Tumour cell adhesion and integrin expression affected by Ganoderma lucidum

Ganoderma lucidum has been widely used as a miraculous herb for health promotion, especially by cancer patients. It has been known that G. lucidum affects cancer cell activities. We examined the effect of different preparations of G. lucidum spores on malignant human breast carcinoma cell adhesion by treating monolayers of cells with G. lucidum. Our experiments indicated that G. lucidum inhibited cancer cell adhesion to different degrees, which were: sporoderm-broken spores (broken by an enzymatic method) > sporoderm-broken spores (broken by a physical method) > intact spores > buffer control. Similarly, polysaccharides from different G. lucidum sources were used to treat breast carcinoma cells, and its effect on cell adhesion was determined. Polysaccharides isolated from G. lucidum fruiting bodies grown on logs of wood exhibited the greatest inhibitory activity on cell adhesion, an effect that was concentration-dependent. Purified polysaccharides also inhibited cell adhesion to various matrix molecules. Experiments were also done where cells were inoculated on polysaccharide-coated Petri plates. This increased cell adhesion, as compared with BSA and PBS controls, suggests that the polysaccharide interacted with cell surface proteins. Western blot analysis indicated that β1-integrin expression was greatly reduced, while β-actin expression was not affected, suggesting a specific activity of G. lucidum products on β1-integrin.