25269613

  14. A novel interaction between the SH2 domain of signaling adaptor protein Nck-1 and the upstream regulator of the Rho family GTPase Rac1 engulfment and cell motility 1 (ELMO1) promotes Rac1 activation and cell motility.

    PubMed

    Zhang, Guo; Chen, Xia; Qiu, Fanghua; Zhu, Fengxin; Lei, Wenjing; Nie, Jing

    2014-08-15

    Nck family proteins function as adaptors to couple tyrosine phosphorylation signals to actin cytoskeleton reorganization. Several lines of evidence indicate that Nck family proteins involve in regulating the activity of Rho family GTPases. In the present study, we characterized a novel interaction between Nck-1 with engulfment and cell motility 1 (ELMO1). GST pull-down and co-immunoprecipitation assay demonstrated that the Nck-1-ELMO1 interaction is mediated by the SH2 domain of Nck-1 and the phosphotyrosine residues at position 18, 216, 395, and 511 of ELMO1. A R308K mutant of Nck-1 (in which the SH2 domain was inactive), or a 4YF mutant of ELMO1 lacking these four phosphotyrosine residues, diminished Nck-1-ELMO1 interaction. Conversely, tyrosine phosphatase inhibitor treatment and overexpression of Src family kinase Hck significantly enhanced Nck-1-ELMO1 interaction. Moreover, wild type Nck-1, but not R308K mutant, significantly augmented the interaction between ELMO1 and constitutively active RhoG (RhoG(V12A)), thus promoted Rac1 activation and cell motility. Taken together, the present study characterized a novel Nck-1-ELMO1 interaction and defined a new role for Nck-1 in regulating Rac1 activity. PMID:24928514

  15. Amphiregulin enhances alpha6beta1 integrin expression and cell motility in human chondrosarcoma cells through Ras/Raf/MEK/ERK/AP-1 pathway.

    PubMed

    Chen, Jui-Chieh; Chen, Yu-Ju; Lin, Chih-Yang; Fong, Yi-Chin; Hsu, Chin-Jung; Tsai, Chun-Hao; Su, Jen-Liang; Tang, Chih-Hsin

    2015-05-10

    Chondrosarcoma is a malignant tumor that produces cartilage matrix. The most lethal aspect is its metastatic property. We demonstrated that amphiregulin (AR) is significantly upregulated in highly aggressive cells. AR silencing markedly suppressed cell migration. Exogenous AR markedly increased cell migration by transactivation of α6β1 integrin expression. A neutralizing α6β1 integrin antibody can abolish AR-induced cell motility. Knockdown of AR inhibits metastasis of cells to the lung in vivo. Furthermore, elevated AR expression is positively correlated with α6β1 integrin levels and higher grades in patients. These findings can potentially serve as biomarker and therapeutic approach for controlling chondrosarcoma metastasis. PMID:25825984

  16. N-(2-methyl-indol-1H-5-yl)-1-naphthalenesulfonamide: A novel reversible antimitotic agent inhibiting cancer cell motility.

    PubMed

    Aceves-Luquero, Clara; Galiana-Roselló, Cristina; Ramis, Guillem; Villalonga-Planells, Ruth; García-España, Enrique; Fernández de Mattos, Silvia; Peláez, Rafael; Llinares, José M; González-Rosende, M Eugenia; Villalonga, Priam

    2016-09-01

    A series of compounds containing the sulfonamide scaffold were synthesized and screened for their in vitro anticancer activity against a representative panel of human cancer cell lines, leading to the identification of N-(2-methyl-1H-indol-5-yl)-1-naphthalenesulfonamide (8e) as a compound showing a remarkable activity across the panel, with IC50 values in the nanomolar-to-low micromolar range. Cell cycle distribution analysis revealed that 8e promoted a severe G2/M arrest, which was followed by cellular senescence as indicated by the detection of senescence-associated β-galactosidase (SA-β-gal) in 8e-treated cells. Prolonged 8e treatment also led to the onset of apoptosis, in correlation with the detection of increased Caspase 3/7 activities. Despite increasing γ-H2A.X levels, a well-established readout for DNA double-strand breaks, in vitro DNA binding studies with 8e did not support interaction with DNA. In agreement with this, 8e failed to activate the cellular DNA damage checkpoint. Importantly, tubulin staining showed that 8e promoted a severe disorganization of microtubules and mitotic spindle formation was not detected in 8e-treated cells. Accordingly, 8e inhibited tubulin polymerization in vitro in a dose-dependent manner and was also able to robustly inhibit cancer cell motility. Docking analysis revealed a compatible interaction with the colchicine-binding site of tubulin. Remarkably, these cellular effects were reversible since disruption of treatment resulted in the reorganization of microtubules, cell cycle re-entry and loss of senescent markers. Collectively, our data suggest that this compound may be a promising new anticancer agent capable of both reducing cancer cell growth and motility. PMID:27349984

  17. Hutchinson-Gilford progeria syndrome alters nuclear shape and reduces cell motility in three dimensional model substrates.

    PubMed

    Booth-Gauthier, Elizabeth A; Du, Vicard; Ghibaudo, Marion; Rape, Andrew D; Dahl, Kris Noel; Ladoux, Benoit

    2013-03-01

    Cell migration through tight interstitial spaces in three dimensional (3D) environments impacts development, wound healing and cancer metastasis and is altered by the aging process. The stiffness of the extracellular matrix (ECM) increases with aging and affects the cells and cytoskeletal processes involved in cell migration. However, the nucleus, which is the largest and densest organelle, has not been widely studied during cell migration through the ECM. Additionally, the nucleus is stiffened during the aging process through the accumulation of a mutant nucleoskeleton protein lamin A, progerin. By using microfabricated substrates to mimic the confined environment of surrounding tissues, we characterized nuclear movements and deformation during cell migration into micropillars where interspacing can be tuned to vary nuclear confinement. Cell motility decreased with decreased micropillar (μP) spacing and correlated with increased dysmorphic shapes of nuclei. We examined the effects of increased nuclear stiffness which correlates with cellular aging by studying Hutchinson-Gilford progeria syndrome cells which are known to accumulate progerin. With the expression of progerin, cells showed a threshold response to decreased μP spacing. Cells became trapped in the close spacing, possibly from visible micro-defects in the nucleoskeleton induced by cell crawling through the μP and from reduced force generation, measured independently. We suggest that ECM changes during aging could be compounded by the increasing stiffness of the nucleus and thus changes in cell migration through 3D tissues. PMID:23370891

  18. Human Granulocyte Macrophage Colony-Stimulating Factor Enhances Antibiotic Susceptibility of Pseudomonas aeruginosa Persister Cells.

    PubMed

    Choudhary, Geetika S; Yao, Xiangyu; Wang, Jing; Peng, Bo; Bader, Rebecca A; Ren, Dacheng

    2015-01-01

    Bacterial persister cells are highly tolerant to antibiotics and cause chronic infections. However, little is known about the interaction between host immune systems with this subpopulation of metabolically inactive cells, and direct effects of host immune factors (in the absence of immune cells) on persister cells have not been studied. Here we report that human granulocyte macrophage-colony stimulating factor (GM-CSF) can sensitize the persister cells of Pseudomonas aeruginosa PAO1 and PDO300 to multiple antibiotics including ciprofloxacin, tobramycin, tetracycline, and gentamicin. GM-CSF also sensitized the biofilm cells of P. aeruginosa PAO1 and PDO300 to tobramycin in the presence of biofilm matrix degrading enzymes. The DNA microarray and qPCR results indicated that GM-CSF induced the genes for flagellar motility and pyocin production in the persister cells, but not the normal cells of P. aeruginosa PAO1. Consistently, the supernatants from GM-CSF treated P. aeruginosa PAO1 persister cell suspensions were found cidal to the pyocin sensitive strain P. aeruginosa PAK. Collectively, these findings suggest that host immune factors and bacterial persisters may directly interact, leading to enhanced susceptibility of persister cells to antibiotics. PMID:26616387

  19. Human Granulocyte Macrophage Colony-Stimulating Factor Enhances Antibiotic Susceptibility of Pseudomonas aeruginosa Persister Cells

    PubMed Central

    Choudhary, Geetika S.; Yao, Xiangyu; Wang, Jing; Peng, Bo; Bader, Rebecca A.; Ren, Dacheng

    2015-01-01

    Bacterial persister cells are highly tolerant to antibiotics and cause chronic infections. However, little is known about the interaction between host immune systems with this subpopulation of metabolically inactive cells, and direct effects of host immune factors (in the absence of immune cells) on persister cells have not been studied. Here we report that human granulocyte macrophage-colony stimulating factor (GM-CSF) can sensitize the persister cells of Pseudomonas aeruginosa PAO1 and PDO300 to multiple antibiotics including ciprofloxacin, tobramycin, tetracycline, and gentamicin. GM-CSF also sensitized the biofilm cells of P. aeruginosa PAO1 and PDO300 to tobramycin in the presence of biofilm matrix degrading enzymes. The DNA microarray and qPCR results indicated that GM-CSF induced the genes for flagellar motility and pyocin production in the persister cells, but not the normal cells of P. aeruginosa PAO1. Consistently, the supernatants from GM-CSF treated P. aeruginosa PAO1 persister cell suspensions were found cidal to the pyocin sensitive strain P. aeruginosa PAK. Collectively, these findings suggest that host immune factors and bacterial persisters may directly interact, leading to enhanced susceptibility of persister cells to antibiotics. PMID:26616387

  20. Archaeal Signal Transduction: Impact of Protein Phosphatase Deletions on Cell Size, Motility, and Energy Metabolism in Sulfolobus acidocaldarius*

    PubMed Central

    Reimann, Julia; Esser, Dominik; Orell, Alvaro; Amman, Fabian; Pham, Trong Khoa; Noirel, Josselin; Lindås, Ann-Christin; Bernander, Rolf; Wright, Phillip C.; Siebers, Bettina; Albers, Sonja-Verena

    2013-01-01

    In this study, the in vitro and in vivo functions of the only two identified protein phosphatases, Saci-PTP and Saci-PP2A, in the crenarchaeal model organism Sulfolobus acidocaldarius were investigated. Biochemical characterization revealed that Saci-PTP is a dual-specific phosphatase (against pSer/pThr and pTyr), whereas Saci-PP2A exhibited specific pSer/pThr activity and inhibition by okadaic acid. Deletion of saci_pp2a resulted in pronounced alterations in growth, cell shape and cell size, which could be partially complemented. Transcriptome analysis of the three strains (Δsaci_ptp, Δsaci_pp2a and the MW001 parental strain) revealed 155 genes that were differentially expressed in the deletion mutants, and showed significant changes in expression of genes encoding the archaella (archaeal motility structure), components of the respiratory chain and transcriptional regulators. Phosphoproteome studies revealed 801 unique phosphoproteins in total, with an increase in identified phosphopeptides in the deletion mutants. Proteins from most functional categories were affected by phosphorylation, including components of the motility system, the respiratory chain, and regulatory proteins. In the saci_pp2a deletion mutant the up-regulation at the transcript level, as well as the observed phosphorylation pattern, resembled starvation stress responses. Hypermotility was also observed in the saci_pp2a deletion mutant. The results highlight the importance of protein phosphorylation in regulating essential cellular processes in the crenarchaeon S. acidocaldarius. PMID:24078887

  1. Feverlike Temperature is a Virulence Regulatory Cue Controlling the Motility and Host Cell Entry of Typhoidal Salmonella.

