O-GlcNAc transferase activates stem-like cell potential in hepatocarcinoma through O-GlcNAcylation of eukaryotic initiation factor 4E
O-GlcNAc transferase activates stem-like cell potential in hepatocarcinoma through O-GlcNAcylation of eukaryotic initiation factor 4E
复制标题
O-GlcNAc 转移酶通过真核起始因子 4E 的 O-GlcNAc 酰化激活肝癌干细胞样细胞潜能
DOI：
10.1111/jcmm.14043
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发表时间：
2019-04-01
影响因子：
5.3
通讯作者：
Jiang, Jianhai
中科院分区：
文献类型：
--
作者：
Cao, Benjin;Duan, Meng;Jiang, Jianhai
O-GlcNAc转移酶（OGT）催化的O-GlcNAc酰化是一种可逆的翻译后修饰。O-GlcNAc化参与转录、表观遗传调节和细胞内信号传导。响应于高葡萄糖或OGT表达的G-GlcNAc酰化的失调已经涉及代谢疾病和癌症。然而，OGT调节肝癌发展的潜在机制仍不清楚。在此，我们采用基于慢病毒shRNA的系统来敲低OGT，以分析OGT在肝癌细胞增殖和干细胞样细胞潜能中的贡献。采用球体形成实验和western blot检测干细胞相关基因表达，评价肝癌细胞的干细胞样潜能。我们发现肝细胞癌中总O-GlcNAc化或OGT蛋白水平升高。OGT通过与干细胞相关基因Sox 2 5 '端非翻译区结合的真核起始因子4 E（eIF 4 E）激活肝癌干细胞样潜能。eIF 4 E在苏氨酸168和苏氨酸177处的O-GlcNAc酰化保护其免于通过蛋白酶体途径降解。采用免疫组化法检测232例肝癌组织中eIF 4 E的表达，Kaplan-Meier生存分析法分析eIF 4 E表达与预后的关系。高糖通过OGT-eIF 4 E轴促进肝癌细胞的干细胞样潜能。总的来说，我们的发现表明OGT通过eIF 4 E的O-GlcNAc化促进肝癌细胞的干细胞样细胞潜能。这些结果提供了HCC发展的机制和HCC发病机制与高糖条件之间的线索。
O-GlcNAcylation catalysed by O-GlcNAc transferase (OGT) is a reversible post-translational modification. O-GlcNAcylation participates in transcription, epigenetic regulation, and intracellular signalling. Dysregulation of G-GlcNAcylation in response to high glucose or OGT expression has been implicated in metabolic diseases and cancer. However, the underlying mechanisms by which OGT regulates hepatoma development remain largely unknown. Here, we employed the lentiviral shRNA-based system to knockdown OGT to analyse the contribution of OGT in hepatoma cell proliferation and stem-like cell potential. The sphere-forming assay and western blot analysis of stem-related gene expression were used to evaluate stem-like cell potential of hepatoma cell. We found that the level of total O-GlcNAcylation or OGT protein was increased in hepatocellular carcinoma. OGT activated stem-like cell potential in hepatoma through eukaryotic initiation factor 4E (elF4E) which bound to stem-related gene Sox2 5'-untranslated region. O-GlcNAcylation of elF4E at threonine 168 and threonine 177 protected it from degradation through proteasome pathway. Expression of elF4E in hepatoma was determined by immunostaining in 232 HCC patients, and Kaplan-Meier survival analysis was used to determine the correlation of elF4E expression with prognosis. High glucose promoted stem-like cell potential of hepatoma cell through OGT-elF4E axis. Collectively, our findings indicate that OGT promotes the stem-like cell potential of hepatoma cell through O-GlcNAcylation of elF4E. These results provide a mechanism of HCC development and a cue between the pathogenesis of HCC and high glucose condition.