Inhibition of autophagic flux by ROS promotes apoptosis during DTT-induced ER/oxidative stress in HeLa cells

  • Authors:
    • Xi-Yan Xiang
    • Xiao-Chun Yang
    • Jin Su
    • Jing-Song Kang
    • Yao Wu
    • Ya-Nan Xue
    • Yu-Tong Dong
    • Lian-Kun Sun
  • View Affiliations

  • Published online on: April 1, 2016     https://doi.org/10.3892/or.2016.4725
  • Pages: 3471-3479
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Abstract

As targets for cancer therapy, endoplasmic reticulum (ER) stress and autophagy are closely linked. However, the signaling pathways responsible for induction of autophagy in response to ER stress and its cellular consequences appear to vary with cell type and stimulus. In the present study, we showed that dithiothreitol (DTT) induced ER stress in HeLa cells in a time- and dose-dependent fashion. With increased ER stress, reactive oxygen species (ROS) production increased and autophagy flux, assessed by intracellular accumulation of LC3B-II and p62, was inhibited. N-acetyl-L-cysteine (NAC), a classic antioxidant, exacerbated cell death induced by 3.2 mM of DTT, but attenuated that induced by 6.4 mM DTT. Low cytotoxic doses of DTT transiently activated c-JNU N-terminal kinase (JNK) and p38, whereas high dose of DTT persistently activated JNK and p38 and simultaneously reduced extracellular signal-regulated kinase (ERK) activity. Combined treatment with DTT and U0126, an inhibitor of ERK upstream activators mitogen-activated protein kinase (MAPK) kinase 1 and 2 (MEK1/2), blocked autophagy flux in HeLa cells. This effect was similar to that caused by a combination of DTT and chloroquine (CQ). These data suggested that insufficient autophagy was accompanied by increased ROS production during DTT-induced ER stress. ROS appeared to regulate MAPK signaling, switching from a pro-survival to a pro-apoptotic signal as ER stress increased. ERK inhibition by ROS during severe ER stress blocked autophagic flux. Impaired autophagic flux, in turn, aggravated ER stress, ultimately leading to cell death. Taken together, our data provide the first reported evidence that ROS may control cell fate through regulating the MAPK pathways and autophagic flux during DTT-induced ER/oxidative stress.
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June-2016
Volume 35 Issue 6

Print ISSN: 1021-335X
Online ISSN:1791-2431

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Spandidos Publications style
Xiang X, Yang X, Su J, Kang J, Wu Y, Xue Y, Dong Y and Sun L: Inhibition of autophagic flux by ROS promotes apoptosis during DTT-induced ER/oxidative stress in HeLa cells. Oncol Rep 35: 3471-3479, 2016
APA
Xiang, X., Yang, X., Su, J., Kang, J., Wu, Y., Xue, Y. ... Sun, L. (2016). Inhibition of autophagic flux by ROS promotes apoptosis during DTT-induced ER/oxidative stress in HeLa cells. Oncology Reports, 35, 3471-3479. https://doi.org/10.3892/or.2016.4725
MLA
Xiang, X., Yang, X., Su, J., Kang, J., Wu, Y., Xue, Y., Dong, Y., Sun, L."Inhibition of autophagic flux by ROS promotes apoptosis during DTT-induced ER/oxidative stress in HeLa cells". Oncology Reports 35.6 (2016): 3471-3479.
Chicago
Xiang, X., Yang, X., Su, J., Kang, J., Wu, Y., Xue, Y., Dong, Y., Sun, L."Inhibition of autophagic flux by ROS promotes apoptosis during DTT-induced ER/oxidative stress in HeLa cells". Oncology Reports 35, no. 6 (2016): 3471-3479. https://doi.org/10.3892/or.2016.4725