Regulation of constitutive cyclooxygenase-2 expression in colon carcinoma cells

Jinyi Shao, Hongmiao Sheng, Hiroyasu Inoue, Jason D. Morrow, Raymond N. DuBois

Research output: Contribution to journalArticle

242 Scopus citations

Abstract

Cyclooxygenase-2 (COX-2) is not normally expressed in the human large intestine, but its levels are increased in the majority of human colorectal carcinomas. Here we investigate the regulation of constitutive COX-2 expression and prostaglandin production in human colorectal carcinoma cells. Both COX-2 mRNA and protein were expressed in well differentiated HCA-7, Moser, LS-174, and HT-29 cells, albeit at different levels. COX-2 expression was not detected in several poorly differentiated colon cancer cell lines including DLD-1. Transeriptional regulation played a key role for the expression of COX-2 in human colon carcinoma cells, and both the nuclear factor for interleukin-6 regulatory element and the cAMP-response element were responsible for regulation of COX-2 transcription. COX-2 mRNA was more stable in HCA-7 cells than in the other cell lines tested. Both transcriptional and post-transcriptional regulation of COX-2 involved the MAP kinase pathway. Modulation of the Akt/protein kinase B or Rho B signaling pathways altered the levels of COX-2 expression. Furthermore, COX-2 protein is degraded through ubiquitin proteolysis, and its half-life was ~3.5-8 h. HCA-7 cells produced significant quantities of prostaglandin E2 and other prostaglandins. Moser and LS-174 cells also generated prostaglandins, but levels were significantly lower than that observed in HCA-7 cells.

Original languageEnglish (US)
Pages (from-to)33951-33956
Number of pages6
JournalJournal of Biological Chemistry
Volume275
Issue number43
DOIs
StatePublished - Oct 27 2000

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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