Format

Send to:

Choose Destination
See comment in PubMed Commons below
PLoS One. 2014 Feb 26;9(2):e90151. doi: 10.1371/journal.pone.0090151. eCollection 2014.

Ambra1 is an essential regulator of autophagy and apoptosis in SW620 cells: pro-survival role of Ambra1.

Author information

  • 1Department of General Surgery, The First Affiliated Hospital of Soochow University, Suzhou, China.
  • 2Department of Hepatobiliary Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China.
  • 3Department of Ultrasonography, Changshu No. 2 People's Hospital, Changshu, China.
  • 4Department of Gastroenterology, The First Affiliated Hospital of SooChow University, Suzhou, China.
  • 5Department of Operating Rooms, The First Affiliated Hospital of SooChow University, Suzhou, China.
  • 6Department of General Surgery, The First Affiliated Hospital of Soochow University, Suzhou, China ; Institute of Health Science and Shanghai Institute of Immunology, Shanghai Institute for Biological Science, Chinese Academy of Science and Shanghai Jiao Tong University School of Medicine, Shanghai, China ; Washington University School of Medicine, St Louis, Missouri, United States of America.

Abstract

Recent research has revealed a role for Ambra1, an autophagy-related gene-related (ATG) protein, in the autophagic pro-survival response, and Ambra1 has been shown to regulate Beclin1 and Beclin1-dependent autophagy in embryonic stem cells. However, whether Ambra1 plays an important role in the autophagy pathway in colorectal cancer cells is unknown. In this study, we hypothesized that Ambra1 is an important regulator of autophagy and apoptosis in CRC cell lines. To test this hypothesis, we confirmed autophagic activity in serum-starved SW620 CRC cells by assessing endogenous microtubule-associated protein 1 light chain 3 (LC3) localization, the presence of autophagosomes (transmission electron microscopy) and LC3 protein levels (Western blotting). Ambra1 expression was detected by Western blot in SW620 cells treated with staurosporine or etoposide. Calpain and caspase inhibitors were employed to verify whether calpains and caspases were responsible for Ambra1 cleavage. To examine the role of Ambra1 in apoptosis, Ambra1 knockdown cells were treated with staurosporine and etoposide. Cell apoptosis and viability were measured by annexin-V and PI staining and MTT assays. We determined that serum deprivation-induced autophagy was associated with Ambra1 upregulation in colorectal cancer cell lines. Ambra1 expression decreased during staurosporine- or etoposide-induced apoptosis. Calpains and caspases may be responsible for Ambra1 degradation. When Ambra1 expression was reduced by siRNA, SW620 cells were more sensitive to staurosporine- or etoposide-induced apoptosis. In addition, starvation-induced autophagy decreased. Finally, Co-immunoprecipitation of Ambra1 and Beclin1 demonstrated that Ambra1 and Beclin1 interact in serum-starved or rapamycin-treated SW620 cells, suggesting that Ambra1 regulates autophagy in CRC cells by interacting with Beclin1. In conclusion, Ambra1 is a crucial regulator of autophagy and apoptosis in CRC cells that maintains the balance between autophagy and apoptosis.

PMID:
24587252
[PubMed - indexed for MEDLINE]
PMCID:
PMC3936000
Free PMC Article
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Public Library of Science Icon for PubMed Central
    Loading ...
    Write to the Help Desk