The generation of locomotory forces in the spontaneous and norepinephrine-induced migration of carcinoma cells

The migration of tumor cells is essential for metastasis development. We distinguish two types of migration with regard to the dynamics and molecular basis: a slow, spontaneous type of migration is induced by the extracellular matrix. This type of migration is myosin II-independent. A fast type of migration is induced by ligands to G protein-coupled receptors, of which norepinephrine is the most potent. This migration depends on the myosin II activity. However, there is still discordance to which part other cytoskeletal components such as actin, myosin and tubulin contribute to these two types of tumor cell migration. Here we present a study on the role of several cytoskeletal proteins in the spontaneous and induced migration of breast and colon carcinoma cells by time-lapse videomicroscopy. The actin reorganization is essential for each type of cell migration. We have shown previously the important function of myosin II for the norepinephrine-induced migration, whereas we show herein that myosin VI is not involved. Most interestingly, stabilization of the microtubules reduced both types of migration, whereas a disruption increased the spontaneous and inhibited the norepinephrine-induced migration. These data suggest that the force generation is different in the spontaneous and the induced migration of carcinoma cells.