Metastatic competence of BW5147 T‐lymphoma cell lines is correlated with in vitro invasiveness, motility and F‐actin content

The aim of our study was to investigate whether the level of actin polymerization plays a role in the motile and tissue infiltrating behavior of malignant lymphoma cells. For a panel of cell lines derived from the murine BW5147 T‐cell lymphoma, we had previously shown a correlation between experimental metastasis formation and in vitro monolayer invasion. We have analyzed the motility and the F‐actin content of six non‐metastatic, noninvasive (meta ‐ inv ‐ ) and five metastatic, invasive (meta + inv + ) variants of BW5147. Fourier analysis of cell contours was used to quantify shape changes of cells. All meta + inv + lines rapidly protruded and retracted pseudopodia, whereas only one of the six meta ‐ inv ‐ lines showed this type of motility. Flow cytometry of cells stained with fluorescein‐labeled phalloidin showed that the motile meta + inv + cell lines have a higher F‐actin content than their nonmotile meta ‐ inv ‐ counterparts. The results indicate that in lymphoma cells a high level of actin polymerization is a prerequisite for the formation of pseudopodia, which in turn are necessary for infiltration of the cells into tissues, and eventually for efficient metastasis formation. A corollary of this conclusion is that regulation of actin polymerization is a possible target for intervention aimed at moderating the spread of malignant lymphoma. J. Leukoc. Biol. 55: 552–556; 1994.