Cadmium-induced autophagy is mediated by oxidative signaling in PC-12 cells and is associated with cytoprotection

Mol Med Rep. 2015 Sep;12(3):4448-4454. doi: 10.3892/mmr.2015.3907. Epub 2015 Jun 11.

Abstract

Oxidative stress induced by cadmium (Cd) is a common phenomenon that has been observed in numerous studies. However, the underlying mechanism remains unknown. Recently, exposure of PC-12 cells to Cd has been shown to activate autophagy, which acts as a temporary survival pathway under stressful conditions by delaying the occurrence of apoptosis. The present study investigated the impact of oxidative stress on Cd‑induced autophagy in PC-12 cells. The results demonstrated that Cd‑induced autophagy (following treatment with Cd for 4 h), increased the levels of intracellular reactive oxygen species (ROS), decreased the mitochondrial membrane potential and resulted in apoptosis. A treatment with chloroquine (CQ; an autophagic inhibitor) sensitized the PC‑12 cells to Cd, due to the increased production of ROS, which was associated with the incapacity to reduce mitochondrial and cell death. N-acetyl-L-cysteine, an antioxidant agent, decreased Cd-induced autophagy and reduced intracellular ROS levels, but enhanced CQ‑induced apoptotic cell death. These findings indicate that moderate levels of ROS are essential in the regulation of Cd-induced autophagy, which subsequently enhances cell survival. Thus, the results of the present study provide an insight for future investigation of Cd-induced neurotoxicity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylcysteine / pharmacology
  • Animals
  • Antioxidants / pharmacology
  • Autophagy / drug effects*
  • Cadmium / toxicity*
  • Cytoprotection
  • Environmental Pollutants / toxicity*
  • Oxidative Stress*
  • PC12 Cells
  • Rats
  • Reactive Oxygen Species / metabolism
  • Signal Transduction

Substances

  • Antioxidants
  • Environmental Pollutants
  • Reactive Oxygen Species
  • Cadmium
  • Acetylcysteine