7-Hydroxy-6,8-dimethoxy-2H-1-benzopyran-2-one (isofraxidin) is a major coumarin component isolated from the stem bark of Acanthopanax senticosus, a widely used Chinese medicinal herb. We investigated isofraxidin in its anti-tumor effects on human hepatoma cell lines HuH-7 and HepG2. Isofraxidin significantly inhibited hepatoma cell invasion, without affecting cell attachment or growth. Expression of 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced matrix metalloproteinase-7 (MMP-7) in hepatoma cells was inhibited by isofraxidin at the both mRNA and protein levels. This inhibition tended to be greater in cells inoculated at low density than in those at high density. Isofraxidin showed an inhibitory effect on the phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2) in hepatoma cells, whereas activator protein-1 (AP-1) DNA binding activity, nuclear factor-kappa B (NF-κB) nuclear translocation, and inhibitory kappa B (IκB) degradation were affected very little. These results indicate that isofraxidin inhibits expression of MMP-7 and in vitro cell invasion at a non-toxic level through inhibiting ERK1/2 phosphorylation in hepatoma cell lines, which suggest isofraxidin might become an effective agent for suppressing hepatoma cell invasion.
2010 The Pharmaceutical Society of Japan