Antitumor Effects of Selenium

Abstract

Functions of selenium are diverse as antioxidant, anti-inflammation, increased immunity, reduced cancer incidence, blocking tumor invasion and metastasis, and further clinical application as treatment with radiation and chemotherapy. These functions of selenium are mostly related to oxidation and reduction mechanisms of selenium metabolites. Hydrogen selenide from selenite, and methylselenol (MSeH) from Se-methylselenocyteine (MSeC) and methylseleninicacid (MSeA) are the most reactive metabolites produced reactive oxygen species (ROS); furthermore, these metabolites may involve in oxidizing sulfhydryl groups, including glutathione. Selenite also reacted with glutathione and produces hydrogen selenide via selenodiglutathione (SeDG), which induces cytotoxicity as cell apoptosis, ROS production, DNA damage, and adenosine-methionine methylation in the cellular nucleus. However, a more pronounced effect was shown in the subsequent treatment of sodium selenite with chemotherapy and radiation therapy. High doses of sodium selenite were effective to increase radiation therapy and chemotherapy, and further to reduce radiation side effects and drug resistance. In our study, advanced cancer patients can tolerate until 5000 μg of sodium selenite in combination with radiation and chemotherapy since the half-life of sodium selenite may be relatively short, and, further, selenium may accumulates more in cancer cells than that of normal cells, which may be toxic to the cancer cells. Further clinical studies of high amount sodium selenite are required to treat advanced cancer patients.

Nuclear and Radiological Emergencies: Biological Effects, Countermeasures and Biodosimetry

“…In vivo, the variability in redox potential gradients, the lower pH and the redox imbalance existing in the cancer microenvironment can facilitate the conversion of Se nanoparticles (SeNPs) into a pro-oxidant agent causing mitochondrial dysfunction, cell cycle arrest, and ultimately cancer cell death [ 217 ]. Organic Se compounds and especially SeNPs are better candidates as radioprotectors and radiosentitizers for their lower toxicity and higher cancer cell selectivity compared to sodium selenite [ 217 , 218 ].…”

Effects of Selenium on Chronic Kidney Disease: A Mendelian Randomization Study

“…Cells need selenium for many processes, such as the antioxidant process, defense against infection and energy transfer [ 11 , 12 ]. Selenium exerts its effect largely through its presence in the active site of several biologically active selenoproteins [ 13 , 14 , 15 ]. Among them, selenium is best known in the form of glutathione peroxidase-3 (GPX-3), the strongest antioxidant enzyme in the body [ 14 ].…”

Selenium metabolism and regulation of immune cells in immune‐associated diseases

“…Targeting tumor cells like leukemia stem cells, selenium can activate ATM kinase to promote the expression of p53 to regulate glycolysis, oxidative phosphorylation, and glutamine pathway of tumor cells, resulting in specific increase of ROS in tumor cells and apoptosis (Diwakar et al, 2017; Gandhi et al, 2021; Jackson, 2012; Kim et al, 2021; Sun et al, 2021). This effect is opposite to what happens in normal cells or damaged normal cells.…”