The role of the HIF‐1α/ALYREF/PKM2 axis in glycolysis and tumorigenesis of bladder cancer

• Published in: Cancer communications (London, England) Vol. 41; no. 7; pp. 560 - 575
• Main Authors: Wang, Jing‐Zi, Zhu, Wei, Han, Jie, Yang, Xiao, Zhou, Rui, Lu, Hong‐Cheng, Yu, Hao, Yuan, Wen‐Bo, Li, Peng‐Chao, Tao, Jun, Lu, Qiang, Wei, Ji‐Fu, Yang, Haiwei
• Format: Journal Article
• Language: English
• Published: United States John Wiley & Sons, Inc 01.07.2021; John Wiley and Sons Inc; Wiley
• Subjects: 5‐methylcytidine modification; ALYREF; Antibodies; Bladder cancer; Carcinogenesis - genetics; Carrier Proteins; Cell Line, Tumor; Gene expression; glycolysis; Glycolysis - genetics; HIF‐1α; Humans; Hypoxia; Hypoxia-Inducible Factor 1, alpha Subunit - genetics; Kinases; Membrane Proteins; Nuclear Proteins; Original; PKM2; Plasmids; Polymerase chain reaction; Proteins; RNA-Binding Proteins; Thyroid Hormone-Binding Proteins; Thyroid Hormones; Transcription Factors; Urinary Bladder Neoplasms - genetics; United States > US; China; 5-methylcytidine modification; HIF-1α; PKM2; ALYREF; bladder cancer; glycolysis
• ISSN: 2523-3548; 2523-3548
• DOI: 10.1002/cac2.12158

Background As a rate‐limiting enzyme of glycolysis, pyruvate kinase muscle isozyme M2 (PKM2) participates in tumor metabolism and growth. The regulatory network of PKM2 in cancer is complex and has not been fully studied in bladder cancer. The 5‐methylcytidine (m5C) modification in PKM2 mRNA might participate in the pathogenesis of bladder cancer and need to be further clarified. This study aimed to investigate the biological function and regulatory mechanism of PKM2 in bladder cancer. Methods The expression of PKM2 and Aly/REF export factor (ALYREF) was measured by Western blotting, qRT‐PCR, and immunohistochemistry. The bioprocesses of bladder cancer cells were demonstrated by a series of experiments in vitro and in vivo. RNA immunoprecipitation, RNA‐sequencing, and dual‐luciferase reporter assays were conducted to explore the potential regulatory mechanisms of PKM2 in bladder cancer. Results In bladder cancer, we first demonstrated that ALYREF stabilized PKM2 mRNA and bound to its m5C sites in 3′‐untranslated regions. Overexpression of ALYREF promoted bladder cancer cell proliferation by PKM2‐mediated glycolysis. Furthermore, high expression of PKM2 and ALYREF predicted poor survival in bladder cancer patients. Finally, we found that hypoxia‐inducible factor‐1alpha (HIF‐1α) indirectly up‐regulated the expression of PKM2 by activating ALYREF in addition to activating its transcription directly. Conclusions The m5C modification in PKM2 mRNA in the HIF‐1α/ALYREF/PKM2 axis may promote the glucose metabolism of bladder cancer, providing a new promising therapeutic target for bladder cancer. Our data suggested that m5C may play a critical role in hypoxia/glycolysis network and targeting HIF‐1α/ALYREF/PKM2 signaling may be a promising therapeutic strategy to treat bladder cancer.