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J Biol Chem. 2018 Mar 9;293(10):3637-3650. doi: 10.1074/jbc.M117.817635. Epub 2018 Jan 17.

TRPM2 channel-mediated regulation of autophagy maintains mitochondrial function and promotes gastric cancer cell survival via the JNK-signaling pathway.

Author information

1
From the Departments of Biology.
2
Pathology.
3
Microbiology and Immunology, and.
4
Physiology, Biophysics Faculty of Life Science, Dalhousie University, Halifax and.
5
the Centre for Innovative and Collaborative Health Services Research, Quality and System Performance, IWK Health Centre, Halifax, Nova Scotia B3H 4R2, Canada.
6
Center for Microbial Pathogenesis, Research Institute at Nationwide Children's Hospital and.
7
the Department of Pediatrics, College of Medicine, Ohio State University, Columbus, Ohio 43205.
8
Physiology, Biophysics Faculty of Life Science, Dalhousie University, Halifax and yassine.elhiani@dal.ca.

Abstract

A lack of effective treatment is one of the main factors contributing to gastric cancer-related death. Discovering effective targets and understanding their underlying anti-cancer mechanism are key to achieving the best response to treatment and to limiting side effects. Although recent studies have shown that the cation channel transient receptor potential melastatin-2 (TRPM2) is crucial for cancer cell survival, the exact mechanism remains unclear, limiting its therapeutic potential. Here, using molecular and functional assays, we investigated the role of TRPM2 in survival of gastric cancer cells. Our results indicated that TRPM2 knockdown in AGS and MKN-45 cells decreases cell proliferation and enhances apoptosis. We also observed that the TRPM2 knockdown impairs mitochondrial metabolism, indicated by a decrease in basal and maximal mitochondrial oxygen consumption rates and ATP production. These mitochondrial defects coincided with a decrease in autophagy and mitophagy, indicated by reduced levels of autophagy- and mitophagy-associated proteins (i.e. ATGs, LC3A/B II, and BNIP3). Moreover, we found that TRPM2 modulates autophagy through a c-Jun N-terminal kinase (JNK)-dependent and mechanistic target of rapamycin-independent pathway. We conclude that in the absence of TRPM2, down-regulation of the JNK-signaling pathway impairs autophagy, ultimately causing the accumulation of damaged mitochondria and death of gastric cancer cells. Of note, by inhibiting cell proliferation and promoting apoptosis, the TRPM2 down-regulation enhanced the efficacy of paclitaxel and doxorubicin in gastric cancer cells. Collectively, we provide compelling evidence that TRPM2 inhibition may benefit therapeutic approaches for managing gastric cancer.

KEYWORDS:

TRPM2; autophagy; cell proliferation; chemotherapy; gastric cancer; mitochondria; transient receptor potential channels (TRP channels)

PMID:
29343514
PMCID:
PMC5846146
DOI:
10.1074/jbc.M117.817635
[Indexed for MEDLINE]
Free PMC Article

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