Research Paper Volume 9, Issue 8 pp 1885—1897
Epigenetic silencing of miR-338 facilitates glioblastoma progression by de-repressing the pyruvate kinase M2-β-catenin axis
- 1 Department of Neurosurgery, The Second Affiliated Hospital of Harbin Medical University, Harbin 150086, China
- 2 Neuroscience Institute, Heilongjiang Academy of Medical Sciences, Harbin 150086, China
- 3 Chinese Glioma Cooperative Group (CGCG), Beijing 100050, China
- 4 Department of Laboratory Diagnosis, The Second Affiliated Hospital of Harbin Medical University, Harbin 150086, China
- 5 Beijing Neurosurgical Institute, Beijing, 100050, China
- 6 Department of Neurosurgery, Huashan Hospital, Fudan University, Shanghai 200040, China
Received: May 14, 2017 Accepted: July 27, 2017 Published: August 2, 2017
https://doi.org/10.18632/aging.101271How to Cite
Copyright: Han et al. This is an open‐access article distributed under the terms of the Creative Commons Attribution License (CC BY 3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Abstract
Glioblastoma is the most malignant type of brain tumor, and its high invasiveness and multiplication severely shortens patients’ overall survival. The embryonic pyruvate kinase M2 (PKM2) isoform is highly expressed in human cancer. We used computational target gene prediction, in vitro cell culture, immunoblotting, quantitative real-time PCR, ATP measurements, luciferase reporter assays, wound-healing assays, Transwell assays, RNA immunoprecipitation PCR, co-immunoprecipitation, flow cytometry and tumor xenografts to study the regulation of the PKM2/β-catenin axis in glioma. PKM2 was predicted to be a potential target of miR-338. MiR-338 was downregulated in high-grade gliomas due to hypermethylation of CpG islands in its promoter, and ectopic expression of miR-338 inhibited cell proliferation, invasion and ATP generation. MiR-338 inhibited PKM2 expression by binding to the 3′ untranslated region of PKM2, which ultimately prevented binding of PKM2 to β-catenin and reduced T-cell factor/lymphoid enhancer factor reporter gene transcriptional activity. MiR-338 also inhibited PKM2 expression, attenuated glioma growth and prolonged survival in an animal model. These results confirm that miR-338, a tumor suppressor, suppresses the PKM2/β-catenin axis and is downregulated in glioblastoma. This provides a theoretical basis for glioma-targeting therapy.