Activating protein 1-mediated cyclooxygenase-2 expression is independent of N-terminal phosphorylation of c-Jun

Lei Chin Chen, Ben Kuen Chen, Wen Chang Chang

Research output: Contribution to journalArticle

22 Citations (Scopus)

Abstract

Transcriptional activation of the cyclooxygenase (COX)-2 gene is responsible for high level of prostaglandin production during inflammation and carcinogenesis. We found previously that c-Jun induction plays a crucial role in epidermal growth factor (EGF)-induced gene expression of COX-2. In this study, the functional role of c-Jun in EGF-induced transcriptional activation of COX-2 in A431 cells was investigated. We found that overexpression of c-Jun N-terminal phosphorylation site mutants had similar stimulatory effects on COX-2 promoter activity and protein expression as c-Jun wild type. TAM-67, a mutant of c-Jun that lacks the N-terminal transactivation domain of c-Jun, also enhanced COX-2 promoter activity and protein expression in cells treated with EGF. In vitro DNA affinity precipitation and reporter assays revealed that regulation of c-Jun C terminus by EGF enhanced c-Jun binding to COX-2 promoter and induced COX-2 expression. Furthermore, we demonstrated that c-Fos, which provides transactivation function in Jun/Fos heterodimer, was required for EGF-induced expression of COX-2. These results indicated that c-Jun N-terminal phosphorylation was not required for EGF-induced expression of COX-2. c-Jun, which could recruit other transcription factors such as c-Fos, was required for EGF-induced expression of COX-2 in A431 cells.

Original languageEnglish
Pages (from-to)2057-2069
Number of pages13
JournalMolecular Pharmacology
Volume67
Issue number6
DOIs
Publication statusPublished - Jun 2005
Externally publishedYes

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ASJC Scopus subject areas

  • Pharmacology

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