Anti Cox-2 Therapy
WHAT ARE CYCLOOXYGENASE (COX) INHIBITORS
Cyclooxygenase (COX) inhibitors are compounds that block the action of cyclooxygenase enzymes, which are produced in response to inflammation and by precancerous and cancerous tissues. Non-steroidal anti-inflammatory drugs (NSAIDs) reduce pain and inflammation from many medical conditions by inhibiting both of these enzymes (COX-1 and COX-2). NSAIDs that inhibit only COX-2 enzymes were created to allow people to have relief from pain and inflammation while reducing the chances of certain medical problems, such as stomach bleeding, that can occur when NSAIDs are taken regularly for long periods of time.
WHY IS THE NATIONAL CANCER INSTITUTE (NCI) STUDYING COX INHIBITORS IN CANCER PREVENTION AND TREATMENT?
More than a decade of epidemiologic research suggests that people who regularly take drugs that block COX enzymes have lower rates of certain precancers, cancers, and cancer-related deaths. The data are most consistent for colorectal cancer, but this reduction in risk is also seen for other cancers. Laboratory and animal studies using a variety of NSAIDs and COX-2 specific inhibitors show a decrease in cancer incidence with the use of these compounds. On a molecular level, studies have shown that the inhibition of the COX pathway changes the characteristics of cancer cells by reducing cell proliferation, increasing programmed cell death, reducing formation of blood vessels to feed cancer cells, and changing the body's immune response. In addition, a laboratory study of colorectal cancer cells that do not produce COX-2, showed that treating these cells with celecoxib resulted in wide-ranging changes in protein production independent of COX-2. Following celecoxib treatment of these cells, researchers observed global changes in proteins involved in a variety of cellular functions, including metabolism, DNA and protein synthesis, protein folding, and the pattern of chemical decorations added to proteins. These results, published in the September 2006 issue of Cancer Epidemiology Biomarkers and Prevention, help explain the ability of celecoxib to prevent colorectal adenoma formation in the absence of COX-2 and could also potentially provide an explanation for the harmful effects of celecoxib observed when the drug is given at high dose.
WHAT IS CELECOXIB (CELEBREX)
Celecoxib (Celebrex) is a COX-2 inhibiting drug, celecoxib was approved by the U.S. Food and Drug Administration (FDA) for the treatment of both osteoarthritis and adult rheumatoid arthritis (diseases in which the joints are inflamed) in December 1998. Because scientific work suggested the potential for COX-2 inhibitors to prevent and treat cancer, the NCI, part of the National Institutes of Health (NIH), formed agreements to study this drug for the prevention and treatment of a variety of cancers.