laboratoire de physique statistique
 
 
laboratoire de physique statistique

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EUROPEAN PHYSICAL JOURNAL PLUS 


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2016
From cellular to tissue scales by asymptotic limits of thermostatted kinetic models - Bianca, Carlo and Dogbe, Christian and Lemarchand, Annie
EUROPEAN PHYSICAL JOURNAL PLUS 131 (2016)

Abstract : Tumor growth strictly depends on the interactions occurring at the cellular scale. In order to obtain the linking between the dynamics described at tissue and cellular scales, asymptotic methods have been employed, consisting in deriving tissue equations by suitable limits of mesoscopic models. In this paper, the evolution at the cellular scale is described by thermostatted kinetic theory that include conservative, nonconservative (proliferation, destruction and mutations), stochastic terms, and the role of external agents. The dynamics at the tissue scale (cell-density evolution) is obtained by performing a low-field scaling and considering the related convergence of the rescaled framework when the scaling parameter goes to zero.
 
2015
Osmotic stress affects functional properties of human melanoma cell lines - La Porta, Caterina A. M. and Ghilardi, Anna and Pasini, Maria and Laurson, Lasse and Alava, Mikko J. and Zapperi, Stefano and Ben Amar, Martine
EUROPEAN PHYSICAL JOURNAL PLUS 130 (2015)

Abstract : Understanding the role of microenvironment in cancer growth and metastasis is a key issue for cancer research. Here, we study the effect of osmotic pressure on the functional properties of primary and metastatic melanoma cell lines. In particular, we experimentally quantify individual cell motility and transmigration capability. We then perform a circular scratch assay to study how a cancer cell front invades an empty space. Our results show that primary melanoma cells are sensitive to a low osmotic pressure, while metastatic cells are less. To better understand the experimental results, we introduce and study a continuous model for the dynamics of a cell layer and a stochastic discrete model for cell proliferation and diffusion. The two models capture essential features of the experimental results and allow to make predictions for a wide range of experimentally measurable parameters.
Morphogenesis of early stage melanoma - Chatelain, Clement and Ben Amar, Martine
EUROPEAN PHYSICAL JOURNAL PLUS 130 (2015)

Abstract : Melanoma early detection is possible by simple skin examination and can insure a high survival probability when successful. However it requires efficient methods for identifying malignant lesions from common moles. This paper provides an overview first of the biological and physical mechanisms controlling melanoma early evolution, and then of the clinical tools available today for detecting melanoma in vivo at an early stage. It highlights the lack of diagnosis methods rationally linking macroscopic observables to the microscopic properties of the tissue, which define the malignancy of the tumor. The possible inputs of multiscale models for improving these methods are shortly discussed.
The role of pressure in cancer growth - Taloni, Alessandro and Ben Amar, Martine and Zapperi, Stefano and La Porta, Caterina A. M.
EUROPEAN PHYSICAL JOURNAL PLUS 130 (2015)

Abstract : The response to external mechanical forces is increasingly seen as a crucial aspect of cancer growth and a topic where the contribution of physics ideas and methods is important. Understanding if tumor progression towards increased malignancy reflects the geometry and mechanics of the microenvironment is an important issue still to be fully explored. In order to grow, tumors have to overcome the mechanical resistance posed by the tissues in which they originate, while cancer cells involved in metastasis are often subject to fluid pressure. Here we review the recent literature describing the role of solid and fluid pressure on tumor growth and progression. We discuss a variety of in vitro experiments as well as computational models used to interpret them. We conclude discussing future perspectives.
 
2011
Cell motility: A viscous fingering analysis of active gels - Ben Amar, M. and Manyuhina, O. V. and Napoli, G.
EUROPEAN PHYSICAL JOURNAL PLUS 126 (2011)

Abstract : The symmetry breaking of the actin network from radial to longitudinal symmetry has been identified as the major mechanism for keratocytes (fish cells) motility on solid substrate. For strong friction coefficient, the two-dimensional actin flow which includes the polymerisation at the edge and depolymerisation in the bulk can be modelled as a Darcy flow, the cell shape and dynamics being then modelled by standard complex analysis methods. We use the theory of active gels to describe the orientational order of the filaments which varies from the border to the bulk. We show analytically that the reorganisation of the cortex is enough to explain the motility of the cell and find the velocity as a function of the orientation order parameter in the bulk.