    PubMed

    Elhadad, Dana; McClelland, Michael; Rahav, Galia; Gal-Mor, Ohad

    2015-07-01

    Human infection with typhoidal Salmonella serovars causes a febrile systemic disease, termed enteric fever. Here we establish that in response to a temperature equivalent to fever (39 °C-42 °C) Salmonella enterica serovars Typhi, Paratyphi A, and Sendai significantly attenuate their motility, epithelial cell invasion, and uptake by macrophages. Under these feverlike conditions, the residual epithelial cell invasion of S. Paratyphi A occurs in a type III secretion system (T3SS) 1-independent manner and results in restrained disruption of epithelium integrity. The impaired motility and invasion are associated with down-regulation of T3SS-1 genes and class II and III (but not I) of the flagella-chemotaxis regulon. In contrast, we demonstrate up-regulation of particular Salmonella pathogenicity island 2 genes (especially spiC) and increased intraepithelial growth in a T3SS-2-dependent manner. These results indicate that elevated physiological temperature is a novel cue controlling virulence phenotypes in typhoidal serovars, which is likely to play a role in the distinct clinical manifestations elicited by typhoidal and nontyphoidal salmonellae. PMID:25492917

  2. Feverlike Temperature is a Virulence Regulatory Cue Controlling the Motility and Host Cell Entry of Typhoidal Salmonella

    PubMed Central

    Elhadad, Dana; McClelland, Michael; Rahav, Galia; Gal-Mor, Ohad

    2015-01-01

    Human infection with typhoidal Salmonella serovars causes a febrile systemic disease, termed enteric fever. Here we establish that in response to a temperature equivalent to fever (39°C–42°C) Salmonella enterica serovars Typhi, Paratyphi A, and Sendai significantly attenuate their motility, epithelial cell invasion, and uptake by macrophages. Under these feverlike conditions, the residual epithelial cell invasion of S. Paratyphi A occurs in a type III secretion system (T3SS) 1–independent manner and results in restrained disruption of epithelium integrity. The impaired motility and invasion are associated with down-regulation of T3SS-1 genes and class II and III (but not I) of the flagella-chemotaxis regulon. In contrast, we demonstrate up-regulation of particular Salmonella pathogenicity island 2 genes (especially spiC) and increased intraepithelial growth in a T3SS-2–dependent manner. These results indicate that elevated physiological temperature is a novel cue controlling virulence phenotypes in typhoidal serovars, which is likely to play a role in the distinct clinical manifestations elicited by typhoidal and nontyphoidal salmonellae. PMID:25492917

  3. The PDZ Protein Na+/H+ Exchanger Regulatory Factor-1 (NHERF1) Regulates Planar Cell Polarity and Motile Cilia Organization

    PubMed Central

    Stolz, Donna B.; Tsang, Michael; Friedman, Peter A.; Romero, Guillermo

    2016-01-01

    Directional flow of the cerebrospinal fluid requires coordinated movement of the motile cilia of the ependymal epithelium that lines the cerebral ventricles. Here we report that mice lacking the Na+/H+ Exchanger Regulatory Factor 1 (NHERF1/Slc9a3r1, also known as EBP50) develop profound communicating hydrocephalus associated with fewer and disorganized ependymal cilia. Knockdown of NHERF1/slc9a3r1 in zebrafish embryos also causes severe hydrocephalus of the hindbrain and impaired ciliogenesis in the otic vesicle. Ultrastructural analysis did not reveal defects in the shape or organization of individual cilia. Similar phenotypes have been described in animals with deficiencies in Wnt signaling and the Planar Cell Polarity (PCP) pathway. We show that NHERF1 binds the PCP core genes Frizzled (Fzd) and Vangl. We further show that NHERF1 assembles a ternary complex with Fzd4 and Vangl2 and promotes translocation of Vangl2 to the plasma membrane, in particular to the apical surface of ependymal cells. Taken together, these results strongly support an important role for NHERF1 in the regulation of PCP signaling and the development of functional motile cilia. PMID:27055101

  4. The post-translational modification of the Clostridium difficile flagellin affects motility, cell surface properties and virulence

    PubMed Central

    Faulds-Pain, Alexandra; Twine, Susan M; Vinogradov, Evgeny; Strong, Philippa C R; Dell, Anne; Buckley, Anthony M; Douce, Gillian R; Valiente, Esmeralda; Logan, Susan M; Wren, Brendan W

    2014-01-01

    Clostridium difficile is a prominent nosocomial pathogen, proliferating and causing enteric disease in individuals with a compromised gut microflora. We characterized the post-translational modification of flagellin in C. difficile 630. The structure of the modification was solved by nuclear magnetic resonance and shown to contain an N-acetylglucosamine substituted with a phosphorylated N-methyl-l-threonine. A reverse genetics approach investigated the function of the putative four-gene modification locus. All mutants were found to have truncated glycan structures by LC-MS/MS, taking into account bioinformatic analysis, we propose that the open reading frame CD0241 encodes a kinase involved in the transfer of the phosphate to the threonine, the CD0242 protein catalyses the addition of the phosphothreonine to the N-acetylglucosamine moiety and CD0243 transfers the methyl group to the threonine. Some mutations affected motility and caused cells to aggregate to each other and abiotic surfaces. Altering the structure of the flagellin modification impacted on colonization and disease recurrence in a murine model of infection, showing that alterations in the surface architecture of C. difficile vegetative cells can play a significant role in disease. We show that motility is not a requirement for colonization, but that colonization was compromised when the glycan structure was incomplete. PMID:25135277

  5. 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

  6. 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.

  7. Sperm Motility in Flow

    NASA Astrophysics Data System (ADS)

    Guasto, Jeffrey; Juarez, Gabriel; Stocker, Roman

    2012-11-01

    A wide variety of plants and animals reproduce sexually by releasing motile sperm that seek out a conspecific egg, for example in the reproductive tract for mammals or in the water column for externally fertilizing organisms. Sperm are aided in their quest by chemical cues, but must also contend with hydrodynamic forces, resulting from laminar flows in reproductive tracts or turbulence in aquatic habitats. To understand how velocity gradients affect motility, we subjected swimming sperm to a range of highly-controlled straining flows using a cross-flow microfluidic device. The motion of the cell body and flagellum were captured through high-speed video microscopy. The effects of flow on swimming are twofold. For moderate velocity gradients, flow simply advects and reorients cells, quenching their ability to cross streamlines. For high velocity gradients, fluid stresses hinder the internal bending of the flagellum, directly inhibiting motility. The transition between the two regimes is governed by the Sperm number, which compares the external viscous stresses with the internal elastic stresses. Ultimately, unraveling the role of flow in sperm motility will lead to a better understanding of population dynamics among aquatic organisms and infertility problems in humans.

  8. From immobilized cells to motile cells on a bed-of-nails: effects of vertical nanowire array density on cell behaviour

    PubMed Central

    Persson, Henrik; Li, Zhen; Tegenfeldt, Jonas O.; Oredsson, Stina; Prinz, Christelle N.

    2015-01-01

    The field of vertical nanowire array-based applications in cell biology is growing rapidly and an increasing number of applications are being explored. These applications almost invariably rely on the physical properties of the nanowire arrays, creating a need for a better understanding of how their physical properties affect cell behaviour. Here, we investigate the effects of nanowire density on cell migration, division and morphology for murine fibroblasts. Our results show that few nanowires are sufficient to immobilize cells, while a high nanowire spatial density enables a ”bed-of-nails” regime, where cells reside on top of the nanowires and are fully motile. The presence of nanowires decreases the cell proliferation rate, even in the “bed-of-nails” regime. We show that the cell morphology strongly depends on the nanowire density. Cells cultured on low (0.1 μm−2) and medium (1 μm−2) density substrates exhibit an increased number of multi-nucleated cells and micronuclei. These were not observed in cells cultured on high nanowire density substrates (4 μm−2). The results offer important guidelines to minimize cell-function perturbations on nanowire arrays. Moreover, these findings offer the possibility to tune cell proliferation and migration independently by adjusting the nanowire density, which may have applications in drug testing. PMID:26691936

  9. From immobilized cells to motile cells on a bed-of-nails: effects of vertical nanowire array density on cell behaviour

    NASA Astrophysics Data System (ADS)

    Persson, Henrik; Li, Zhen; Tegenfeldt, Jonas O.; Oredsson, Stina; Prinz, Christelle N.

    2015-12-01

    The field of vertical nanowire array-based applications in cell biology is growing rapidly and an increasing number of applications are being explored. These applications almost invariably rely on the physical properties of the nanowire arrays, creating a need for a better understanding of how their physical properties affect cell behaviour. Here, we investigate the effects of nanowire density on cell migration, division and morphology for murine fibroblasts. Our results show that few nanowires are sufficient to immobilize cells, while a high nanowire spatial density enables a ”bed-of-nails” regime, where cells reside on top of the nanowires and are fully motile. The presence of nanowires decreases the cell proliferation rate, even in the “bed-of-nails” regime. We show that the cell morphology strongly depends on the nanowire density. Cells cultured on low (0.1 μm-2) and medium (1 μm-2) density substrates exhibit an increased number of multi-nucleated cells and micronuclei. These were not observed in cells cultured on high nanowire density substrates (4 μm-2). The results offer important guidelines to minimize cell-function perturbations on nanowire arrays. Moreover, these findings offer the possibility to tune cell proliferation and migration independently by adjusting the nanowire density, which may have applications in drug testing.

  10. High-Frequency Stimulation of Excitable Cells and Networks

    PubMed Central

    Weinberg, Seth H.

    2013-01-01

    High-frequency (HF) stimulation has been shown to block conduction in excitable cells including neurons and cardiac myocytes. However, the precise mechanisms underlying conduction block are unclear. Using a multi-scale method, the influence of HF stimulation is investigated in the simplified FitzhHugh-Nagumo and biophysically-detailed Hodgkin-Huxley models. In both models, HF stimulation alters the amplitude and frequency of repetitive firing in response to a constant applied current and increases the threshold to evoke a single action potential in response to a brief applied current pulse. Further, the excitable cells cannot evoke a single action potential or fire repetitively above critical values for the HF stimulation amplitude. Analytical expressions for the critical values and thresholds are determined in the FitzHugh-Nagumo model. In the Hodgkin-Huxley model, it is shown that HF stimulation alters the dynamics of ionic current gating, shifting the steady-state activation, inactivation, and time constant curves, suggesting several possible mechanisms for conduction block. Finally, we demonstrate that HF stimulation of a network of neurons reduces the electrical activity firing rate, increases network synchronization, and for a sufficiently large HF stimulation, leads to complete electrical quiescence. In this study, we demonstrate a novel approach to investigate HF stimulation in biophysically-detailed ionic models of excitable cells, demonstrate possible mechanisms for HF stimulation conduction block in neurons, and provide insight into the influence of HF stimulation on neural networks. PMID:24278435

  11. Skin cell proliferation stimulated by microneedles.

    PubMed

    Liebl, Horst; Kloth, Luther C

    2012-03-01

    A classical wound may be defined as a disruption of tissue integrity. Wounds, caused by trauma from accidents or surgery, that close via secondary intention rely on the biological phases of healing, i.e., hemostasis, inflammation, proliferation, and remodeling (HIPR). Depending on the wound type and severity, the inflammation phase begins immediately after injury and may last for an average of 7-14 days. Concurrent with the inflammation phase or slightly delayed, cell proliferation is stimulated followed by the activation of the remodeling (maturation) phase. The latter phase can last as long as 1 year or more, and the final healed state is represented by a scar tissue, a cross-linked collagen formation that usually aligns collagen fibers in a single direction. One may assume that skin microneedling that involves the use of dozens or as many as 200 needles that limit penetration to 1.5 mm over 1 cm(2) of skin would cause trauma and bleeding followed by the classical HIPR. However, this is not the case or at least the HIPR phases are significantly curtailed and healing never ends in a scar formation. Conversely dermabrasion used in aesthetic medicine for improving skin quality is based on "ablation" (destruction or wounding of superficial skin layers), which requires several weeks for healing that involves formation of new skin layers. Such procedures provoke an acute inflammatory response. We believe that a less intense inflammatory response occurs following microneedle perforation of the skin. However, the mechanism of action of microneedling appears to be different. Here we review the potential mechanisms by which microneedling of the skin facilitates skin repair without scarring after the treatment of superficial burns, acne, hyperpigmentation, and the non-advancing periwound skin surrounding the chronic ulcerations of the integument. PMID:24527373

  12. Skin Cell Proliferation Stimulated by Microneedles

    PubMed Central

    Liebl, Horst; Kloth, Luther C.

    2012-01-01

    A classical wound may be defined as a disruption of tissue integrity. Wounds, caused by trauma from accidents or surgery, that close via secondary intention rely on the biological phases of healing, i.e., hemostasis, inflammation, proliferation, and remodeling (HIPR). Depending on the wound type and severity, the inflammation phase begins immediately after injury and may last for an average of 7–14 days. Concurrent with the inflammation phase or slightly delayed, cell proliferation is stimulated followed by the activation of the remodeling (maturation) phase. The latter phase can last as long as 1 year or more, and the final healed state is represented by a scar tissue, a cross-linked collagen formation that usually aligns collagen fibers in a single direction. One may assume that skin microneedling that involves the use of dozens or as many as 200 needles that limit penetration to 1.5 mm over 1 cm2 of skin would cause trauma and bleeding followed by the classical HIPR. However, this is not the case or at least the HIPR phases are significantly curtailed and healing never ends in a scar formation. Conversely dermabrasion used in aesthetic medicine for improving skin quality is based on “ablation” (destruction or wounding of superficial skin layers), which requires several weeks for healing that involves formation of new skin layers. Such procedures provoke an acute inflammatory response. We believe that a less intense inflammatory response occurs following microneedle perforation of the skin. However, the mechanism of action of microneedling appears to be different. Here we review the potential mechanisms by which microneedling of the skin facilitates skin repair without scarring after the treatment of superficial burns, acne, hyperpigmentation, and the non-advancing periwound skin surrounding the chronic ulcerations of the integument. PMID:24527373

  13. Controlled electromechanical cell stimulation on-a-chip

    PubMed Central

    Pavesi, Andrea; Adriani, Giulia; Rasponi, Marco; Zervantonakis, Ioannis K.; Fiore, Gianfranco B.; Kamm, Roger D.

