Vanderbilt University has published a study that reports human cells moving in what seem to be independent ways similar to amoebae and bacteria. These results are thought to be a first in cell biology and were inspired in a unique way. The researchers’ adopted some new assumptions

after reading a paper that appeared in the February 2008 issue of the journal Nature titled, “Scaling laws of marine predator search behaviour.”

The analysis of the movements of a variety of radio-tagged marine predators, including sharks, sea turtles and penguins showed that the predators used a foraging strategy very close to a specialized random walk pattern, called a Lévy walk, an optimal method for searching complex landscapes.

“As far as we can tell, this is the first time this type of behavior has been reported in cells that are part of a larger organism,” says Peter T. Cummings, John R. Hall Professor of Chemical Engineering, who directed the study that is described in the March 10 issue of the Public Library of Science journal PLoS ONE.

The discovery was the unanticipated result of a study the Cummings group conducted to test the hypothesis that the freedom with which different cancer cells move – a concept called motility – could be correlated with their aggressiveness: That is, the faster a given type of cancer cell can move through the body, the more aggressive it is.

“Our results refute that hypothesis—the correlation between motility and aggressiveness that we found among three different types of cancer cells was very weak,” Cummings says. “In the process, however, we began noticing that the cell movements were unexpectedly complicated.”

With this perspective in mind, Alka Potdar, now a post-doctoral fellow at Case Western Reserve University and the Cleveland Clinic, cultured cells from three human mammary epithelial cell lines on two-dimensional plastic plates and tracked the cell motions for two-hour periods in a “random migration” environment free of any directional chemical signals. Epithelial cells are found throughout the body, lining organs and covering external surfaces. They move relatively slowly, at about a micron per minute, which corresponds to two thousandths of an inch per hour.

When Potdar carefully analyzed these cell movements, she found that they all followed the same pattern. However, it was not the Lévy walk that they expected, but a closely related search pattern called a bimodal correlated random walk (BCRW). This is a two-phase movement: a run phase in which the cell travels primarily in one direction, and a re-orientation phase in which it stays in place and reorganizes itself internally to move in a new direction.

See full article from Vanderbilt University.

In similar news, the Laurence Berkeley National Laboratory just released a story titled "Berkeley Scientists Find New Way to Get Physical in the Fight Against Cancer". See excerpt from the release:

"Conventional biological wisdom holds that living cells interact with their environment through an elaborate network of chemical signals. As a result many therapies for the treatment of cancer and other diseases in which cell behavior goes awry focus on drugs that block or disrupt harmful chemical signals. Now, a new road for future therapies may have been opened with scientific evidence for a never seen before way in which cells can also sense and respond to physical forces.

A team of researchers with the Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California (UC) Berkeley has shown that the biochemical activity of a cellular protein system, which plays a key role in cancer metastasis, can be altered by the application of a direct physical force. This discovery sheds important new light on how the protein signaling complex known as EphA2/ephrin-A1 contributes to the initiation, growth and progression of cancerous cells, and also suggests how the activity of cancer cells can be affected by surrounding tissue."

See the full article: Berkeley Scientists Find New Way to Get Physical in the Fight Against Cancer on LabGrab's Posterous Account

“Scaling laws of marine predator search behaviour.”
http://www.nature.com/nature/journal/v451/n7182/full/nature06518.html

Link to the Quaranta Lab at Vanderbilt