Tumor cell migration may favor local mass expansion and metastasis dissemination. Several tumors were found to express the receptor for platelet-activating factor (PAF), a potent mediator of leukocyte chemotaxis and endothelial cell migration. However, its functional role on tumor cells is largely unexplored. In the present study, we evaluated the motogenic effect of PAF on Chinese hamster ovarian (CHO) cancer cells transfected with the human PAF-receptor cDNA (CHO PAF-R). By using time-lapse recording, we detected a rapid motogenic response to PAF stimulation on CHO PAF-R, whereas no effect was evident on vector-only transfected cells. Such an effect was observed on scattered cell motility, on cells seeded on a fibronectin- or collagen-coated surface, and on migration of confluent monolayer cells. Cell speed increased at 1 h and was maximal 6-8 h after PAF stimulation on CHO PAF-R. Concomitantly, PAF induced marked changes in cytoskeleton actin distribution with cell contraction, assembling of stress fibers, and polar foci of adhesion. In conclusion, the present study demonstrates that PAF is a potent inducer of tumor cell motility, thus suggesting a role for this mediator in tumor growth and dissemination.
Copyright 2000 Wiley-Liss, Inc.