title: Ultraviolet A and B affect human melanocytes and keratinocytes differently. A study of oxidative alterations and apoptosis.
abstract: Ultraviolet (UV) radiation is an etiologic agent for malignant melanoma and non-melanoma skin cancer, but the spectral range responsible for tumor induction is still to be elucidated. In this study, we compared effects of UVA and UVB irradiation on normal human melanocytes (MCs) and keratinocytes (KCs) in vitro. We demonstrate that UVA irradiation induces immediate loss of reduced glutathione (GSH) in both MCs and KCs. Exposure to UVA also causes reduced plasma membrane stability, in both cell types, as estimated by fluorescein diacetate retention and flow cytometry. Furthermore, we noted reduction in proliferation and higher apoptosis frequency 24 h after UVA irradiation. UVB irradiation of KCs caused instant reduction of reduced GSH and impaired plasma membrane stability. We also found decline in proliferation and increased apoptosis after 24 h. In MCs, on the other hand, UVB had no effect on GSH level or plasma membrane stability, although increased apoptotic cell death and reduced proliferation was detected. In summary, MCs and KCs showed similar response towards UVA, while UVB had more pronounced effects on KCs as compared to MCs. These results might have implications for the induction of malignant melanoma and non-melanoma skin cancer.
authors.affiliation: Department of Biomedicine and Surgery, Division of Dermatology, Faculty of Health Sciences, Linköping University, Linköping, Sweden. petla@ibk.liu.se
authors.forename: Petra
authors.initials: P
authors.lastname: Larsson
authors.forename: Eva
authors.initials: E
authors.lastname: Andersson
authors.forename: Uno
authors.initials: U
authors.lastname: Johansson
authors.forename: Karin
authors.initials: K
authors.lastname: Ollinger
authors.forename: Inger
authors.initials: I
authors.lastname: Rosdahl
mesh_terms: D017209:Apoptosis; D020169:Caspases / Q000378:metabolism; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000378:metabolism / Q000528:radiation effects*; D049109:Cell Proliferation; D002470:Cell Survival; D002478:Cells, Cultured; D004307:Dose-Response Relationship, Radiation; D005434:Flow Cytometry; D005452:Fluoresceins / Q000494:pharmacology; D005978:Glutathione / Q000378:metabolism; D006801:Humans; D015603:Keratinocytes / Q000528:radiation effects*; D008544:Melanocytes / Q000528:radiation effects*; D008545:Melanoma / Q000209:etiology; D010100:Oxygen / Q000378:metabolism*; D012878:Skin Neoplasms / Q000209:etiology; D013997:Time Factors; D014466:Ultraviolet Rays
chemical_list: D005452:Fluoresceins; D020169:Caspases; D005978:Glutathione; D010100:Oxygen; C018506:diacetylfluorescein