Inhibition of TPA-induced protein kinase C and transcription activator protein-1 binding activities by theaflavin-3,3'-digallate from black tea in NIH3T3 cells

Yen Chou Chen, Yu Chih Liang, Shoei Yn Lin-Shiau, Chi Tang Ho, Jen Kun Lin

研究成果: 雜誌貢獻文章同行評審

53 引文 斯高帕斯(Scopus)

摘要

Tea is one of the most popular beverages in the world. Several reports have shown that both green tea and black tea were able to inhibit tumor cell proliferation in animal models. In this study, we investigated the inhibitory effects of black tea polyphenols including theaflavin (TF-1), the mixture (TF-2) of theaflavin-3-gallate (TF-2a), and theaflavin-3'-gallate (TF-2b), theaflavin-3,3'-digallate (TF-3), thearubigin (TR), and a major green tea polyphenol (-)-epigallocatechin-3-gallate (EGCG) on 12-O- tetradecanoylphorbol 13-acetate (TPA)-induced protein kinase C (PKC) and transcription activator protein-1 (AP-1) binding activities in NIH3T3 cells. On analysis of PKC activity with partial purified preparation, TPA (100 ng/mL) treatment was able to elevate membrane-associated PKC activity ~3- fold, and treatment with TF-3 (20 μM) and EGCG (20 μM) showed 94.5% and 9.4% suppression on TPA-induced PKC activity, respectively. Translocation of PKCα protein from cytosol to membrane was detected in TPA-treated NIH3T3 cells, and TF-3 was able to block its translocation. By in vitro kinase assay using myelin basic protein (MBP) as a PKC-specific substrate, we found that TPA treatment was able to increase PKC kinase activity by detection of phosphorylated MBP protein and TF-3 showed strongest inhibitory effect on its phosphorylation while EGCG was shown to be less effective. We also analyzed the AP-1 binding activity by electrophoretic mobility shift assay and c-Jun gene expression by northern blot and western blot, the results showed that TF-3 is the most potent inhibitor on TPA-induced AP-1 binding activity and c- Jun gene expression among these five tea polyphenols. Our results might provide new molecular basis for understanding the inhibitory effects of tea polyphenols on TPA-mediated tumor promotion.
原文英語
頁(從 - 到)1416-1421
頁數6
期刊Journal of Agricultural and Food Chemistry
47
發行號4
DOIs
出版狀態已發佈 - 4月 1999
對外發佈

ASJC Scopus subject areas

  • 農業與生物科學(雜項)
  • 食品科學
  • 化學(雜項)

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