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標題: S-adenosylhomocysteine enhances hydrogen peroxide-induced DNA damage by inhibition of DNA repair in two cell lines
作者: Yang, T.H.
Yang, N.C.
Hu, M.L.
關鍵字: cardiovascular-disease;plasma homocysteine;folate-deficiency;oxidative stress;uracil misincorporation;lymphocyte dna;tissue-levels;in-vitro;hypomethylation;transmethylation
Project: Nutrition and Cancer-an International Journal
期刊/報告no:: Nutrition and Cancer-an International Journal, Volume 47, Issue 1, Page(s) 70-75.
It has been proposed that hyperhomocysteinemia may exert its pathogenic effects largely through metabolic accumulation of S-adenosylhomocysteine (SAH), a strong noncompetitive inhibitor of most methyltransferases. Here, we investigated the effects of SAH on H2O2-induced cellular DNA damage in comparison with the effects of homocysteine (Hcy) in a mouse endothelial cell line and a human intestinal cell line. Cells were preincubated for 2 It with H2O2 (20,muM) followed by incubation with SAH or Hcy for 3 h. DNA strand breakage was determined using comet assay and DNA repair capacity determined using the same assay over time at 1, 2, and 3 h during SAH incubation. In both types of cells, SAH at 0.25-2,muM strongly and dose dependently enhanced H2O2-dependent DNA damage and inhibited DNA repair, whereas Hcy had a much weaker effect. SAH markedly increased uracil misincorporation, and this effect was also much stronger than that of Hcy. Taken together our results show that SAH potentiates H2O2-induced DNA damage in cell cultures through impaired DNA repair capability and suggest that such effects are related to uracil misincorporation. Although the in vivo relevance of our findings is unclear the biological significance of SAH-mediated detrimental effect, secondary to elevated intracellular Hcy, is an interesting area awaiting further exploration.
ISSN: 0163-5581
DOI: 10.1207/s15327914nc4701_9
Appears in Collections:食品暨應用生物科技學系

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