[Sulfur Metabolism in Cancer Malignancy and Its Potential for Therapeutic Application]

Sulfur, like oxygen, belongs to Group 16 of the periodic table and is characterized by its flexibility in both donating and accepting electrons, as well as its wide range of oxidation states. These properties enable sulfur to participate in diverse redox reactions. In biological systems, sulfur plays vital roles as a component of catalytic centers of enzymes and as a redox sensor. Moreover, sulfur is the only element known to form stable linear chains through homoelemental bonding, a phenomenon known as catenation, resulting in a variety of allotropes present widely in nature. Advances in analytical techniques have recently revealed the endogenous presence of"supersulfides", which contain sulfur catenation structures. The physiological and pathological functions of these species are gradually being elucidated. This review focuses on the chemical properties and biological functions of supersulfides, with particular emphasis on their roles in cancer. Furthermore, we discuss the therapeutic potential of targeting the"over-reduced state,"a redox imbalance caused by excessive production of supersulfides.