According to People's Daily Online: Zhou Yongchang, director of the Department of Breast Surgery at the University of Hong Kong Medical Center, began researching the use of epoxide (COX-2) inhibitors in 2008 to inhibit the proliferation of cancer cells and control the disease.
Zhou Yongchang and his researchers are currently conducting Phase III clinical research on this therapy. About 500 mid-term breast cancer patients from Queen Mary Hospital and Donghua Hospital in Hong Kong participated. Studies have shown that inhibitors have a good effect on inhibiting vascular proliferation of cancer cells and have no adverse effects on normal blood vessels.
Zhou Yongchang explained that when cancer cells grow up to one to two millimeters, they secrete substances to make blood vessels proliferate, providing nutrients to cancer cells to help continue to grow and increase. Studies have shown that vascular proliferation has also become a way for cancer cells to spread, until cancer cells metastasize to other organs, making the disease worse. Therefore, cutting off the blood source of the
tumor can cut off the required nutrients, causing the tumor to shrink or even disappear. Angiogenesis is a new oncology study, and COX-2 inhibitors are enzymes that delay or prevent the formation of blood vessels.
COX-2: tumor growth promoter
COX is a 70kD glycoprotein located on the cell membrane, encoded by two different genes, the products encoded by the genes are COX-1 and COX-2; under normal circumstances, COX-1 is in most tissues. Expression to maintain the body's physiological function; while COX-2 is not expressed, in some pathological conditions, such as inflammation or tumors, the expression of COX-2 rapidly increased. The stronger the inhibition of COX-1, the greater the adverse reactions caused; the stronger the inhibition of COX-2, the more significant the anti-tumor, anti-inflammatory and analgesic effects.
Early studies have found that COX-2 is associated with mucosal repair of gastritis, gastric ulcer and enteritis, and its role in the development of tumors has received increasing attention in recent years.
COX-2 is not only a key enzyme to initiate inflammatory response, but also participates in the development and progression of malignant tumors by promoting cell proliferation, inhibiting apoptosis, promoting tumor neovascularization, promoting tumor cell infiltration, promoting invasion, and promoting inflammation. process.
Studies have shown that COX-2 selective inhibitors can significantly inhibit tumor growth and tumor angiogenesis, induce tumor cell apoptosis, and also enhance the cytotoxicity of chemotherapy drugs and tumor radiosensitivity.
For example, the molecularly targeted drug celecoxib (celecoxib) is a cyclooxygenase-2 inhibitor, which was originally used as a prescription drug for anti-inflammatory and analgesic. However, in recent studies, it has been found that Celebrex can inhibit tumor regeneration around tumors and promote tumor cell apoptosis. Some of the COX-2 inhibitors, ibuprofen, which were originally used for anti-inflammatory and analgesic, have been found to have a good inhibitory effect on cancer cells.
Phycocyanin: a special COX-2 inhibitor
Phycocyanin has been shown to be a potent inhibitor of COX-2, but for COX-1, phycocyanin has no effect (in other words, it has no toxic side effects on the human body, old-fashioned painkillers such as aspirin, which simultaneously block Broken COX-1 and COX-2 enzymes have side effects on the human body).
Data from two related assay systems (enzyme extraction assays and whole blood assays) reported that phycocyanin is a selective inhibitor of COX-2 with a very low IS50 value: COX-2/IS50COX -1ratio(0.04). The phycocyanin inhibits the IS50 value (18OMn) obtained by COX-2 and the well-known COX-2 selective inhibitor rofeeoxib (Chinese name: rofecoxib) (401nM) and eeleeoxib (Chinese name: celecoxib) (255nM) ) is much smaller than that. In human whole blood tests, phycocyanin is very effective in inhibiting COX-2 with an IS50 value of 80 Mn. After reducing phycocyanin and PCB chromophore, there is only a weak inhibitory effect and loss of COX-2 selectivity. It is suggested that phycocyanin plays an important role in the selective inhibition of COX-2.
The study also pointed out that the biological properties of phycocyanin, such as liver protection, anti-inflammatory, analgesic and anti-arthritis, may also be partly due to its selective inhibition of COX-2, of course, effective removal of free radicals and effective inhibition of fat. The nature of the peroxidation reaction is also one of the reasons.