谷氨酰胺-果糖-6-磷酸酰胺转移酶1（GFAT1）是己糖胺生物合成途径（HBP）中的第一个限速酶，是调节HBP通量的关键蛋白。尽管其HBP中的重要性已确立，但GFAT1在肝细胞癌（HCC）中作用的分子基础仍有待阐明。本研究发现，GFAT1在HCC中表达上调，且高GFAT1水平与患者不良预后相关。体外和体内研究表明，GFAT1通过其酶活性增强HBP和O-连接N-乙酰葡糖胺修饰（O-GlcNAc糖基化修饰），从而促进肝癌细胞的增殖和侵袭。通过O-GlcNAc修饰组学检测，发现血管内皮锌指蛋白1（VEZF1）是GFAT1过表达的肝癌细胞中被高度O-GlcNAc修饰的关键底物。值得注意的是，VEZF1内特定丝氨酸残基（Ser123和Ser124）的O-GlcNAc修饰减弱了其蛋白酶体降解，从而增强了其蛋白质稳定性并促进了HCC中张力蛋白1（TNS1）的转录。此外，我们设计了一种具有生物活性的VEZF1衍生肽，用于竞争性抑制GFAT1介导的VEZF1 O-GlcNAc修饰。该干预措施有效降低了TNS1的表达，并在小鼠模型中抑制了HCC的进展。总之，该研究结果提示靶向GFAT1-VEZF1-TNS1信号轴在肝癌中的治疗潜力。
GFAT1 promotes the progression of hepatocellular carcinoma via enhancing the O-GlcNAcylation of VEZF1
Jia-yao Yang（杨佳瑶）, Rong Zhang（张容）, Zhi-rong Zhang（张芷榕）, Shan Li, De-ao Gong, Chen-hao Li, Chang Chen, Lu-yi Huang, Ai-long Huang, Ni Tang, Kai Wang
Abstract
Glutamine-fructose-6-phosphate amidotransferase 1 (GFAT1), the first rate-limiting enzyme in the hexosamine biosynthetic pathway (HBP), is a pivotal regulator of HBP flux. Despite its established significance, the molecular underpinnings of GFAT1’s role in hepatocellular carcinoma (HCC) remain to be elucidated. Here, we found that GFAT1 was upregulated in HCC, and high GFAT1 level was correlated with poor patient prognosis. Our in vitro and in vivo studies demonstrated that GFAT1 facilitated hepatoma cell proliferation and invasion by enhancing HBP and O-GlcNAcylation through its enzymatic activity. Global profiling of O-GlcNAcylation identified vascular endothelial zinc finger protein 1 (VEZF1) as a key substrate heavily O-GlcNAcylated in GFAT1-overexpressing hepatoma cells. Notably, O-GlcNAcylation at specific serine residues (Ser123 and Ser124) within VEZF1 attenuated its proteasomal degradation, thereby enhancing its protein stability and promoting tensin 1 (TNS1) transcription in HCC. In addition, we designed a bioactive VEZF1-derived peptide to competitively inhibit GFAT1-mediated O-GlcNAcylation of VEZF1. This intervention effectively reduced TNS1 expression and suppressed the progression of HCC in a mouse model. Collectively, our findings underscore the therapeutic potential of targeting the GFAT1-VEZF1-TNS1 signaling axis in HCC.
DOI: https://doi.org/10.1038/s41419-025-07975-5
原文链接：https://www.nature.com/articles/s41419-025-07975-5
