Modulation of glutathione promotes apoptosis in triple-negative breast cancer cells

Tara Miran, Andreas T. J. Vogg, Natascha Drude, Felix M. Mottaghy, Agnieszka Morgenroth*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

22 Citations (Web of Science)

Abstract

Triple-negative breast cancer has an extremely high rate of relapse. This is particularly due to the existence and survival of cancer stem cells (CSCs) characterized by increased amounts of glutathione (GSH). In this study, we evaluated the potential of pharmacological GSH depletion to sensitize CSCs to ionizing radiotherapy with an I-125-labeled nucleoside analog, 5-iodo-4'-thio-2'-deoxyuridine (ITdU). CSCs were isolated using CD24(-) and CD44(+)-specific microbeads. GSH and reactive oxygen species (ROS) were evaluated by fluorescence-activated cell sorting. GSH synthesis was inhibited with buthionine sulfoximine (BSO). Apoptotic cells were identified with propidium iodide and double-strand DNA breaks were detected by gamma-H2AX staining. For therapy study, BSO treated and untreated mice xenografted with breast CSCs received weekly I-125-ITdU. Therapy efficiency was monitored by fluorodeoxyglucose-18-mu-positron emission tomography. We showed that GSH modulation sensitizes CD24(-) and CD44(+) breast cancer cells to endogenous nanoradiotherapy. BSO synergistically affects ROS generation induced by I-125-ITdU. In an in vivo study, we demonstrated a complete tumor regression as a consequence of preconditioning with a GSH-synthesis inhibitor prior to treatment with I-125-ITdU. GSH modulation in combination with an oxidative stress-generating treatment such as endogenous radiotherapy using an Auger emitter offers an extraordinary opportunity for selective and efficient eradication of drug-resistant CSCs.
Original languageEnglish
Pages (from-to)2803-2813
Number of pages11
JournalFaseb Journal
Volume32
Issue number5
DOIs
Publication statusPublished - 1 May 2018

Keywords

  • endogenous radiotherapy
  • Auger electron emitter
  • nucleoside analogs
  • OXIDATIVE STRESS
  • STEM-CELLS
  • GLUCOSE-METABOLISM
  • BUTHIONINE SULFOXIMINE
  • HUMAN-LYMPHOCYTES
  • AUGER ELECTRONS
  • TUMOR
  • HYPOXIA
  • MTOR
  • GROWTH

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