    2015-01-01

    Stem cell research has yielded promising advances in regenerative medicine, but standard assays generally lack the ability to combine different cell stimulations with rapid sample processing and precise fluid control. In this work, we describe the design and fabrication of a micro-scale cell stimulator capable of simultaneously providing mechanical, electrical, and biochemical stimulation, and subsequently extracting detailed morphological and gene-expression analysis on the cellular response. This micro-device offers the opportunity to overcome previous limitations and recreate critical elements of the in vivo microenvironment in order to investigate cellular responses to three different stimulations. The platform was validated in experiments using human bone marrow mesenchymal stem cells. These experiments demonstrated the ability for inducing changes in cell morphology, cytoskeletal fiber orientation and changes in gene expression under physiological stimuli. This novel bioengineering approach can be readily applied to various studies, especially in the fields of stem cell biology and regenerative medicine. PMID:26135970

  14. 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

  15. Vasodilator-stimulated phosphoprotein restricts cell-to-cell spread of Shigella flexneri at the cell periphery.

    PubMed

    Lee, Soo Young; Gertler, Frank B; Goldberg, Marcia B

    2015-11-01

    Shigella spp. are intracellular bacterial pathogens that cause diarrhoeal disease in humans. Shigella utilize the host actin cytoskeleton to enter cells, move through the cytoplasm of cells and pass into adjacent cells. Ena/VASP family proteins are highly conserved proteins that participate in actin-dependent dynamic cellular processes. We tested whether Ena/VASP family members VASP (vasodilator-stimulated phosphoprotein), Mena (mammalian-enabled) or EVL (Ena-VASP-like) contribute to Shigella flexneri spread through cell monolayers. VASP and EVL restricted cell-to-cell spread without significantly altering actin-based motility, whereas Mena had no effect on these processes. Phosphorylation of VASP on Ser153, Ser235 and Thr274 regulated its subcellular distribution and function. VASP derivatives that lack the Ena/VASP homology 1 (EVH1) domain or contain a phosphoablative mutation of Ser153 were defective in restricting S. flexneri spread, indicating that the EVH1 domain and phosphorylation on Ser153 are required for this process. The EVH1 domain and Ser153 of VASP were required for VASP localization to focal adhesions, and localization of VASP to focal adhesions and/or the leading edge was required for restriction of spread. The contribution of the EVH1 domain was from both the donor and the recipient cell, whereas the contribution of Ser153 phosphorylation was only from the donor cell. Thus, unlike host proteins characterized in Shigella pathogenesis that promote bacterial spread, VASP and EVL function to limit it. The ability of VASP and EVL to limit spread highlights the critical role of focal adhesion complexes and/or the leading edge in bacterial passage between cells. PMID:26358985

  16. 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

  17. 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

  18. CDK1 Phosphorylation of YAP Promotes Mitotic Defects and Cell Motility and Is Essential for Neoplastic Transformation

    PubMed Central

    Yang, Shuping; Zhang, Lin; Liu, Miao; Chong, Rong; Ding, Shi-Jian; Chen, Yuanhong; Dong, Jixin

    2013-01-01

    The Yes-associated protein YAP is a downstream effector of the Hippo pathway of cell cycle control which plays important roles in tumorigenesis. Hippo-mediated phosphorylation YAP, mainly at S127, inactivates YAP function. In this study, we define a mechanism for positive regulation of YAP activity that is critical for its oncogenic function. Specifically, we found that YAP is phosphorylated in vitro and in vivo by the cell cycle kinase CDK1 at T119, S289, and S367 during G2/M phase of the cell cycle. We also found that ectopic expression of a phosphomimetic YAP mutant (YAP3D, harboring T119D/S289D/S367D) was sufficient to induce mitotic defects in immortalized epithelial cells, including centrosome amplification, multipolar spindles and chromosome missegregation. Finally, we documented that mitotic phosphorylation of YAP was sufficient to promote cell migration and invasion in a manner essential for neoplastic cell transformation. In support of our findings, CDK1 inhibitors largely suppressed cell motility mediated by activated YAP-S127A but not the phosphomimetic mutant YAP3D. Collectively, our results reveal a previously unrecognized mechanism for controlling the activity of YAP that is crucial for its oncogenic function mediated by mitotic dysregulation. PMID:24101154

  19. An extracellular matrix, calmodulin-binding protein from Dictyostelium with EGF-like repeats that enhance cell motility.

    PubMed

    Suarez, Andres; Huber, Robert J; Myre, Michael A; O'Day, Danton H

    2011-07-01

    CyrA is a novel cysteine-rich protein with four EGFL repeats that was isolated using the calmodulin (CaM) binding overlay technique (CaMBOT), suggesting it is a CaM-binding protein (CaMBP). The full-length 63kDa cyrA is cleaved into two major C-terminal fragments, cyrA-C45 and cyrA-C40. A putative CaM-binding domain was detected and both CaM-agarose binding and CaM immunoprecipitation verified that cyrA-C45 and cyrA-C40 each bind to CaM in both a Ca(2+)-dependent and -independent manner. cyrA-C45 was present continuously throughout growth and development but was secreted at high levels during the multicellular slug stage of Dictyostelium development. At this time, cyrA localizes to the extracellular matrix (ECM). ECM purification verified the presence of cyrA-C45. An 18 amino acid peptide (DdEGFL1) from the first EGFL repeat sequence of cyrA (EGFL1) that is present in both cyrA-C45 and -C40 enhances both random cell motility and cAMP-mediated chemotaxis. Here we reveal that the dose-dependent enhancement of motility by DdEGFL1 is related to the time of cell starvation. Addition of DdEGFL1 also inhibits cyrA proteolysis. The status of cyrA as an extracellular CaMBP was further clarified by the demonstration that CaM is secreted during development. Antagonism of CaM with W7 resulted in enhanced cyrA proteolysis suggesting a functional role for extracellular CaM in protecting CaMBPs from proteolysis. cyrA is the first extracellular CaMBP identified in Dictyostelium and since it is an ECM protein with EGF-like repeats that enhance cell motility and it likely also represents the first matricellular protein identified in a lower eukaryote. PMID:21402150

  20. The natural compound codonolactone attenuates TGF-β1-mediated epithelial-to-mesenchymal transition and motility of breast cancer cells.

    PubMed

    Fu, Jianjiang; Ke, Xiaoqin; Tan, Songlin; Liu, Ting; Wang, Shan; Ma, Junchao; Lu, Hong

    2016-01-01

    Codonolactone (CLT), a natural product, is the major bioactive component of Atractylodes lancea, and also found in a range of other medical herbs, such as Codonopsis pilosula, Chloranthus henryi Hemsl and Atractylodes macrocephala Koidz. This sesquiterpene lactone has been demonstrated to exhibit a range of activities, including anti-allergic activity, anti-inflammatory, anticancer, gastroprotective and neuroprotective activity. Previously, we found that CLT showed significant anti-metastatic properties in vitro and in vivo. In order to determine whether EMT-involved mechanisms contribute to the anti-metastatic effects of CLT, we checked the anti-EMT properties of CLT and its potential mechanisms. Here it was demonstrated that CLT inhibited TGF-β1-induced epithelial-mesenchymal transition (EMT) in vitro and in vivo. Furthermore, downregulation of TGF-β signaling was associated with the anti-EMT properties of CLT. Data from western blotting showed that, in breast cancer cells, TGF-β1 stimulated the activation of Runx2, and CLT blocked the activation of Runx2. Finally, to verify whether CLT-induced EMT inhibition leads to suppression of metastatic potential, the effects of CLT on cell invasion and migration were determined. It was found that TGF-β1-induced migration and invasion was significantly blocked by CLT in both MDA-MB-231 and MDA-MB-468 cells. Collectively, our findings demonstrated that CLT inhibited programming of EMT in vitro and in vivo, resulting in inhibition of motility of metastatic breast cancer cells. The inhibitory effect of CLT was due to its ability to inhibit TGF-β signaling and Runx2 phosphorylation. PMID:26549400

  1. A novel small-molecule compound targeting CD147 inhibits the motility and invasion of hepatocellular carcinoma cells

    PubMed Central

    Peng, Jian-long; Wang, Shi-jie; Geng, Jie-jie; Liu, Ji-de; Feng, Fei; Song, Fei; Li, Ling; Zhu, Ping; Jiang, Jian-li; Chen, Zhi-nan

    2016-01-01

    CD147, a type I transmembrane glycoprotein, is highly expressed in various cancer types and plays important roles in tumor progression, especially by promoting the motility and invasion of hepatocellular carcinoma (HCC) cells. These crucial roles make CD147 an attractive target for therapeutic intervention in HCC, but no small-molecule inhibitors of CD147 have been developed to date. To identify a candidate inhibitor, we used a pharmacophore model derived from the structure of CD147 to virtually screen over 300,000 compounds. The 100 highest-ranked compounds were subjected to biological assays, and the most potent one, dubbed AC-73 (ID number: AN-465/42834501), was studied further. We confirmed that AC-73 targeted CD147 and further demonstrated it can specifically disrupt CD147 dimerization. Moreover, molecular docking and mutagenesis experiments showed that the possible binding sites of AC-73 on CD147 included Glu64 and Glu73 in the N-terminal IgC2 domain, which two residues are located in the dimer interface of CD147. Functional assays revealed that AC-73 inhibited the motility and invasion of typical HCC cells, but not HCC cells that lacked the CD147 gene, demonstrating on-target action. Further, AC-73 reduced HCC metastasis by suppressing matrix metalloproteinase (MMP)-2 via down-regulation of the CD147/ERK1/2/signal transducer and activator of transcription 3 (STAT3) signaling pathway. Finally, AC-73 attenuated progression in an orthotopic nude mouse model of liver metastasis, suggesting that AC-73 or its derivatives have potential for use in HCC intervention. We conclude that the novel small-molecule inhibitor AC-73 inhibits HCC mobility and invasion, probably by disrupting CD147 dimerization and thereby mainly suppressing the CD147/ERK1/2/STAT3/MMP-2 pathways, which are crucial for cancer progression. PMID:26882566

  2. A novel small-molecule compound targeting CD147 inhibits the motility and invasion of hepatocellular carcinoma cells.

    PubMed

    Fu, Zhi-Guang; Wang, Li; Cui, Hong-Yong; Peng, Jian-Long; Wang, Shi-Jie; Geng, Jie-Jie; Liu, Ji-D; Feng, Fei; Song, Fei; Li, Ling; Zhu, Ping; Jiang, Jian-Li; Chen, Zhi-Nan

    2016-02-23

    CD147, a type I transmembrane glycoprotein, is highly expressed in various cancer types and plays important roles in tumor progression, especially by promoting the motility and invasion of hepatocellular carcinoma (HCC) cells. These crucial roles make CD147 an attractive target for therapeutic intervention in HCC, but no small-molecule inhibitors of CD147 have been developed to date. To identify a candidate inhibitor, we used a pharmacophore model derived from the structure of CD147 to virtually screen over 300,000 compounds. The 100 highest-ranked compounds were subjected to biological assays, and the most potent one, dubbed AC-73 (ID number: AN-465/42834501), was studied further. We confirmed that AC-73 targeted CD147 and further demonstrated it can specifically disrupt CD147 dimerization. Moreover, molecular docking and mutagenesis experiments showed that the possible binding sites of AC-73 on CD147 included Glu64 and Glu73 in the N-terminal IgC2 domain, which two residues are located in the dimer interface of CD147. Functional assays revealed that AC-73 inhibited the motility and invasion of typical HCC cells, but not HCC cells that lacked the CD147 gene, demonstrating on-target action. Further, AC-73 reduced HCC metastasis by suppressing matrix metalloproteinase (MMP)-2 via down-regulation of the CD147/ERK1/2/signal transducer and activator of transcription 3 (STAT3) signaling pathway. Finally, AC-73 attenuated progression in an orthotopic nude mouse model of liver metastasis, suggesting that AC-73 or its derivatives have potential for use in HCC intervention. We conclude that the novel small-molecule inhibitor AC-73 inhibits HCC mobility and invasion, probably by disrupting CD147 dimerization and thereby mainly suppressing the CD147/ERK1/2/STAT3/MMP-2 pathways, which are crucial for cancer progression. PMID:26882566

  3. Ophiobolin A from Bipolaris oryzae Perturbs Motility and Membrane Integrities of Porcine Sperm and Induces Cell Death on Mammalian Somatic Cell Lines

    PubMed Central

    Bencsik, Ottó; Papp, Tamás; Berta, Máté; Zana, Annamária; Forgó, Péter; Dombi, György; Andersson, Maria A.; Salkinoja-Salonen, Mirja; Vágvölgyi, Csaba; Szekeres, András

    2014-01-01

    Bipolaris oryzae is a phytopathogenic fungus causing a brown spot disease in rice, and produces substance that strongly perturbs motility and membrane integrities of boar spermatozoa. The substance was isolated from the liquid culture of the fungal strain using extraction and a multi-step semi-preparative HPLC procedures. Based on the results of mass spectrometric and 2D NMR techniques, the bioactive molecule was identified as ophiobolin A, a previously described sesterterpene-type compound. The purified ophiobolin A exhibited strong motility inhibition and viability reduction on boar spermatozoa. Furthermore, it damaged the sperm mitochondria significantly at sublethal concentration by the dissipation of transmembrane potential in the mitochondrial inner membrane, while the plasma membrane permeability barrier remained intact. The study demonstrated that the cytotoxicity of ophiobolin A toward somatic cell lines is higher by 1–2 orders of magnitude compared to other mitochondriotoxic mycotoxins, and towards sperm cells unique by replacing the progressive motility by shivering tail beating at low exposure concentration. PMID:25251540

  4. Ophiobolin A from Bipolaris oryzae perturbs motility and membrane integrities of porcine sperm and induces cell death on mammalian somatic cell lines.

