  Understanding the role of microenvironment in cancer growth and metastasis is
a key issue for cancer research. Here, we study the effect of osmotic pressure
on the functional properties of primary and metastatic melanoma cell lines. In
particular, we experimentally quantify individual cell motility and
transmigration capability. We then perform a circular scratch assay to study
how a cancer cell front invades an empty space. Our results show that primary
melanoma cells are sensitive to a low osmotic pressure, while metastatic cells
are less. To better understand the experimental results, we introduce and study
a continuous model for the dynamics of a cell layer and a stochastic discrete
model for cell proliferation and diffusion. The two models capture essential
features of the experimental results and allow to make predictions for a wide
range of experimentally measurable parameters.
