The cystine/cysteine cycle and GSH are independent and crucial antioxidant systems in malignant melanoma cells and represent druggable targets

Roberta Venè, Patrizia Castellani, Laura Delfino, Maria Lucibello, Maria Rosa Ciriolo, Anna Rubartelli

Research output: Contribution to journalArticle

Abstract

Aims: Cancer chemoresistance is often due to upregulation of antioxidant systems. Therapeutic targeting of these systems is however hampered by their redundancy. Here, we have performed a functional dissection of the antioxidant systems in different melanoma cases aimed at the identification of the most effective redox active drug. Results: We have identified two crucial antioxidant mechanisms: glutathione (GSH), the major intracellular redox buffer, and the cystine/cysteine cycle, which switches the extracellular redox state from an oxidized to a reduced state. The two mechanisms are independent in melanoma cells and may be substitutes for each other, but targeting both of them is lethal. Exposure to the pro-oxidant compound As 2O 3 induces an antioxidant response. However, while in these cells the intracellular redox balance remains almost unaffected, a reduced environment is generated extracellularly. GSH depletion by buthioninesulfoximine (BSO), or cystine/cysteine cycle inhibition by (S)-4-carboxyphenylglycine (sCPG), enhanced the sensitivity to As 2O 3. Remarkably, sCPG also prevented the remodeling of the microenvironment redox state. Innovation: We propose that the definition of the prevalent antioxidant system(s) in tumors is crucial for the design of tailored therapies involving redox-directed drugs in association with pro-oxidant drugs. Conclusion: In melanoma cells, BSO is the best enhancer of As 2O 3 sensitivity. However, since the strong remodeling of the microenvironmental redox state caused by As 2O 3 may promote tumor progression, the concomitant use of cystine/cysteine cycle blockers is recommended.

Original languageEnglish
Pages (from-to)2439-2453
Number of pages15
JournalAntioxidants and Redox Signaling
Volume15
Issue number9
DOIs
Publication statusPublished - Nov 1 2011

ASJC Scopus subject areas

  • Biochemistry
  • Cell Biology
  • Molecular Biology
  • Physiology
  • Clinical Biochemistry

Fingerprint Dive into the research topics of 'The cystine/cysteine cycle and GSH are independent and crucial antioxidant systems in malignant melanoma cells and represent druggable targets'. Together they form a unique fingerprint.

  • Cite this