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Modeling Colitis-Associated Cancer with Azoxymethane AOM and Dextran Sulfate Sodium DSS
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Increased cyclooxygenase-2 levels in carcinogen-induced rat colonic tumors

R N DuBois1, A Radhika, B S Reddy

  • 1Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA.

Gastroenterology
|April 1, 1996
PubMed
Abstract

Insights

Nonsteroidal anti-inflammatory drugs (NSAIDs) may prevent colon cancer by targeting cyclooxygenase-2 (COX-2). This study found elevated COX-2 gene expression in rodent colon tumors, suggesting COX-2 as a potential chemopreventive target.

Area of Science:

  • Molecular biology
  • Cancer research
  • Pharmacology

Background:

  • Nonsteroidal anti-inflammatory drugs (NSAIDs) are linked to reduced colon cancer risk.
  • Cyclooxygenase (COX) enzymes, specifically COX-1 and COX-2, are implicated targets of NSAIDs.
  • Previous research suggests a role for NSAIDs in cancer prevention.

Purpose of the Study:

  • To investigate the differential expression of COX-1 and COX-2 in colonic tumors.
  • To determine if COX-2 is upregulated in a rodent model of colon cancer.
  • To assess the potential of COX-2 as a therapeutic target for colorectal cancer.

Main Methods:

  • Northern blot analysis was used to quantify COX-1 and COX-2 messenger RNA (mRNA) levels in tumor and normal colonic tissues.
  • Western blotting was employed to measure COX-2 protein expression.
  • Azoxymethane-treated rats served as the model for colon carcinogenesis.

Main Results:

  • COX-2 mRNA levels were significantly elevated in six out of six colonic tumors compared to adjacent normal mucosa.
  • COX-1 mRNA levels remained consistent between tumor and normal tissues.
  • Increased COX-2 protein levels were observed in four out of five colonic tumor samples.

Conclusions:

  • Gene expression of COX-2, but not COX-1, is markedly upregulated in most colonic tumors in this rodent model.
  • These findings highlight COX-2 as a promising molecular target for colorectal cancer chemoprevention strategies.

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