Regulation of cell proliferation and urokinase plasminogen activation of human breast epithelial cells by carrageenans.

Carrageenans, a family of polysulphated carbohydrates, are able to inhibit the binding to cells of growth factors such as transforming growth factor 1 (TGF 1), fibroblast growth factor-2 (FGF-2) and platelet-derived growth factor (PDGF) and so modulate cell invasion and proliferation. We studied the effects of carrageenans on the proliferation and on the uPA/PAI-1 system in breast epithelial cells. Carrageenans were able to inhibit the proliferation of both normal breast epithelial cells (NBEC) and breast epithelial cancer cell lines (MDA-MB-231 and MCF-7) but could only inhibit the uPA activity in the MDA-MB-231 cells. Moreover, carrageenans inhibited FGF-2 binding in all three cell types, suggesting that they regulate cell proliferation and uPA/PAI-1 system through two distinct mechanisms. These molecules could be considered as potentially useful anti-cancer agents.