Normal and tumoral melanocytes exhibit q-Gaussian random search patterns

In multicellular organisms, cell motility is central in all morphogenetic processes, tissue maintenance, wound healing and immune surveillance, and failures in its regulation potentiates numerous diseases, particularly cancer metastasis. Here, cell migration assays on plastic 2D surfaces were performed using normal (Melan A) and tumoral (B16F10) murine melanocytes in random motility conditions, i.e., in the absence of any external gradient of chemotactic signal. The trajectories of the centroids of the cell perimeters were tracked through time-lapse microscopy. The statistics of these trajectories was analyzed by building velocity and turn angle distributions, as well as velocity autocorrelations and the scaling of mean-squared displacements. We find that these cells exhibit a crossover from a normal to a super-diffusive motion with non-Gaussian velocity distributions, q-exponentially velocity autocorrelations, and trajectories without angular persistence at long time scales. Furthermore, our results reveal that B16F10 cells infected by mycoplasmas exhibits essentially the same diffusivity than their healthy counterparts. Also, varying the initial density of plated cells, we find that there is a crossover from anomalous ($q>1$) to normal ($q=1$, Gaussian) migration regime as this density increases. Finally, a q-Gaussian random walk model was proposed to account for these cell search patterns. Simulations based on this model correctly describes the crossover to super-diffusivity in the cell migration tracks.

This work was partially supported by FAPEMIG.