Role of Actin Cytoskeletal Structure for Cell Migration on Micro-Structured Surfaces
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a contracting ellipsoid. We find that our model recapitu-deformations typically measured around invasive tumorarge contraction of the gel surface above the cell.
oskeletal Structure for Cell Migration on Micro-
ngmyoung Ju1, Sang Min Lee2, Dong Jin Cho2,dachi3, Yutaka Yamagata1.pan, 2Pusan National University, Busan, Korea,niversity, Kyoto, Japan.
ior is known to be remarkably affected by the interactiongraphy at multiple scales, ranging from nanometers toHere, our aim is to clarify the interaction between cellstopography based on the role of actin cytoskeletal struc-
1112-PlatFlow Mechanotransduction Regulates Traction Forces, Intercellular
tionsahn, Nathan J. Sniadecki.eattle, WA, USA.r stresses with mechanotransduction responses thatcell-cell contacts. Cultures of endothelial cells weremicropost arrays and different shear flow profilesthe interplay between traction forces, intercellulars (AC). Cells exposed to laminar flow had elevatedatic conditions while cells experiencing unsteady or
r Tumor Spheroidseti1, Danijela Vignjevic1,ancois Joanny1.France.trast with the genetic aberrations,nd its interplay with the tumor is
ches to measure the effect of me-he first setup use osmotic pressurepressure on a multicellular tumorodulate tumor growth dependingonstrate quantitatively that cellsthey are located in the core or inp is amicrofluidic based integrated
220a Monday, February 27, 2012ture. We fabricated silicon microstructured surfaces with microgrooves of vari-ous sizes, and characterized the behavior of cells moving from the flat surface tothe grooved surface. The intersecting grooves with a size that allow a cell to ex-perience multiple grooves absorbed cells with a higher angle of approach, andrepelled cells with a lower angle of approach. Similarly, the single line grooveshowed a tendency to repel cells with a lower angle of approach and absorb cellswith a higher angle of approach. However, the tendency with the single linegroovewas less clear than that with the intersecting grooves. The result indicatesthat the intersecting grooves had a better discrimination performance of the anglea collagen gel aroundlates the complex gelcells, such as a very l
1111-PlatRole of Actin CytStructured SurfacesHiromi Miyoshi1, JuJong Soo Ko2, Taiji A1RIKEN, Saitama, JaRepublic of, 3Kyoto UCell migratory behavwith the surface topotens of micrometers.and micrometer scaleto study cell migration. Spatio-Temporal Image Correlation Spectroscopy(STICS) can create vector maps of protein velocities inside a living cell whileTraction Force Microscopy (TFM) allows us to measure the forces applied bya cell on a substrate, which play a crucial role in cell migration. Using these tech-niques together allows us to simultaneously compare adhesion protein velocitiesinside the cells and the underlying traction forces exerted by the cell, to providegreater insight into cell migration. We show that traction forces and retrogradepaxillin flow exhibit directional correlation but an inverse magnitude relation-ship in motile U2OS cells, indicating slippage at the molecular clutch level.By coating poly-acrylamide gelswith different li-gands, we observedifferences in thestrength of thoseintegin-ligand bind-ing pairs. Finally,a new correlationanalysis is intro-duced that can dif-ferentiate betweenpotential adhesionmovement models.
