Role of selenium in cell death

Selenium is an essential nutrient closely related to redox homeostasis in the body.A redox imbalance will adversely affect the microenvironment inside and outside the cell,leading to cell death.Various types of cell death have been discovered in recent years,but the role(s)of selenium and the associated mechanism(s)of action require further elaboration.We review the roles and mechanisms of action of selenium in cell necrosis,apoptosis,ferroptosis,autophagy,and pyroptosis.Under normal conditions,selenium inhibits cell necrosis,apoptosis,ferroptosis,autophagy,and pyroptosis by downregulating the nuclear factorκB pathway,upregulating antiapoptotic proteins,decreasing oxidative stress,increasing antioxidant enzyme activity,enhancing the mTOR pathway,and downregulating the NLRP3/caspase-1 pathway,thereby helping to maintain the normal physiological functions of cells.On the other hand,selenium deficiency leads to activation of the PI3K/AKT and Notch/Hes1 pathways,causing a significant increase in the level of oxidative stress in the organism,resulting in cell necrosis,apoptosis,and pyroptosis.In the case of malignancy,the in vivo metabolite of inorganic selenium,hydrogen selenide,plays an antitumor role by inducing apoptosis and ferroptosis in tumor cells because of its high redox activity.In conclusion,an adequate level of selenium in the body is essential for maintaining normal cellular physiological functions and reducing fibrotic alterations.Furthermore,the in vivo metabolites of inorganic selenium may have some clinical value in antitumor therapy.