The complicated interaction of anti-canerous substances in mushroom Ganoderma lucidum (ling zhi, picture) and green tea has been shown to suppress progression and invasiveness of metastatic breast cancers, according to a study carried out at the Cancer Investigation Laboratory, Methodist Study Institute, Indianapolis. Epidemiological studies have suggested that consumption of green tea may possibly lower the risk of a range of cancers. In addition, Ganoderma lucidum has been used for the promotion of well being, longevity and therapy of cancer in standard Chinese medicine.
In the present study, the researchers showed that that extract from green tea increased the anticancer effect of Ganoderma lucidum extract on cell proliferation as well as colony formation of breast cancer cells.
This impact was mediated by the down-regulation of expression of oncogene c-myc in breast cancer cells (MDA-MB-231 cells), i.e. desensitized genes that increase the malignancy of a tumour cell.
Down regulation is the method by which a cell decreases the quantity of receptors to a given hormone or neurotransmitter to lessen its sensitivity to this molecule. This is a locally acting negative feedback mechanism. An improve of receptors is referred to as up regulation.
What is oncogene c-myc? c-myc is a proto-oncogene. An oncogene is a modified gene, or a set of nucleotides that codes for a protein, that increases the malignancy of a tumour cell. Some oncogenes, typically involved in early stages of cancer development, boost the opportunity that a standard cell develops into a tumour cell, possibly resulting in cancer. The proto-oncogene c-myc could play a function in controlling the growth and division of standard cells, and abnormalities of the gene have been implicated in the genesis of a substantial selection of human tumours.
c-myc is expressed in proliferating cells in the body, such as keratinocytes, hepatocytes, bone marrow cells, fibroblasts, and vascular smooth muscle cells. It is repressed when these cells withdraw from the cell cycle.
Despite the fact that individual extract from green tea and Ganoderma lucidum extract independently inhibited adhesion, migration and invasion of the breast cancer cells, their combination demonstrated a synergistic impact, which was mediated by the suppression of secretion of urokinase plasminogen activator (uPA) from breast cancer cells, which plays an crucial role in malignant tumour progression.What is urokinase plasminogen activator receptor (uPAR)? uPAR is a cell-surface molecule that urokinase plasminogen activator (uPA) binds to. When bound to uPAR, uPA is activated converting plasminogen into plasmin. Plasmin digests fibrin, permitting space for endothelial tube formation. The urokinase plasminogen activator system plays a central role in malignant tumour progression. The researchers suggest combined green tea and G. lucidum extracts has the possible to suppress growth and invasiveness of metastatic breast cancers.
[Int J Oncol. 2007 Apr30(four):963-9.]
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