Molecular and Cellular Biochemistry

, Volume 374, Issue 1, pp 181–190

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
Article

DOI: 10.1007/s11010-012-1518-1

Cite this article as:
You, M., Savaraj, N., Kuo, M.T. et al. Mol Cell Biochem (2013) 374: 181. doi:10.1007/s11010-012-1518-1

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.

Keywords

TRAIL ADI-PEG20 Autophagy Caspase Beclin-1 Atg5 

Abbreviations

ADI

Arginine deiminase

ASS

Argininosuccinate synthetase

DMSO

Dimethyl sulfoxide

DPBS

Dulbecco’s phosphate-buffered saline

FBS

Fetal bovine serum

FITC

Fluorescein isothiocyanate

HIF1α

Hypoxia-inducible factor 1 alpha

kDa

Kilodalton

MEM

Minimum essential media

PEG

Polyethylene glycol

PI

Propidium iodide

PVDF

Polyvinylidene fluoride

SD

Standard deviation

SDS-PAGE

Sodium dodecyl sulfate polyacrylamide gel electrophoresis

siRNA

Small interfering ribonucleic acid

TBS

Tris(hydroxymethyl)aminomethane-buffered saline

TRAIL

Tumor necrosis factor-related apoptosis-inducing ligand

Copyright information

© Springer Science+Business Media New York 2012

Authors and Affiliations

  • Min You
    • 1
  • Niramol Savaraj
    • 1
    • 2
  • Macus T. Kuo
    • 3
  • Medhi Wangpaichitr
    • 2
    • 4
  • Javier Varona-Santos
    • 1
  • Chunjing Wu
    • 2
  • Dao M. Nguyen
    • 1
    • 4
  • Lynn Feun
    • 1
  1. 1.Sylvester Comprehensive Cancer Center, University of Miami Miller School of MedicineMiamiUSA
  2. 2.Division of Hematology and OncologyMiami Veterans Affairs Healthcare SystemMiamiUSA
  3. 3.Department of Molecular PathologyM.D. Anderson Cancer Center, University of TexasHoustonUSA
  4. 4.Department of SurgeryUniversity of Miami Miller School of MedicineMiamiUSA

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