Because of results seen in flat lab dishes, biologists have believed that cancer cells move through the body in a slow, aimless fashion—much like an intoxicated person unable to walk in a straight line.
While this behavior, called a random walk, may hold true for cells traveling across two-dimensional lab containers, researchers at Johns Hopkins have discovered that for cells moving through three-dimensional spaces within the body, the “drunken” model of movement simply doesn’t hold true.
This discovery, detailed online this month in Proceedings of the National Academy of Sciences, is important because it should help scientists more accurately predict how cancer will spread through the body. The study’s authors have produced a new mathematical formula that they say better reflects the behavior of cells migrating through 3D environments.
The research was supervised by Denis Wirtz, a professor of chemical and biomolecular engineering, materials science, pathology, and oncology. Wirtz said the discovery is part of a current shift toward studying how cells move within three dimensions. In earlier studies, his team showed that cells in 2D and 3D environments behave differently, contrary the previous belief that this behavior is the same, regardless of the environment.
“Cancer cells that break away from a primary tumor will seek out blood vessels and lymph nodes to escape and metastasize to distant organs,” Wirtz says. “For a long time, researchers have believed that these cells make their way to these blood vessels through random walks. In this study, we found out that they do not. Instead, we saw that these cells will follow more direct, almost straight-line trajectories. This gives them a more efficient way to reach blood vessels—and a more effective way to spread cancer.”
For researchers trying to understand how metastasis occurs, he added, this finding has critical implications.
“This means that the time these cancer cells need to make their way out of connective tissues is much shorter than previous estimates,” says Wirtz, who was recently named the university’s vice provost for research.
This video shows some of the groups findings by showing an example of a cancer cell moving through a 3D Collagen.