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BP: Fachverband Biologische Physik

BP 28: Biomedical Applications

BP 28.3: Vortrag

Freitag, 30. März 2007, 11:30–11:45, H44

CXCR2 determines invasiveness, traction forces and cytoskeletal dynamics of tumor cells — •Claudia Tanja Mierke, Philip Kollmannsberger, Daniel Paranhos Zitterbart, Carina Raupach, and Ben Fabry — Biophysics, University Erlangen, Germany

Tumor cells consist of populations with different capacities to invade and different CXCR2 expression. We tested the hypothesis that highly invasive tumor cells reorganize their cytoskeleton more rapidly and can generate higher tractions than less-invasive cells. We isolated a highly- and a low-invasive variant of MDA-MB-231 carcinoma cells (231-high/-low) with a 5-fold difference in CXCR2 expression. Invasiveness was analysed in a collagen gel. Cytoskeletal dynamics was determined from the creep response of cells and from spontaneous nanoscale-movements of magnetic particles. Step forces from 1-10 nN were applied to fibronectin-coated beads. Bead displacement vs. time followed a power-law. The exponent was taken as a measure of cytoskeletal dynamics, with low values corresponding to a solid-like, static and high corresponding to a liquid-like, dynamic behavior. 231-high cells had a substantially higher exponent compared to 231-low cells. Spontaneous bead motion showed significantly more superdiffusive behavior in 231-high compared to 231-low cells. Tractions measured during adhesion onto collagen-coated gels showed that 231-high cells generate 8x higher contractile forces compared to 231-low cells. In summary, the ability of tumor cells to remodel their cytoskeleton and to generate high tractions seems be key factors for metastasis formation.