Related Experiment Videos
Cyclooxygenase-2 inhibitors in tumorigenesis (part I)
1Laboratory of Biomedical Genetics, Graduate School of Pharmaceutical Sciences, University of Tokyo, Bunkyo, Japan. taketo@mol.f.u-tokyo.ac.jp
Abstract:
The rate-limiting enzyme in arachidonate metabolism is mediated by enzymes known as cyclooxygenases (COXs). These enzymes catalyze the biosynthesis of prostaglandin H2, the precursor of molecules, such as prostaglandins, prostacyclin, and thromboxanes. The COX enzyme family consists of the classical COX-1 enzyme, which is constitutively expressed in many tissues, and a second enzyme, i.e., COX-2, which is induced by various stimuli, such as mitogens and cytokines, and is involved in many inflammatory reactions. Because nonsteroidal anti-inflammatory drugs inhibit both COX-1 and COX-2, these drugs also cause unwanted side effects, exemplified by gastrointestinal bleeding. Accumulating evidence indicates that nonsteroidal anti-inflammatory drugs can reduce the incidence of colorectal cancers in human and experimental animals and can reduce the polyp number and size in patients with familial adenomatous polyposis. This Part I (of a two-part review) focuses on the discovery of the COXs; their biochemical, molecular, and structural properties; and on the discovery of isozyme-specific inhibitors of COX activity.
Insights
Cyclooxygenases (COX) are key enzymes in arachidonate metabolism. Inhibiting COX enzymes, particularly COX-2, may offer new strategies for preventing colorectal cancers and reducing inflammation.
Area of Science:
- Biochemistry
- Molecular Biology
- Pharmacology
Background:
- Cyclooxygenases (COX) mediate arachidonate metabolism, synthesizing prostaglandin H2, a precursor to prostaglandins, prostacyclin, and thromboxanes.
- COX enzymes include COX-1 (constitutively expressed) and COX-2 (induced by stimuli, involved in inflammation).
- Nonsteroidal anti-inflammatory drugs (NSAIDs) inhibit both COX-1 and COX-2, leading to side effects like gastrointestinal bleeding.
Purpose of the Study:
- To review the discovery and properties of cyclooxygenase enzymes.
- To explore the development of isozyme-specific COX inhibitors.
- To discuss the role of COX enzymes in colorectal cancer and inflammation.
Main Methods:
- Literature review of COX enzyme discovery.
- Analysis of biochemical, molecular, and structural properties of COX enzymes.
- Examination of NSAID mechanisms and their link to colorectal cancer prevention.
Main Results:
- NSAIDs reduce colorectal cancer incidence and polyp burden in patients with familial adenomatous polyposis.
- Evidence suggests a link between COX inhibition and cancer chemoprevention.
- The review focuses on the discovery of COX isozymes and specific inhibitors.
Conclusions:
- Understanding COX enzyme properties is crucial for developing targeted therapies.
- Isozyme-specific COX inhibitors hold promise for reducing inflammation and cancer risk with fewer side effects.
- Further research into COX pathways can lead to novel therapeutic strategies.