Neutrophils, the white blood cells that protect us from harmful microbes, have some remarkable capabilities. Despite being less than 10 microns in diameter, neutrophils can be very smart about the direction in which they move. For example, more than 90% of the human neutrophils are able to pick up the shorter route towards a chemical stimulus. Here you can see how "smart" neutrophils are at asymmetric and symmetric bifurcations. The ability of neutrophils to orient is lost in patients with severe burn injuries, contributing to the higher rates of infections in these patients.
The ability of cells to migrate and orient could also be a problem. When it happens in cancer cells, it enables these cells to migrate away from the primary tumor and form metastases, which are ultimately responsible for 90% of deaths in cancer patients. We were very surprised to find that cancer cells are able find the shortest path to exit microscopic mazes, even in the absence of any externally imposed gradients. Here you can see for yourself how cancer cells navigate through a maze . Our evidence provides support for an novel self-guidance mechanism that epithelial cells can employ when confined in small spaces.
We also know for some time that cancer cells can move several times their body length every hour. To put things into perspective, it would take less than one month for a breast cancer cell moving through the lymphatic vessels, to travel from a tumor in the breast to a local lymph node. Here you can watch some breast cancer cells "speeding" through small channels at 200 µm/hour .
Taken together, our observations are not just fascinating examples of biological sophistication. They could also open exciting opportunities for probing into disease processes in novel ways. And, one day, lead to new approaches to treating acute infections, resolving chronic inflammation, and stopping the progression of cancers...
Cite this work
Researchers should cite this work as follows:
Daniel Irimia, 2012, Cells in Action: Precision Measurements of Neutrophil Motility in Medicine