The cyclooxygenase inhibitor sulindac sulfide inhibits EP4 expression and suppresses the growth of glioblastoma cells.

Abstract

EP4 expression in human glioblastoma cells correlates with growth on soft agar. The cyclooxygenase inhibitor sulindac sulfide first altered specificity protein-1 (Sp-1) and early growth response gene-1 expression, then increased the expression of nonsteroidal anti-inflammatory drug-activated gene 1 and activating transcription factor 3, and then decreased EP4 expression. EP4 suppression was dependent on blocking the Sp-1 binding sites in the human EP4 promoter. Mutation in the Sp-1 sites in EP4 altered the promoter activity and abolished sulindac sulfide effects. The inhibitory effect of sulindac sulfide on EP4 expression was reversed by PD98059, a mitogen-activated protein/extracellular signal-regulated kinase kinase-1/extracellular signal-regulated kinase inhibitor. Sp-1 phosphorylation was dependent on sulindac sulfide-induced Erk activation. Chromatin immunoprecipitation assay confirmed that Sp-1 phosphorylation decreases Sp-1 binding to DNA and leads to the suppression of EP4. Inhibition of cell growth on soft agar assay was found to be a highly complex process and seems to require not only the inhibition of cyclooxygenase activity but also increased expression of nonsteroidal anti-inflammatory drug-activated gene 1 and activating transcription factor 3 and suppression of EP4 expression. Our data suggest that the suppression of EP4 expression by sulindac sulfide represents a new mechanism for understanding the tumor suppressor activity.

• Authors: Atsushi Kambe, Hiroki Yoshioka, Hideki Kamitani, Takashi Watanabe, Seung Joon Baek, Thomas E Eling
• Journal: Cancer prevention research (Philadelphia, Pa.) (Cancer Prev Res (Phila)) Vol. 2 Issue 12 Pg. 1088-99 (Dec 2009) ISSN: 1940-6215 [Electronic] United States
• PMID: 19934343 (Publication Type: Journal Article, Research Support, N.I.H., Extramural)

Chemical References

• Activating Transcription Factor 3
• Anti-Inflammatory Agents, Non-Steroidal
• Cyclooxygenase Inhibitors
• Early Growth Response Protein 1
• Flavonoids
• NBAS protein, human
• Neoplasm Proteins
• PTGER4 protein, human
• RNA, Messenger
• RNA, Small Interfering
• Receptors, Prostaglandin E
• Receptors, Prostaglandin E, EP4 Subtype
• Sp1 Transcription Factor
• Sulindac
• sulindac sulfide
• Luciferases
• Calcium-Calmodulin-Dependent Protein Kinases
• Mitogen-Activated Protein Kinase 3
• Mitogen-Activated Protein Kinases
• 2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one

Topics

• Activating Transcription Factor 3 (metabolism)
• Anti-Inflammatory Agents, Non-Steroidal (pharmacology)
• Blotting, Western
• Brain Neoplasms (pathology)
• Calcium-Calmodulin-Dependent Protein Kinases (antagonists & inhibitors)
• Chromatin Immunoprecipitation
• Colony-Forming Units Assay
• Cyclooxygenase Inhibitors (pharmacology)
• Early Growth Response Protein 1 (metabolism)
• Flavonoids (pharmacology)
• Glioblastoma (pathology)
• Humans
• Immunoprecipitation
• Luciferases (metabolism)
• Mitogen-Activated Protein Kinase 3 (antagonists & inhibitors, metabolism)
• Mitogen-Activated Protein Kinases (antagonists & inhibitors, metabolism)
• Neoplasm Proteins (metabolism)
• Phosphorylation
• Promoter Regions, Genetic (genetics)
• RNA, Messenger (genetics, metabolism)
• RNA, Small Interfering (pharmacology)
• Receptors, Prostaglandin E (antagonists & inhibitors, genetics, metabolism)
• Receptors, Prostaglandin E, EP4 Subtype
• Reverse Transcriptase Polymerase Chain Reaction
• Sp1 Transcription Factor (metabolism)
• Sulindac (analogs & derivatives, pharmacology)
• Tumor Cells, Cultured