Singlet oxygen mediated DNA damage induced phototoxicity by ketoprofen resulting in mitochondrial depolarization and lysosomal destabilization

• Photomodification and phototixicity of KP at ambient environmental intensities of UV-radiation.
• Phototoxicity of KP through type-II photodynamic reaction by generating 1O2.
• Role of DNA damage and lipid peroxidation in KP phototoxicity.
• Apototic cell death and involvement of lysosomes and mitochondria.
• Cytochrome-c release from mitochondria and up-regulation of p21 and Bax genes expression.

Ketoprofen (KP) is a widely used nonsteroidal anti-inflammatory drug for the treatment of osteoarthritis and various rheumatic diseases. Currently, KP is applied topically on skin as gel to treat symptoms of pain and inflammation. We have studied the photomodification of KP under natural environmental conditions. KP generates reactive oxygen species (ROS) like 1O2 through Type-II photodynamic reaction. 1O2 mediated 2′-dGuO photodegradation, single and double strand breakage were significantly induced by photosensitized KP under sunlight/UV-R exposure. Significant intracellular ROS generation was measured through DCF-DA fluorescence. Linoleic acid photoperoxidation and role of 1O2 were substantiated by using specific quencher like sodium azide. KP induced cell cycle arrest in G2/M phase and cell death through MTT assay. We found apoptosis as the pattern of cell death which was confirmed through caspase-3 activation, cytochrome-c release from mitochondria, up-regulation of Bax protein and phosphatidylserine translocation. Our RT-PCR result strongly supports our view point of apoptotic cell death through up-regulation of p21 and pro-apoptotic Bax genes expression. Mitochondrial depolarization and lysosomal destabilization were also parallel to apoptotic process. Therefore, much attention should be paid to the topical application of KP and sunlight exposure in the light of skin related photosensitivity and cancers.

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