Real-time Visualization of Photochemically Induced Fluorescence of 8-Halogenated Quinolones: Lomefloxacin, Clinafloxacin and Bay3118 in Live Human HaCaT Keratinocytes

Halogenoquinolones are potent and widely used antimicrobials blocking microbial DNA synthesis. However, they induce adverse photoresponses through the absorption of UV light, including phototoxicity and photocarcinogenicity. The phototoxic responses may be the result of photosensitization of singlet...

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Bibliographic Details
Published in:Photochemistry and photobiology 2010-07, Vol.86 (4), p.792-797
Main Authors: Koker, Edmond B., Bilski, Piotr J., Motten, Ann G., Zhao, Baozhong, Chignell, Colin F., He, Yu-Ying
Format: Article
Language:English
Subjects:
Deoxyribonucleic acid
DNA
Environmental health
Fluorescence
Fluorides
Fluoroquinolones - chemistry
Fluoroquinolones - metabolism
Free radicals
Health sciences
Humans
Hydrogen-Ion Concentration
Keratinocytes - chemistry
Keratinocytes - metabolism
Keratinocytes - radiation effects
Molecular Structure
Photochemistry
Studies
Time Factors
Ultraviolet Rays
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Summary:Halogenoquinolones are potent and widely used antimicrobials blocking microbial DNA synthesis. However, they induce adverse photoresponses through the absorption of UV light, including phototoxicity and photocarcinogenicity. The phototoxic responses may be the result of photosensitization of singlet oxygen, production of free radicals and/or other reactive species resulting from photodehalogenation. Here, we report the use of laser scanning confocal microscopy to detect and to follow the fluorescence changes of one monohalogenated and three di‐halogenated quinolones in live human epidermal keratinocyte cells during in situ irradiation by confocal laser in real time. Fluorescence image analysis and co‐staining with the LysoTracker probe showed that lysosomes are a preferential site of drug localization and phototransformations. As the lysosomal environment is relatively acidic, we also determined how low pH may affect the dehalogenation and concomitant fluorescence. With continued UV irradiation, fluorescence increased in the photoproducts from BAY y3118 and clinafloxacin, whereas it decreased for lomefloxacin and moxifloxacin. Our images not only help to localize these phototoxic agents in the cell, but also provide means for dynamic monitoring of their phototransformations in the cellular environment.
ISSN:0031-8655
1751-1097
DOI:10.1111/j.1751-1097.2010.00741.x