DNA lesions caused by UV damage are thought to be repaired solely by the nucleotide excision repair (NER) pathway in human cells. Patients carrying mutations within genes functioning in this pathway display a range of pathologies, including an increased susceptibility to cancer, premature aging, and neurological defects. There are currently no curative therapies available. Here we performed a high-throughput chemical screen for agents that could alleviate the cellular sensitivity of NER-deficient cells to UV-induced DNA damage. This led to the identification of the clinically approved anti-diabetic drug acetohexamide, which promoted clearance of UV-induced DNA damage without the accumulation of chromosomal aberrations, hence promoting cellular survival. Acetohexamide exerted this protective function by antagonizing expression of the DNA glycosylase, MUTYH. Together, our data reveal the existence of an NER-independent mechanism to remove UV-induced DNA damage and prevent cell death.
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http://dx.doi.org/10.1016/j.molcel.2017.10.021 | DOI Listing |
Ultraviolet (UV)-induced DNA mutations produce genetic drivers of cutaneous melanoma initiation and numerous neoantigens that can trigger anti-tumor immune responses in the host. Consequently, melanoma cells must rapidly evolve to evade immune detection by simultaneously modulating cell-autonomous epigenetic mechanisms and tumor-microenvironment interactions. Angiogenesis has been implicated in this process; although an increase of vasculature initiates the immune response in normal tissue, solid tumors manage to somehow enhance blood flow while preventing immune cell infiltration.
View Article and Find Full Text PDFWhile the genetic paradigm of cancer etiology has proven powerful, it remains incomplete as evidenced by the widening spectrum of non-cancer cell-autonomous "hallmarks" of cancer. Studies have demonstrated the commonplace presence of high oncogenic mutational burdens in homeostatically-stable epithelia. Hence, the presence of driver mutations alone does not result in cancer.
View Article and Find Full Text PDFSci Rep
December 2024
Univ. Grenoble Alpes, CEA, Inserm, IRIG, UA13 BGE, Biomics, Grenoble, 38000, France.
Xeroderma pigmentosum group C (XPC) is a versatile protein crucial for sensing DNA damage in the global genome nucleotide excision repair (GG-NER) pathway. This pathway is vital for mammalian cells, acting as their essential approach for repairing DNA lesions stemming from interactions with environmental factors, such as exposure to ultraviolet (UV) radiation from the sun. Loss-of-function mutations in the XPC gene confer a photosensitive phenotype in XP-C patients, resulting in the accumulation of unrepaired UV-induced DNA damage.
View Article and Find Full Text PDFIn Saccharomyces cerevisiae cells, the bulk of mitochondrial DNA (mtDNA) replication is mediated by the replicative high-fidelity DNA polymerase γ. However, upon UV irradiation low-fidelity translesion polymerases: Polη, Polζ and Rev1, participate in an error-free replicative bypass of UV-induced lesions in mtDNA. We analysed how translesion polymerases could function in mitochondria.
View Article and Find Full Text PDFACS Omega
December 2024
Department of Physics, Institute of Biosciences, Humanities and Exact Sciences, São Paulo State University (UNESP), São José do Rio Preto, 15054-000 São Paulo, Brazil.
Tunneling times were calculated in electron transfer processes using an asymmetric harmonic double-well model. The simplicity of a direct variational calculation in the approximate solution of the Schrödinger equation, along with the interpretation of tunneling times within the probabilistic framework of a two-level system, allows for the efficient and accurate determination of tunneling times with minimal computational cost. These calculations were applied to electron transfer processes in the study of the photosynthetic reaction center and in the context of catalysis in UV-induced DNA lesion repair and are in agreement with the experimental, computational, and theoretical results with which they were compared.
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