Anticancer Effect of Fucoidan in Combination with Tyrosine Kinase Inhibitor Lapatinib

Background. Despite a number of in vitro and in vivo studies reporting the efficacy of fucoidan in treating various cancers, few studies have measured the efficacy of dietary fucoidan (DF) in combination with cancer drugs. Thus, we examined the sensitivity of DF in combination with the EGFR/ERBB2-targeting reagent lapatinib on cancer cells. Method. We selected six EGFR/ERBB2-amplified cancer cell lines (OE19, NCI-N87, OE33, ESO26, MKN7, and BT474) as an in vitro model and tested their sensitivity to DF alone and to DF in combination with the well-known EGFR/ERBB2-targeting reagent lapatinib. Result. Overall, in drug independent sensitivity test, DF alone did not significantly inhibit the growth of EGFR/ERBB2-amplified cancer cells in vitro. When DF was given in combination with lapatinib, however, it tended to synergistically inhibit cell growth in OE33 but antagonized the action of lapatinib in ESO26, NCI-N87, and OE19. Conclusion. This study suggests that DF has the potential to increase or decrease the effects of certain anticancer drugs on certain cancer cell types. Further study is needed to explore the mechanism of interaction and synergistic antitumor activity of DF in combination with chemotherapy and targeted therapy.