    PubMed

    Bencsik, Ottó; Papp, Tamás; Berta, Máté; Zana, Annamária; Forgó, Péter; Dombi, György; Andersson, Maria A; Salkinoja-Salonen, Mirja; Vágvölgyi, Csaba; Szekeres, András

    2014-09-01

    Bipolaris oryzae is a phytopathogenic fungus causing a brown spot disease in rice, and produces substance that strongly perturbs motility and membrane integrities of boar spermatozoa. The substance was isolated from the liquid culture of the fungal strain using extraction and a multi-step semi-preparative HPLC procedures. Based on the results of mass spectrometric and 2D NMR techniques, the bioactive molecule was identified as ophiobolin A, a previously described sesterterpene-type compound. The purified ophiobolin A exhibited strong motility inhibition and viability reduction on boar spermatozoa. Furthermore, it damaged the sperm mitochondria significantly at sublethal concentration by the dissipation of transmembrane potential in the mitochondrial inner membrane, while the plasma membrane permeability barrier remained intact. The study demonstrated that the cytotoxicity of ophiobolin A toward somatic cell lines is higher by 1-2 orders of magnitude compared to other mitochondriotoxic mycotoxins, and towards sperm cells unique by replacing the progressive motility by shivering tail beating at low exposure concentration. PMID:25251540

  5. The hippo pathway effector YAP regulates motility, invasion, and castration-resistant growth of prostate cancer cells.

    PubMed

    Zhang, Lin; Yang, Shuping; Chen, Xingcheng; Stauffer, Seth; Yu, Fang; Lele, Subodh M; Fu, Kai; Datta, Kaustubh; Palermo, Nicholas; Chen, Yuanhong; Dong, Jixin

    2015-04-01

    Yes-associated protein (YAP) is an effector of the Hippo tumor suppressor pathway. The functional significance of YAP in prostate cancer has remained elusive. In this study, we first show that enhanced expression of YAP is able to transform immortalized prostate epithelial cells and promote migration and invasion in both immortalized and cancerous prostate cells. We found that YAP mRNA was upregulated in androgen-insensitive prostate cancer cells (LNCaP-C81 and LNCaP-C4-2 cells) compared to the level in androgen-sensitive LNCaP cells. Importantly, ectopic expression of YAP activated androgen receptor signaling and was sufficient to promote LNCaP cells from an androgen-sensitive state to an androgen-insensitive state in vitro, and YAP conferred castration resistance in vivo. Accordingly, YAP knockdown greatly reduced the rates of migration and invasion of LNCaP-C4-2 cells and under androgen deprivation conditions largely blocked cell division in LNCaP-C4-2 cells. Mechanistically, we found that extracellular signal-regulated kinase-ribosomal s6 kinase signaling was downstream of YAP for cell survival, migration, and invasion in androgen-insensitive cells. Finally, immunohistochemistry showed significant upregulation and hyperactivation of YAP in castration-resistant prostate tumors compared to their levels in hormone-responsive prostate tumors. Together, our results identify YAP to be a novel regulator in prostate cancer cell motility, invasion, and castration-resistant growth and as a potential therapeutic target for metastatic castration-resistant prostate cancer (CRPC). PMID:25645929

  6. A novel serotonin-secreting cell type regulates ciliary motility in the mucociliary epidermis of Xenopus tadpoles.

    PubMed

    Walentek, Peter; Bogusch, Susanne; Thumberger, Thomas; Vick, Philipp; Dubaissi, Eamon; Beyer, Tina; Blum, Martin; Schweickert, Axel

    2014-04-01

    The embryonic skin of Xenopus tadpoles serves as an experimental model system for mucociliary epithelia (MCE) such as the human airway epithelium. MCEs are characterized by the presence of mucus-secreting goblet and multiciliated cells (MCCs). A third cell type, ion-secreting cells (ISCs), is present in the larval skin as well. Synchronized beating of MCC cilia is required for directional transport of mucus. Here we describe a novel cell type in the Xenopus laevis larval epidermis, characterized by serotonin synthesis and secretion. It is termed small secretory cell (SSC). SSCs are detectable at early tadpole stages, unlike MCCs and ISCs, which are specified at early neurulation. Subcellularly, serotonin was found in large, apically localized vesicle-like structures, which were entirely shed into the surrounding medium. Pharmacological inhibition of serotonin synthesis decreased the velocity of cilia-driven fluid flow across the skin epithelium. This effect was mediated by serotonin type 3 receptor (Htr3), which was expressed in ciliated cells. Knockdown of Htr3 compromised flow velocity by reducing the ciliary motility of MCCs. SSCs thus represent a distinct and novel entity of the frog tadpole MCE, required for ciliary beating and mucus transport across the larval skin. The identification and characterization of SSCs consolidates the value of the Xenopus embryonic skin as a model system for human MCEs, which have been known for serotonin-dependent regulation of ciliary beat frequency. PMID:24598162

  7. Motility of Mollicutes

    NASA Astrophysics Data System (ADS)

    Wolgemuth, Charles; Igoshin, Oleg; Oster, George

    2003-03-01

    Recent experiments show that the conformation of filament proteins play a role in the motility and morphology of many different types of bacteria. Conformational changes in the protein subunits may produce forces to drive propulsion and cell division. Here we present a molecular mechanism by which these forces can drive cell motion. Coupling of a biochemical cycle, such as ATP hydrolysis, to the dynamics of elastic filaments enable elastic filaments to propagate deformations that generate propulsive forces. We demonstrate this possibility for two classes of wall-less bacteria called mollicutes: the swimming of helical shaped Spiroplasma, and the gliding motility of Mycoplasma. Similar mechanisms may explain the locomotion of other prokaryotes, including the swimming of Synechococcus and the gliding of some myxobacteria.

  8. Quantitative analysis of Plasmodium ookinete motion in three dimensions suggests a critical role for cell shape in the biomechanics of malaria parasite gliding motility.

    PubMed

    Kan, Andrey; Tan, Yan-Hong; Angrisano, Fiona; Hanssen, Eric; Rogers, Kelly L; Whitehead, Lachlan; Mollard, Vanessa P; Cozijnsen, Anton; Delves, Michael J; Crawford, Simon; Sinden, Robert E; McFadden, Geoffrey I; Leckie, Christopher; Bailey, James; Baum, Jake

    2014-05-01

    Motility is a fundamental part of cellular life and survival, including for Plasmodium parasites--single-celled protozoan pathogens responsible for human malaria. The motile life cycle forms achieve motility, called gliding, via the activity of an internal actomyosin motor. Although gliding is based on the well-studied system of actin and myosin, its core biomechanics are not completely understood. Currently accepted models suggest it results from a specifically organized cellular motor that produces a rearward directional force. When linked to surface-bound adhesins, this force is passaged to the cell posterior, propelling the parasite forwards. Gliding motility is observed in all three life cycle stages of Plasmodium: sporozoites, merozoites and ookinetes. However, it is only the ookinetes--formed inside the midgut of infected mosquitoes--that display continuous gliding without the necessity of host cell entry. This makes them ideal candidates for invasion-free biomechanical analysis. Here we apply a plate-based imaging approach to study ookinete motion in three-dimensional (3D) space to understand Plasmodium cell motility and how movement facilitates midgut colonization. Using single-cell tracking and numerical analysis of parasite motion in 3D, our analysis demonstrates that ookinetes move with a conserved left-handed helical trajectory. Investigation of cell morphology suggests this trajectory may be based on the ookinete subpellicular cytoskeleton, with complementary whole and subcellular electron microscopy showing that, like their motion paths, ookinetes share a conserved left-handed corkscrew shape and underlying twisted microtubular architecture. Through comparisons of 3D movement between wild-type ookinetes and a cytoskeleton-knockout mutant we demonstrate that perturbation of cell shape changes motion from helical to broadly linear. Therefore, while the precise linkages between cellular architecture and actomyosin motor organization remain unknown, our

  9. Colony stimulating factor 1 is an extrinsic stimulator of mouse spermatogonial stem cell self-renewal

    PubMed Central

    Oatley, Jon M.; Oatley, Melissa J.; Avarbock, Mary R.; Tobias, John W.; Brinster, Ralph L.

    2009-01-01

    Summary Self-renewal and differentiation of spermatogonial stem cells (SSCs) provide the foundation for testis homeostasis, yet mechanisms that control their functions in mammals are poorly defined. We used microarray transcript profiling to identify specific genes whose expressions are augmented in the SSC-enriched Thy1+ germ cell fraction of mouse pup testes. Comparisons of gene expression in the Thy1+ germ cell fraction with the Thy1-depleted testis cell population identified 202 genes that are expressed 10-fold or higher in Thy1+ cells. This database provided a mining tool to investigate specific characteristics of SSCs and identify novel mechanisms that potentially influence their functions. These analyses revealed that colony stimulating factor 1 receptor (Csf1r) gene expression is enriched in Thy1+ germ cells. Addition of recombinant colony stimulating factor 1 (Csf1), the specific ligand for Csf1r, to culture media significantly enhanced the self-renewal of SSCs in heterogeneous Thy1+ spermatogonial cultures over a 63-day period without affecting total germ cell expansion. In vivo, expression of Csf1 in both pre-pubertal and adult testes was localized to clusters of Leydig cells and select peritubular myoid cells. Collectively, these results identify Csf1 as an extrinsic stimulator of SSC self-renewal and implicate Leydig and myoid cells as contributors of the testicular stem cell niche in mammals. PMID:19270176

  10. Cellular mechanics and motility

    NASA Astrophysics Data System (ADS)

    Hénon, Sylvie; Sykes, Cécile

    2015-10-01

    The term motility defines the movement of a living organism. One widely known example is the motility of sperm cells, or the one of flagellar bacteria. The propulsive element of such organisms is a cilium(or flagellum) that beats. Although cells in our tissues do not have a flagellum in general, they are still able to move, as we will discover in this chapter. In fact, in both cases of movement, with or without a flagellum, cell motility is due to a dynamic re-arrangement of polymers inside the cell. Let us first have a closer look at the propulsion mechanism in the case of a flagellum or a cilium, which is the best known, but also the simplest, and which will help us to define the hydrodynamic general conditions of cell movement. A flagellum is sustained by cellular polymers arranged in semi-flexible bundles and flagellar beating generates cell displacement. These polymers or filaments are part of the cellular skeleton, or "cytoskeleton", which is, in this case, external to the cellular main body of the organism. In fact, bacteria move in a hydrodynamic regime in which viscosity dominates over inertia. The system is thus in a hydrodynamic regime of low Reynolds number (Box 5.1), which is nearly exclusively the case in all cell movements. Bacteria and their propulsion mode by flagella beating are our unicellular ancestors 3.5 billion years ago. Since then, we have evolved to form pluricellular organisms. However, to keep the ability of displacement, to heal our wounds for example, our cells lost their flagellum, since it was not optimal in a dense cell environment: cells are too close to each other to leave enough space for the flagella to accomplish propulsion. The cytoskeleton thus developed inside the cell body to ensure cell shape changes and movement, and also mechanical strength within a tissue. The cytoskeleton of our cells, like the polymers or filaments that sustain the flagellum, is also composed of semi-flexible filaments arranged in bundles, and also in

  11. Cyclic GMP and Cilia Motility

    PubMed Central

    Wyatt, Todd A.

    2015-01-01

    Motile cilia of the lungs respond to environmental challenges by increasing their ciliary beat frequency in order to enhance mucociliary clearance as a fundamental tenant of innate defense. One important second messenger in transducing the regulable nature of motile cilia is cyclic guanosine 3′,5′-monophosphate (cGMP). In this review, the history of cGMP action is presented and a survey of the existing data addressing cGMP action in ciliary motility is presented. Nitric oxide (NO)-mediated regulation of cGMP in ciliated cells is presented in the context of alcohol-induced cilia function and dysfunction. PMID:26264028

  12. 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

  13. Epigenetic Silencing of SPINT2 promotes Cancer Cell Motility via HGF-MET Pathway Activation in Melanoma

    PubMed Central

    Hwang, Soonyean; Kim, Hye-Eun; Min, Michelle; Raghunathan, Rekha; Panova, Izabela P.; Munshi, Ruchi; Ryu, Byungwoo

    2015-01-01

    Aberrant HGF-MET signaling activation via interactions with surrounding stromal cells in tumor microenvironment plays significant roles in malignant tumor progression. However, extracellular proteolytic regulation of HGF activation which is influenced by the tumor microenvironment and its consequential effects on melanoma malignancy remain uncharacterized. In this study we identified SPINT2: a proteolytic inhibitor of hepatocyte growth factor activator (HGFA), which plays a significant role in the suppression of the HGF-MET pathway and malignant melanoma progression. SPINT2 expression is significantly lower in metastatic melanoma tissues compared to those in early stage primary melanomas which also corresponded with DNA methylation levels isolated from tissue samples. Treatment with the DNA hypomethylating agent decitabine in cultured melanoma cells induced transcriptional reactivation of SPINT2, suggesting that this gene is epigenetically silenced in malignant melanomas. Furthermore, we show that ectopically expressed SPINT2 in melanoma cells inhibits HGF induced MET-AKT signaling pathway and decreases malignant phenotype potential such as cell motility, and invasive growth of melanoma cells. These results suggest that SPINT2 is associated with tumor suppressive functions in melanoma by inhibiting an extracellular signal regulator of HGF which is typically activated by tumor-stromal interactions. These findings indicate that epigenetic impairment of the tightly regulated cytokine-receptor communications in tumor microenvironment may contribute to malignant tumor progression. PMID:25910030

  14. Retinoic Acid Stimulates Regeneration of Mammalian Auditory Hair Cells

    NASA Astrophysics Data System (ADS)

    Lefebvre, Philippe P.; Malgrange, Brigitte; Staecker, Hinrich; Moonen, Gustave; van de Water, Thomas R.

