Actin Polymerization and Gel Osmotic Swelling in Tumor Cell Pseudopod Formation

Active tumor cell motility has long been appreciated to play a major role in invasion and metastasis. Tumor cells exhibit an amoeboid movement similar to that of polymorphonuclear (PMN) leukocytes and the lower eukaryote Dictyostelium, characterized by pseudopod protrusion at the leading edge of the cell (Oster and Perelson 1987; Guirguis et al 1987; Condeelis 1992; Condeelis et al 1988, 1990, 1992; Stossel 1989, 1990, 1993; Usami et al 1992; Liotta 1992). Most of the current knowledge of mechanisms of amoeboid Chemotaxis is derived from studies of PMN leukocytes and Dictyostelium amoebae, which have revealed many similarities between the two different eukaryotic models.