Antimetastatic activity of polyphenol-rich extract of Ecklonia cava through the inhibition of the Akt pathway in A549 human lung cancer cells

An ethyl acetate extract (ECE) of a brown alga, Ecklonia cava, was examined for its anti-metastatic effect, using A549 human lung carcinoma cells. ECE treatment significantly suppressed the migration and invasion of A549 cells in a concentration-dependent manner. It also strongly down-regulated the matrix metalloproteinase (MMP)-2 activity of the cancer cells by gelatin zymography assay. For elucidating its mechanism of action in cancer cell metastasis, ECE was further investigated for various cell signalling pathways, including JNK, ERK, p38, and Akt. In this, ECE showed an anti-metastatic effect in a concentration- and time-dependent manner by the mechanism of suppression of Akt and p38, but not JNK and ERK. These results, for the first time, suggest that ECE (a polyphenol-enriched, highly anti-oxidative fraction of brown alga, E. cava) may have therapeutic potential in metastatic lung cancer, based on its strong inhibitory effects on the migration and invasiveness of A549 human lung adenocarcinoma cells.