    1993-04-01

    Sensorineural hearing loss resulting from the loss of auditory hair cells is thought to be irreversible in mammals. This study provides evidence that retinoic acid can stimulate the regeneration in vitro of mammalian auditory hair cells in ototoxic-poisoned organ of Corti explants in the rat. In contrast, treatment with retinoic acid does not stimulate the formation of extra hair cells in control cultures of Corti's organ. Retinoic acid-stimulated hair cell regeneration can be blocked by cytosine arabinoside, which suggests that a period of mitosis is required for the regeneration of auditory hair cells in this system. These results provide hope for a recovery of hearing function in mammals after auditory hair cell damage.

  15. Motility of Mycoplasma pneumoniae.

    PubMed Central

    Radestock, U; Bredt, W

    1977-01-01

    Cell of Mycoplasma pneumoniae FH gliding on a glass surface in liquid medium were examined by microscopic observation and quantitatively by microcinematography (30 frames per min). Comparisons were made only within the individual experiments. The cells moved in an irregular pattern with numerous narrow bends and circles. They never changed their leading end. The average speed (without pauses) was relatively constant between o.2 and 0.5 mum/s. The maximum speed was about 1.5 to 2.0 mum/s. The movements were interrupted by resting periods of different lengths and frequency. Temperature, viscosity, pH, and the presence of yeast extract in the medium influenced the motility significantly; changes in glucose, calcium ions, and serum content were less effective. The movements were affected by iodoacetate, p-mercuribenzoate, and mitomycin C at inhibitory or subinhibitory concentrations. Sodium fluoride, sodium cyanide, dinitrophenol, chloramphenicol, puromycin, cholchicin, and cytochalasin B at minimal inhibitory concentrations did not affect motility. The movements were effectively inhibited by anti-M. pneumoniae antiserum. Studies with absorbed antiserum suggested that the surface components involved in motility are heat labile. The gliding of M. pneumoniae cells required an intact energy metabolism and the proteins involved seemed to have a low turnover. Images PMID:14925

  16. Myosin-dependent endoplasmic reticulum motility and F-actin organization in plant cells

    PubMed Central

    Ueda, Haruko; Yokota, Etsuo; Kutsuna, Natsumaro; Shimada, Tomoo; Tamura, Kentaro; Shimmen, Teruo; Hasezawa, Seiichiro; Dolja, Valerian V.; Hara-Nishimura, Ikuko

    2010-01-01

    Plants exhibit an ultimate case of the intracellular motility involving rapid organelle trafficking and continuous streaming of the endoplasmic reticulum (ER). Although it was long assumed that the ER dynamics is actomyosin-driven, the responsible myosins were not identified, and the ER streaming was not characterized quantitatively. Here we developed software to generate a detailed velocity-distribution map for the GFP-labeled ER. This map revealed that the ER in the most peripheral plane was relatively static, whereas the ER in the inner plane was rapidly streaming with the velocities of up to ∼3.5 μm/sec. Similar patterns were observed when the cytosolic GFP was used to evaluate the cytoplasmic streaming. Using gene knockouts, we demonstrate that the ER dynamics is driven primarily by the ER-associated myosin XI-K, a member of a plant-specific myosin class XI. Furthermore, we show that the myosin XI deficiency affects organization of the ER network and orientation of the actin filament bundles. Collectively, our findings suggest a model whereby dynamic three-way interactions between ER, F-actin, and myosins determine the architecture and movement patterns of the ER strands, and cause cytosol hauling traditionally defined as cytoplasmic streaming. PMID:20351265

  17. Unconventional Specimen Preparation Techniques Using High Resolution Low Voltage Field Emission Scanning Electron Microscopy to Study Cell Motility, Host Cell Invasion, and Internal Cell Structures in Toxoplasma gondii

    NASA Astrophysics Data System (ADS)

    Schatten, Heide; Ris, Hans

    2002-04-01

    Apicomplexan parasites employ complex and unconventional mechanisms for cell locomotion, host cell invasion, and cell division that are only poorly understood. While immunofluorescence and conventional transmission electron microscopy have been used to answer questions about the localization of some cytoskeletal proteins and cell organelles, many questions remain unanswered, partly because new methods are needed to study the complex interactions of cytoskeletal proteins and organelles that play a role in cell locomotion, host cell invasion, and cell division. The choice of fixation and preparation methods has proven critical for the analysis of cytoskeletal proteins because of the rapid turnover of actin filaments and the dense spatial organization of the cytoskeleton and its association with the complex membrane system. Here we introduce new methods to study structural aspects of cytoskeletal motility, host cell invasion, and cell division of Toxoplasma gondii, a most suitable laboratory model that is representative of apicomplexan parasites. The novel approach in our experiments is the use of high resolution low voltage field emission scanning electron microscopy (LVFESEM) combined with two new specimen preparation techniques. The first method uses LVFESEM after membrane extraction and stabilization of the cytoskeleton. This method allows viewing of actin filaments which had not been possible with any other method available so far. The second approach of imaging the parasite's ultrastructure and interactions with host cells uses semithick sections (200 nm) that are resin de-embedded (Ris and Malecki, 1993) and imaged with LVFESEM. This method allows analysis of structural detail in the parasite before and after host cell invasion and interactions with the membrane of the parasitophorous vacuole as well as parasite cell division.

  18. Analysis of Stem Cell Motility In Vivo Based on Immunodetection of Planarian Neoblasts and Tracing of BrdU-Labeled Cells After Partial Irradiation.

    PubMed

    Tasaki, Junichi; Uchiyama-Tasaki, Chihiro; Rouhana, Labib

    2016-01-01

    Planarian flatworms have become an important system for the study of stem cell behavior and regulation in vivo. These organisms are able to regenerate any part of their body upon damage or amputation. A crucial cellular event in the process of planarian regeneration is the migration of pluripotent stem cells (known as neoblasts) to the site of injury. Here we describe two approaches for analyzing migration of planarian stem cells to an area where these have been ablated by localized X-ray irradiation. The first approach involves immunolabeling of mitotic neoblasts, while the second is based on tracing stem cells and their progeny after BrdU incorporation. The use of planarians in studies of cell motility is suitable for the identification of factors that influence stem cell migration in vivo and is amenable to RNA interference or pharmacological screening. PMID:26498794

  19. Atrazine represses S100A4 gene expression and TPA-induced motility in HepG2 cells.

    PubMed

    Peyre, Ludovic; Zucchini-Pascal, Nathalie; Rahmani, Roger

    2014-03-01

    Atrazine (ATZ) is probably the most widely used herbicide in the world. However there are still many controversies regarding its impacts on human health. Our investigations on the role of pesticides in liver dysfunctions have led us to detect an inhibition of FSP1 expression of 70% at 50μm and around 95% at 500μM of ATZ (p<0.01). This gene encodes the protein S100a4 and is a clinical biomarker of epithelial-mesenchymal transition (EMT), a key step in the metastatic process. Here we investigated the possible effect of ATZ on cell migration and noticed that it prevents the EMT and motility of the HepG2 cells induced by the phorbol ester TPA. ATZ decreases Fak pathway activation but has no effect on the Erk1/2 pathway known to be involved in metastasis in this cell line. These results suggest that ATZ could be involved in cell homeostasis perturbation, potentially through a S100a4-dependant mechanism. PMID:24211529

  20. Chitosan drives anti-inflammatory macrophage polarisation and pro-inflammatory dendritic cell stimulation.

    PubMed

    Oliveira, Marta I; Santos, Susana G; Oliveira, Maria J; Torres, Ana L; Barbosa, Mário A

    2012-01-01

    Macrophages and dendritic cells (DC) share the same precursor and play key roles in immunity. Modulation of their behaviour to achieve an optimal host response towards an implanted device is still a challenge. Here we compare the differentiation process and polarisation of these related cell populations and show that they exhibit different responses to chitosan (Ch), with human monocyte-derived macrophages polarising towards an anti-inflammatory phenotype while their DC counterparts display pro-inflammatory features. Macrophages and DC, whose interactions with biomaterials are frequently analysed using fully differentiated cells, were cultured directly on Ch films, rather than exposed to the polymer after complete differentiation. Ch was the sole stimulating factor and activated both macrophages and DC, without leading to significant T cell proliferation. After 10 d on Ch, macrophages significantly down-regulated expression of pro-inflammatory markers, CD86 and MHCII. Production of pro-inflammatory cytokines, particularly TNF-α, decreased with time for cells cultured on Ch, while anti-inflammatory IL-10 and TGF-β1, significantly increased. Altogether, these results suggest an M2c polarisation. Also, macrophage matrix metalloproteinase activity was augmented and cell motility was stimulated by Ch. Conversely, DC significantly enhanced CD86 expression, reduced IL-10 secretion and increased TNF-α and IL-1β levels. Our findings indicate that cells with a common precursor may display different responses, when challenged by the same biomaterial. Moreover, they help to further comprehend macrophage/DC interactions with Ch and the balance between pro- and anti-inflammatory signals associated with implant biomaterials. We propose that an overall pro-inflammatory reaction may hide the expression of anti-inflammatory cytokines, likely relevant for tissue repair/regeneration. PMID:22828991

  1. 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

  2. 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

  3. Giant scaffolding protein AHNAK1 interacts with β-dystroglycan and controls motility and mechanical properties of Schwann cells.

    PubMed

    von Boxberg, Ysander; Soares, Sylvia; Féréol, Sophie; Fodil, Redouane; Bartolami, Sylvain; Taxi, Jacques; Tricaud, Nicolas; Nothias, Fatiha

    2014-09-01

    The profound morphofunctional changes that Schwann cells (SCs) undergo during their migration and elongation on axons, as well as during axon sorting, ensheathment, and myelination, require their close interaction with the surrounding laminin-rich basal lamina. In contrast to myelinating central nervous system glia, SCs strongly and constitutively express the giant scaffolding protein AHNAK1, localized essentially underneath the outer, abaxonal plasma membrane. Using electron microscopy, we show here that in the sciatic nerve of ahnak1(-) (/) (-) mice the ultrastructure of myelinated, and unmyelinated (Remak) fibers is affected. The major SC laminin receptor β-dystroglycan co-immunoprecipitates with AHNAK1 shows reduced expression in ahnak1(-) (/) (-) SCs, and is no longer detectable in Cajal bands on myelinated fibers in ahnak1(-) (/) (-) sciatic nerve. Reduced migration velocity in a scratch wound assay of purified ahnak1(-) (/) (-) primary SCs cultured on a laminin substrate indicated a function of AHNAK1 in SC motility. This was corroborated by atomic force microscopy measurements, which revealed a greater mechanical rigidity of shaft and leading tip of ahnak1(-) (/) (-) SC processes. Internodal lengths of large fibers are decreased in ahnak1(-) (/) (-) sciatic nerve, and longitudinal extension of myelin segments is even more strongly reduced after acute knockdown of AHNAK1 in SCs of developing sciatic nerve. Together, our results suggest that by interfering in the cross-talk between the transmembrane form of the laminin receptor dystroglycan and F-actin, AHNAK1 influences the cytoskeleton organization of SCs, and thus plays a role in the regulation of their morphology and motility and lastly, the myelination process. PMID:24796807

  4. Raft-Dependent Endocytosis of Autocrine Motility Factor/Phosphoglucose Isomerase: A Potential Drug Delivery Route for Tumor Cells

    PubMed Central

    Kojic, Liliana D.; Wiseman, Sam M.; Ghaidi, Fariba; Joshi, Bharat; Nedev, Hinyu; Saragovi, H. Uri; Nabi, Ivan R.

