8th Annual Symposium
Physics of Cancer
October 4-6, 2017
|PoC - Physics of Cancer - Annual Symposium|
Collectively emerging nematic order in populations of fibroblasts
Institut Curie, Centre de Recherche,, 26 rue d’Ulm, 75248 Paris Cedex 05, France
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Cancer-associated fibroblasts (CAFs) self-organize in thin “shells” around tumors. In these circumstances, these CAFs spontaneously orient along a common local direction and form a nematic phase. Such a situation can be reproduced in vitro with cultures of spindle-shaped cells such as NIH-3t3 fibroblasts.
In undefined monolayers, these cells form domains of common orientation that don’t fuse because of the presence of intrinsic topological defects characteristic of these nematic phases. The characteristic size of these domains is very large compared to a cell size (~ 500 µm).
To control the density and position of these defects, we confine the nematic monolayers in well-defined micropatterned geometries such as linear stripes or circular domains. In stripes, cells can reach a perfect macroscopic alignment. In contrast, the disk geometry imposes a pair of defects whose position indicates that cell activity is eventually overcome by friction with the underlying substrate.
Finally, we will describe other situations where the nematic arrangement is more complex and is coupled to spontaneous flows. This particular situation is very similar to in vivo observations where strands of cancer cells escaping collectively from a tumor can locally migrate in antiparallel directions within the same strand.