Journal Article

Influence of glutathione levels and heat-shock on the steady-state levels of oxidative DNA base modifications in mammalian cells

Olaf Will, Hanns-Christian Mahler, André-Patrick Arrigo and Bernd Epe

in Carcinogenesis

Volume 20, issue 2, pages 333-337
Published in print February 1999 | ISSN: 0143-3334
Published online February 1999 | e-ISSN: 1460-2180 | DOI: http://dx.doi.org/10.1093/carcin/20.2.333
Influence of glutathione levels and heat-shock on the steady-state levels of oxidative DNA base modifications in mammalian cells

More Like This

Show all results sharing this subject:

  • Clinical Cytogenetics and Molecular Genetics

GO

Show Summary Details

Preview

The effects of thiols, ascorbic acid and thermal stress on the basal (steady-state) levels of oxidative DNA base modifications were studied. In various types of untreated cultured mammalian cells, the levels of total glutathione were found to be inversely correlated with the levels of DNA base modifications sensitive to the repair endonuclease Fpg protein, which include 8-hydroxyguanine (8-oxoG). A depletion of glutathione by treatment with buthionine sulphoximine increased the steady-state level in AS52 Chinese hamster cells by ~50%. However, additional thiols in the culture medium did not reduce the level of Fpg-sensitive base modifications: 0–10 mM N-acetylcysteine had no effect, whereas cysteine ethylester even increased the oxidative DNA damage at concentrations >0.1 mM. Similarly, ascorbic acid (0–20 mM) failed to reduce the steady-state levels. When AS52 cells were grown at elevated temperature (41°C), the steady-state level of the oxidative DNA modifications increased by 40%, in spite of a concomitant 1.6-fold increase of the cellular level of total glutathione. Depletion of glutathione at 41°C nearly doubled the already elevated level of oxidative damage. A constitutive expression of the heat-shock protein Hsp27 in L929 mouse fibrosarcoma cells at 37°C increased the glutathione level by 60%, but had little effect on the level of oxidative DNA damage.

Keywords: BSO, buthionine[S,R]sulphoximine; CYSET, cysteine ethylester; DTNB, 5,5′-dithio-(2-nitrobenzoic acid); GSH, glutathione (reduced form); GSSG, glutathione (oxidized form); NAC, N-acetylcysteine; 8-oxoG, 8-hydroxyguanine; ROS, reactive oxygen species; s.s.b., single-strand breaks; TNFα, tumour necrosis factor α.

Journal Article.  4108 words.  Illustrated.

Subjects: Clinical Cytogenetics and Molecular Genetics

Full text: subscription required

How to subscribe Recommend to my Librarian

Users without a subscription are not able to see the full content. Please, subscribe or login to access all content.