hispolon and Liver-Neoplasms

Hispolon is an active phenolic compound of Phellinus igniarius , a mushroom that has recently been shown to have antioxidant, anti-inflammatory, and anticancer activities. This study investigated the antiproliferative effect of hispolon on human hepatocellular carcinoma Hep3B cells by using the MTT assay, DNA fragmentation, DAPI (4,6-diamidino-2-phenylindole dihydrochloride) staining, and flow cytometric analyses. Hispolon inhibited cellular growth of Hep3B cells in a time-dependent and dose-dependent manner, through the induction of cell cycle arrest at S phase measured using flow cytometric analysis and apoptotic cell death, as demonstrated by DNA laddering. Hispolon-induced S-phase arrest was associated with a marked decrease in the protein expression of cyclins A and E and cyclin-dependent kinase (CDK) 2, with concomitant induction of p21waf1/Cip1 and p27Kip1. Exposure of Hep3B cells to hispolon resulted in apoptosis as evidenced by caspase activation, PARP cleavage, and DNA fragmentation. Hispolon treatment also activated JNK, p38 MAPK, and ERK expression. Inhibitors of ERK (PB98095), but not those of JNK (SP600125) and p38 MAPK (SB203580), suppressed hispolon-induced S-phase arrest and apoptosis in Hep3B cells. These findings establish a mechanistic link between the MAPK pathway and hispolon-induced cell cycle arrest and apoptosis in Hep3B cells.

Topics: Apoptosis; Basidiomycota; Carcinoma, Hepatocellular; Catechols; Cell Cycle; Cell Line, Tumor; Enzyme Inhibitors; Extracellular Signal-Regulated MAP Kinases; Humans; Liver Neoplasms; Phosphorylation

Cancer metastasis is a primary cause of cancer death. Hispolon is an active phenolic compound of Phellinus linteus, a mushroom that has recently been shown to have antioxidant and anticancer activities. In this study, we first observed that hispolon exerted a dose-dependent inhibitory effect on invasion and motility, but not on adhesion, of the highly metastatic SK-Hep1 cells in the absence of cytotoxicity. Mechanistically, hispolon decreased the expression of matrix metalloproteinase-2 (MMP-2), matrix metalloproteinase-9 (MMP-9), and urokinase-plasminogen activator (uPA) in a concentration-dependent manner. Hispolon also inhibited phosphorylation of extracellular signaling-regulating kinase1/2 (ERK1/2), phosphatidylinositol-3-kinase/serine/threonine protein kinase (or protein kinase B (PI3K/Akt), and focal adhesion kinase (FAK). Furthermore, treatment of SK-Hep1 cells with an inhibitor specific for ERK1/2 (PD98256) decreased the expression of MMP-2, and MMP-9. These results demonstrate that hispolon can inhibit the metastasis of SK-Hep1 cells by reduced expression of MMP-2, MMP-9, and uPA through the suppression of the FAK signaling pathway and of the activity of PI3K/Akt and Ras homologue gene family, member A (RhoA). These findings suggest that hispolon may be used as an antimetastatic agent.

Topics: Carcinoma, Hepatocellular; Catechols; Cell Adhesion; Cell Line, Tumor; Cell Movement; Humans; Liver Neoplasms; Magnetic Resonance Spectroscopy; Matrix Metalloproteinase Inhibitors; Neoplasm Metastasis; Protein Kinases; Signal Transduction; Urokinase-Type Plasminogen Activator