Exploiting cancer metabolism for the clinical benefit of patients with hepatocellular carcinoma (HCC) is a topic under active investigation. Ubiquitin-specific peptidase 48 (USP48), a member of the ubiquitin-specific protease family, is involved in tumor growth, inflammation, and genome stability. However, the role of USP48 in HCC tumorigenesis remains unknown. In this study, we report that expression of USP48 is downregulated in diethylnitrosamine-induced liver tumorigenesis in mice as well as in human HCC. USP48 physically bound and stabilized SIRT6 by K48-linked deubiquitination at the K33 and K128 sites of SIRT6, which impeded metabolic reprogramming to hamper HCC tumorigenesis. Moreover, methyltransferase-like 14 (Mettl14)-induced m6A modification participated in the regulation of USP48 in HCC by maintaining USP48 mRNA stability. Our work uncovers the tumor-suppressive function of the Mettl14-USP48-SIRT6 axis via modulation of glycolysis, providing new insights into the critical roles of metabolic activities in HCC and identifying an attractive target for future treatment studies. SIGNIFICANCE: These findings demonstrate that USP48 is regulated by Mettl14-induced m6A modification and stabilizes SIRT6 to attenuate HCC glycolysis and malignancy.
©2021 American Association for Cancer Research.