TNFα promotes glioblastoma A172 cell mitochondrial apoptosis via augmenting mitochondrial fission and repression of MAPK–ERK–YAP signaling pathways
Authors Lu C, Chen X, Wang Q, Xu X, Xu B
Received 17 August 2018
Accepted for publication 25 September 2018
Published 18 October 2018 Volume 2018:11 Pages 7213—7227
Checked for plagiarism Yes
Review by Single anonymous peer review
Peer reviewer comments 3
Editor who approved publication: Dr Leo Jen-Liang Su
Changyu Lu, Xiaolei Chen, Qun Wang, Xinghua Xu, Bainan Xu
Department of Neurosurgery, Chinese PLA General Hospital, Beijing 100853, China
Background and objective: The present study was designed to explore the roles of mitochondrial fission and MAPK–ERK–YAP signaling pathways and to determine their mutual relationship in TNFα-mediated glioblastoma mitochondrial apoptosis.
Materials and methods: Cellular viability was measured via TUNEL staining, MTT assays, and Western blot. Immunofluorescence was performed to observe mitochondrial fission. YAP overexpression assays were conducted to observe the regulatory mechanisms of MAPK–ERK–YAP signaling pathways in mitochondrial fission and glioblastoma mitochondrial apoptosis.
Results: The results in our present study indicated that TNFα treatment dose dependently increased the apoptotic rate of glioblastoma cells. Functional studies confirmed that TNFα-induced glioblastoma apoptosis was attributable to increased mitochondrial fission. Excessive mitochondrial fission promoted mitochondrial dysfunction, as evidenced by decreased mitochondrial potential, repressed ATP metabolism, elevated ROS synthesis, and downregulated antioxidant factors. In addition, the fragmented mitochondria liberated cyt-c into the cytoplasm/nucleus where it activated a caspase-9-involved mitochondrial apoptosis pathway. Furthermore, our data identified MAPK–ERK–YAP signaling pathways as the primary molecular mechanisms by which TNFα modulated mitochondrial fission and glioblastoma apoptosis. Reactivation of MAPK–ERK–YAP signaling pathways via overexpression of YAP neutralized the cytotoxicity of TNFα, attenuated mitochondrial fission, and favored glioblastoma cell survival.
Conclusion: Overall, our data highlight that TNFα-mediated glioblastoma apoptosis stems from increased mitochondrial fission and inactive MAPK–ERK–YAP signaling pathways, which provide potential targets for new therapies against glioblastoma.
Keywords: glioblastoma, apoptosis, mitochondrion, TNFα, mitochondrial fission, MAPK-ERK-YAP signaling pathways
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