Ganoderiol F, a ganoderma triterpene, induces senescence in hepatoma HepG2 cells.

Ganoderiol F (GolF), a tetracyclic triterpene, was isolated from Ganoderma amboinense and found to induce senescence of cancer cell lines. GolF induced growth arrest of cancer cell lines HepG2, Huh7 and K562, but exerted much less effect in hepatoma Hep3B cells and normal lung fibroblast MRC5 cells, and no effect on peripheral blood mononuclear cells. GolF treatment of the cancer cells, with the exception of Hep3B, resulted in prompt inhibition of DNA synthesis and arrest of cell progression cycle in G1 phase. Short-term exposure of HepG2 cells to GolF temporarily arrested progression of the cell cycle; cell growth was recovered if the drug was withdrawn from the medium after a 24-h exposure. After 18 days of continuous treatment of HepG2 cells with 30 muM GolF, over 50% of cells were found to be enlarged and flattened, and were beta-galactosidase positive phenotypes of senescent cells. GolF was found to inhibit activity of topoisomerases in vitro, which may contribute to the inhibition of cellular DNA synthesis. Activation of the mitogen-activated protein kinase EKR and up-regulation of cyclin-dependent kinase inhibitor p16 were found in early stages of GolF treatment and were presumed to cause cell-cycle arrest and trigger premature senescence of HepG2 cells. The growth-arrest and senescence induction capability on cancer cells suggest anticancer potential of GolF.

Ganoderic acid X, a lanostanoid triterpene, inhibits topoisomerases and induces apoptosis of cancer cells.

Lanostanoid triterpenes isolated from Ganoderma amboinense were found to inhibit the growth of numerous cancer cell lines, and some of them inhibited the activities of topoisomerases I and IIalpha in vitro. Among the bioactive isolates, one of the most potent triterpene was identified to be 3 alpha-hydroxy-15 alpha-acetoxy-lanosta-7,9(11),24-trien-26-oic acid, ganoderic acid X (GAX). Treatment of human hepatoma HuH-7 cells with GAX caused immediate inhibition of DNA synthesis as well as activation of ERK and JNK mitogen-activated protein kinases, and cell apoptosis. Molecular events of apoptosis including degradation of chromosomal DNA, decrease in the level of Bcl-xL, the disruption of mitochondrial membrane, cytosolic release of cytochrome c and activation of caspase-3 were elucidated. The ability of GAX to inhibit topoisomerases and to sensitize the cancer cells toward apoptosis fulfills the feature of a potential anticancer drug.

Triterpene-enriched extracts from Ganoderma lucidum inhibit growth of hepatoma cells via suppressing protein kinase C, activating mitogen-activated protein kinases and G2-phase cell cycle arrest.

The medicinal mushroom Ganoderma lucidum (G. lucidum) has been used in the Orient for the prevention and treatment of various diseases including cancer. Except for the immune enhancing properties of its polysaccharide constituent, very little is known about the anticancer activity of another major constituent, triterpenes. In this report, we studied the anticancer mechanism of triterpene-enriched extracts from G. lucidum. The triterpene-enriched fraction, WEES-G6, was prepared from mycelia of G. lucidum by sequential hot water extraction, removal of ethanol-insoluble polysaccharides and then gel-filtration chromatography. We found that WEES-G6 inhibited growth of human hepatoma Huh-7 cells, but not Chang liver cells, a normal human liver cell line. Treatment with WEES-G6 caused a rapid decrease in the activity of cell growth regulative protein, PKC, and the activation of JNK and p38 MAP kinases. The changes in these molecules resulted in a prolonged G2 cell cycle phase and strong growth inhibition. None of these effects were seen in the normal liver cells. Our findings suggest that the triterpenes contained in G. lucidum are potential anticancer agents.