Inhibition of tumor promoter-induced activator protein 1 activation and cell transformation by tea polyphenols, (-)-epigallocatechin gallate, and theaflavins

Zigang Dong, Wei Ya Ma, Chuanshu Huang, Chung S. Yang

Research output: Contribution to journalArticlepeer-review

348 Scopus citations

Abstract

(-)-Epigallocatechin gallate (EGCG) and theaflavins are believed to be key active components in tea for the chemoprevention against cancer. However, the molecular mechanisms by which EGCG and theaflavins block carcinogenesis are not clear. We have used the JB6 mouse epidermal cell line, a system that has been used extensively as an in vitro model for tumor promotion studies, to examine the anti-tumor promotion effects of EGCG and theaflavins at the molecular level. EGCG and theaflavins inhibited epidermal growth factor- or 12-O-tetradecanoylphorbol-13-acetate-induced cell transformation in a dose- dependent manner. At the dose range (5-20 μM) that inhibited cell transformation, EGCG and theaflavins also inhibited AP-1-dependent transcriptional activity and DNA binding activity. The inhibition of AP-1 activation occurs through the inhibition of a c-Jun NH2-terminal kinase- dependent, but not an extracellular signal-regulated protein kinase (Erk) 1- dependent or Erk2-dependent, pathway. Because the transcription factor AP-1 is important for tumor promoter-induced neoplastic transformation, the inhibitory effects on AP-1 activation by EGCG and theaflavins may further explain the anti-tumor promotion action of these tea constituents.

Original languageEnglish (US)
Pages (from-to)4414-4419
Number of pages6
JournalCancer Research
Volume57
Issue number19
StatePublished - Oct 1 1997

All Science Journal Classification (ASJC) codes

  • Oncology
  • Cancer Research

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