Molecular mechanisms involved in UV-induced apoptotic cell death.

Ultraviolet radiation (UV) induces a variety of biological effects which include the induction of programmed cell death. UV-induced apoptosis seems to represent a controlled scavenging mechanism which protects cells from malignant transformation in human skin. To exert these effects on a cellular base, UV uses a variety of signaling pathways, involving nuclear DNA damage as a predominant pathway, since experimental reduction of DNA damage is associated with a loss of these effects. On the other hand, UV has been found to utilize extranuclear components located in the cytoplasm or at the cell membrane for signaling. UV can directly activate cell surface death receptors, thereby triggering the apoptotic machinery. Oxidative stress accompanied by mitochondrial changes and cytochrome c release are further involved in UV-mediated apoptosis. The following review will briefly discuss current aspects of the interplay between the different signaling pathways involved in UV-induced apoptosis. Copyright 2002 S. Karger AG, Basel