Oxidative stress signalling: A potential mediator of tumour necrosis factor α-induced genomic instability in primary vascular endothelial cells

Mohan Natarajan, C. F. Gibbons, S. Mohan, Stephen Moore, M. A. Kadhim

Research output: Contribution to journalArticle

24 Citations (Scopus)

Abstract

Studying the potential role of tumour necrosis factor (TNF)α in the initiation of genomic instability is necessary to understand whether TNFα can serve as a signalling mediator of radiation-induced genomic instability in non-irradiated bystander cells. In this study, we examined whether TNFα could initiate processes through oxidative stress signalling that lead to DNA damage and genomic instability in primary vascular endothelium. In these cells, low linear energy transfer (LET) radiation (0.1-2 Gy) induced the secretion of TNFα into the culture medium. When added ectopically, TNFα at concentrations ranging from 0.1 ng ml-1 to 10 ng ml-1 increased (twofold to threefold) intracellular oxidative stress. Next, to examine whether TNFα induces genetic damage, cells were treated with TNFα for 5 h and analysed immediately using the single cell gel electrophoresis assay or after 3 days, 12 days and 20 days using solid stain chromosomal analysis. Cells exposed to 0.1 Gy, 1 Gy or 2 Gy or treated with 100 μM H2O2 were used as positive controls. The results showed that TNFα as low as 0.1 ng ml-1 could initiate increased DNA damage compared with untreated controls. When examined in the progeny cells after several generations, the chromosomal instability appeared to be carried over even after day 12 and day 20. The increased genetic damage is inhibited in cells that are pre-incubated with the antioxidant enzyme catalase, the antioxidant N-acetyl-L-cysteine or the metal chelator pyrrolidine dithiocarbamate. These results clearly indicate that TNFα at concentrations at which no cytotoxicity is observed could induce genetic damage through free radical generation, which could, in turn, lead to the delayed events associated with genomic instability.

Original languageEnglish (US)
JournalBritish Journal of Radiology
Volume80
Issue numberSPEC. ISS. 1
DOIs
StatePublished - 2007
Externally publishedYes

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Genomic Instability
Oxidative Stress
Endothelial Cells
Tumor Necrosis Factor-alpha
DNA Damage
Antioxidants
Radiation
Linear Energy Transfer
Chromosomal Instability
Comet Assay
Vascular Endothelium
Acetylcysteine
Chelating Agents
Catalase
Free Radicals
Culture Media
Coloring Agents
Metals
Enzymes

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging

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Oxidative stress signalling : A potential mediator of tumour necrosis factor α-induced genomic instability in primary vascular endothelial cells. / Natarajan, Mohan; Gibbons, C. F.; Mohan, S.; Moore, Stephen; Kadhim, M. A.

In: British Journal of Radiology, Vol. 80, No. SPEC. ISS. 1, 2007.

Research output: Contribution to journalArticle

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