Redox Modulation in Therapy of Cancer: Some Pros and Cons

Redox potential controls a vast array of biochemical reactions, and its changes influence the transition from normal to pathological states. However, cellular redox potential is primarily assessed after extraction of water-soluble components (reduced and oxidized) from biological material, particularly glutathione, which, due to its abundance, determines intracellular redox potential. This process involves mechanistic averaging of redox potential values across tissue or cell, although existing data suggest, and sometimes directly indicate, heterogeneity in redox potential both within cells and within tissue. We argue that mitochondria determine cellular redox state, in particular through changes in the state of the mitochondrial reticulum caused by various internal and external factors. We describe the possibilities for regulation of redox status of the cell and organ as a potential therapy for various pathologies, particularly cancer, and propose intensifying efforts to utilize <i>intrinsic</i> redox indicators. We specifically examine the possibility of changes the redox potential in cancer cells through the use of oxidative phosphorylation uncouplers and propose mechanisms by which cancer cells may be killed using uncouplers. Particular attention is paid to the mitochondrial membrane potential as a powerful regulator of cellular metabolism, possibly unrelated to the regulation of reactive oxygen species levels, with the possible existence of a membrane potential sensor in cells.