Inducible nitric oxide synthase (NOS2) produces high local concentrations of nitric oxide (NO), and its expression is associated with inflammation, cellular stress signals, and cellular transformation. Additionally, NOS2 expression results in aggressive cancer cell phenotypes and is correlated with poor outcomes in patients with breast cancer. DNA hypomethylation, especially of noncoding repeat elements, is an early event in carcinogenesis and is a common feature of cancer cells. In addition to altered gene expression, DNA hypomethylation results in genomic instability via retrotransposon activation. Here, we show that NOS2 expression and associated NO signaling results in substantial DNA hypomethylation in human cell lines by inducing the degradation of DNA (cytosine-5)–methyltransferase 1 (DNMT1) protein. Similarly, NOS2 expression levels were correlated with decreased DNA methylation in human breast tumors. NOS2 expression and NO signaling also resulted in long interspersed noncoding element 1 (LINE-1) retrotransposon hypomethylation, expression, and DNA damage. DNMT1 degradation was mediated by an NO/p38-MAPK/lysine acetyltransferase 5–dependent mechanism. Furthermore, we show that this mechanism is required for NO-mediated epithelial transformation. Therefore, we conclude that NOS2 and NO signaling results in DNA damage and malignant cellular transformation via an epigenetic mechanism.
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http://dx.doi.org/10.1073/pnas.2200022119 | DOI Listing |
Funct Integr Genomics
January 2025
School of Medical Technology, Tianjin Medical University, Tianjin, 300203, China.
Clear cell renal cell carcinoma (ccRCC) is a highly malignant tumor characterized by a significant propensity for recurrence and metastasis. DNA methylation has emerged as a critical epigenetic mechanism with substantial utility in cancer diagnosis. In this study, multi-omics data were utilized to investigate the target genes regulated by the transcription factor MYC-associated zinc finger protein (MAZ) in ccRCC, leading to the identification of thymidine phosphorylase (TYMP) as a gene with notably elevated expression in ccRCC.
View Article and Find Full Text PDFInt J Mol Sci
January 2025
Department of Clinical Laboratory, School of Medicine, International University of Health and Welfare, Otawara 324-8501, Japan.
Intrauterine growth restriction (IUGR) is a risk factor for postnatal cardiovascular, metabolic, and psychiatric disorders. In most IUGR models, placental dysfunction that causes reduced 11β-hydroxysteroid dehydrogenase 2 (11βHSD2) activity, which degrades glucocorticoids (GCs) in the placenta, resulting in fetal GC overexposure. This overexposure to GCs continues to affect not only intrauterine fetal development itself, but also the metabolic status and neural activity in adulthood through epigenetic changes such as microRNA change, histone modification, and DNA methylation.
View Article and Find Full Text PDFInt J Mol Sci
December 2024
Animal Genomics and Improvement Laboratory, Beltsville Agricultural Research Center, Agricultural Research Service, United States Department of Agriculture, Beltsville, MD 20705, USA.
DNA methylation (DNAm) regulates gene expression and genomic imprinting. This study aimed to investigate the effect of gastrointestinal (GI) nematode infection on host DNAm. Helminth-free Holstein steers were either infected with (the brown stomach worm) or given tap water only as a control.
View Article and Find Full Text PDFJ Hypertens
December 2024
Institute for Fetology, The First Affiliated Hospital of Soochow University, Jiangsu.
Background: Paternal preconception alcohol exposure affects fetal development; however, it is largely unknown about the influences on offspring vasculature and mechanisms.
Methods: Offspring born form paternal rats treated with alcohol or water before pregnant was raised until 3 months of age. Vessel tone of mesenteric arteries was detected using myograph system; whole-cell calcium channel current in smooth muscle cells was tested using patch-clamp; molecule expressions were detected with real-time PCR, western blotting, and Dihydroethidium (DHE); DNA methylations were determined using targeted bisulfate sequencing assay.
PLoS One
January 2025
Faculty of Biology, VNU University of Science, Vietnam National University, Hanoi, Vietnam.
The autonomous and active Long-Interspersed Element-1 (LINE-1, L1) and the non-autonomous Alu retrotransposon elements, contributing to 30% of the human genome, are the most abundant repeated sequences. With more than 90% of their sequences being methylated in normal cells, these elements undeniably contribute to the global DNA methylation level and constitute a major part of circulating-cell-free DNA (cfDNA). So far, the hypomethylation status of LINE-1 and Alu in cellular and extracellular DNA has long been considered a prevailing hallmark of ageing-related diseases and cancer.
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