Tumor cells get primitive

When metastatic tumor cells migrate through connective tissue, they use proteases to chew a path for themselves. This finding led to the development of protease inhibitors as potential cancer therapies, but some animal and human clinical tests of these drugs have been disappointing. Wolf et al., reporting on page 267, may have found one reason why: when proteolysis is inhibited, tumor cells resort to an amoeboid type of movement that allows them to squeeze through cracks in the matrix. The results provide substantial new insight into cell migration in multicellular organisms.

Using both in vitro and in vivo cell migration systems, the authors investigated the effects of inhibiting proteases that degrade the extracellular matrix. Normally, transformed cells migrate through three-dimensional collagen matrices or the mouse dermis as individual, spindle-shaped cells, using several proteolytic enzymes and...