Roles of ERK and p38 mitogen-activated protein kinases in phorbol ester-induced NF-κB activation and COX-2 expression in human breast epithelial cells

Jung Hwan Kim, Hye Kyung Na, Youngmi K. Pak, Yun Sil Lee, Su Jae Lee, Aree Moon, Young Joon Surh

Research output: Contribution to journalArticlepeer-review

30 Scopus citations


Inappropriate up-regulation of cyclooxygenase-2 (COX-2) has been implicated in pathogenesis of various types of human cancer. Thus, COX-2 has been recognized as an important target for the chemoprevention of several human malignancies including breast cancer. COX-2 expression is known to be regulated by the eukaryotic transcription factor NF-κB. In an attempt to link the NF-κB activation and COX-2 induction during mammary carcinogenesis, we have examined the effects of 12-O-tetradecanoylphorbol-13-acetate (TPA), a prototype tumor promoter and a mitogen, on NF-κB activation and COX-2 expression in the immortalized human breast epithelial cell line (MCF10A). Treatment of MCF10A cells with TPA resulted in transient induction of NF-κB DNA binding with maximal activation observed at 30 min. Increased DNA binding of NF-κB was accompanied by enhancement of its transcriptional activity as determined by the luciferase reporter gene assay. Under the same experimental conditions, expression of COX-2 mRNA and its protein product peaked at 2 h and 4 h, respectively. TPA treatment caused an increase in the production of prostaglandin E2. Treatment of cells with the NF-κB inhibitor pyrrolidine dithiocarbamate resulted in significant suppression of TPA-induced COX-2 expression. TPA induced activation of ERK1/2 and p38 mitogen-activated protein kinases (MAPK) via phosphorylation. PD98059 (ERK inhibitor) and SB203580 (p38 MAPK inhibitor) down-regulated the COX-2 expression induced by TPA. Furthermore, TPA-induced COX-2 induction as well as NF-κB activation was blocked in MCF10A cells transfected with dominant negative mutant ERK1/2 or p38 MAPK. These results suggest that both p38 and ERK MAPKs activates NF-κB signaling, which in turn induces COX-2 expression in TPA-stimulated human mammary epithelial cells.

Original languageEnglish
Pages (from-to)133-141
Number of pages9
JournalChemico-Biological Interactions
Issue number2
StatePublished - 30 Jan 2008

Bibliographical note

Funding Information:
This work was supported by the National Research Laboratory fund (to Y.–J. Surh), Ministry of Science and Technology, Republic of Korea.


  • Chemoprevention
  • Cyclooxygenase-2
  • Human breast epithelial cells
  • Mitogen-activated protein kinase
  • NF-κB
  • Phorbol ester


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