Overexpression of Mst1 reduces gastric cancer cell viability by repressing the AMPK-Sirt3 pathway and activating mitochondrial fission
Authors Yao S, Yan W
Received 19 July 2018
Accepted for publication 18 October 2018
Published 29 November 2018 Volume 2018:11 Pages 8465—8479
Checked for plagiarism Yes
Review by Single-blind
Peer reviewer comments 3
Editor who approved publication: Dr Federico Perche
Shiwei Yao,1,* Wei Yan2,*
1Department of Gastroenterology, Beijing Tiantan Hospital Affiliated to Capital Medical University, Beijing, China; 2Department of Gastroenterology, The First Hospital of Tsinghua University, Beijing, China
*These authors contributed equally to this work
Background and objective: Mammalian sterile 20-like kinase 1 (Mst1) plays a critical role in regulating cell survival and apoptosis. However, its influence on gastric cancer cell viability is not understood. Our study aims to explore the specific role of Mst1 in gastric cancer.
Materials and methods: Cellular viability was measured via TUNEL staining, MTT assays, and Western blotting. Immunofluorescence was performed to observe mitochondrial fission. Mst1 overexpression assays were conducted to observe the regulatory mechanisms of Mst1 in mitochondrial fission and cell apoptosis.
Results: The results demonstrated that Mst1 was downregulated in AGS cells when compared with GES-1 cells. However, overexpression of Mst1 reduced cell viability and increased apoptosis in AGS cells. Molecular experiments showed that Mst1 overexpression mediated mitochondrial damage, as evidenced by decreased ATP production, increased ROS generation, more cyt-c translocation from the mitochondria into the cytoplasm and nucleus, and activated the caspase-9-related apoptotic pathway. Furthermore, we found that mitochondrial fission was required for Mst1-induced mitochondrial dysfunction; inhibition of mitochondrial fission sustained mitochondrial homeostasis in response to Mst1 overexpression. In addition, our data revealed that Mst1 controlled mitochondrial fission via repressing the AMPK-Sirt3 pathway. Activation of the AMPK-Sirt3 pathway negated the promoting effect of Mst1 overexpression on mitochondrial fission.
Conclusion: Altogether, our data identified Mst1 as a novel tumor-suppressive factor in promoting cell death in gastric cancer cells by triggering mitochondrial fission and blocking the AMPK-Sirt3 axis.
Keywords: Mst1, gastric cancer, mitochondrial fission, apoptosis, AMPK-Sirt3 pathway
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