Because of results seen in flat lab dishes, biologists have believed that cancers cells move through the body in a slow, aimless fashion, resembling an intoxicated person who cannot walk three steps in a straight line. This pattern, called a random walk, may hold true for cells traveling across two-dimensional lab containers, but Johns Hopkins researchers have discovered that for cells moving through three-dimensional spaces within the body, the “drunken” model doesn’t hold true.
This finding, reported in the March 4 online Early Edition of Proceedings of the American Academy of Sciences, is important because it should lead to more accurate results for scientists studying how cancer spreads through the body, often leading to a grim prognosis. To address this dimensional disagreement, 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, the university’s Theophilus H. Smoot Professor, with appointments in the departments of Chemical and Biomolecular Engineering, Pathology and Oncology within Johns Hopkins’ Whiting School of Engineering and School of Medicine. Wirtz said the discovery reinforces the current shift toward studying how cells move in three dimensions. His lab team has conducted earlier studies showing that that cells in 2D and 3D environments behave differently, which affects how cancer migrates within the body.
“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 said. “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.”