    2008-01-01

    Background Autocrine motility factor/phosphoglucose isomerase (AMF/PGI) is the extracellular ligand for the gp78/AMFR receptor overexpressed in a variety of human cancers. We showed previously that raft-dependent internalization of AMF/PGI is elevated in metastatic MDA-435 cells, but not metastatic, caveolin-1-expressing MDA-231 cells, relative to non-metastatic MCF7 and dysplastic MCF10A cells suggesting that it might represent a tumor cell-specific endocytic pathway. Methodology/Principal Findings Similarly, using flow cytometry, we demonstrate that raft-dependent endocytosis of AMF/PGI is increased in metastatic HT29 cancer cells expressing low levels of caveolin-1 relative to metastatic, caveolin-1-expressing, HCT116 colon cells and non-metastatic Caco-2 cells. Therefore, we exploited the raft-dependent internalization of AMF/PGI as a potential tumor-cell specific targeting mechanism. We synthesized an AMF/PGI-paclitaxel conjugate and found it to be as efficient as free paclitaxel in inducing cytotoxicity and apoptosis in tumor cells that readily internalize AMF/PGI compared to tumor cells that poorly internalize AMF/PGI. Murine K1735-M1 and B16-F1 melanoma cells internalize FITC-conjugated AMF/PGI and are acutely sensitive to AMF/PGI-paclitaxel mediated cytotoxicity in vitro. Moreover, following in vivo intratumoral injection, FITC-conjugated AMF/PGI is internalized in K1735-M1 tumors. Intratumoral injection of AMF/PGI-paclitaxel induced significantly higher tumor regression compared to free paclitaxel, even in B16-F1 cells, known to be resistant to taxol treatment. Treatment with AMF/PGI-paclitaxel significantly prolonged the median survival time of tumor bearing mice. Free AMF/PGI exhibited a pro-survival role, reducing the cytotoxic effect of both AMF/PGI-paclitaxel and free paclitaxel suggesting that AMF/PGI-paclitaxel targets a pathway associated with resistance to chemotherapeutic agents. AMF/PGI-FITC uptake by normal murine spleen and thymus cells was

  5. Parathyroid Hormone Induces Bone Cell Motility and Loss of Mature Osteocyte Phenotype through L-Calcium Channel Dependent and Independent Mechanisms

    PubMed Central

    Prideaux, Matthew; Dallas, Sarah L.; Zhao, Ning; Johnsrud, Erica D.; Veno, Patricia A.; Guo, Dayong; Mishina, Yuji; Harris, Stephen E.; Bonewald, Lynda F.

    2015-01-01

    Parathyroid Hormone (PTH) can exert both anabolic and catabolic effects on the skeleton, potentially through expression of the PTH type1 receptor (PTH1R), which is highly expressed in osteocytes. To determine the cellular and molecular mechanisms responsible, we examined the effects of PTH on osteoblast to osteocyte differentiation using primary osteocytes and the IDG-SW3 murine cell line, which differentiate from osteoblast to osteocyte-like cells in vitro and express GFP under control of the dentin matrix 1 (Dmp1) promoter. PTH treatment resulted in an increase in some osteoblast and early osteocyte markers and a decrease in mature osteocyte marker expression. The gene expression profile of PTH-treated Day 28 IDG-SW3 cells was similar to PTH treated primary osteocytes. PTH treatment induced striking changes in the morphology of the Dmp1-GFP positive cells in IDG-SW3 cultures and primary cells from Dmp1-GFP transgenic mice. The cells changed from a more dendritic to an elongated morphology and showed increased cell motility. E11/gp38 has been shown to be important for cell migration, however, deletion of the E11/gp38/podoplanin gene had no effect on PTH-induced motility. The effects of PTH on motility were reproduced using cAMP, but not with protein kinase A (PKA), exchange proteins activated by cAMP (Epac), protein kinase C (PKC) or phosphatidylinositol-4,5-bisphosphonate 3-kinase (Pi3K) agonists nor were they blocked by their antagonists. However, the effects of PTH were mediated through calcium signaling, specifically through L-type channels normally expressed in osteoblasts but decreased in osteocytes. PTH was shown to increase expression of this channel, but decrease the T-type channel that is normally more highly expressed in osteocytes. Inhibition of L-type calcium channel activity attenuated the effects of PTH on cell morphology and motility but did not prevent the downregulation of mature osteocyte marker expression. Taken together, these results show

  6. Oxidative phenomena are implicated in human T-cell stimulation.

    PubMed Central

    Sekkat, C; Dornand, J; Gerber, M

    1988-01-01

    Phytohaemagglutinin (PHA), phorbol myristate acetate (PMA) and PHA + PMA stimulation of T-enriched peripheral blood lymphocytes (PBL) and the Jurkat malignant T-cell line leads to oxidative-product formation, as evaluated by flow cytofluorometric studies, an increase in K+ flux across the membrane, cGMP production and a depolarization of the cell membrane. Irradiation (20 Gy), which enhances IL-2 synthesis by activated T-enriched PBL and Jurkat cells, also increases oxidative product formation, K+ flux, cGMP production, and induces cell membrane depolarization. Conversely, irradiation does not produce a rise in intracellular free Ca2+, as measured in PHA-stimulated Jurkat cells. PMA is also without effect on intracellular free Ca2+, added before or after PHA stimulation. Thus, except for the rise in intracellular free Ca2+, irradiation and stimulation exert similar effects on some of the events observed in IL-2-producing Jurkat cells, but these effects are not additive. Stimulation and irradiation effects are shown to be additive or synergistic only for cGMP production. It is proposed that irradiation may increase IL-2 synthesis by participating in an additional signal related to the oxidative metabolism of arachidonic acid (AA). PMID:3258279

  7. Oxidative phenomena are implicated in human T-cell stimulation.

    PubMed

    Sekkat, C; Dornand, J; Gerber, M

    1988-03-01

    Phytohaemagglutinin (PHA), phorbol myristate acetate (PMA) and PHA + PMA stimulation of T-enriched peripheral blood lymphocytes (PBL) and the Jurkat malignant T-cell line leads to oxidative-product formation, as evaluated by flow cytofluorometric studies, an increase in K+ flux across the membrane, cGMP production and a depolarization of the cell membrane. Irradiation (20 Gy), which enhances IL-2 synthesis by activated T-enriched PBL and Jurkat cells, also increases oxidative product formation, K+ flux, cGMP production, and induces cell membrane depolarization. Conversely, irradiation does not produce a rise in intracellular free Ca2+, as measured in PHA-stimulated Jurkat cells. PMA is also without effect on intracellular free Ca2+, added before or after PHA stimulation. Thus, except for the rise in intracellular free Ca2+, irradiation and stimulation exert similar effects on some of the events observed in IL-2-producing Jurkat cells, but these effects are not additive. Stimulation and irradiation effects are shown to be additive or synergistic only for cGMP production. It is proposed that irradiation may increase IL-2 synthesis by participating in an additional signal related to the oxidative metabolism of arachidonic acid (AA). PMID:3258279

  8. WHAMY is a novel actin polymerase promoting myoblast fusion, macrophage cell motility and sensory organ development in Drosophila.

    PubMed

    Brinkmann, Klaus; Winterhoff, Moritz; Önel, Susanne-Filiz; Schultz, Jörg; Faix, Jan; Bogdan, Sven

    2016-02-01

    Wiskott-Aldrich syndrome proteins (WASPs) are nucleation-promoting factors (NPF) that differentially control the Arp2/3 complex. In Drosophila, three different family members, SCAR (also known as WAVE), WASP and WASH (also known as CG13176), have been analyzed so far. Here, we characterized WHAMY, the fourth Drosophila WASP family member. whamy originated from a wasp gene duplication and underwent a sub-neofunctionalization. Unlike WASP, we found that WHAMY specifically interacted with activated Rac1 through its two CRIB domains, which were sufficient for targeting WHAMY to lamellipodial and filopodial tips. Biochemical analyses showed that WHAMY promoted exceptionally fast actin filament elongation, although it did not activate the Arp2/3 complex. Loss- and gain-of-function studies revealed an important function of WHAMY in membrane protrusions and cell migration in macrophages. Genetic data further implied synergistic functions between WHAMY and WASP during morphogenesis. Double mutants were late-embryonic lethal and showed severe defects in myoblast fusion. Trans-heterozygous mutant animals showed strongly increased defects in sensory cell fate specification. Thus, WHAMY is a novel actin polymerase with an initial partitioning of ancestral WASP functions in development and subsequent acquisition of a new function in cell motility during evolution. PMID:26675239

  9. 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

  10. Sur8/Shoc2 promotes cell motility and metastasis through activation of Ras-PI3K signaling

    PubMed Central

    Kaduwal, Saluja; Jeong, Woo-Jeong; Park, Jong-Chan; Lee, Kug Hwa; Lee, Young-Mi; Jeon, Soung-Hoo; Lim, Yong-Beom; Min, Do Sik; Choi, Kang-Yell

    2015-01-01

    Sur8 (also known as Shoc2) is a Ras-Raf scaffold protein that modulates signaling through extracellular signal-regulated kinase (ERK) pathway. Although Sur8 has been shown to be a scaffold protein of the Ras-ERK pathway, its interaction with other signaling pathways and its involvement in tumor malignancy has not been reported. We identified that Sur8 interacts with the p110α subunit of phosphatidylinositol 3-kinase (PI3K), as well as with Ras and Raf, and these interactions are increased in an epidermal growth factor (EGF)- and oncogenic Ras-dependent manner. Sur8 regulates cell migration and invasion via activation of Rac and matrix metalloproteinases (MMPs). Interestingly, using inhibitors of MEK and PI3K we found Sur8 mediates these cellular behaviors predominantly through PI3K pathway. We further found that human metastatic melanoma tissues had higher Sur8 content followed by activations of Akt, ERK, and Rac. Lentivirus-mediated Sur8-knockdown attenuated metastatic potential of highly invasive B16-F10 melanoma cells indicating the role of Sur8 in melanoma metastasis. This is the first report to identify the role of scaffold protein Sur8 in regulating cell motility, invasion, and metastasis through activation of both ERK and PI3K pathways. PMID:26384305

  11. Endothelial Cell Stimulation by Candida albicans

    PubMed Central

    Phan, Quynh T.; Filler, Scott G.

    2013-01-01

    The opportunistic fungal pathogen, Candida albicans, enters the bloodstream and causes hematogenously disseminated infection in hospitalized patients. During the initiation of a hematogenously disseminated infection, endothelial cells are one of the first host cells to come in contact with C. albicans. Endothelial cells can significantly influence the local host response to C. albicans by expressing leukocyte adhesion molecules and pro-inflammatory cytokines. Thus, it is of interest to investigate the response of endothelial cells to C. albicans in vitro. We describe the use of real-time PCR and enzyme immunoassays to measure the effects of C. albicans on the endothelial cell production of E-selectin and tumor necrosis factor α in vitro. PMID:19089392

  12. Modeling the role of nuclear mechanics in determining cell shape and motility through microfluidic channels

    NASA Astrophysics Data System (ADS)

    Shechter, Jake; Maki, Kara; Das, Moumita

    2014-03-01

    Cell mechanics and migration through tight spaces are critical to life processes such as immune response and fertilization, in several diseases, and in diagnostics and drug delivery. For example, breast cancer cells have been shown to deform more easily and transit more rapidly through microfluidic channels than healthy breast cells. In this computational biophysics project, we simulate a cell moving through a microfluidic channel. We calculate the deformation energy of a model cell, which includes contributions from the cell cytoskeleton and the cell nucleus. We study how the model cell deforms in response to external forces, focusing on the deformability of the cell as it squeezes into and through a microfluidic channel and how the nucleus plays a part in this. Recent experiments suggest that the nucleus can be up to an order of magnitude stiffer than the rest of the cell and our results may provide insights into how the nucleus influences cell mechanics and migration. This work was supported by a FEAD grant from the College of Science at Rochester Institute of Technology.

  13. 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

  14. Generation of compartmentalized pressure by a nuclear piston governs cell motility in a 3D matrix.

    PubMed

    Petrie, Ryan J; Koo, Hyun; Yamada, Kenneth M

    2014-08-29

    Cells use actomyosin contractility to move through three-dimensional (3D) extracellular matrices. Contractility affects the type of protrusions cells use to migrate in 3D, but the mechanisms are unclear. In this work, we found that contractility generated high-pressure lobopodial protrusions in human cells migrating in a 3D matrix. In these cells, the nucleus physically divided the cytoplasm into forward and rear compartments. Actomyosin contractility with the nucleoskeleton-intermediate filament linker protein nesprin-3 pulled the nucleus forward and pressurized the front of the cell. Reducing expression of nesprin-3 decreased and equalized the intracellular pressure. Thus, the nucleus can act as a piston that physically compartmentalizes the cytoplasm and increases the hydrostatic pressure between the nucleus and the leading edge of the cell to drive lamellipodia-independent 3D cell migration. PMID:25170155

  15. Electroactive biocompatible materials for nerve cell stimulation

    NASA Astrophysics Data System (ADS)

    Yang, Mei; Liang, Youlong; Gui, Qingyuan; Chen, Jun; Liu, Yong

    2015-04-01

    In the past decades, great efforts have been developed for neurobiologists and neurologists to restore nervous system functions. Recently much attention has been paid to electrical stimulation (ES) of the nervous system as a potential way to repair it. Various conductive biocompatible materials with good electrical conductivity, biocompatibility, and long-term ES or electrical stability have been developed as the substrates for ES. In this review, we summarized different types of materials developed in the purpose for ES of nervous system, including conducting polymers, carbon nanomaterials and composites from conducting polymer/carbon nanomaterials. The present review will give our perspective on the future research directions for further investigation on development of ES particularly on the nerve system.

