Cellular and sub-cellular responses to UVA in relation to carcinogenesis.
OBJECTIVE
UVA radiation (315-400 nm) contributes to skin aging and carcinogenesis. The aim of this review is to consider the mechanisms that underlie UVA-induced cellular damage, how this damage may be prevented or repaired and the signal transduction processes that are elicited in response to it.


RESULTS
Exposure to ultraviolet (UV) light is well-established as the causative factor in skin cancer. Until recently, most work on the mechanisms that underlie skin carcinogenesis focused on shorter wavelength UVB radiation (280-315 nm), however in recent years there has been increased interest in the contribution made by UVA. UVA is able to cause a range of damage to cellular biomolecules including lipid peroxidation, oxidized protein and DNA damage, such as 8-oxoguanine and cyclobutane pyrimidine dimers. Such damage is strongly implicated in both cell death and malignant transformation and cells have a number of mechanisms in place to mitigate the effects of UVA exposure, including antioxidants, DNA repair, and stress signalling pathways.


CONCLUSIONS
The past decade has seen a surge of interest in the biological effects of UVA exposure as its significance to the process of photo-carcinogenesis has become increasingly evident. However, unpicking the unique complexity of the cellular response to UVA, which is only now becoming apparent, will be a major challenge for the field of photobiology in the 21st century.
Ridley
Andrew J
AJ
Division of Biomedical and Life Sciences, School of Health and Medicine, Lancaster University, UK. s.allinson@lancaster.ac.uk
Whiteside
James R
JR
McMillan
Trevor J
TJ
Allinson
Sarah L
SL
D000975:Antioxidants / Q000378:metabolism; D002471:Cell Transformation, Neoplastic / Q000378:metabolism / Q000528:radiation effects*; D004249:DNA Damage / Q000528:radiation effects*; D004260:DNA Repair; D006801:Humans; D015227:Lipid Peroxidation / Q000528:radiation effects; D020935:MAP Kinase Signaling System / Q000502:physiology; D009381:Neoplasms, Radiation-Induced / Q000209:etiology* / Q000378:metabolism / Q000473:pathology; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology; D015595:Skin Aging / Q000528:radiation effects; D012878:Skin Neoplasms / Q000209:etiology* / Q000378:metabolism / Q000473:pathology; D012880:Skin Pigmentation; D014466:Ultraviolet Rays / Q000009:adverse effects*
D000975:Antioxidants; D017382:Reactive Oxygen Species