[Molecular targets of tea polyphenols and its roles of anticancer drugs in experimental therapy].

ABSTRACT

Tea polyphenols (TPs), major biological active constituents of green tea, exert moderate and selective anticancer effects. Molecular mechanisms of TPs in cancer prevention and treatment involve multiple potential molecular targets. TPs inhibit growth factor receptor-mediated signal transduction pathway, decrease the activities of mitogen activated protein kinases and activator protein transcription factor-1, block nuclear factor-kappaB signaling pathway, reduce proteasome activity, lower overexpression of COX-2, subside dihydrofolate reductase and telomerase, and inhibit DNA methylation and matrix metalloproteinases. Furthermore, TPs enhance the inhibitory effect on the growth of cancers by traditional anticancer drugs or targeted antitumor drugs in vitro and in vivo and reverse multidrug resistances of cancer cells to vincristine, doxorubicin, and 5-fluorouracil. Besides, TPs reduce the nephrotoxicity induced by cisplatin, ameliorate irinotecan-induced side effects in the small intestine of mice, and decrease bleomycin-caused DNA damage in human leukocytes. TPs also increase antitumor activity of vaccine through immunological modulation. TPs play roles of the augmentation of antitumor effects, the reversal of multidrug resistance, and the reduction of side effects of chemotherapeutic drugs. TPs could be used as biochemical modulators in cancer therapy.