|Life Extension Update Exclusive |
Tea polyphenols’ mechanism for halting prostate tumor growth and metastasis revealed
A study published in the December 1 2004 issue of the journal Cancer Research (http://cancerres.aacrjournals.org/) revealed mechanisms by which polyphenols derived from green tea not only help prevent the growth of tumors, but aid in preventing their spread.
Researchers from the University of Wisconsin and Case Western Reserve University in Cleveland, Ohio, supplied mice bred to develop prostate cancer with drinking water to which green tea polyphenols had been added over a twenty-four week period. A control group received water without any additives. The mice used in the study had been the subjects of previous research which found an inhibition in prostate cancer and development when the animals were give tea polyphenols.
The current study found a decrease in insulin-like growth factor-1 ( (IGF-1) and an increase in insulin-like growth factor binding protein (IGFBP3) in the prostate glands of the mice who received green tea polyphenols, as well as inhibition of specific cell survival proteins. Elevations of IGF-1 and decreases in its binding protein have been found to be associated with cancer in this model as well as with an increased risk of some human cancers.
The team also found that markers of metastasis were reduced. In addition, vascular endothelial growth factor, a polypeptide that forms new blood vessels, was lowered following treatment with green tea polyphenols. The formation of new blood vessels, or angiogenesis, is necessary for a tumor to receive nutrients and grow.
Senior author Hasan Mukhtar, PhD, of the Department of Dermatology at the University of Wisconsin, stated, "These observations bear significance in light of studies that indicate increased levels of IGF-1 are associated with increased risk of several cancers, such as prostate, breast, lung and colon."
The authors “suggest that IGF-I/IGFBP-3 signaling pathway is a prime pathway for green tea polyphenol-mediated inhibition of prostate cancer that limits the progression of cancer through inhibition of angiogenesis and metastasis.”