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Cell Signal. 2014 Mar;26(3):611-8. doi: 10.1016/j.cellsig.2013.11.024. Epub 2013 Dec 11.

Extrinsic sphingosine 1-phosphate activates S1P5 and induces autophagy through generating endoplasmic reticulum stress in human prostate cancer PC-3 cells.

Author information

  • 1Department of Biotechnology, College of Health Science, Asia University, Taichung, Taiwan, ROC; Graduate Institute of Basic Medical Science, China Medical University and Hospital, Taichung, Taiwan.
  • 2Department of Life Science, College of Life Science, National Taiwan University, Taipei, Taiwan, ROC.
  • 3Graduate Institute of Basic Medical Science, China Medical University and Hospital, Taichung, Taiwan.
  • 4Instrumentation Center, College of Life Science, National Taiwan University, Taipei, Taiwan, ROC; Technology Commons, College of Life Science, National Taiwan University, Taipei, Taiwan, ROC.
  • 5Department of Life Science, College of Life Science, National Taiwan University, Taipei, Taiwan, ROC; Technology Commons, College of Life Science, National Taiwan University, Taipei, Taiwan, ROC. Electronic address: wphuang@ntu.edu.tw.
  • 6Department of Life Science, College of Life Science, National Taiwan University, Taipei, Taiwan, ROC; Institute of Zoology, College of Life Science, National Taiwan University, Taipei, Taiwan, ROC; Center for Biotechnology, National Taiwan University, Taipei, Taiwan, ROC; Angiogenesis Research Center, National Taiwan University, Taipei, Taiwan, ROC; Research Center for Developmental Biology and Regenerative Medicine, National Taiwan University, Taipei, Taiwan, ROC. Electronic address: hsinyu@ntu.edu.tw.

Abstract

Sphingosine 1-phosphate (S1P) is a bioactive lysophospholipid that binds to a family of G protein-coupled receptors (GPCRs), termed S1P1-S1P5. Our previous study has reported that S1P induces autophagy in human prostate cancer PC-3 cell. In addition, S1P-induced autophagy plays a prosurvival role in PC-3 cells. Accumulating evidence has shown that the autophagy responses triggered by ER stress signaling have cytoprotective effects. Thus, we attempted to investigate whether S1P-induced autophagy is a result of triggering ER stress in PC-3 cells. By monitoring XBP-1 mRNA splicing, a characteristic of ER stress, we demonstrate that S1P triggers ER stress in a concentration-dependent and time-dependent manner. Moreover, DiH S1P, a membrane-nonpermeable S1P analog without intracellular effects also enhances ER stress. Meanwhile, we also show that S1P5 is required for S1P-induced ER stress by using RNA interference experiments. Furthermore, signaling analyses revealed that PI3K, PLC, and ROS production were involved in S1P's effects on ER stress induction. On the other hand, knockdown of XBP-1 abolished S1P-induced autophagy. In summary, our results demonstrate for the first time that the extracellular S1P-triggered ER stress is responsible for autophagy induction in PC-3 cells.

Copyright © 2013 Elsevier Inc. All rights reserved.

KEYWORDS:

Autophagy; ER stress; Prostate cancer; Sphingosine 1-phosphate

PMID:
24333325
[PubMed - indexed for MEDLINE]
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