5-Fluorouracil (FUra) was previously demonstrated to be incorporated into DNA at cytotoxic concentrations in mouse bone marrow cells. Subsequently, we showed that under these conditions FUra exhibited a time-dependent removal from DNA accompanied by a decrease in DNA strand length. In the present study we utilized hydroxyurea to inhibit semiconservative DNA synthesis while monitoring DNA repair by measuring the incorporation of [3H]dThd into double-stranded DNA (DNAds), which can be separated from DNA at the replication fork (DNAss) by benzoylated-naphthoylated-DEAE cellulose. Under these conditions we assessed DNA repair in cells that had previously been exposed for 1 h to varying cytotoxic concentrations of FUra. The results demonstrate an increase in labelling of DNAds with increasing FUra concentrations, with no appreciable increase in incorporation of label into DNAss. In conclusion, this study demonstrates that DNA repair occurs following incorporation of FUra. The failure to repair DNA damage at higher FUra concentrations may have a role in the cytotoxicity of this drug.
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http://dx.doi.org/10.1007/BF00262771 | DOI Listing |
Cytotherapy
November 2024
Institute of Immunology and Immunotherapy, College of Medicine and Health, University of Birmingham, Birmingham, UK. Electronic address:
Background Aims: Extracellular vesicles (EVs) have gained traction as potential cell-free therapeutic candidates. Development of purification methods that are scalable and robust is a major focus of EV research. Yet there is still little in the literature that evaluates purification methods against potency of the EV product.
View Article and Find Full Text PDFEur J Pharmacol
January 2025
Department of Conservative Dentistry & Endodontics, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai 600077, Tamil Nadu, India. Electronic address:
Oral squamous cell carcinoma (OSCC) remains a major cause of morbidity and mortality worldwide with high recurrence rates and resistance to conventional therapies. Recent studies have highlighted the pivotal role of oral cancer stem cells (OCSCs) in driving treatment resistance and tumor recurrence. OCSCs possess unique properties, including self-renewal, differentiation potential, and resistance to chemotherapy and radiotherapy, which contribute to their ability to survive treatment and initiate tumor relapse.
View Article and Find Full Text PDFInt Immunopharmacol
January 2025
Department of Molecular Pathology, The Affiliated Cancer Hospital of Zhengzhou University, Henan Cancer Hospital, Zhengzhou, Henan, China; Henan Key Laboratory of Molecular Pathology, Zhengzhou, Henan, China. Electronic address:
Background: Lung squamous cell carcinoma (LUSC) is a significant health concern, characterized by a lack of specific therapies and limited treatment options for patients in advanced stages. This study aims to identify key molecules of prognostic importance in LUSC and provide an experimental foundation for their potential therapeutic applications.
Methods: Immune-related transcriptome expression analysis was performed on LUSC samples using the NanoString digital gene analysis system to develop a prognostic transcriptomic signature.
ESMO Open
January 2025
Uro-Gynecologic Oncology Unit, Istituto Nazionale Tumori IRCCS Fondazione G. Pascale, Naples, Italy. Electronic address:
Background: Ovarian cancer (OvC) constitutes significant management challenges primarily due to its late-stage diagnosis and the development of resistance to chemotherapy. The standard treatment regimen typically includes carboplatin and paclitaxel, with the addition of poly (ADP-ribose) polymerase inhibitors for patients with high-grade serous ovarian cancer (HGSOC) harboring BRCA1/2 mutations. However, the variability in treatment responses suggests the need to investigate factors beyond BRCA1/2 mutations, such as DNA repair mechanisms and epigenetic alterations.
View Article and Find Full Text PDFBioorg Med Chem
December 2024
Borch Department of Medicinal Chemistry and Molecular Pharmacology, Purdue Institute for Drug Discovery, Purdue University Center for Cancer Research, Purdue University, West Lafayette, IN 47907, United States. Electronic address:
Protein methylation regulates diverse cellular processes including gene expression and DNA repair. This review discusses the methods of identifying and validating substrates for protein methyltransferases (MTases), as well as the biological roles of methylation. Meanwhile, we outline continued efforts necessary to fully map MTase-substrate pairs and uncover the complex regulatory roles of protein methylation in cellular function.
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