Multidrug Resistance-associated Protein-1 (MRP-1)-dependent Glutathione Disulfide (GSSG) Efflux as a Critical Survival Factor for Oxidant-enriched Tumorigenic Endothelial Cells

J Biol Chem. 2016 May 6;291(19):10089-103. doi: 10.1074/jbc.M115.688879. Epub 2016 Mar 9.

Abstract

Endothelial cell tumors are the most common soft tissue tumors in infants. Tumor-forming endothelial (EOMA) cells are able to escape cell death fate despite excessive nuclear oxidant burden. Our previous work recognized perinuclear Nox-4 as a key contributor to EOMA growth. The objective of this work was to characterize the mechanisms by which EOMA cells evade oxidant toxicity and thrive. In EOMA cells, compared with in the cytosol, the nuclear GSSG/GSH ratio was 5-fold higher. Compared to the ratio observed in healthy murine aortic endothelial (MAE) cells, GSSG/GSH was over twice as high in EOMA cells. Multidrug resistance-associated protein-1 (MRP-1), an active GSSG efflux mechanism, showed 2-fold increased activity in EOMA compared with MAE cells. Hyperactive YB-1 and Ape/Ref-1 were responsible for high MRP-1 expression in EOMA. Proximity ligand assay demonstrated MRP-1 and YB-1 binding. Such binding enabled the nuclear targeting of MRP-1 in EOMA in a leptomycin-B-sensitive manner. MRP-1 inhibition as well as knockdown trapped nuclear GSSG, causing cell death of EOMA. Disulfide loading of cells by inhibition of GSSG reductase (bischoloronitrosourea) or thioredoxin reductase (auranofin) was effective in causing EOMA death as well. In sum, EOMA cells survive a heavy oxidant burden by rapid efflux of GSSG, which is lethal if trapped within the cell. A hyperactive MRP-1 system for GSSG efflux acts as a critical survival factor for these cells, making it a potential target for EOMA therapeutics.

Keywords: Ape/Ref-1; NADPH oxidase; Nox-4; YB-1; endothelial cell; multidrug transporter; thioredoxin; tumor.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Auranofin / pharmacology
  • Cell Line, Tumor
  • Cell Survival / drug effects
  • Cell Survival / genetics
  • DNA-(Apurinic or Apyrimidinic Site) Lyase / genetics
  • DNA-(Apurinic or Apyrimidinic Site) Lyase / metabolism
  • Endothelial Cells / metabolism*
  • Endothelial Cells / pathology
  • Fatty Acids, Unsaturated / pharmacology
  • Gene Expression Regulation, Neoplastic / drug effects
  • Glutathione Disulfide / genetics
  • Glutathione Disulfide / metabolism*
  • Mice
  • Multidrug Resistance-Associated Proteins / genetics
  • Multidrug Resistance-Associated Proteins / metabolism*
  • Neoplasm Proteins / genetics
  • Neoplasm Proteins / metabolism*
  • Transcription Factors / genetics
  • Transcription Factors / metabolism
  • Vascular Neoplasms / drug therapy
  • Vascular Neoplasms / genetics
  • Vascular Neoplasms / metabolism*
  • Vascular Neoplasms / pathology

Substances

  • Fatty Acids, Unsaturated
  • Multidrug Resistance-Associated Proteins
  • Neoplasm Proteins
  • Transcription Factors
  • YB-1 protein, mouse
  • Auranofin
  • Apex1 protein, mouse
  • DNA-(Apurinic or Apyrimidinic Site) Lyase
  • Glutathione Disulfide
  • leptomycin B
  • multidrug resistance-associated protein 1