Production of ROS by Photosensitized Anthracene Under Sunlight and UV‐R at Ambient Environmental Intensities

Abstract

The aim of this study was to analyze the photostability and phototoxicity mechanism of anthracene (ANT) in a human skin epidermal cell line (HaCaT) at ambient environmental intensities of sunlight/UV-R (UV-A and UV-B). Photomodification of ANT under sunlight/UV-R exposure produced two photoproducts, anthrone and 9,10 anthracenedione. Generation of (1)O(2), O(2)(•-) and (•)OH was measured under UV-R/sunlight exposure. Involvement of reactive oxygen species (ROS) was further substantiated by their quenching with free radical quenchers. Photodegradation of 2-deoxyguanosine and linoleic acid peroxidation showed that ROS were mainly responsible for ANT phototoxicity. ANT generates significant amount of intracellular ROS in cell line. Maximum cell viability (85%) was reduced under sunlight exposure (30 min). Results of MTT assay accord NRU assay. ANT (0.01 μg mL(-1)) induced cell-cycle arrest at G1 phase. RT-PCR demonstrated constitutive inducible mRNA expression of CYP 1A1 and 1B1 genes. Photosensitive ANT upregulates CYP 1A1 (2.2-folds) and 1B1 (4.1-folds) genes. Thus, the study suggests that ROS and DNA damage were mainly responsible for ANT phototoxicity. ANT exposure may be deleterious to human health at ambient environmental intensities reaching the earth's surface through sunlight.

Involvement of cathepsin B in mitochondrial apoptosis by p-phenylenediamine under ambient UV radiation

“…The fixed cells were washed twice with PBS and treated with RNase (0.1 mg/mL) for 30 min at 37 • C. Finally, cells were stained with propidium iodide (50 g/mL) and incubated in dark for 30 min prior to analysis. Cellular DNA content was determined by flow cytometry (Becton -Dickinson LSR-II, USA) using the Cell Quest program and Mod Fit software [21]. Lysosomal membrane integrity was measured by acridine orange staining [22].…”

Ambient UVA‐Induced Expression of p53 and Apoptosis in Human Skin Melanoma A375 Cell Line by Quinine

“…The reaction mixtures (10 mL each) containing Q from 5 to 25 μg mL −1 were irradiated under UVA (1.8 J cm −2 ) and absorbance of NBF thus formed, was measured. Photochemical generation of O 2 •− was further confirmed by dismutating O 2 •− by SOD (25 U mL −1 ) .…”

“…Cells were then washed twice with HBSS and 100 μL DMSO was added to each well and kept on rocker shaker (NuRS‐60; Nulife) for 20 min to dissolve the formazan crystals. The absorbance was read at 530 nm by micro plate reader (Fluostar Omega‐ BMG Labtech) .…”

“…Plates were then kept on a rocker shaker for 20 min. The absorbance was read at 540 nm by micro plate reader (Fluostar Omega‐BMG Labtech) .…”

9-phenyl acridine photosensitizes A375 cells to UVA radiation

“…Generation of cytotoxic ROS has thus been associated with the mechanism of action for several photosensitizers. Phototoxicity of UVA radiation was enhanced on anthracene, quinine or benz(e)acephenanthrylene treatment through the production of ROS [ 50 , 51 , 61 , 62 ]. It was important to know whether generation of ROS was involved in the cell killing process during ACPH associated photosensitization of UVA.…”