title: Light-activated indole-3-acetic acid induces apoptosis in g361 human melanoma cells.
abstract: Indole-3-acetic acid (IAA) activation by horseradish peroxidase (HRP) has been suggested as a new cancer therapy. Interestingly, we found that ultraviolet B UVB radiation also can activate IAA and produce free radicals in a dose-dependent manner. In this study, we attempted to identify the free radicals generated by UVB-irradiated IAA (IAAUVB), and to determine whether IAAUVB can induce the apoptosis of G361 human melanoma cells. Since IAA/HRP produces reactive oxygen species (ROS), we examined whether IAAUVB-generated radicals include ROS. Our results show that IAAUVB-induced free radical production is not inhibited by catalase, superoxide dismutase, or sodium formate, indicating that ROS are not generated by IAAUVB. On the other hand, IAAUVB caused lipid peroxidation, and this was blocked by Trolox, a water-soluble vitamin E derivative. Moreover, we found that IAAUVB caused apoptotic cell death and that this was inhibited by a low temperature. We further investigated IAAUVB-mediated apoptotic pathways, and found that IAAUVB causes caspase-8, Bid, caspase-3 activation, and poly (ADP-ribose) polymerase (PARP) cleavage. In addition, these apoptotic pathways were also blocked by low temperature. From these results, we propose that IAAUVB-induced free radicals cause human melanoma cell apoptosis via a death receptor-mediated apoptotic pathway.
authors.affiliation: Department of Dermatology, Seoul National University College of Medicine, Korea.
authors.forename: Dong-Seok
authors.initials: DS
authors.lastname: Kim
authors.forename: So-Young
authors.initials: SY
authors.lastname: Kim
authors.forename: Yun-Mi
authors.initials: YM
authors.lastname: Jeong
authors.forename: Sang-Eun
authors.initials: SE
authors.lastname: Jeon
authors.forename: Myo-Kyoung
authors.initials: MK
authors.lastname: Kim
authors.forename: Sun-Bang
authors.initials: SB
authors.lastname: Kwon
authors.forename: Jung-Im
authors.initials: JI
authors.lastname: Na
authors.forename: Kyoung-Chan
authors.initials: KC
authors.lastname: Park
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D045744:Cell Line, Tumor; D003080:Cold Temperature; D005434:Flow Cytometry; D006801:Humans; D007210:Indoleacetic Acids / Q000494:pharmacology*; D008027:Light; D015227:Lipid Peroxidation; D008545:Melanoma / Q000378:metabolism / Q000473:pathology*; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D007210:Indoleacetic Acids; D017382:Reactive Oxygen Species; C030737:indoleacetic acid