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Double-strand DNA breaks (DSBs) are among the most cytotoxic DNA lesions, which can lead to chromosomal instability and eventually cell death. The substances that can potentially induce DSB formation are thus regarded as genotoxic. To date, many genotoxicity tests for detecting DNA breaks have been designed. However, there are limited options available for measuring the accumulation of DSBs in vivo. In this study, we aimed to evaluate a method of detecting the DSBs formed by the direct action of genotoxic substances using pulsed-field gel electrophoresis (PFGE). This approach has the advantage of making it easier to distinguish between DSBs and single-strand DNA breaks (SSBs) induced by the direct action of genotoxic substances. To confirm the detection of DSBs using PFGE, we investigated their accumulation after treatment with cis-diamminedichloroplatinum(II) (cisplatin) or γ-rays in mouse organs. The results revealed the successful detection of cisplatin-induced DSB formation in mouse kidney and thymus and γ-ray-induced DSB formation in all organs. We also discuss the advantages of PFGE-based detection of DSBs in vivo.
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http://dx.doi.org/10.1016/j.taap.2025.117278 | DOI Listing |
Cancer Lett
September 2025
Cancer Center, Shanghai General Hospital of Nanjing Medical University, Shanghai, China; Shanghai Key Laboratory for Pancreatic Diseases and Cancer Center, Shanghai, China. Electronic address:
Radiotherapy, a pivotal treatment for colorectal cancer, is compromised by tumor repopulation, which is characterized by accelerated growth and increased treatment resistance. Although radiation-induced DNA breaks eliminate most cells, a subset of polyploid giant cancer cells (PGCCs) evade death through massive genomic amplification, subsequently undergoing depolyploidization via a viral budding-like process to generate proliferative progeny. Critically, these PGCCs drive tumor repopulation and underpin therapeutic failure.
View Article and Find Full Text PDFDNA Repair (Amst)
August 2025
Department of Molecular Genetics, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, the Netherlands; Department of Vascular Surgery, Erasmus University Medical Center, Rotterdam, the Netherlands; Department of Radiotherapy, Erasmus MC Cancer Institute, Erasmus University Med
DNA crosslink-inducing drugs are widely used in clinical settings for treatment of solid tumors. Double strand breaks (DSBs) that arise during interstrand crosslink (ICL) repair are crucial determinants of the therapeutic response, as they lead to cell death if not repaired. DSBs can be repaired through non-homologous end joining (NHEJ), theta-mediated end joining (TMEJ), and homologous recombination (HR).
View Article and Find Full Text PDFGenes Immun
September 2025
Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH, USA.
Double-strand breaks represent the most dangerous form of DNA damage, and in resting cells, these breaks are sealed via the non-homologous end joining (NHEJ) factor Ligase IV (LIG4). Excessive NHEJ may be genotoxic, necessitating multiple mechanisms to control NHEJ activity. However, a clear mechanism of transcriptional control for them has not yet been identified.
View Article and Find Full Text PDFCancer Lett
September 2025
Department of Cell, Development and Cancer Biology, Knight Cancer Institute, Oregon Health and Sciences University, Portland, OR, USA; Brenden-Colson Center for Pancreatic Care, Oregon Health and Science University, Portland, OR, USA.
Gemcitabine, a ribonucleotide reductase (RNR) inhibitor, is active in pancreatic ductal carcinoma (PDAC) patients, but unfortunately has a limited impact on long term outcomes. Gemcitabine induces nucleotide deficiency, DNA damage including single stranded DNA (ssDNA) and replication stress (RS). DNA damage can activate cyclic GMP-AMP synthase (cGAS), leading to genome instability, micronucleus generation, and immune activation.
View Article and Find Full Text PDFPLoS Genet
September 2025
Department of Molecular and Cellular Biology, University of California Davis, Davis, California, United States of America.
The synaptonemal complex (SC) is a meiosis-specific structure that aligns homologous chromosomes and promotes the repair of meiotic DNA double-strand breaks (DSBs). To investigate how defects in SC formation affect gametogenesis in zebrafish, we analyzed mutations in two genes encoding core SC components: syce2 and sycp1. In syce2 mutants, chromosomes exhibit partial synapsis, primarily at sub-telomeric regions, whereas sycp1 mutant chromosomes display early prophase co-alignment but fail to synapse.
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