title: Blue light inhibits the growth of B16 melanoma cells.
abstract: Although a number of studies have been carried out to examine the biological effects of radiation and ultraviolet radiation (UV), little is known concerning the effects of visible light. In the present study, exposure of B16 melanoma cells to blue light (wavelength 470 nm, irradiance 5.7 mW / cm(2)) from a light-emitting diode (LED) inhibited cell growth in proportion to the period of exposure, with no increase observed in the number of dead cells. The number of B16 melanoma colonies that formed after exposure to blue light for 20 min was only slightly less than that in non-exposed controls, but the colony size as assessed by the area covered by colonies and cell counts per colony were markedly decreased. The percentages of G0 / G1 and G2 / M phase cells were markedly increased, with a reduction in S phase cells as determined by flow cytometry after exposure to blue light. Furthermore, analysis of the incorporation of 5-bromo-2'-deoxyuridine (BrdU) into DNA also showed a reduction in the percentage of S phase cells after exposure. These results indicate that blue light exerts cytostatic effects, but not a cytocidal action, on B16 melanoma cells.
authors.affiliation: Department of Environment and Mutation, Research Institute for Radiation Biology and Medicine, Hiroshima University, Minami-ku, Hiroshima 734-8553. oharams@otsukakj.co.jp
authors.forename: Masayuki
authors.initials: M
authors.lastname: Ohara
authors.forename: Yuzo
authors.initials: Y
authors.lastname: Kawashima
authors.forename: Osamu
authors.initials: O
authors.lastname: Katoh
authors.forename: Hiromitsu
authors.initials: H
authors.lastname: Watanabe
mesh_terms: D000818:Animals; D001973:Bromodeoxyuridine / Q000494:pharmacology; D016923:Cell Death / Q000528:radiation effects; D002455:Cell Division; D004396:Coloring Agents / Q000494:pharmacology; D005434:Flow Cytometry; D016193:G1 Phase; D016195:G2 Phase; D008027:Light; D008546:Melanoma, Experimental; D051379:Mice; D008938:Mitosis; D016192:Resting Phase, Cell Cycle; D016196:S Phase; D013997:Time Factors; D014407:Tumor Cells, Cultured; D014466:Ultraviolet Rays
chemical_list: D004396:Coloring Agents; D001973:Bromodeoxyuridine