Inhibitory effects of fucoidan on activation of epidermal growth factor receptor and cell transformation in JB6 Cl41 cells

Algal fucoidan is a marine sulfated polysaccharide with a wide variety of biological activities including anti-thrombotic, anti-inflammatory, and anti-tumor activities. In this study, we tested the hypothesis that fucoidan may suppress neoplastic cell transformation by inhibiting the phosphorylation of epidermal growth factor receptor (EGFR) in mouse epidermal JB6 Cl41 cells. Our results provided the first evidence that fucoidan from Laminaria guryanovae exerted a potent inhibitory effect on EGF-induced phosphorylation of EGFR. Consistent with its inhibitory action on phosphorylation of EGFR, fucoidan clearly suppressed the phosphorylation of extracellular signal-regulated kinase or c-jun N-terminal kinases induced by EGF. Moreover, EGF-induced the c-fos and c-jun transcriptional activities were inhibited by fucoidan, resulting to suppressing of activator protein-1 (AP-1) activity and cell transformation induced by EGF. Taken together, these results indicate that fucoidan might exert chemopreventive effects through the inhibition of phosphorylation of the EGFR.