Gloiopeltis furcata is a kind of edible seaweed that mainly grows in the temperate seaside areas of the northwest pacific including Korea, Japan and China, and has been known to exert pharmacological activities including antioxidant, antimutagenic and anticancer activity. However, the molecular mechanisms of G. furcata in malignant cells have not been clearly elucidated yet. In this study, it was investigated the effects of ethyl methanol extract of G. furcata (MEGF) on the anti-proliferative effects of U937 human leukemia cells. MEGF treatment resulted in a concentration-dependent growth inhibition by including apoptosis, which could be proved by MTT assay, DAPI staining, agarose gel electrophoresis and flow cytometry analysis. The increase in apoptosis induced by MEGF treatment was correlated with up-regulation of pro-apoptotic Bax expression and down-regulation of anti-apoptotic Bcl-2 and Bcl-xL expression. MEGF treatment inhibited the levels of IAP family members such as XIAP and cIAP-1 and induced the proteolytic activation of caspase-3 and caspase-9, and a concomitant degradation of poly (ADP-ribose) polymerase and Ղ-catenin. Taken together, these findings provide important new insights into the possible molecular mechanisms of the anti-cancer activity of G. furcata. (Cancer Prev Res 14, 274-281, 2009)

Keywords: Gloiopeltis furcata, U937, Apoptosis, Bax, Caspase