Cyclooxygenase-2 Inhibitors Down-Regulate Osteopontin and Nr4A2-new Therapeutic Targets for Colorectal Cancers

Gastroenterology. 2009 Oct;137(4):1358-66.e1-3. doi: 10.1053/j.gastro.2009.06.039. Epub 2009 Jun 21.

Abstract

Background & aims: Cyclooxygenase-2 inhibitors reduce colon cancer risk by mechanisms that are not fully understood. We performed microarray analysis of adenomas from Apc(Delta14/+) mice to identify genes that respond to these drugs.

Methods: Apc(Delta14/+) mice were given a single daily injection of parecoxib for up to 9 weeks; intestinal tracts of these and control mice were analyzed by microarray analysis, immunohistochemistry, in situ hybridization, and quantitative real-time polymerase chain reaction. Findings were further assessed using Apc(lox/lox)vil-CreER(T2) mice, the CT26 cancer cell line, and human colon tumor samples.

Results: Microarray analysis revealed that osteopontin, a marker of colon cancer progression, was down-regulated in polyps from Apc(Delta14/+) mice given parecoxib compared with controls. Apc(Delta14/+) mice given parecoxib had longer survival times and reduced polyp burdens. Osteopontin was quickly down-regulated by parecoxib in intestinal polyps from Apc(Delta14/+) mice, and 2 components of the osteopontin regulatory network-the orphan nuclear receptor NR4A2 and Wnt/beta-catenin signaling-were sequentially repressed. NR4A2 activated the osteopontin promoter in CT26 cells; this effect was blocked by mutation of the NR4A2 binding response element, cotransfection of a dominant-negative form of NR4A2, and small inhibitory RNA against NR4A2. NR4A2 levels were increased throughout tumor progression in Apc(Delta14/+) mice but, unlike osteopontin, did not correlate with tumor stage. NR4A2 levels were reduced in adenomas from patients treated with rofecoxib.

Conclusions: Down-regulation of osteopontin, probably through blockade of NR4A2 and Wnt signaling, is an important component of the antitumor activity of cyclooxygenase-2 inhibitors. These factors might be developed as therapeutic targets for intestinal cancers.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenomatous Polyposis Coli / drug therapy*
  • Adenomatous Polyposis Coli / enzymology
  • Adenomatous Polyposis Coli / genetics
  • Animals
  • Antineoplastic Agents / pharmacology*
  • Cell Line, Tumor
  • Cell Survival
  • Colonic Polyps / drug therapy*
  • Colonic Polyps / enzymology
  • Colonic Polyps / genetics
  • Colorectal Neoplasms / drug therapy*
  • Colorectal Neoplasms / enzymology
  • Colorectal Neoplasms / genetics
  • Cyclooxygenase 2 / metabolism*
  • Cyclooxygenase Inhibitors / therapeutic use*
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism*
  • Down-Regulation
  • Gene Expression Profiling / methods
  • Gene Expression Regulation, Neoplastic
  • Genes, APC
  • Humans
  • Isoxazoles / therapeutic use
  • Lactones / therapeutic use
  • Mice
  • Mice, Mutant Strains
  • Nuclear Receptor Subfamily 4, Group A, Member 2
  • Oligonucleotide Array Sequence Analysis
  • Osteopontin / genetics
  • Osteopontin / metabolism*
  • Promoter Regions, Genetic
  • RNA Interference
  • Signal Transduction
  • Sulfones / therapeutic use
  • Time Factors
  • Transcription Factors / genetics
  • Transcription Factors / metabolism*
  • Transfection
  • Wnt Proteins / metabolism
  • beta Catenin / metabolism

Substances

  • Antineoplastic Agents
  • CTNNB1 protein, mouse
  • Cyclooxygenase Inhibitors
  • DNA-Binding Proteins
  • Isoxazoles
  • Lactones
  • NR4A2 protein, human
  • Nr4a2 protein, mouse
  • Nuclear Receptor Subfamily 4, Group A, Member 2
  • SPP1 protein, human
  • Spp1 protein, mouse
  • Sulfones
  • Transcription Factors
  • Wnt Proteins
  • beta Catenin
  • rofecoxib
  • Osteopontin
  • parecoxib
  • Ptgs2 protein, mouse
  • Cyclooxygenase 2
  • PTGS2 protein, human