Regulation of Nrf2- and AP-1-mediated gene expression by epigallocatechin-3-gallate and sulforaphane in prostate of Nrf2-knockout or C57BL/6J mice and PC-3 AP-1 human prostate cancer cells

Acta Pharmacol Sin. 2010 Sep;31(9):1223-40. doi: 10.1038/aps.2010.147. Epub 2010 Aug 23.

Abstract

Aim: To examine the regulatory crosstalk between the transcription factors Nrf2 and AP-1 in prostate cancer (PCa) by dietary cancer chemopreventive compounds (-)epigallocatechin-3-gallate (EGCG) from green tea and sulforaphane (SFN) from cruciferous vegetables.

Methods: We performed (i) in vitro studies including luciferase reporter gene assays, MTS cell viability assays, and quantitative real-time PCR (qRT-PCR) in PC-3 AP-1 human PCa cells, (ii) in vivo temporal (3 h and 12 h) microarray studies in the prostate of Nrf2-deficient mice that was validated by qRT-PCR, and (iii) in silico bioinformatic analyses to delineate conserved Transcription Factor Binding Sites (TFBS) in the promoter regions of Nrf2 and AP-1, as well as coregulated genes including ATF-2 and ELK-1.

Results: Our study shows that AP-1 activation was attenuated by the combinations of SFN (25 micromol/L) and EGCG (20 or 100 micromol/L) in PC-3 cells. Several key Nrf2-dependent genes were down-regulated (3-fold to 35-fold) after in vivo administration of the combination of EGCG (100 mg/kg) and SFN (45 mg/kg). Conserved TFBS signatures were identified in the promoter regions of Nrf2, AP-1, ATF2, and ELK-1 suggesting a potential regulatory mechanism of crosstalk between them.

Conclusion: Taken together, our present study of transcriptome profiling the gene expression changes induced by dietary phytochemicals SFN and EGCG in Nrf2-deficient mice and in PC-3 cells in vitro demonstrates that the effects of SFN+EGCG could be mediated via concerted modulation of Nrf2 and AP-1 pathways in the prostate.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Anticarcinogenic Agents / pharmacology*
  • Antineoplastic Combined Chemotherapy Protocols
  • Binding Sites
  • Catechin / analogs & derivatives*
  • Catechin / pharmacology
  • Cell Line, Tumor
  • Cell Survival / drug effects
  • Gene Expression Regulation, Neoplastic / drug effects*
  • Humans
  • Isothiocyanates
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • NF-E2-Related Factor 2 / genetics*
  • NF-E2-Related Factor 2 / metabolism
  • Promoter Regions, Genetic
  • Prostatic Neoplasms / drug therapy*
  • Prostatic Neoplasms / genetics
  • Sulfoxides
  • Thiocyanates / pharmacology*
  • Transcription Factor AP-1 / genetics*
  • Transcription Factor AP-1 / metabolism

Substances

  • Anticarcinogenic Agents
  • Isothiocyanates
  • NF-E2-Related Factor 2
  • Sulfoxides
  • Thiocyanates
  • Transcription Factor AP-1
  • Catechin
  • epigallocatechin gallate
  • sulforaphane