Induction of Egr-1 is associated with anti-metastatic and anti-invasive ability of β-lapachone in human hepatocarcinoma cells

beta-lapachone, a quinone compound obtained from the bark of the lapacho tree (Tabebuia avellanedae), was reported to have anti-inflammatory and anti-cancer activities. In this study, we investigated novel functions of beta-lapachone in terms of anti-metastasis and antiinvasion abilities using human hepatocarcinoma cell lines, HepG2 and Hep3B. beta-lapachone dose-dependently inhibited cell viability and migration of both HepG2 and Hep3B cells, as determined by methylthiazoletetrazolium (MTT) assay and wound healing assay. RT-PCR and Western blot data revealed that beta-lapachone dramatically increased the levels of protein, as well as mRNA expression of early growth response gene-1 (Egr-1) and throbospondin-1 (TSP-1) at an early point in time, and then decreased in a time-dependent manner. In addition, down-regulation of Snail and up-regulation of E-cadherin expression were observed in beta-lapachonetreated HepG2 and Hep3B cells, and this the associated with decreased invasive ability as measured by matrigel invasion assay. Taken together, our results strongly suggest that beta-lapachone may be expected to inhibit the progression and metastasis of hepatoma cells, at least in part by inhibiting the invasive ability of the cells via up-regulation of the expression of the Egr-1, TSP-1, and E-cadherin.