Blocking adhesion of cancer cells to endothelial cell types by S. agalactiae type-specific polysaccharides.

By using immortalized and normal endothelial cells, we were able to detect inhibitory effects of type specific polysaccharides from Streptococcus agalactiae on adhesion of cancer cells to endothelial cells, which is an essential step of cancer metastatis. The inhibition was probably due to specific structures of the bacterial polysaccharides, since the structures of the saccharides are very similar to those of cancer specific sialyl Lewis carbohydrates (sialyl Le(a) and Le(x)) which bind to ELAM-1 of endothelial cells. This result indicated that the bacterial polysaccharides from S. agalactiae could be very useful and hopeful as cancer metastasis inhibitors.