Deubiquitinases Maintain Protein Homeostasis and Survival of Cancer Cells upon Glutathione Depletion

Cell Metab. 2019 May 7;29(5):1166-1181.e6. doi: 10.1016/j.cmet.2019.01.020. Epub 2019 Feb 21.


Cells are subjected to oxidative stress during the initiation and progression of tumors, and this imposes selective pressure for cancer cells to adapt mechanisms to tolerate these conditions. Here, we examined the dependency of cancer cells on glutathione (GSH), the most abundant cellular antioxidant. While cancer cell lines displayed a broad range of sensitivities to inhibition of GSH synthesis, the majority were resistant to GSH depletion. To identify cellular pathways required for this resistance, we carried out genetic and pharmacologic screens. Both approaches revealed that inhibition of deubiquitinating enzymes (DUBs) sensitizes cancer cells to GSH depletion. Inhibition of GSH synthesis, in combination with DUB inhibition, led to an accumulation of polyubiquitinated proteins, induction of proteotoxic stress, and cell death. These results indicate that depletion of GSH renders cancer cells dependent on DUB activity to maintain protein homeostasis and cell viability and reveal a potentially exploitable vulnerability for cancer therapy.

Keywords: GCLC; HSF1; UPR; antioxidants; cancer; deubiquitinase; glutamate-cysteine ligase catalytic subunit; glutathione; heat shock factor 1; high-throughput screening; oxidative stress; proteotoxic stress; unfolded protein response.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • A549 Cells
  • Aminopyridines / pharmacology
  • Animals
  • Antioxidants / metabolism*
  • Buthionine Sulfoximine / pharmacology
  • Catalytic Domain / drug effects
  • Cell Survival / drug effects*
  • Deubiquitinating Enzymes / antagonists & inhibitors
  • Deubiquitinating Enzymes / metabolism*
  • Female
  • Glutamate-Cysteine Ligase / antagonists & inhibitors
  • Glutamate-Cysteine Ligase / chemistry
  • Glutamate-Cysteine Ligase / metabolism
  • Glutathione / metabolism*
  • Humans
  • MCF-7 Cells
  • Mammary Glands, Animal / cytology
  • Mammary Glands, Human / cytology
  • Mice
  • Mice, Inbred C57BL
  • Mice, Nude
  • Organoids / drug effects
  • Oxidative Stress / drug effects
  • Proteostasis / drug effects*
  • Thiocyanates / pharmacology
  • Tumor Burden / drug effects
  • Ubiquitinated Proteins / metabolism
  • Xenograft Model Antitumor Assays


  • 2,6-diaminopyridine-3,5-bis(thiocyanate)
  • Aminopyridines
  • Antioxidants
  • Thiocyanates
  • Ubiquitinated Proteins
  • Buthionine Sulfoximine
  • Deubiquitinating Enzymes
  • Glutamate-Cysteine Ligase
  • Glutathione