Abstract
Coordination between actin cytoskeleton assembly and localized polarization of intracellular trafficking routes is crucial for cancer cell migration. ARF6 has been implicated in the endocytic recycling of surface receptors and membrane components and in actin cytoskeleton remodeling. Here we show that overexpression of an ARF6 fast-cycling mutant in MDA-MB-231 breast cancer-derived cells to mimick ARF6 hyperactivation observed in invasive breast tumors induced a striking rearrangement of the actin cytoskeleton at the ventral cell surface. This phenotype consisted in the formation of dynamic actin-based podosome rosette-like structures expanding outward as wave positive for F-actin and actin cytoskeleton regulatory components including cortactin, Arp2/3 and SCAR/WAVE complexes and upstream Rac1 regulator. Ventral rosette-like structures were similarly induced in MDA-MB-231 cells in response to epidermal growth factor (EGF) stimulation and to Rac1 hyperactivation. In addition, interference with ARF6 expression attenuated activation and plasma membrane targeting of Rac1 in response to EGF treatment. Our data suggest a role for ARF6 in linking EGF-receptor signaling to Rac1 recruitment and activation at the plasma membrane to promote breast cancer cell directed migration.
Highlights
Reorganization of the actin cytoskeleton is critical for invasive cell behavior of metastatic cancer cells by generating forces needed to move and to overcome physical resistance of three-dimensional (3D) tissue environment [1, 2]
Both in ARF6T157N-expressing cells and parental MDA-MB-231 cells, F-actin and cortactin accumulated in peripheral lamellipodia (Fig. 1A, arrows) and in cytoplasmic dot-like structures (Fig. 1A, asterisks) corresponding to F-actin/cortactin double-positive puncta associated with endocytic compartments [38]
We investigated the distribution of nucleation promoting factors (NPFs) known to activate the Arp2/3 complex i.e. WASP family proteins N-WASP, SCAR/WAVE and WASH
Summary
Reorganization of the actin cytoskeleton is critical for invasive cell behavior of metastatic cancer cells by generating forces needed to move and to overcome physical resistance of three-dimensional (3D) tissue environment [1, 2]. Cancer cells plated on 2D matrix substrates in vitro form typical plasma membrane protrusive structures including lamellipodia, sheet-like protruding leading edge of migrating cells and invadopodia, ventral degradative protrusions enriched in membrane-type 1 matrix metalloproteinase (MT1-MMPs), the enzyme responsible for pericellular degradation of ECM components [3]. Lamellipodia and invadopodia are PLOS ONE | DOI:10.1371/journal.pone.0121747. ARF6 Control Actin-Based Rosette Formation in Breast Cancer Cells and analysis, decision to publish, or preparation of the manuscript
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