  16. Diversity in cell motility reveals the dynamic nature of the formation of zebrafish taste sensory organs.

    PubMed

    Soulika, Marina; Kaushik, Anna-Lila; Mathieu, Benjamin; Lourenço, Raquel; Komisarczuk, Anna Z; Romano, Sebastian Alejo; Jouary, Adrien; Lardennois, Alicia; Tissot, Nicolas; Okada, Shinji; Abe, Keiko; Becker, Thomas S; Kapsimali, Marika

    2016-06-01

    Taste buds are sensory organs in jawed vertebrates, composed of distinct cell types that detect and transduce specific taste qualities. Taste bud cells differentiate from oropharyngeal epithelial progenitors, which are localized mainly in proximity to the forming organs. Despite recent progress in elucidating the molecular interactions required for taste bud cell development and function, the cell behavior underlying the organ assembly is poorly defined. Here, we used time-lapse imaging to observe the formation of taste buds in live zebrafish larvae. We found that tg(fgf8a.dr17)-expressing cells form taste buds and get rearranged within the forming organs. In addition, differentiating cells move from the epithelium to the forming organs and can be displaced between developing organs. During organ formation, tg(fgf8a.dr17) and type II taste bud cells are displaced in random, directed or confined mode relative to the taste bud they join or by which they are maintained. Finally, ascl1a activity in the 5-HT/type III cell is required to direct and maintain tg(fgf8a.dr17)-expressing cells into the taste bud. We propose that diversity in displacement modes of differentiating cells acts as a key mechanism for the highly dynamic process of taste bud assembly. PMID:27122167

  17. Transferrin receptor expression by stimulated cells in mixed lymphocyte culture.

    PubMed Central

    Salmon, M; Bacon, P A; Symmons, D P; Walton, K W

    1985-01-01

    Transferrin receptor (TRFr) expression by cells in mixed lymphocyte culture increases steadily for the first 5 days, but then reaches a plateau. By the sixth day in culture, about 20% of viable cells express TRFr in two-way mixed lymphocyte reactions. This subpopulation of TRFr-positive cells represents the proliferating population; it is heterogeneous, containing T-cell blasts and smaller cells which are a mixture of T and non-T cells. A small group of non-T cells have phenotypic similarity to natural killer (NK) cells. T cells appear to divide earlier in the course of the response than non-T cells. The biphasic nature of this response and the slower non-T reactivity may be due to a secondary stimulation of non-T cells by factors released from activated T cells (such as interleukin-2). PMID:2982734

  18. Probabilistic Voxel-Fe model for single cell motility in 3D

    PubMed Central

    Borau, Carlos; Polacheck, William J; Kamm, Roger D; García-Aznar, José Manuel

    2015-01-01

    Background Cells respond to a variety of external stimuli regulated by the environment conditions. Mechanical, chemical and biological factors are of great interest and have been deeply studied. Furthermore, mathematical and computational models have been rapidly growing over the past few years, permitting researches to run complex scenarios saving time and resources. Usually these models focus on specific features of cell migration, making them only suitable to study restricted phenomena. Methods Here we present a versatile finite element (FE) cell-scale 3D migration model based on probabilities depending in turn on ECM mechanical properties, chemical, fluid and boundary conditions. Results With this approach we are able to capture important outcomes of cell migration such as: velocities, trajectories, cell shape and aspect ratio, cell stress or ECM displacements. Conclusions The modular form of the model will allow us to constantly update and redefine it as advancements are made in clarifying how cellular events take place. PMID:26290806

  19. Nanostructured cavity devices for extracellular stimulation of HL-1 cells.

    PubMed

    Czeschik, Anna; Rinklin, Philipp; Derra, Ulrike; Ullmann, Sabrina; Holik, Peter; Steltenkamp, Siegfried; Offenhäusser, Andreas; Wolfrum, Bernhard

    2015-01-01

    Microelectrode arrays (MEAs) are state-of-the-art devices for extracellular recording and stimulation on biological tissue. Furthermore, they are a relevant tool for the development of biomedical applications like retina, cochlear and motor prostheses, cardiac pacemakers and drug screening. Hence, research on functional cell-sensor interfaces, as well as the development of new surface structures and modifications for improved electrode characteristics, is a vivid and well established field. However, combining single-cell resolution with sufficient signal coupling remains challenging due to poor cell-electrode sealing. Furthermore, electrodes with diameters below 20 µm often suffer from a high electrical impedance affecting the noise during voltage recordings. In this study, we report on a nanocavity sensor array for voltage-controlled stimulation and extracellular action potential recordings on cellular networks. Nanocavity devices combine the advantages of low-impedance electrodes with small cell-chip interfaces, preserving a high spatial resolution for recording and stimulation. A reservoir between opening aperture and electrode is provided, allowing the cell to access the structure for a tight cell-sensor sealing. We present the well-controlled fabrication process and the effect of cavity formation and electrode patterning on the sensor's impedance. Further, we demonstrate reliable voltage-controlled stimulation using nanostructured cavity devices by capturing the pacemaker of an HL-1 cell network. PMID:25939765

  20. CD271 regulates the proliferation and motility of hypopharyngeal cancer cells.

    PubMed

    Mochizuki, Mai; Tamai, Keiichi; Imai, Takayuki; Sugawara, Sayuri; Ogama, Naoko; Nakamura, Mao; Matsuura, Kazuto; Yamaguchi, Kazunori; Satoh, Kennichi; Sato, Ikuro; Motohashi, Hozumi; Sugamura, Kazuo; Tanaka, Nobuyuki

    2016-01-01

    CD271 (p75 neurotrophin receptor) plays both positive and negative roles in cancer development, depending on the cell type. We previously reported that CD271 is a marker for tumor initiation and is correlated with a poor prognosis in human hypopharyngeal cancer (HPC). To clarify the role of CD271 in HPC, we established HPC cell lines and knocked down the CD271 expression using siRNA. We found that CD271-knockdown completely suppressed the cells' tumor-forming capability both in vivo and in vitro. CD271-knockdown also induced cell-cycle arrest in G0 and suppressed ERK phosphorylation. While treatment with an ERK inhibitor only partially inhibited cell growth, CDKN1C, which is required for maintenance of quiescence, was strongly upregulated in CD271-depleted HPC cells, and the double knockdown of CD271 and CDKN1C partially rescued the cells from G0 arrest. In addition, either CD271 depletion or the inhibition of CD271-RhoA signaling by TAT-Pep5 diminished the in vitro migration capability of the HPC cells. Collectively, CD271 initiates tumor formation by increasing the cell proliferation capacity through CDKN1C suppression and ERK-signaling activation, and by accelerating the migration signaling pathway in HPC. PMID:27469492

  1. Synthetic control of mammalian-cell motility by engineering chemotaxis to an orthogonal bioinert chemical signal

    PubMed Central

    Park, Jason S.; Rhau, Benjamin; Hermann, Aynur; McNally, Krista A.; Zhou, Carmen; Gong, Delquin; Weiner, Orion D.; Conklin, Bruce R.; Onuffer, James; Lim, Wendell A.

    2014-01-01

    Directed migration of diverse cell types plays a critical role in biological processes ranging from development and morphogenesis to immune response, wound healing, and regeneration. However, techniques to direct, manipulate, and study cell migration in vitro and in vivo in a specific and facile manner are currently limited. We conceived of a strategy to achieve direct control over cell migration to arbitrary user-defined locations, independent of native chemotaxis receptors. Here, we show that genetic modification of cells with an engineered G protein-coupled receptor allows us to redirect their migration to a bioinert drug-like small molecule, clozapine-N-oxide (CNO). The engineered receptor and small-molecule ligand form an orthogonal pair: The receptor does not respond to native ligands, and the inert drug does not bind to native cells. CNO-responsive migration can be engineered into a variety of cell types, including neutrophils, T lymphocytes, keratinocytes, and endothelial cells. The engineered cells migrate up a gradient of the drug CNO and transmigrate through endothelial monolayers. Finally, we demonstrate that T lymphocytes modified with the engineered receptor can specifically migrate in vivo to CNO-releasing beads implanted in a live mouse. This technology provides a generalizable genetic tool to systematically perturb and control cell migration both in vitro and in vivo. In the future, this type of migration control could be a valuable module for engineering therapeutic cellular devices. PMID:24711398

  2. Inhibition of breast cancer cell motility with a non-cyclooxygenase inhibitory derivative of sulindac by suppressing TGFβ/miR-21 signaling

    PubMed Central

    Ma, Ruixia; Feng, Xiangling; Li, Wei; Piazza, Gary A.; Xi, Yaguang

    2016-01-01

    Compelling efficacy on intervention of tumorigenesis by nonsteroidal anti-inflammatory drugs (NSAIDs) has been documented intensively. However, the toxicities related to cyclooxygenase (COX) inhibition resulting in suppression of physiologically important prostaglandins limit their clinical use for human cancer chemoprevention. A novel derivative of the NSAID sulindac sulfide (SS), referred as sulindac sulfide amide (SSA), was recently developed, which lacks COX inhibitory activity, yet shows greater suppressive effect than SS on growth of various cancer cells. In this study, we focus on the inhibitory activity of SSA on breast tumor cell motility, which has not been studied previously. Our results show that SSA treatment at non-cytotoxic concentrations can specifically reduce breast tumor cell motility without influencing tumor cell growth, and the mechanism of action involves the suppression of TGFβ signaling by directly blocking Smad2/3 phosphorylation. Moreover, miR-21, a well-documented oncogenic miRNA for promoting tumor cell metastasis, was also found to be involved in inhibitory activity of SSA in breast tumor cell motility through the modulation of TGFβ pathway. In conclusion, we demonstrate that a non-COX inhibitory derivative of sulindac can inhibit breast tumor metastasis by a mechanism involving the TGFβ/miR-21 signaling axis. PMID:26769851

  3. Milk stimulates growth of prostate cancer cells in culture.

    PubMed

    Tate, Patricia L; Bibb, Robert; Larcom, Lyndon L

    2011-11-01

    Concern has been expressed about the fact that cows' milk contains estrogens and could stimulate the growth of hormone-sensitive tumors. In this study, organic cows' milk and two commercial substitutes were digested in vitro and tested for their effects on the growth of cultures of prostate and breast cancer cells. Cows' milk stimulated the growth of LNCaP prostate cancer cells in each of 14 separate experiments, producing an average increase in growth rate of over 30%. In contrast, almond milk suppressed the growth of these cells by over 30%. Neither cows' milk nor almond milk affected the growth of MCF-7 breast cancer cells or AsPC-1 pancreatic cancer cells significantly. Soy milk increased the growth rate of the breast cancer cells. These data indicate that prostate and breast cancer patients should be cautioned about the possible promotional effects of commercial dairy products and their substitutes. PMID:22043817

  4. Mechanism of Actin-Based Motility

    NASA Astrophysics Data System (ADS)

    Pantaloni, Dominique; Le Clainche, Christophe; Carlier, Marie-France

    2001-05-01

    Spatially controlled polymerization of actin is at the origin of cell motility and is responsible for the formation of cellular protrusions like lamellipodia. The pathogens Listeria monocytogenes and Shigella flexneri, which undergo actin-based propulsion, are acknowledged models of the leading edge of lamellipodia. Actin-based motility of the bacteria or of functionalized microspheres can be reconstituted in vitro from only five pure proteins. Movement results from the regulated site-directed treadmilling of actin filaments, consistent with observations of actin dynamics in living motile cells and with the biochemical properties of the components of the synthetic motility medium.

  5. CD271 regulates the proliferation and motility of hypopharyngeal cancer cells

    PubMed Central

    Mochizuki, Mai; Tamai, Keiichi; Imai, Takayuki; Sugawara, Sayuri; Ogama, Naoko; Nakamura, Mao; Matsuura, Kazuto; Yamaguchi, Kazunori; Satoh, Kennichi; Sato, Ikuro; Motohashi, Hozumi; Sugamura, Kazuo; Tanaka, Nobuyuki

    2016-01-01

    CD271 (p75 neurotrophin receptor) plays both positive and negative roles in cancer development, depending on the cell type. We previously reported that CD271 is a marker for tumor initiation and is correlated with a poor prognosis in human hypopharyngeal cancer (HPC). To clarify the role of CD271 in HPC, we established HPC cell lines and knocked down the CD271 expression using siRNA. We found that CD271-knockdown completely suppressed the cells’ tumor-forming capability both in vivo and in vitro. CD271-knockdown also induced cell-cycle arrest in G0 and suppressed ERK phosphorylation. While treatment with an ERK inhibitor only partially inhibited cell growth, CDKN1C, which is required for maintenance of quiescence, was strongly upregulated in CD271-depleted HPC cells, and the double knockdown of CD271 and CDKN1C partially rescued the cells from G0 arrest. In addition, either CD271 depletion or the inhibition of CD271-RhoA signaling by TAT-Pep5 diminished the in vitro migration capability of the HPC cells. Collectively, CD271 initiates tumor formation by increasing the cell proliferation capacity through CDKN1C suppression and ERK-signaling activation, and by accelerating the migration signaling pathway in HPC. PMID:27469492

  6. Cell cycle propagation is driven by light-dark stimulation in a cultured symbiotic dinoflagellate isolated from corals

    NASA Astrophysics Data System (ADS)

    Wang, L.-H.; Liu, Y.-H.; Ju, Y.-M.; Hsiao, Y.-Y.; Fang, L.-S.; Chen, C.-S.

