COX-1 (cyclooxygenase-1) and COX-2 (cyclooxygenase-2) enzymes control the onset and progression of a number of cancers. COX-1 and COX-2 inhibitors are well known anti-inflammatory enzymes found in plants. Pharmaceutical versions of these two inhibitors are available.
NSAIDs (nonsteroidal anti-inflammatory drugs), such as aspirin, are believed to inhibit cancer by inhibition of COX activity, and long-term use of NSAIDs reduces risk of a number of cancers. Furthermore, routine use of ibuprofen reduces the risk of breast cancer by 50%, and, in a 1999 study, long term use of aspirin reduces the risk by 40%.
The present study was designed to show the activity of COX inhibitors on ovarian cancer in mice. COX-1 has increased activity in ovarian cancer, and COX-2 activity is elevated in colorectal, gastric, breast, thyroid and ovarian cancers. The researchers examined whether a combination of COX-1 and COX-2 inhibitors works better in fighting cancer together than either one does alone.
Mice with ovarian cancer were treated in 3 groups. One group received a COX-1 inhibitor (3 mg/kg SC-560) alone. Another group received a COX-2 inhibitor (25 mg/kg celecoxib) alone. A third group received both the COX-1 and COX-2 inhibitors. Treatments were given twice a day for 3 weeks.
Human ovarian cancer cells were implanted under the skin of mice. After treatment with COX inhibitors, the cancers were removed. The cancers were studied microscopically to determine the effect of the COX-1 and COX-2 inhibitors. The cancer cells were studied with stains designed to evaluate rates of cell apoptosis (cell death by suicide).
The result was that mice which received both COX-1 and COX-2 inhibitors had over 35% tumor growth inhibition. The group which received combination therapy showed that growth of the cancer was “substantially suppressed”. The COX-1 or COX-2 inhibitors taken alone did not prevent ovarian cancer growth. Importantly, the combination therapies resulted in greatly increased rates of apoptosis.
Taken alone, the COX-1 and COX-2 inhibitors each reduced tumor growth by 13.57% and 15.16%. Adding these together yielded 28.73% inhibition, less than the effect of taking both at 35.54%.
CONCLUSION: COX inhibitors and inhibitor combinations are synergistic and show potential for ovarian cancer prevention.
NOTE: Natural COX inhibitors from plants are available, such as grapeseed and grapeskin extracts, scallions and Xyflamend.
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