Human mammary epithelial cells exhibit a bimodal correlated random walk pattern.
BACKGROUND
Organisms, at scales ranging from unicellular to mammals, have been known to exhibit foraging behavior described by random walks whose segments confirm to Lévy or exponential distributions. For the first time, we present evidence that single cells (mammary epithelial cells) that exist in multi-cellular organisms (humans) follow a bimodal correlated random walk (BCRW).


RESULTS
Cellular tracks of MCF-10A pBabe, neuN and neuT random migration on 2-D plastic substrates, analyzed using bimodal analysis, were found to reveal the BCRW pattern. We find two types of exponentially distributed correlated flights (corresponding to what we refer to as the directional and re-orientation phases) each having its own correlation between move step-lengths within flights. The exponential distribution of flight lengths was confirmed using different analysis methods (logarithmic binning with normalization, survival frequency plots and maximum likelihood estimation).


CONCLUSIONS
Because of the presence of non-uniform turn angle distribution of move step-lengths within a flight and two different types of flights, we propose that the epithelial random walk is a BCRW comprising of two alternating modes with varying degree of correlations, rather than a simple persistent random walk. A BCRW model rather than a simple persistent random walk correctly matches the super-diffusivity in the cell migration paths as indicated by simulations based on the BCRW model.
Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee, United States of America.
Alka A
AA
Potdar
Junhwan
J
Jeon
Alissa M
AM
Weaver
Vito
V
Quaranta
Peter T
PT
Cummings
D000465:Algorithms; D002465:Cell Movement; D003198:Computer Simulation; D004058:Diffusion; D004847:Epithelial Cells / Q000473:pathology* / Q000502:physiology; D006801:Humans; D016013:Likelihood Functions; D042361:Mammary Glands, Human / Q000473:pathology* / Q000502:physiology; D008954:Models, Biological; D015233:Models, Statistical; D008962:Models, Theoretical; D016011:Normal Distribution