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Identification of Intracellular Signaling Events Induced in Viable Cells by Interaction with Neighboring Cells Undergoing Apoptotic Cell Death
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Autophagy inhibition through PI3K/Akt increases apoptosis by sodium selenite in NB4 cells

Yun Ren1, Fang Huang, Yuan Liu

  • 1National Laboratory of Medical Molecular Biology, Department of Biochemistry and Molecular Biology, Institute of Basic Medical Science, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People's Republic of China.

BMB Reports
|October 1, 2009
PubMed

Insights

Sodium selenite enhances cancer cell death (apoptosis) by inhibiting autophagy, a cellular self-cleaning process. This mechanism, involving the PI3K/Akt pathway, offers a potential strategy for cancer chemotherapy.

Area of Science:

  • Cell Biology
  • Molecular Oncology
  • Cancer Therapeutics

Background:

  • Selenium compounds exhibit chemotherapeutic properties by inducing cancer cell apoptosis with minimal toxicity to normal cells.
  • The precise mechanism of selenium's anti-cancer effects, particularly its interaction with cellular processes like autophagy, remains incompletely understood.
  • Autophagy and apoptosis are increasingly recognized as interconnected cellular pathways with implications for cancer development and treatment.

Purpose of the Study:

  • To investigate the role of autophagy in sodium selenite-induced apoptosis in NB4 cancer cells.
  • To elucidate the molecular mechanisms underlying selenium's chemotherapeutic effects, focusing on the interplay between autophagy and apoptosis.

Main Methods:

  • NB4 cells were treated with sodium selenite.
  • Autophagy levels were assessed using electron microscopy, acridine orange staining, and Western blot analysis.
  • The involvement of the PI3K/Akt signaling pathway was examined using specific inhibitors and Western blotting.

Main Results:

  • Sodium selenite treatment suppressed autophagy in NB4 cells.
  • Combining selenite with an autophagy inhibitor enhanced apoptosis induction.
  • The PI3K/Akt signaling pathway was downregulated by selenite, and its inhibition further decreased autophagic levels, correlating with increased apoptosis.

Conclusions:

  • Sodium selenite promotes apoptosis in NB4 cells primarily through the inhibition of autophagy.
  • The PI3K/Akt signaling pathway is a key mediator in selenite-induced autophagy suppression and subsequent apoptosis.
  • Targeting autophagy inhibition represents a viable strategy to potentiate the anti-cancer effects of selenium compounds.

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