1110-PlatEstimation of Cellular Forces during Migration through Non-Linear andNon-Affine Collagen NetworksJulian Steinwachs1, Claus Metzner1, Nadine Lang1, Stefan Munster2,Ben Fabry1.1University Erlangen Nuremberg, Erlangen, Germany, 2Harvard University,Cambridge, MA, USA.Reconstituted collagen gels are a widely used environment to study cell migra-tion in three dimensions. Collagen gels show strain stiffening and a strong lat-eral contraction during extension (Poisson ratio > 0.5). This behavior is notexplained by linear elastic theory. To make quantitative estimates about the cel-lular forces and local mechanical properties of the matrix that the migrating cellencounters, a constitutive model of the gel is needed. On a microscopic scale,collagen gels consist of a network of mechanically coupled collagen fibrils thatshow buckling under compression and tautening and alignment under exten-sion. These effects give rise to non-affine behavior of the network, which is vir-tually impossible to model or simulate numerically on a larger scale. Instead,we take advantage of the fact that the effects of a non-affine deformation iswell captured by an affine network with non-linear elements. We extract thenonlinear force-length relationship of the network elements from two typesof rheological measurements. First, we stretch and compress a collagen gelin the horizontal direction and measure its vertical contraction and dilation.From this we extract the asymmetry of the force-length relationship betweenextension and compression. Second, we shear a collagen gel in a cone plate rhe-ometer. From this we extract the force-length relationship under extension.Finally, with a finite element analysis we compute the deformation field ofof approachof the cells than a single line groove. Themechanismof thismotility-based filtering is supposed to be primarily explained based on the lamellar drag-system which enables to feed and visualize spheroids in the same time that weapply a known pressure. We compare the results to numerical and analyticmodels developed to describe the role of mechanics in cancer progression.Fabien Montel, Morgan Delarue, Jens Elgeti, Laurent Malaquin, MarkusBasan, Thomas Risler,Bernard Cabane, DanijelaVignjevic, Jacques Prost,Giovanni Cappello andJean-Francois Joanny.Stress clamp experimentson multicellular tumorspheroids. Physical Re-view Letters. In press.
Platform: Membrane Physical Chemistry I
1114-PlatPeptide Perturbations in Model MembranesRobin L. Samuel, Susan D. Gillmor.George Washington University, Washington, DC, USA.1113-PlatStress Clamp Experiments on MulticellulaFabien Montel1, Morgan Delarue1, Jens ElgGiovanni Cappello1, Jacques Prost2, Jean-Fr1Institut Curie, Paris, France, 2ESPCI, Paris,Cancer progress is a multistep process. In conthe precise role of the micro-environment astill poorly understood.In this work, we present two different approachanical stress on tissue growth and death. Tto deform a dialysis bag and exert a knownspheroid. Our results indicate the ability to mon the applied pressure. Moreover, we demhave a different response to stress whetherthe periphery of the spheroid. The second setudisturbed flow exhibited lower traction forces (F). Similarly, the size of celladherens junctions increased after laminar flow and decreased after disturbedflow.Decreasing cytoskeletal tensionwithY-27632 decreased the size of adherensjunctions (D), while increasing tension through Calyculin-A increased their size(E).Anovel approach tomeasure intercellularforces between cells in the monolayers wasdeveloped (G) and these forces were foundto be significantly higher for laminar flowthan for static or disturbed conditions (H)with adherens junction size reflecting thesetension changes. These results indicate thatlaminar flow can increase cytoskeletaltension while disturbed flow decreases cyto-skeletal tension. The corresponding changein cytoskeletal tension under shear can pro-duce intercellular forces that can potentiallyaffect the assembly of adherens junction.Forces, and Adherens JuncLucas H. Ting, Jessica R. JUniversity of Washington, SEndothelial cells react to sheamodify the cytoskeleton andpatterned as monolayers onwere applied to investigateforces, and adherens junctiontraction forces compared to stging effect by the preferential lamellar protrusion into the grooves due to theme-chanical restriction provided by the actin cytoskeleton. If the lamellar draggingeffect is sufficiently high, the cells are absorbed by the grooved surface. In con-trast, if the dragging effect is not enough to draw the cell body into the grooves,the cells are repelled by the grooved surface. This study provides a framework totailor themicrogrooved surface control of cell migration by usingmicrogrooves.We investigate peptide interactions with model membranes and how theyaffect phase dynamics and mobility. Previously, we have studied lipid phase
Estimation of Cellular Forces during Migration through Non-Linear and Non-Affine Collagen NetworksRole of Actin Cytoskeletal Structure for Cell Migration on Micro-Structured SurfacesFlow Mechanotransduction Regulates Traction Forces, Intercellular Forces, and Adherens JunctionsStress Clamp Experiments on Multicellular Tumor SpheroidsPeptide Perturbations in Model Membranes