8th Annual Symposium
Physics of Cancer
October 4-6, 2017
|PoC - Physics of Cancer - Annual Symposium|
Tissue surface tension in simple models of dense biological tissues
Syracuse University, College of Arts and Sciences, Department of Physics, Syracuse, NY 13244, USA
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Recent experimental work has found that tissues – in contexts ranging from wound healing to embryonic development to cancer metastasis – often lie close to a transition between a fluid and solid state. Recent theoretical efforts have interpreted these systems in terms of vertex-like models that describe dense cells as interacting polygons or polyhedra. We now have direct evidence that the origin of the fluid-solid transition in these models is of an unusual character, and we briefly comment on the relevance of this unusual transition to experimental data. In addition, while these models are able to capture many essential features of interacting cells, relatively little work has been done to understand the effects of interfacial surface tension, which may be important for understanding the integrity of cancer tumor boundaries. Here we extend existing models by allowing cells to independently regulate their (a) homotypic interfacial tensions (governed by adhesion between cells of the same type) and (b) heterotypic interfacial tensions (between cells of different types). This generates a direct mechanism for cell segregation -- the effective surface tension between two tissue types. We measure this quantity in simulations using parallel plate compression and find that it is directly proportional to the single-cell heterotypic interfacial tension. Quite surprisingly, however, it does not match the value for surface tension extracted by monitoring fluctuations at the interface: the interface between unlike cell populations is an order of magnitude sharper than expected. We develop a novel stability argument to explain this result.