TRAIL induces autophagic protein cleavage through caspase activation in melanoma cell lines under arginine deprivation

Min You, Niramol Savaraj, MacUs T. Kuo, Medhi Wangpaichitr, Javier Varona-Santos, Chunjing Wu, Dao M. Nguyen, Lynn Feun

Research output: Contribution to journalArticlepeer-review

39 Scopus citations

Abstract

Arginine deprivation is a promising strategy for treating ASS-negative malignant tumors including melanoma. However, autophagy can potentially counteract the effectiveness of this treatment by acting as a pro-survival pathway. By combining tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) with arginine deprivation using ADI-PEG20 (pegylated arginine deiminase), we achieved enhanced apoptosis and accelerated cell death in melanoma cell lines. This implies a switch from autophagy to apoptosis. In our current investigation, we found that TRAIL could induce the cleavage of two key autophagic proteins, Beclin-1 and Atg5, in the combination treatment. Using specific inhibitors for individual caspases, we found that caspase-8 inhibitor could completely abolish the cleavage. Furthermore, caspase-8 inhibitor was able to fully reverse the enhanced cytotoxicity induced by TRAIL. Inhibitors for caspase-3, 6, 9, and 10 were able to block the cleavage of these two autophagic proteins to some extent and correspondingly rescue cells from the cytotoxicity of the combination of TRAIL and arginine deprivation. In contrast, calpain inhibitor could not prevent the cleavage of either Beclin-1 or Atg5, and was unable to prevent cell death. Overall, our data indicate that the cleavage of Beclin-1 and Atg5 by TRAIL-initiated caspase activation is one of the mechanisms that lead to the enhancement of the cytotoxicity in the combination treatment.

Original languageEnglish (US)
Pages (from-to)181-190
Number of pages10
JournalMolecular and Cellular Biochemistry
Volume374
Issue number1-2
DOIs
StatePublished - Feb 2013

Keywords

  • ADI-PEG20
  • Atg5
  • Autophagy
  • Beclin-1
  • Caspase
  • TRAIL

ASJC Scopus subject areas

  • Clinical Biochemistry
  • Molecular Biology
  • Cell Biology

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