The Mystery of How Cancer Cells Barrel Through Your Body

(WIRED) Gabriel Popkin, September 9, 2016 — The subtle mechanics of densely packed cells may help explain why some cancerous tumors stay put while others break off and spread through the body.

IN 1995, WHILE he was a graduate student at McGill University in Montreal, the biomedical scientist Peter Friedl saw something so startling it kept him awake for several nights. Coordinated groups of cancer cells he was growing in his adviser’s lab started moving through a network of fibers meant to mimic the spaces between cells in the human body.

For more than a century, scientists had known that individual cancer cells can metastasize, leaving a tumor and migrating through the bloodstream and lymph system to distant parts of the body. But no one had seen what Friedl had caught in his microscope: a phalanx of cancer cells moving as one. It was so new and strange that at first he had trouble getting it published. “It was rejected because the relevance [to metastasis] wasn’t clear,” he said. Friedl and his co-authors eventually published a short paper in the journal Cancer Research.

Two decades later, biologists have become increasingly convinced that mobile clusters of tumor cells, though rarer than individual circulating cells, are seeding many—perhaps most—of the deadly metastatic invasions that cause 90 percent of all cancer deaths. But it wasn’t until 2013 that Friedl, now at Radboud University in the Netherlands, really felt that he understood what he and his colleagues were seeing. Things finally fell into place for him when he read a paper by Jeffrey Fredberg, a professor of bioengineering and physiology at Harvard University, which proposed that cells could be “jammed”—packed together so tightly that they become a unit, like coffee beans stuck in a hopper.

Fredberg’s research focused on lung cells, but Friedl thought his own migrating cancer cells might also be jammed. “I realized we had exactly the same thing, in 3-D and in motion,” he said. “That got me very excited, because it was an available concept that we could directly put onto our finding.” He soon published one of the first papers applying the concept of jamming to experimental measurements of cancer cells.

Source: The Mystery of How Cancer Cells Barrel Through Your Body | WIRED