Genistein inhibits phorbol ester-induced NF-κB transcriptional activity and COX-2 expression by blocking the phosphorylation of p65/RelA in human mammary epithelial cells

Mutat Res. 2014 Oct;768:74-83. doi: 10.1016/j.mrfmmm.2014.04.003. Epub 2014 Apr 15.

Abstract

Genistein, an isoflavone present in soy products, has chemopreventive effects on mammary carcinogenesis. In the present study, we have investigated the effects of genistein on phorbol ester-induced expression of cyclooxygenase-2 (COX-2) that plays an important role in the pathophysiology of inflammation-associated carcinogenesis. Pretreatment of cultured human breast epithelial (MCF10A) cells with genistein reduced COX-2 expression induced by 12-O-tetradecanoylphorbol-13-acetate (TPA). There are multiple lines of evidence supporting that the induction of COX-2 is regulated by the eukaryotic transcription factor NF-κB. Genistein failed to inhibit TPA-induced nuclear translocation and DNA binding of NF-κB as well as degradation of IκB. However, genistein abrogated the TPA-induced transcriptional activity of NF-κB as determined by the luciferase reporter gene assay. Genistein inhibited phosphorylation of the p65 subunit of NF-κB and its interaction with cAMP regulatory element-binding protein-binding protein (CBP)/p300 and TATA-binding protein (TBP). TPA-induced NF-κB phosphorylation was abolished by pharmacological inhibition of extracellular signal-regulated kinase (ERK). Likewise, pharmacologic inhibition or dominant negative mutation of ERK suppressed phosphorylation of p65. The above findings, taken together, suggest that genistein inhibits TPA-induced COX-2 expression in MCF10A cells by blocking ERK-mediated phosphorylation of p65 and its subsequent interaction with CBP and TBP.

Keywords: Chemoprevention; Cyclooxygenase-2; Genistein; MCF10A cells; NF-κB.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Active Transport, Cell Nucleus / drug effects
  • Active Transport, Cell Nucleus / genetics
  • Anticarcinogenic Agents / pharmacology*
  • CREB-Binding Protein
  • Carcinogens / pharmacology*
  • Cell Line, Tumor
  • Cell Nucleus / genetics
  • Cell Nucleus / metabolism*
  • Cyclooxygenase 2 / biosynthesis*
  • Cyclooxygenase 2 / genetics
  • Extracellular Signal-Regulated MAP Kinases / genetics
  • Extracellular Signal-Regulated MAP Kinases / metabolism
  • Female
  • Gene Expression Regulation, Enzymologic / drug effects*
  • Genistein / pharmacology*
  • Humans
  • Mammary Glands, Human
  • Mutation
  • Tetradecanoylphorbol Acetate / pharmacology*
  • Transcription Factor RelA / metabolism*

Substances

  • Anticarcinogenic Agents
  • Carcinogens
  • RELA protein, human
  • Transcription Factor RelA
  • Genistein
  • Cyclooxygenase 2
  • PTGS2 protein, human
  • CREB-Binding Protein
  • CREBBP protein, human
  • Extracellular Signal-Regulated MAP Kinases
  • Tetradecanoylphorbol Acetate