Abstract
Cyclooxygenase (COX), the key regulatory enzyme for prostaglandin synthesis is transcribed from two distinct genes. COX-1 is expressed constitutively in most tissues, and COX-2 is induced by a wide variety of stimuli and was initially identified as an immediate-early growth response gene. In addition, COX-2 expression is markedly increased in 85-90% of human colorectal adenocarcinomas, whereas COX-1 levels remain unchanged. Several epidemiological studies have reported a 40-50% reduction in the risk of developing colorectal cancer in persons who chronically take such nonsteroidal anti-inflammatory drugs (NSAIDs) as aspirin, which are classic inhibitors of cyclooxygenase. Genetic evidence also supports a role for COX-2, since mice null for COX-2 have an 86% reduction in tumor multiplicity in a background containing a mutated APC allele. These results strongly suggest that COX-2 contributes to the development of intestinal tumors and that inhibition of COX is chemo-preventative.
MeSH terms
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Animals
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Anti-Inflammatory Agents, Non-Steroidal / pharmacology
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Anti-Inflammatory Agents, Non-Steroidal / therapeutic use
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Aspirin / pharmacology
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Aspirin / therapeutic use
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Cyclooxygenase 2
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Cyclooxygenase 2 Inhibitors
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Cyclooxygenase Inhibitors / pharmacology*
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Cyclooxygenase Inhibitors / therapeutic use
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Gene Expression Regulation, Neoplastic
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Genetic Predisposition to Disease
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Humans
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Intestinal Neoplasms / enzymology*
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Intestinal Neoplasms / etiology
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Intestinal Neoplasms / genetics
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Intestinal Neoplasms / prevention & control
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Isoenzymes / genetics
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Isoenzymes / metabolism*
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Isoenzymes / pharmacology
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Membrane Proteins
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Mice
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Mice, Knockout
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Prostaglandin-Endoperoxide Synthases / genetics
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Prostaglandin-Endoperoxide Synthases / metabolism*
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Prostaglandin-Endoperoxide Synthases / pharmacology
Substances
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Anti-Inflammatory Agents, Non-Steroidal
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Cyclooxygenase 2 Inhibitors
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Cyclooxygenase Inhibitors
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Isoenzymes
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Membrane Proteins
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Cyclooxygenase 2
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PTGS2 protein, human
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Prostaglandin-Endoperoxide Synthases
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Aspirin