title: Photosensitized mefloquine induces ROS-mediated DNA damage and apoptosis in keratinocytes under ambient UVB and sunlight exposure.
abstract: The present study illustrates the photosensitizing behavior of mefloquine (MQ) in human skin keratinocytes under ambient doses of UVB and sunlight exposure. Photochemically, MQ generated reactive oxygen species superoxide radical, hydroxyl radical, and singlet oxygen through type I and type II photodynamic reactions, respectively, which caused photooxidative damage to DNA and formed localized DNA lesions cyclobutane pyrimidine dimers. Photosensitized MQ reduced the viability of keratinocytes to 25 %. Significant level of intracellular reactive oxygen species (ROS) generation was estimated through fluorescence probe DCF-H2. Increased apoptotic cells were evident through AO/EB staining and phosphatidyl serine translocation in cell membrane. Single-stranded DNA damage was marked through single-cell gel electrophoresis. Mitochondrial membrane depolarization and lysosomal destabilization were evident. Upregulation of Bax and p21 and downregulation of Bcl-2 genes and corresponding protein levels supported apoptotic cell death of keratinocyte cells. Cyclobutane pyrimidine dimers (CPDs) were confirmed through immunofluorescence. In addition, hallmarks of apoptosis and G2/M phase cell cycle arrest were confirmed through flow cytometry analysis. Our findings suggest that MQ may damage DNA and produce DNA lesions which may induce differential biological responses in the skin on brief exposure to UVB and sunlight.
authors.affiliation: Photobiology Division, CSIR-Indian Institute of Toxicology Research, M.G. Marg, Lucknow, 226001, Uttar Pradesh, India, nee9jan@gmail.com.
authors.forename: Neera
authors.initials: N
authors.lastname: Yadav
authors.forename: Ashish
authors.initials: A
authors.lastname: Dwivedi
authors.forename: Syed Faiz
authors.initials: SF
authors.lastname: Mujtaba
authors.forename: Ankit
authors.initials: A
authors.lastname: Verma
authors.forename: Rajnish
authors.initials: R
authors.lastname: Chaturvedi
authors.forename: Ratan Singh
authors.initials: RS
authors.lastname: Ray
authors.forename: Gajendra
authors.initials: G
authors.lastname: Singh
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D002478:Cells, Cultured; D004249:DNA Damage / Q000187:drug effects*; D059565:G2 Phase Cell Cycle Checkpoints / Q000187:drug effects; D006801:Humans; D015603:Keratinocytes / Q000187:drug effects* / Q000378:metabolism; D059566:M Phase Cell Cycle Checkpoints / Q000187:drug effects; D015767:Mefloquine / Q000494:pharmacology*; D017319:Photosensitizing Agents / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D012867:Skin / Q000187:drug effects / Q000378:metabolism; D013472:Sunlight / Q000009:adverse effects; D014466:Ultraviolet Rays / Q000009:adverse effects*; D051028:bcl-2-Associated X Protein / Q000378:metabolism
chemical_list: D017319:Photosensitizing Agents; D017382:Reactive Oxygen Species; D051028:bcl-2-Associated X Protein; D015767:Mefloquine