DNA damage and somatic mutations in mammalian cells after irradiation with a nail polish dryer

Nail polish dryers commonly emit ultraviolet A (UVA) light, but the effects of this irradiation on mammalian cells remain unclear. Here, the authors examine the effects of UVA irradiation by a nail polish dryer on the genomes of mammalian cell lines, finding high levels of reactive oxygen species and related mutational signatures. Ultraviolet A light is commonly emitted by UV-nail polish dryers with recent reports suggesting that long-term use may increase the risk for developing skin cancer. However, the effect of radiation emitted by UV-nail polish dryers on the physiology and mutagenesis of mammalian cells remains unclear. Here, we show that irradiation by a UV-nail polish dryer causes high levels of reactive oxygen species, consistent with 8-oxo-7,8-dihydroguanine damage and mitochondrial dysfunction. Analysis of somatic mutations reveals a dose-dependent increase of C:G>A:T substitutions in irradiated samples with mutagenic patterns similar to mutational signatures previously attributed to reactive oxygen species. In summary, this study demonstrates that radiation emitted by UV-nail polish dryers can both damage DNA and permanently engrave mutations on the genomes of primary mouse embryonic fibroblasts, human foreskin fibroblasts, and human epidermal keratinocytes.