High Melanin Content in Melanoma Cells Contributes to Enhanced DNA Damage after Rose Bengal Photosensitization

• Published in: Photochemistry and photobiology 2022-11, Vol.98 (6), p.1355-1364
• Main Authors: Kalegari, Paloma, Leme, Daniela Morais, Disner, Geonildo Rodrigo, Cestari, Marta Margarete, Lima Bellan, Daniel, Meira, Willian Vanderlei, Mazepa, Ester, Martinez, Glaucia Regina
• Format: Article
• Language: English
• Subjects: Acetic acid; Bioassays; Comet assay; Cyclobutane; Cyclobutane pyrimidine dimers; Damage detection; Deoxyguanosine; Deoxyribonucleic acid; DNA; DNA - radiation effects; DNA Damage; Endonuclease; Endonuclease V; Enzymes; Humans; Irradiation; Lesions; Melanin; Melanins; Melanocytes; Melanoma; Melanoma - pathology; Oxidative stress; Oxygen; Photosensitivity Disorders; Photosensitization; Reactive Oxygen Species; Rose Bengal - pharmacology; Singlet Oxygen; Tumors; Ultraviolet Rays
• ISSN: 0031-8655; 1751-1097
• DOI: 10.1111/php.13632

Melanoma is a type of tumor that originates from melanocytes. Irradiation of melanin with UVA and visible light can produce reactive oxygen species (ROS) such as singlet molecular oxygen (1O2). The objective of this study was to examine DNA damage in melanoma cells (B16‐F10) with different melanin contents, subjected to 1O2 generation. To this end, we used the photosensitizer Rose Bengal acetate (RBAc) and irradiation with visible light (526 nm) (RBAc‐PDT). We used the modified comet assay with the repair enzymes hOGG1 and T4 endonuclease V to detect the DNA damage associated with 8‐oxo‐7,8‐dihydro‐2′‐deoxyguanosine and cyclobutane pyrimidine dimers lesions, respectively. We observed increased formation of hOGG1‐ and T4endoV‐sensitive DNA lesions after light exposure (with or without RBAc). Furthermore, 18 h after irradiation, hOGG1‐sensitive DNA lesions increased compared to that at the initial time point (0 h), which shows that a high melanin content contributes to post‐irradiation formation of them, mainly via sustained oxidative stress, as confirmed by the measurement of ROS levels and activity of antioxidant enzymes. Contrastingly, the number of T4endoV‐sensitive DNA lesions decreased over time (18 h). Our data indicate that in melanoma cells, a higher amount of melanin may affect DNA damage levels when subjected to RBAc‐PDT. We examined DNA damage in melanoma cells (B16‐F10) with different melanin contents, subjected to 1O2 generation by Rose Bengal acetate (RBAc) and irradiation with visible light (526 nm) (RBAc‐PDT). We used the modified comet assay with the repair enzymes hOGG1 and T4 endonuclease V to detect the DNA damage associated with 8‐oxo‐7,8‐dihydro‐2′‐deoxyguanosine (8‐oxodGuo) and cyclobutane pyrimidine dimers (CPD) lesions, respectively. We observed increased formation of hOGG1‐ and T4endoV‐sensitive DNA lesions after light exposure. Furthermore, 18 h after irradiation, hOGG1‐sensitive DNA lesions increased compared to that at the initial time point (0 h). Contrastingly, the number of T4endoV‐sensitive DNA lesions decreased over time (18 h).