Cooperative Roles of SDF-1 alpha and EGF Gradients on Tumor Cell Migration Revealed by a Robust 3D Microfluidic Model

Melody Swartz, Mingming Wu
Public Library of Science, 2013
Article

Résumé

Chemokine-mediated directed tumor cell migration within a three dimensional (3D) matrix, or chemoinvasion, is an important early step in cancer metastasis. Despite its clinical importance, it is largely unknown how cytokine and growth factor gradients within the tumor microenvironment regulate chemoinvasion. We studied tumor cell chemoinvasion in well-defined and stable chemical gradients using a robust 3D microfluidic model. We used CXCL12 (also known as SDF-1 alpha) and epidermal growth factor (EGF), two well-known extracellular signaling molecules that co-exist in the tumor microenvironment (e. g. lymph nodes or intravasation sites), and a malignant breast tumor cell line, MDA-MB-231, embedded in type I collagen. When subjected to SDF-1 alpha gradients alone, MDA-MB-231 cells migrated up the gradient, and the measured chemosensitivity (defined as the average cell velocity along the direction of the gradient) followed the ligand - receptor (SDF-1 alpha - CXCR4) binding kinetics. On the other hand, when subjected to EGF gradients alone, tumor cells increased their overall motility, but without statistically significant chemotactic (directed) migration, in contrast to previous reports using 2D chemotaxis assays. Interestingly, we found that the chemoinvasive behavior to SDF-1 alpha gradients was abrogated or even reversed in the presence of uniform concentrations of EGF; however, the presence of SDF-1 alpha and EGF together modulated tumor cell motility cooperatively. These findings demonstrate the capabilities of our microfluidic model in re-creating complex microenvironments for cells, and the importance of cooperative roles of multiple cytokine and growth factor gradients in regulating cell migration in 3D environments.

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https://infoscience.epfl.ch/record/189456?ln=fr

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Melody Swartz, Mingming Wu
Public Library of Science, 2013
Article

Résumé

Official source

https://infoscience.epfl.ch/record/189456?ln=fr

À propos de ce résultat

Concepts associés (17)

Concepts associés

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Publications associées (75)

Publications associées

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Dendritic cell chemotaxis in 3D

Ulrike Haessler

Dendritic cells (DCs) are crucial for the onset of adaptive immunity. Their outstanding migratory capacities in combination with their antigen presenting properties make them perfectly suited to pick up antigens in the periphery and transport them to the lymph nodes, where antigen presentation to T-cells is most efficient [1]. Their migration from the periphery to the lymph nodes, called DCs cell homing, is involved in both mounting effective adaptive immune responses as well as maintaining tolerance to self-antigens [2]. Both of them need to be balanced to maintain a healthy organism. So far two alternative mechanisms have been proposed to guide DCs from the interstitium through the extracellular matrix to the proximal lymphatic vessel [3]. One of these mechanisms is based on paracrine chemotaxis towards a CCL21 gradient created by the proximal lymphatic vessel. The second mechanism, called autologous chemotaxis, describes how cells can follow an autocrine gradient, created by the biasing of self-secreted chemokine by interstitial flow [4, 5]. To answer the question of how these two mechanisms contribute to DC homing, a quantitative understanding of how cells respond to gradients and interstitial flow present in their physiological microenvironment is needed [6]. To date, appropriate tools to study DC migration under defined gradients and in the presence of tunable interstitial flow rates in a 3D environment have been lacking. Within this thesis, we present two micro-scale devices that allow live cell observation on an inverted microscope. The first was optimized to expose cells to a steady-state chemokine gradient within a 3D microenvironment and is based on a microfluidic agarose scaffold which functions as a gradient buffer (Chapter 3). The novelty of a gradient buffer allows us to quickly establish stable gradients, which is an important feature in order to create stable and precisely defined gradients during tracking of fast-moving cells like DCs. We then performed an in-depth study of DC cell chemotactic responses towards the CCR7 ligands (CCL19 and CCL21) in 3D using this new agarose chamber (Chapter 4). With the help of an integrated computational model, we could precisely predict the gradient formation of matrix-bound CCL21 versus soluble CCL19 in the microcellular environment and found that DC answer differently to the two chemokines in response to gradient steepness. Furthermore, CCL21 was more chemoattractive than CCL19 when cells were exposed to competing gradients of both chemokines, and this was independent of the CCL21-binding properties. This represents the first quantitative study of CCR7-mediated DC chemotaxis in 3D in response to well-defined ligand gradients. The second device we developed for studying the effects of the physiological flow environment, which cells experience in capillary-fed tissues, on cell migration [6]. A 2-gel strategy allowed us to flexibly fine tune interstitial flow velocities and to precisely determine the actual flow rate for each position imaged on a microscope. We exposed DCs to a wide range of flow rates and observed an increase in persistence under flow compared to static (Chapter 6). In conclusion, this work presents quantitative insights into DC migration within precisely controlled 3D-microenvironments using new devices. It also highlights the role of a quantitative understanding of biological processes to distinguish between chemotactic mechanisms of DC cells.

