The Role of Selenium in Cancer Prevention

Cancer is a major public health problem. Currently, it causes more than 7 million deaths peryear. With the existing knowledge, at least one-third of all cancer cases are preventable.Research shows that a large percentage of cancer-related deaths are directly linked tolifestyle choices such as smoking, drinking, lack of exercise, and particularly nutritionalstatus. A variety of micronutrients play important roles in cancer prevention such ascarotenoids, vitamin C, vitamin E, biotin, copper, iron, zinc and selenium (Se). Interventionalstudies have shown that Se is one of the most promising agents in limiting the risk of cancer.An inverse correlation between serum Se level and the risk of colorectal, prostate, lung,bladder, esophageal, and gastric cancers was found. The dominant forms of Se found indietary intake are selenomethionine and selenocysteine (organic forms), sodium selenite andsmaller amounts of methylated selenides (inorganic forms). Each form has its own set ofabilities. Several selenium-mediated anticancer mechanisms have been proposed: 1-Affecting oxidative stress by being an integral part of antioxidant enzymes of glutathioneperoxidase and thioredoxin reductase, catalyzing oxidation-reduction reactions. Also, thesereactions may lead to apoptotic death in cancerous cells. 2-Increasing DNA methylation,therefore dietary deficiency in selenium induces DNA damage and mutation. 3- Inhibitingcancer cell growth by decreasing cell proliferation through the cell cycle arrest and/orincreasing apoptosis. 4- Enhancing the immune systems ability to respond to infections andinduces the natural killer cells activity. 5- Being an essential part of the cytochrome P450enzyme system, which in the liver is responsible for detoxification of some carcinogenicmolecules. 6-Inhibiting proliferation, survival and matrix degradation of endothelial cellscritical for angiogenesis. In this review, we addressed the possible roles of Se in cancerprevention and treatment.

کلیدواژه ها:

Selenium ، Cancer ، Oxidative Stress ، Cell Proliferation ، Antioxidant Enzymes