    2008-12-01

    Endosymbiosis is an intriguing plant-animal interaction in the dinoflagellate-Cnidaria association. Throughout the life span of the majority of corals, the dinoflagellate Symbiodinium sp. is a common symbiont residing inside host gastrodermal cells. The mechanism of regulating the cell proliferation of host cells and their intracellular symbionts is critical for a stable endosymbiotic association. In the present study, the cell cycle of a cultured Symbiodinium sp. (clade B) isolated from the hermatypic coral Euphyllia glabrescens was investigated using flow cytometry. The results showed that the external light-dark (L:D) stimulation played a pivotal role in regulating the cell cycle process. The sequential light (40-100 μmol m-2 s-1 ~ 12 h) followed by dark (0 μmol m-2 s-1 ~ 12 h) treatment entrained a single cell cycle from the G1 to the S phase, and then to the G2/M phase, within 24 h. Blue light (~450 nm) alone mimicked regular white light, while lights of wavelengths in the red and infrared area of the spectrum had little or no effect in entraining the cell cycle. This diel pattern of the cell cycle was consistent with changes in cell motility, morphology, and photosynthetic efficiency ( F v / F m ). Light treatment drove cells to enter the growing/DNA synthesis stage (i.e., G1 to S to G2/M), accompanied by increasing motility and photosynthetic efficiency. Inhibition of photosynthesis by 3-(3, 4-dichlorophenyl)-1, 1-dimethyl-urea (DCMU) treatment blocked the cell proliferation process. Dark treatment was required for the mitotic division stage, where cells return from G2/M to G1. Two different pools of adenylyl cyclase (AC) activities were shown to be involved in the growing/DNA synthesis and mitotic division states, respectively.

  7. Microfluidic cell arrays for metabolic monitoring of stimulated cardiomyocytes.

    PubMed

    Cheng, Wei; Klauke, Norbert; Smith, Godfrey; Cooper, Jonathan M

    2010-04-01

    An array of PDMS microchambers was aligned to an array of sensor electrodes and stimulating microelectrodes, which was used for the electrochemical monitoring of the metabolic activity of single isolated adult ventricular myocytes inside the chamber array, stimulated within a transient electric field. The effect of the accumulation of metabolic byproducts in the limited extracellular volume of the picolitre chambers was demonstrated by measuring single muscle cell contraction optically, while concomitant changes in intracellular calcium transients and pH were recorded independently using fluorescent indicator dyes. Both the amplitude of the cell shortening and the magnitude of the intracellular calcium transients decreased over time and both nearly ceased after 20 min of continuous stimulation in the limited extracellullar volume. The intracellular pH decreased gradually during 20 min of continuous stimulation after which a dramatic pH drop was observed, indicating the breakdown of the intracellular buffering capacity. After continuous stimulation, intracellular lactate was released into the microchamber through cell electroporation and was detected electrochemically at a lactate microbiosensor, within the chamber. A mitochondrial uncoupler was used to mimic ischaemia and thus to enhance the cellular content of lactate. Under these circumstances, intracellular lactate concentrations were found to have risen to approximately 15 mM. This array system has the potential of simultaneous electrochemical and optical monitoring of extracellular and intracellular metabolites from single beating heart cells at a controlled metabolic state. PMID:20333720

  8. Proteomic Signatures of Acquired Letrozole Resistance in Breast Cancer: Suppressed Estrogen Signaling and Increased Cell Motility and Invasiveness*

    PubMed Central

    Tilghman, Syreeta L.; Townley, Ian; Zhong, Qiu; Carriere, Patrick P.; Zou, Jin; Llopis, Shawn D.; Preyan, Lynez C.; Williams, Christopher C.; Skripnikova, Elena; Bratton, Melyssa R.; Zhang, Qiang; Wang, Guangdi

    2013-01-01

    proteomic signatures of a letrozole-resistant cell line associated with hormone independence, enhanced cell motility, EMT and the potential values of several altered proteins as novel prognostic markers or therapeutic targets for letrozole resistant breast cancer. PMID:23704778

  9. SNAIL transcription factor increases the motility and invasive capacity of prostate cancer cells.

    PubMed

    Osorio, Luis A; Farfán, Nancy M; Castellón, Enrique A; Contreras, Héctor R

    2016-01-01

    The incidence and mortality rates of prostate cancer (PCa) are increasing, and PCa is almost the second‑leading cause of cancer‑associated mortality in men. During tumor progression, epithelial cells decrease the number of adhesion molecules, change their polarity and position, rearrange their cytoskeleton and increase their migratory and invasive capacities. These changes are known under the concept of epithelial‑mesenchymal transition (EMT). EMT is characterized by an upregulation of certain transcription factors, including SNAIL1, which represses genes that are characteristic of an epithelial phenotype, including E‑cadherin, and indirectly increase the expression levels of genes, which are associated with the mesenchymal phenotype. It has been suggested that the transcription factor, SNAIL1, decreases the proliferation and increases the migratory and invasive capacities of PCa cell lines. The present study was performed using LNCaP and PC3 cell lines, in which the expression levels of SNAIL1 were increased or silenced through the use of lentiviral vectors. The expression levels of EMT markers were quantified using reverse transcription‑quantitative polymerase chain reaction and western blot analysis. In addition, cell survival was analyzed using an MTS assay; cell proliferation was examined using an antibody targeting Ki‑67; migration on plates with 8 µm pores to allow the passage of cells; and invasiveness was analyzed using a membrane chamber covered in dried basement membrane matrix solution. The levels of apoptosis were determined using a Caspase 3/7 assay containing a substrate modified by caspases 3 and 7. The results demonstrated that the overexpression and silencing of SNAIL1 decreased cell proliferation and survival. However, the overexpression of SNAIL1 decreased apoptosis, compared with cells with the SNAIL1‑silenced cells, in which cell apoptosis increased. The migration and invasive capacities increased in the cells overexpressing

  10. SNAIL transcription factor increases the motility and invasive capacity of prostate cancer cells

    PubMed Central

    OSORIO, LUIS A.; FARFÁN, NANCY M.; CASTELLÓN, ENRIQUE A.; CONTRERAS, HÉCTOR R.

    2016-01-01

    The incidence and mortality rates of prostate cancer (PCa) are increasing, and PCa is almost the second-leading cause of cancer-associated mortality in men. During tumor progression, epithelial cells decrease the number of adhesion molecules, change their polarity and position, rearrange their cytoskeleton and increase their migratory and invasive capacities. These changes are known under the concept of epithelial-mesenchymal transition (EMT). EMT is characterized by an upregulation of certain transcription factors, including SNAIL1, which represses genes that are characteristic of an epithelial phenotype, including E-cadherin, and indirectly increase the expression levels of genes, which are associated with the mesenchymal phenotype. It has been suggested that the transcription factor, SNAIL1, decreases the proliferation and increases the migratory and invasive capacities of PCa cell lines. The present study was performed using LNCaP and PC3 cell lines, in which the expression levels of SNAIL1 were increased or silenced through the use of lentiviral vectors. The expression levels of EMT markers were quantified using reverse transcription-quantitative polymerase chain reaction and western blot analysis. In addition, cell survival was analyzed using an MTS assay; cell proliferation was examined using an antibody targeting Ki-67; migration on plates with 8 µm pores to allow the passage of cells; and invasiveness was analyzed using a membrane chamber covered in dried basement membrane matrix solution. The levels of apoptosis were determined using a Caspase 3/7 assay containing a substrate modified by caspases 3 and 7. The results demonstrated that the overexpression and silencing of SNAIL1 decreased cell proliferation and survival. However, the overexpression of SNAIL1 decreased apoptosis, compared with cells with the SNAIL1-silenced cells, in which cell apoptosis increased. The migration and invasive capacities increased in the cells overexpressing SNAIL1, and

  11. Wnt5a uses CD146 as a receptor to regulate cell motility and convergent extension

    NASA Astrophysics Data System (ADS)

    Ye, Zhongde; Zhang, Chunxia; Tu, Tao; Sun, Min; Liu, Dan; Lu, Di; Feng, Jing; Yang, Dongling; Liu, Feng; Yan, Xiyun

    2013-12-01

    Dysregulation of Wnt signalling leads to developmental defects and diseases. Non-canonical Wnt signalling via planar cell polarity proteins regulates cell migration and convergent extension; however, the underlying mechanisms are poorly understood. Here we report that Wnt5a uses CD146 as a receptor to regulate cell migration and zebrafish embryonic convergent extension. CD146 binds to Wnt5a with the high affinity required for Wnt5a-induced activation of Dishevelled (Dvl) and c-jun amino-terminal kinase (JNK). The interaction between CD146 and Dvl2 is enhanced on Wnt5a treatment. Mutation of the Dvl2-binding region impairs its ability to activate JNK, promote cell migration and facilitate the formation of cell protrusions. Knockdown of Dvls impairs CD146-induced cell migration. Interestingly, CD146 inhibits canonical Wnt signalling by promoting β-catenin degradation. Our results suggest a model in which CD146 acts as a functional Wnt5a receptor in regulating cell migration and convergent extension, turning off the canonical Wnt signalling branch.

  12. Cell motility regulation on a stepped micro pillar array device (SMPAD) with a discrete stiffness gradient.

    PubMed

    Lee, Sujin; Hong, Juhee; Lee, Junghoon

    2016-02-28

    Our tissues consist of individual cells that respond to the elasticity of their environment, which varies between and within tissues. To better understand mechanically driven cell migration, it is necessary to manipulate the stiffness gradient across a substrate. Here, we have demonstrated a new variant of the microfabricated polymeric pillar array platform that can decouple the stiffness gradient from the ECM protein area. This goal is achieved via a "stepped" micro pillar array device (SMPAD) in which the contact area with the cell was kept constant while the diameter of the pillar bodies was altered to attain the proper mechanical stiffness. Using double-step SU-8 mold fabrication, the diameter of the top of every pillar was kept uniform, whereas that of the bottom was changed, to achieve the desired substrate rigidity. Fibronectin was immobilized on the pillar tops, providing a focal adhesion site for cells. C2C12, HeLa and NIH3T3 cells were cultured on the SMPAD, and the motion of the cells was observed by time-lapse microscopy. Using this simple platform, which produces a purely physical stimulus, we observed that various types of cell behavior are affected by the mechanical stimulus of the environment. We also demonstrated directed cell migration guided by a discrete rigidity gradient by varying stiffness. Interestingly, cell velocity was highest at the highest stiffness. Our approach enables the regulation of the mechanical properties of the polymeric pillar array device and eliminates the effects of the size of the contact area. This technique is a unique tool for studying cellular motion and behavior relative to various stiffness gradients in the environment. PMID:26787193

  13. Motility mutants of Dictyostelium discoideum

    PubMed Central

    1982-01-01

    We describe six motility mutants of Dictyostelium discoideum in this report. They were identified among a group of temperature-sensitive growth (Tsg) mutants that had been previously isolated using an enrichment for phagocytosis-defective cells. The Tsg mutants were screened for their ability to produce tracks on gold-coated cover slips, and several strains were found that were temperature-sensitive for migration in this assay. Analysis of spontaneous Tsg+ revertants of 10 migration-defective strains identified six strains that co-reverted the Tsg and track formation phenotypes. Characterization of these six strains indicated that they were defective at restrictive temperature in track formation, phagocytosis of bacteria, and pseudopodial and filopodial activity, while retaining normal rates of oxygen consumption and viability. Because they had lost this group of motile capabilities, these strains were designated motility mutants. The Tsg+ revertants of these mutants, which coordinately recovered all of the motile activities, were found at frequencies consistent with single genetic events. Analysis of the motility mutants and their revertants suggests a relationship between the motility mutations in some of these strains and genes affecting axenic growth. PMID:7118999

  14. Actin-based phagosome motility.

    PubMed

    Zhang, Fangliang; Southwick, Frederick S; Purich, Daniel L

    2002-10-01

    Despite abundant evidence of actin's involvement at the particle internalization stage of phagocytosis, little is known about whether phagosomes undergo the same type of actin-based motility as observed with endocytic vesicles or such intracellular pathogens as Listeria and Shigella. By employing video microscopy to follow the fate of latex bead-containing phagosomes within the cytoplasm of bone marrow macrophages, we have made the novel observation of actin-based phagosome motility. Immunofluorescence microscopy c