An Edible, High Molecular Weight Glycoprotein Fraction from Ganoderma Lucidum Inhibits the Akt Pathway in Resistant Myeloma Cell Lines Decreasing Mcl-1 Expression, Up-Regulating FKHR and Inducing Apoptosis.

We observed apparent synergy between dexamethsone and a nutritional supplement taken by a patient with poor prognosis plasma cell leukima. The rapidity of the clinical remission induction and the duration of remission, which was sustained without consolidation, suggested possible inhibition of the Akt pathway. A review of the supplements ingested indicated two mycelial derivatives, one of which was Ganoderma Lucidum, (Ling-Zhi, Reishi) a traditional Chinese medicine used to prevent kidney and liver disease and to promote anti-tumor immunity. We obtained a known quantity of certified shell broken spore of G Lucidum from China. Dissolved in 70 degree C water and then diluted as a 2.5% v/v solution in RPMI1640, it induced apoptosis of 80% of OPM6 cells by 72 hours, which was only marginally improved by the addition of1uM dexamethasone. It induced 70% cell death in MM.R cells by 72 hours. This was associated with a 90% reduction in measurable Mcl-1 by Western blot after two hours of incubation. In additon phosphorylation of FKHR was reduced 70% at 2 hours and was undetectable after 72 hours. Phosphorylation of Akt at threonine 308 was reduced 75%. To further purify this activity we separated out molecular weight fractions by Centricon centrifugation. We were able to 10 fold concentrate the active material in the >100,000 MW fraction by centrifugation. Used in the same relative dilution of 2.5% v/v, this concentrate killed between 90% and 96% of glucocorticoid resistant cells at 72 houyrs. Of interest the concentrate induced a lesser degree of apoptosis in corticosteroid sensitive cells, but enhanced the activity of dexamethasone. Spectrophotometry followed by oxidation with sodium meta-periodate and measurement absorption at 550 nm suggested a glycoprotein enrichment in this concentration. Further isolation of the active component of this fraction is underway in order to determine if it is the Lin-Zhi 8 protein sequenced in 1991 or a distinct glycoprotein from the Ganoderma Lucidum. It appears to be an orally tolerable inhibitor of the Akt pathway. It also shows activty in rheumatoid arthritis synovium RAS cells and may have usefulness in T cell supression and graft tolerance.Pre-clinical testing in a SCID mouse model has been begun.