Affiliations: Saitama Cancer Center Research Institute, Ina,
Kitaadachi-gun, Saitama 362-0806, Japan
Note: [] Present address: Saga Medical School, 5-1-1 Nabeshima, Saga
849-0937, Japan
Note: [] Saitama Cancer Center Research Institute, Ina, Kitaadachi-gun,
Saitama 362-0806, Japan. Fax: +81 48 722 1739
Abstract: Among various biochemical and biological activities of tea
polyphenols, we believe inhibition of the expression and release of tumor
necrosis factor-\alpha (TNF-\alpha) is
crucial, since our study with TNF-\alpha-deficient mice has
revealed that TNF-\alpha is an essential factor in tumor
promotion. We found that EGCG dose-dependently inhibited AP-1 and
NF-\kappaB activation in BALB/3T3 cells treated with okadaic
acid, resulting in inhibition of TNF-\alpha gene expression.
Furthermore, treatment with 0.1% gene expression as well as
TNF-\alpha protein level in the lung of
TNF-\alpha transgenic mice; and IL-1\beta
and IL-10 gene expression in the lung was also inhibited by treatment with
green tea extract, indicating that green tea inhibits both
TNF-\alpha and the cytokines induced by
TNF-\alpha in organs. We recently found synergistic effects
of EGCG and cancer preventive agents such as tamoxifen and sulindac, on cancer
preventive activity. Taken together, the results show that green tea is
efficacious as a non-toxic cancer preventive for humans.
