Circular RNA MAT2B Promotes Glycolysis and Malignancy of... : Hepatology (original) (raw)

Original Articles: HEPATOBILIARY MALIGNANCIES

Circular RNA MAT2B Promotes Glycolysis and Malignancy of Hepatocellular Carcinoma Through the miR‐338‐3p/PKM2 Axis Under Hypoxic Stress

Li, Qing1,2,†; Pan, Xiongxiong1,†; Zhu, Deming1; Deng, Zhengming1; Jiang, Runqiu*,3,4; Wang, Xuehao*,1,2

1Hepatobiliary Center, The First Affiliated Hospital of Nanjing Medical University, Key Laboratory of Liver Transplantation, Chinese Academy of Medical SciencesNHC Key Laboratory of Living Donor Liver TransplantationNanjingChina

2School of MedicineSoutheast UniversityNanjingChina

3Department of Hepatobiliary SurgeryThe Affiliated Drum Tower Hospital of Nanjing University Medical SchoolNanjingChina

4Medical School of Nanjing UniversityNanjingChina

*Address Correspondence and Reprint Requests to:
Xuehao Wang, Ph.D., M.D.
Hepatobiliary Center, The First Affiliated Hospital of Nanjing Medical University, Key Laboratory of Liver Transplantation, Chinese Academy of Medical Sciences Nanjing Medical University
No. 300, Guangzhou Road
Nanjing, Jiangsu Province, China
E‐mail: [email protected]
or
Runqiu Jiang, Ph.D., M.D.
Medical School of Nanjing University
No. 22, Hankou Road
Nanjing, Jiangsu Province, China
E‐mail: [email protected]

†These authors contributed equally to this work.

Abstract

Glucose metabolism reprogramming, which is a well‐established characteristic of multiple cancers, demands a higher rate of glycolysis to meet the increasing demands for macromolecular synthesis and to maintain rapid proliferation in a hypoxic environment. However, the mechanism underlying this switch remains to be elucidated. In this study, we investigated the function of circular RNA MAT2B (circMAT2B) in hepatocellular carcinoma (HCC) glucose metabolism reprogramming and malignancy. CircMAT2B was identified by bioinformatics analysis of Gene Expression Omnibus data sets. CircMAT2B expression was up‐regulated in HCC tissues and cell lines. HCC patients with high circMAT2B expression had shortened overall survival. We analyzed the positive correlation between glycolysis and circMAT2B expression in HCC using a maximum standardized uptake value determined by preoperative positron emission tomography/computed tomography scanning combined with high‐performance liquid chromatography assessment of the metabolites of glycolysis and the citric acid cycle. The effect of circMAT2B on glycolysis was validated in vitro and in vivo under hypoxic (1% O2) conditions. Functional assays were performed in HCC cells, HCC organoids, and nude mice to explore the tumor‐promoting roles of circMAT2B in HCC. Biotin‐coupled probe pull‐down assays, biotin‐coupled microRNA capture, luciferase reporter assays, fluorescence in situ hybridization, and RNA immunoprecipitation assays were performed to confirm the interaction among different RNAs. Mechanistically, we demonstrated that circMAT2B up‐regulated expression levels of the microRNA (miR)‐338‐3p target gene PKM2, which encodes a key enzyme in the process of glycolysis, through “sponging” miR‐338‐3p; thus, glycolysis and HCC progression are promoted through this mechanism. Conclusion: CircMAT2B promoted HCC progression by enhanced glycolysis by activating the circMAT2B/miR‐338‐3p/PKM2 axis under hypoxia, which may provide a therapeutic target for HCC.