Tight Squeeze

 TIGHT SQUEEZE: Many cancer biologists believe that tumor metastases could be prevented by inhibiting the proteolytic enzymes that chew through the extracellular matrix. When Peter Friedl's team at the University of Wuerzburg, Germany blocked all proteolytic activity of the cancer cells (blue) they found that the cells took a surprising alternate route, squeezing their way through small gaps in the matrix. Friedl speculates that mammalian cells can revert to this amoeboid-like movement when necessary. (K. Wolf et al., "Compensation mechanism in tumor cell migration: Mesenchymal-amoeboid transition after blocking of pericell-ular proteolysis," J Cell Biol, 160:267-77, Jan. 20, 2003.)