O-GlcNAc modified-TIP60/KAT5 is required for PCK1 deficiency-induced HCC metastasis

Aberrant glucose metabolism and elevated O-linked beta-N-acetylglucosamine modification (O-GlcNAcylation) are hallmarks of hepatocellular carcinoma (HCC). Loss of phosphoenolpyruvate carboxykinase 1 (PCK1), the major rate-limiting enzyme of hepatic gluconeogenesis, increases hexosamine biosynthetic pathway (HBP)-mediated protein O-GlcNAcylation in hepatoma cell and promotes cell growth and proliferation. However, whether PCK1 deficiency and hyper O-GlcNAcylation can induce HCC metastasis is largely unknown. Here, gain- and loss-of-function studies demonstrate that PCK1 suppresses HCC metastasis in vitro and in vivo. Specifically, lysine acetyltransferase 5 (KAT5), belonging to the MYST family of histone acetyltransferases (HAT), is highly modified by O-GlcNAcylation in PCK1 knockout hepatoma cells. Mechanistically, PCK1 depletion suppressed KAT5 ubiquitination by increasing its O-GlcNAcylation, thereby stabilizing KAT5. KAT5 O-GlcNAcylation epigenetically activates TWIST1 expression via histone H4 acetylation, and enhances MMP9 and MMP14 expression via c-Myc acetylation, thus promoting epithelial-mesenchymal transition (EMT) in HCC. In addition, targeting HBP-mediated O-GlcNAcylation of KAT5 inhibits lung metastasis of HCC in hepatospecific Pck1-deletion mice. Collectively, our findings demonstrate that PCK1 depletion increases O-GlcNAcylation of KAT5, epigenetically induces TWIST1 expression and promotes HCC metastasis, and link metabolic enzyme, post-translational modification (PTM) with epigenetic regulation.

Automated summary

Aberrant glucose metabolism and elevated O-linked beta-N-acetylglucosamine modification are common in hepatocellular carcinoma (HCC), with loss of phosphoenolpyruvate carboxykinase 1 (PCK1) leading to increased protein O-GlcNAcylation and promoting HCC metastasis. Through gain- and loss-of-function studies, it was demonstrated that PCK1 suppresses HCC metastasis by regulating KAT5 O-GlcNAcylation and epigenetically activating TWIST1 and c-Myc to promote epithelial-mesenchymal transition (EMT) in HCC. Targeting HBP-mediated O-GlcNAcylation of KAT5 inhibits lung metastasis of HCC in hepatospecific Pck1-deletion mice, highlighting the link between metabolic enzyme deficiency and epigenetic regulation in HCC metastasis.