Anti-invasive effect of a rare mushroom, Ganoderma colossum , on human hepatoma cells

Ganoderma colossum is a rare species of the Ganodermataceae family with biological activity but has not been widely used to date. Because of its rareness and hard availability, the literature regarding the bioactivity of G. colossum is very limited and the bioactive components in G. colossum have never been explored. In the present study, an ethanol extract was prepared from the fruiting body of a G. colossum strain (EEGC) and then fractionated by reverese-phase high-performance liquid chromatography (HPLC). The inhibitory effects and molecular mechanisms of the EEGC on the phorbol-12-myristate-13-acetate (PMA)-induced invasion of HepG2 cells were investigated. The fractions of the EEGC cannot be totally identified, but the lucidenic acids were considered as the major component. When HepG2 cells were treated with the EEGC, the PMA-induced invasion was reduced in a dose-dependent manner and the PMA-induced matrix metalloproteinase (MMP)-9 was also suppressed at the transcriptional level. The EEGC also showed an inhibitory effect on the PMA-induced phosphorylation of extracellular signal-regulated kinase (ERK1/2) and protein kinase B (Akt) in cytosol, as well as the activator protein-1 (AP-1) and nuclear factor-kappaB (NF-kappaB) levels in the nucleus of HepG2 cells. This study provides the first evidence demonstrating that the EEGC is an effective inhibitior on the PMA-induced invasion of hepatoma cell. The EEGC could be further tested by an in vivo model to verify whether it is effective for the prevention of hepatoma invasion or metastasis.