Cancer chemoprevention by tea polyphenols through modulating signal transduction pathways.

摘要: The action mechanisms of several chemopreventive agents derived from herbal medicine and edible plants have become attractive issues in cancer research. Tea is the most widely consumed beverage worldwide. Recently, actions tea been intensively investigated. It demonstrated that active principles were attributed to their polyphenols. tremendous progress has made elucidating molecular chemoprevention by suppression various tumor biomarkers including growth factor receptor tyrosine kinases, cytokine PI3K, phosphatases, ras, raf, MAPK cascades, N x FB, I B kinase, PKA, PKB, PKC, c-jun, c-fos, c-myc, cdks, cyclins, related transducing proteins polyphenols studied our laboratory others. kinase (IKK) activity LPS-activated murine macrophages (RAW 264.7 cells) was found be inhibited (-) epigallocatechin-3-gallate (EGCG), theaflavin (TF-1), theaflavin-3-gallate (TF-2) theaflavin-3,3'-digallate (TF-3). TF-3 IKK activated more strongly than did other both IKK1 IKK2 prevented degradation macrophage cells. results suggested inhibition could occur a direct effect on IKKs or upstream events signal transduction pathway. blocked phosphorylation IB cytosolic fraction, NFB increases inducible nitric oxide synthase levels macrophage. also activities xanthine oxidase, cyclooxygenase, EGF-receptor protein C. These suggest may exert through suppressing promotion inflammation blocking transduction. this due blockade mitogenic differentiating signals modulating EGFR function, NFkappaB activation as well c-jun c-fos expression.