UV-INDUCED REACTIVE OXYGEN SPECIES IN PHOTOCARCINOGENESIS AND PHOTOAGING

The increase in UV irradiation on earth due to the stratospheric ozone depletion represents a major environmental threat to the skin increas ing its risk of photooxidative damage by UV-induced reactive oxygen sp ecies (ROS), Increased ROS load has been implicated in several patholo gical states including photoaging and photocarcinogenesis of the skin, Large efforts have been made to better define the involvement of dist inct ROS in photocarcinogenesis and photoaging, Both pathological proc esses share common features; however, they reveal unique molecular cha racteristics which finally determine the fate of the cell and its host , As well as causing permanent genetic changes involving protooncogene s and tumor suppressor genes, ROS activate cytoplasmic signal transduc tion pathways that are related to growth differentiation, senescence, transformation and tissue degradation. This review focuses on the role of UV-induced ROS in the photodamage of the skin resulting in biochem ical and clinical characteristics of photocarcinogenesis and photoagin g. A decrease in the ROS load by efficient sunscreens and/or otherwise protective agents may represent a promising strategy to prevent or at least minimize ROS induced cutaneous pathological states.