Thioredoxin reductase 1 deficiency enhances selenite toxicity in cancer cells via a thioredoxin-independent mechanism

Ryuta Tobe, Min Hyuk Yoo, Noelia Fradejas, Bradley A. Carlson, Soledad Calvo, Vadim N. Gladyshev, Dolph L. Hatfield

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)

Abstract

Selenium is an essential trace element in mammals, but is toxic at high levels. It is best known for its cancer prevention activity, but cancer cells are more sensitive to selenite toxicity than normal cells. Since selenite treatment leads to oxidative stress, and the Trx (thioredoxin) system is a major antioxidative system, we examined the interplay between TR1 (Trx reductase 1) and Trx1 deficiencies and selenite toxicity in DT cells, a malignant mouse cell line, and the corresponding parental NIH 3T3 cells. TR1-deficient cells were far more sensitive to selenite toxicity than Trx1-deficient or control cells. In contrast, this effect was not seen in cells treated with hydrogen peroxide, suggesting that the increased sensitivity of TR1 deficiency to selenite was not due to oxidative stress caused by this compound. Further analyses revealed that only TR1-deficient cells manifested strongly enhanced production and secretion of glutathione, which was associated with increased sensitivity of the cells to selenite. The results suggest a new role for TR1 in cancer that is independent of Trx reduction and compensated for by the glutathione system. The results also suggest that the enhanced selenite toxicity of cancer cells and simultaneous inhibition of TR1 can provide a new avenue for cancer therapy.

Original languageEnglish
Pages (from-to)423-430
Number of pages8
JournalBiochemical Journal
Volume445
Issue number3
DOIs
Publication statusPublished - 2012 Aug 1

Keywords

  • Cancer
  • Glutathione
  • Selenium cytotoxicity
  • Selenoprotein
  • Thioredoxin
  • Thioredoxin reductase 1

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