Regensburg 2010 – scientific programme
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BP: Fachverband Biologische Physik
BP 9: Physics of Cells I
BP 9.11: Talk
Tuesday, March 23, 2010, 12:30–12:45, H43
Strain Energy and its Density Distribution around Invasive and Non-Invasive Carcinoma Cells in 3D Collagen Gels — •Thorsten Koch1, Stefan Münster1, Claudia Mierke1, James Butler2, and Ben Fabry1 — 1Department of Physics, University of Erlangen-Nuremberg, Germany — 2Physiology Program, Harvard School of Public Health, Boston, MA, USA
Cell invasion through a 3D matrix is believed to depend on the ability of cells to generate traction forces. To quantify the role of cell tractions during invasion in a collagen gel (shear modulus 118 Pa, 500 µm thickness, mesh size 1.6 µm), we measured the strain energy of invasive MDA-MB-231 breast and A-125 lung carcinoma cells, as well as non-invasive MCF-7 breast and A-431 lung carcinoma cells for comparison. In all cases, cells locally contracted the gel, quantified by tracking 3D positions of embedded fluorescent beads. These positions served as nodes in a finite element mesh used to compute the strain energy. The strain energy of invasive breast carcinoma cells (1.4 ± 0.2 pJ, n=31) was significantly higher than that of non-invasive breast carcinoma cells (0.8 ± 0.1 pJ, n=28). Surprisingly, the strain energy of non-invasive lung carcinoma cells (4.2 ± 0.7 pJ, n=31) was similar to that of invasive lung carcinoma cells (3.5 ± 0.4 pJ, n=34). Invasive cells assumed an elongated morphology as opposed to the round shape of non-invasive cells. Accordingly, the distribution of strain energy density around invasive cells followed patterns of increased anisotropy. These results suggest that magnitude and directionality of traction generation are important for cell invasion in 3D collagen gels.