Hydrogen peroxide - Production, fate and role in redox signaling of tumor cells

Abstract

Hydrogen peroxide (H 2 O 2) is involved in various signal transduction pathways and cell fate decisions. The mechanism of the so called "redox signaling" includes the H 2 O 2 -mediated reversible oxidation of redox sensitive cysteine residues in enzymes and transcription factors thereby altering their activities. Depending on its intracellular concentration and localization, H 2 O 2 exhibits either pro- or anti-apoptotic activities. In comparison to normal cells, cancer cells are characterized by an increased H 2 O 2 production rate and an impaired redox balance thereby affecting the microenvironment as well as the anti-tumoral immune response. This article reviews the current knowledge about the intracellular production of H 2 O 2 along with redox signaling pathways mediating either the growth or apoptosis of tumor cells. In addition it will be discussed how the targeting of H 2 O 2 -linked sources and/or signaling components involved in tumor progression and survival might lead to novel therapeutic targets.