Bryostatin-1 Stimulates the Transcription of Cyclooxygenase-2: Evidence for an Activator Protein-1-Dependent Mechanism

Mariana S. De Lorenzo, Kentaro Yamaguchi, Kotha Subbaramaiah, Andrew Dannenberg

Research output: Contribution to journalArticle

16 Scopus citations

Abstract

Bryostatin-1 (bryostatin) is a macrocyclic lactone derived from Bugula neritina, a marine bryozoan. On the basis of the strength of in vitro and animal studies, bryostatin is being investigated as a possible treatment for a variety of human malignancies. Severe myalgias are a common dose-limiting side effect. Because cyclooxygenase-2 (COX-2)-derived prostaglandins can cause pain, we investigated whether bryostatin induced COX-2. Bryostatin (1-10 nM) induced COX-2 mRNA, COX-2 protein, and prostaglandin biosynthesis. These effects were observed in macrophages as well as in a series of human cancer cell lines. Transient transfections localized the stimulatory effects of bryostatin to the cyclic AMP response element of the COX-2 promoter. Electrophoretic mobility shift assays and supershift experiments revealed a marked increase in the binding of activator protein-1 (AP-1)(c-Jun/c-Fos) to the cyclic AMP response element of the COX-2 promoter. Pharmacological and transient transfection studies indicated that bryostatin stimulated COX-2 transcription via the protein kinase C→mitogen-activated protein kinase→AP-1 pathway. All-trans-retinoic acid, a prototypic AP-1 antagonist, blocked bryostatin-mediated induction of COX-2. Taken together, these results suggest that bryostatin-mediated induction of COX-2 can help to explain the myalgias that are commonly associated with treatment. Moreover, it will be worthwhile to evaluate whether the addition of a selective COX-2 inhibitor can increase the antitumor activity of bryostatin.

Original languageEnglish (US)
Pages (from-to)5036-5043
Number of pages8
JournalClinical Cancer Research
Volume9
Issue number13
StatePublished - Oct 15 2003

ASJC Scopus subject areas

  • Oncology
  • Cancer Research

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