Dresden 2006 – scientific programme
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AKB: Biologische Physik
AKB 25: Cell Mechanics I
AKB 25.11: Talk
Thursday, March 30, 2006, 17:30–17:45, ZEU 260
Force Generation during Tumor Cell Invasion in Three-Dimensional Collagen Gels — •Thorsten Koch, Johannes Pauli, Claudia Mierke, and Ben Fabry — Friedrich-Alexander-Universität Erlangen-Nürnberg - Zentrum für Medizinische Physik und Technik - Lehrstuhl für Physikalisch-Medizinische Technik - Henkestraße 91 - D-91052 Erlangen
Tumor cells exert forces on surrounding tissue during invasion, but the magnitudes of these forces are unknown. We measured forces during invasion by extending methods for 2-D traction microscopy to 3-D. We used collagen gels (E=300 Pa) to provide an in vitro environment for tumor cell invasion. MDA-MB-231 breast cancer cells were plated on the gel surface and allowed to invade for two days. Cells assumed a spindle-shaped morphology and contracted the gel mainly along their primary axis. To quantify gel contraction, fluorescent beads serving as fiducial markers were embedded in the gels. The 3-D bead positions were determined with a center-of-mass algorithm applied to images taken at various focal depths. To obtain the undeformed state of the gels, we disrupted the actin cytoskeleton and hence force transmission by treatment with cytochalasin-D (4 µM). We then calculated the dipole moment of the cells from the bead displacements between the initial and cytochalasin-D treated states. The magnitudes of dipole moments were on the order of 10−12 Nm, comparable to those generated by maximally contracted smooth muscle cells in 2-D culture (Butler JP et al., Am J Physiol Cell Physiol 282:C595, 2002). Our results show that MDA-MB-231 tumor cells exert substantial forces on surrounding tissue during invasion.