The invasion of
cancer cells at primary
tumor sites and their migration during metastatic spread require the expression of cell adhesion and
motility proteins. Whether accelerated cell motility is necessary in these two processes is not universally accepted. In this study we took advantage that CD44, a cell adhesion
protein, has different metastatic potentials depending on its splicing
isoforms to examine how they affect cell motility. We established stable transfectants of standard and variant
isoforms of CD44 in SW620 cells, a human colon
carcinoma cell line that does not express CD44. The morphology of the cells varied according to the CD44
isoform expressed, but actin filament distribution remained unchanged. Using the
wound assay in a two-dimensional in vitro cell motility system, we found that the expression of standard CD44 increases cell motility, whereas CD44
isoforms containing an exon sequence associated with metastatic dissemination has a slowing effect. Cell proliferation was also decreased by the expression of variant CD44
isoforms. Overall,
colon cancer cells expressing variant CD44
isoforms had slower cell motility, possibly due to alterations in their cell adhesion properties. In conclusion, this study suggests that, contrary to common models, the metastatic phenotype is associated with a slow rate of cell migration when tested in vitro.