Pre-mutagenic and mutagenic properties of ultraviolet radiation emitted by a nail polish dryer on mammalian cells. Mus musculus

Ultraviolet A (UVA) is a long-waved electromagnetic radiation that can penetrate the deeper layers of the skin. UVA is emitted by a multitude of artificial sources, including ones utilized in medical laboratories, dentistry, and cosmetics. UVA lamps are commonly used in nail polish dryers with recent reports suggesting that long-term exposure to UV-nail polish dryers may increase the risk for developing skin cancer. However, no experimental evidence has been provided about the effect of radiation emitted by UV-nail polish dryers on mammalian cells. Here, we perform a comprehensive experimental evaluation of the pre-mutagenic and mutagenic properties of ultraviolet radiation emitted by a nail polish dryer on the genomes of mammalian cells. Specifically, human and murine primary cell models were irradiated using multiple acute and chronic exposure protocols, subjected to several assays for assessing DNA damage, and whole genome sequenced after clonal expansion. Our findings demonstrate that radiation from UV-nail polish dryer is both cytotoxic and genotoxic, including single and double DNA strand breaks. Importantly, high levels of reactive oxygen species were observed in irradiated samples. Analysis of somatic mutations revealed a dose-dependent increase of C:G>A:T substitutions in irradiated samples with a pattern consistent to the one of COSMIC signature SBS18, a mutational signature attributed to reactive oxygen species. Re-examination of previously generated skin cancer genomics data revealed that SBS18 is widely present in both melanoma and skin cutaneous carcinoma. Overall, this study provides the first experimental confirmation of the DNA damaging and mutagenic properties of radiation emitted by UV-nail polish dryer on mammalian cells. The results have far reaching implications in regard to public health and to preventing skin cancer due to occupational- or consumer-based exposure to ultraviolet light.