The Interplay of Reactive Oxygen Species, Hypoxia, Inflammation, and Sirtuins in Cancer Initiation and Progression

Table 1

Classes of ROS and their properties.

Radical	Structure	Reactivity	Half-life	Production/localization	Diffusion	Targets	Biological effect	Pathological effect
Hydroxyl radical		High	10^−9 sec	Mitochondria; Phagosome; Endoplasmic reticulum (ER)	Highly localized where is produced	Any cell component	Unknown	Toxicity
Superoxide		Low	1–15 minutes	Mitochondria cytosol; ER; Peroxisome	Localized, it can diffuse through an anion channel	Fe-S centers; Nitric oxide	Protein modification (activation or inhibition)	Protein damage
Hydrogen peroxide	H2O2	Moderate; Reversible	Hours to days	Mitochondria cytosol; ER; Peroxisome	Diffuse, it can travel through aquaporins	Iron-sulphur; Cysteine residues	Activation of signaling	Mutation, accumulation, and genomic instability