Journal Article

Glutathione depletion by buthionine sulfoximine induces DNA deletions in mice

Ramune Reliene and Robert H. Schiestl

in Carcinogenesis

Volume 27, issue 2, pages 240-244
Published in print February 2006 | ISSN: 0143-3334
Published online August 2005 | e-ISSN: 1460-2180 | DOI: http://dx.doi.org/10.1093/carcin/bgi222
Glutathione depletion by buthionine sulfoximine induces DNA deletions in mice

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Oxidative stress and genomic rearrangements play a role in cancer development. l-Buthionine-sulfoximine (BSO) induces oxidative stress in a cell by irreversibly inhibiting γ-glutamylcysteine synthetase, an essential enzyme for the synthesis of glutathione (GSH). We postulated that oxidative stress induced by GSH depletion might lead to genomic rearrangements, such as DNA deletions, and that counteracting such pro-oxidant conditions by the exogenous antioxidant N-acetyl-l-cysteine (NAC), might suppress DNA deletions. Therefore, we determined the frequency of 70 kb DNA deletions and thiol levels in mouse fetuses exposed to BSO (alone or in combination with NAC) via drinking water given to female mice during gestation. BSO treatment resulted in a significantly increased frequency of DNA deletions and decreased concentrations of GSH and cysteine. An amount of 2 mM BSO treatment resulted in a 30% higher DNA deletion frequency, 45% lower GSH and 27% lower cysteine levels, when compared with the untreated control and 20 mM BSO treatment caused a 40% higher DNA deletion frequency, 70% lower GSH and 55% lower cysteine levels. In combination BSO and NAC resulted in reduced levels of GSH consistent with the effect of BSO; however, cysteine levels increased and the frequency of DNA deletions was within the normal range. Thus, NAC protected against genome rearrangements caused by GSH depletion. This study showed that lowering the concentrations of thiol antioxidants results in DNA deletions that may play a role in carcinogenesis.

Keywords: d.p.c., days post coitum; d.p.p., days post partum; DSBs, double strand breaks; γ-GCS, γ-glutamylcysteine synthetase; GSH, glutathione; BSO, buthionine sulfoximine; 8-OHdG, 8-OH deoxyguanosine; NAC, N-acetyl cysteine; p, pink-eyed dilution; pun, pink-eyed unstable; ROS reactive oxygen species; RPE, retinal pigment epithelium; SSBs, single strand breaks

Journal Article.  4689 words.  Illustrated.

Subjects: Clinical Cytogenetics and Molecular Genetics

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