EPFL2010

Chargement

Tissue morphogenesis and remodeling is often orchestrated by cell-secreted proteins, referred to as morphogens that can trigger cellular responses in addition to modifying the local extracellular matrix (ECM). Of specific interest is the distribution of cell secreted proteins in the cell microenvironment and how this distribution can lead to varied responses. Morphogens often provide directional cues, and as such their specific distribution is critical to the signaling that they induce, in other words cells are sensitive to morphogen gradients and not just absolute amounts. Natural cellular environments in native tissue involve three dimensional ECM and are typically subjected to dynamic conditions such as interstitial flow (IF). Despite the importance of the extracellular environment in signaling, very little is known regarding the effects of mechanical stresses and subtle interstitial flows. This thesis examines the role of IF on morphogen gradients using mass transport models to elucidate mechanisms responsible for several specific biological phenomena including in vitro capillary formation and lymphatic metastasis of tumor cells. In vitro capillary formation had been shown in our lab to be separately enhanced by bound VEGF alone and slow IF alone, with the combination of these two conditions resulting in marked increase in organization. Using our computational model we were able to propose a novel mechanistic model to explain this synergy. Specifically showed how, through the combined effects of IF and matrix-bound growth factors, cells could create their own biased chemokine gradients without recourse to internal amplification methods. This process, which we have termed "autologous chemotaxis," drives directional signaling and migration in the direction of flow. This can occur even at very low Peclet numbers, when diffusion still dominates the overall transport, but convection changes the shape of the gradient, which is what a cell responds to. We then examined the effects of IF on tumor cell migration to explore a novel mechanism of lymphatic metastasis. Tumors often produce high amounts of proteoglycans creating a microenvironment is rich in morphogen binding sites, and tumors are also a source of interstitial flow due to their leaky vasculature. The lymphatic system drains interstitial fluid, therefore IF is always directed toward lymphatic capillaries. The lymphatic system is also a common route of tumor metastasis, which is what lead us to study the role of IF mediated chemotaxis. A computational model of an in vitro tumor invasion assay was constructed that predicted tumor cell migration that was in very good agreement with the in vitro experimental results. This phenomenon was further studied by modeling an in vivo geometry and examining the factors controlling autologous gradient formation in a physiological setting. In conclusion, we have demonstrated the importance of convective mass transport at very low flow velocities in a biological context. While these velocities are low enough that the convective effects would typically be ignored, their subtle effects on pericellular mass transport can be translated into relevant and observable morphogenic responses.

EPFL2007

Chargement

Expression of E-Cadherin in Epithelial Cancer Cells Increases Cell Motility and Directionality through the Localization of ZO-1 during Collective Cell Migration

Hwanseok Jang

Collective cell migration of epithelial tumor cells is one of the important factors for elucidating cancer metastasis and developing novel drugs for cancer treatment. Especially, new roles of E-cadherin in cancer migration and metastasis, beyond the epithelial-mesenchymal transition, have recently been unveiled. Here, we quantitatively examined cell motility using micropatterned free edge migration model with E-cadherin re-expressing EC96 cells derived from adenocarcinoma gastric (AGS) cell line. EC96 cells showed increased migration features such as the expansion of cell islands and straightforward movement compared to AGS cells. The function of tight junction proteins known to E-cadherin expression were evaluated for cell migration by knockdown using sh-RNA. Cell migration and straight movement of EC96 cells were reduced by knockdown of ZO-1 and claudin-7, to a lesser degree. Analysis of the migratory activity of boundary cells and inner cells shows that EC96 cell migration was primarily conducted by boundary cells, similar to leader cells in collective migration. Immunofluorescence analysis showed that tight junctions (TJs) of EC96 cells might play important roles in intracellular communication among boundary cells. ZO-1 is localized to the base of protruding lamellipodia and cell contact sites at the rear of cells, indicating that ZO-1 might be important for the interaction between traction and tensile forces. Overall, dynamic regulation of E-cadherin expression and localization by interaction with ZO-1 protein is one of the targets for elucidating the mechanism of collective migration of cancer metastasis.

MDPI2021

Chargement

Dendritic cell chemotaxis in 3D

Ulrike Haessler

EPFL2010

EPFL2007