Blue light is phototoxic for B16F10 murine melanoma and bovine endothelial cell lines by direct cytocidal effect.
The large number of studies devoted to the effect of ultraviolet light on biological systems, contrasts with the lack of experimental data concerning the direct effects of visible light. It has been shown that blue light inhibited the growth of B16F10 melanoma cell lines and reduced the percentage of S phase cells. Yet these effects are poorly understood.


METHODS
Two cell lines and irradiation with blue light were used. Cell mortality and a possible mechanism of action were investigated.


RESULTS
Exposure of B16F10 melanoma and bovine endothelial cells to blue light (wavelength 450 nm, 10 J/cm(2) from a Waldman lamp) induced a rapid and large reduction in viability followed by the death of virtually all the irradiated cells within 24 h. These results led us to expose a patient with haemorrhagic cutaneous melanoma metastasis to blue light. Irradiation led to an immediate arrest of haemorrhage, an inhibition of tumour growth and extensive tumour necrosis 24h after irradiation.


CONCLUSIONS
Exposure to blue light may offer new approaches to the treatment of superficial skin carcinomas in humans.
Département de Dermatologie, CHRU Dupuytren, 2, Avenue Martin Luther King, 87042 Limoges, France. a.sparsa@free.fr
Agnes
A
Sparsa
Karine
K
Faucher
Vincent
V
Sol
Helene
H
Durox
Serge
S
Boulinguez
Valerie
V
Doffoel-Hantz
Claude-Alain
CA
Calliste
Jeanne
J
Cook-Moreau
Pierre
P
Krausz
Franck G
FG
Sturtz
Christophe
C
Bedane
Marie-Odile
MO
Jauberteau-Marchan
Marie-Helene
MH
Ratinaud
Jean-Marie
JM
Bonnetblanc
D000818:Animals; D002417:Cattle; D002470:Cell Survival / Q000528:radiation effects; D042783:Endothelial Cells / Q000166:cytology / Q000378:metabolism / Q000528:radiation effects*; D008027:Light; D015227:Lipid Peroxidation / Q000528:radiation effects; D008546:Melanoma, Experimental / Q000378:metabolism / Q000473:pathology / Q000628:therapy*; D051379:Mice; D010789:Phototherapy / Q000379:methods*