UVA-light-induced mutagenesis in the exome of human nucleotide excision repair-deficient cells

Autor(es)

Quintero-Ruiz, Nathalia ; Corradi, Camila ; Moreno, Natalia Cestari ; de Souza, Tiago Antonio ; Menck, Carlos Frederico Martins

• Tipo de documento: Artigo Científico
• Fonte: PHOTOCHEMICAL & PHOTOBIOLOGICAL SCIENCES; v. 24, n. 3, p. 21-pg., 2025-03-10.

Resumo

Skin cancer is associated with genetic mutations caused by sunlight exposure, primarily through ultraviolet (UV) radiation that damages DNA. While UVA is less energetic, it is the predominant solar UV component reaching the Earth's surface. However, the mechanisms of UVA-induced mutagenesis and its role in skin cancer development remain poorly understood. This study employed whole exome sequencing of clones from human XP-C cells, which lack nucleotide excision repair (NER), to characterize somatic mutations induced by UVA exposure. DNA sequence analysis of UVA-irradiated XP-C cells revealed a marked increase in mutation frequency across nearly all types of base substitutions, with particular enrichment in C > T transitions within the CCN and TCN trinucleotide context-potential sites for pyrimidine dimer formation. The C > T mutation primarily occurred at the 3 ' base of the 5 ' TC dimer, and an enrichment of CC > TT tandem mutations. We also identified the SBS7b COSMIC mutational signature within irradiated cells, which has been associated with tumors in sun-exposed skin. C > A transversions, often linked to oxidized guanine, were the second most frequently induced mutation, although a specific context for this base substitution was not identified. Moreover, C > T mutations were significantly increased in unirradiated XP-C compared to NER-proficient cells, which may be caused by unrepaired spontaneous DNA damage. Thus, this study indicates that pyrimidine dimers are the primary lesions contributing to UVA-induced mutagenesis in NER-deficient human cells and demonstrates that UVA generates mutational signatures similar to those of UVB irradiation. (AU)

• Processo FAPESP: 19/19435-3 - Papel de danos no DNA e função mitocondrial em envelhecimento vascular, imune e neurológico (DNA MoVINg)
• Beneficiário: Carlos Frederico Martins Menck
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 14/15982-6 - Consequências de deficiências de reparo de lesões no genoma
• Beneficiário: Carlos Frederico Martins Menck
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 13/08028-1 - CEGH-CEL - Centro de Estudos do Genoma Humano e de Células-Tronco
• Beneficiário: Mayana Zatz
• Modalidade de apoio: Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs