Department of Biliary-Pancreatic Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science & Technology, Wuhan, P.R. China.
Hepatic Surgery Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science & Technology, Wuhan, P.R. China.
Liver Int. 2021 Aug;41(8):1933-1944. doi: 10.1111/liv.14904. Epub 2021 May 28.
Liver cancer is a major public health concern, but the mechanistic actions of biomarkers contributing to liver cancer remain to be determined. In this study, we aimed to investigate the regulatory cascade of microRNA-424-5p (miR-424-5p), X-inactive-specific transcript (XIST) and O-GlcNAc transferase (OGT) in liver cancer.
Differentially expressed miRNAs and target genes related to liver cancer were predicted by bioinformatics analyses, and their expression was determined in liver tissues of patients with liver cancer and liver cancer cells. The RNA immunoprecipitation (RIP), RNA pull-down and dual luciferase reporter assay were used to examine the binding affinity among XIST and miR-424-5p and OGT. Then, gain- and loss-of-function assays were conducted to evaluate the effects of the XIST/miR-424-5p/OGT axis on malignant phenotypes. A nude mouse model of liver cancer was further established for in vivo substantiation.
XIST and OGT were up-regulated in liver cancer tissues and cells, responsible for poor prognosis in patients with liver cancer, while miR-424-5p was down-regulated. XIST competitively bound to miR-424-5p to increase OGT expression. XIST silencing inhibited malignant phenotypes of liver cancer cells, while miR-424-5p down-regulation negated its effect. miR-424-5p suppressed RAF1 glycosylation by negatively regulating OGT expression and promoted its ubiquitination/degradation. Furthermore, XIST knockdown inhibited tumour growth and metastasis in nude mice, while ectopic OGT reversed its effect.
These results reveal a novel mechanism by which the interaction of XIST/miR-424-5p/OGT participates in the malignancy and metastasis of liver cancer.
肝癌是一个主要的公共健康关注点，但导致肝癌的生物标志物的作用机制仍有待确定。在这项研究中，我们旨在研究微小 RNA-424-5p（miR-424-5p）、X 失活特异性转录本（XIST）和 O-连接的 N-乙酰氨基葡萄糖转移酶（OGT）在肝癌中的调控级联。
通过生物信息学分析预测与肝癌相关的差异表达 miRNA 和靶基因，并在肝癌患者的肝组织和肝癌细胞中测定其表达。采用 RNA 免疫沉淀（RIP）、RNA 下拉和双荧光素酶报告基因检测实验来检测 XIST 与 miR-424-5p 和 OGT 之间的结合亲和力。然后，进行增益和缺失功能实验来评估 XIST/miR-424-5p/OGT 轴对恶性表型的影响。进一步建立裸鼠肝癌模型进行体内验证。
XIST 和 OGT 在肝癌组织和细胞中上调，与肝癌患者的不良预后相关，而 miR-424-5p 下调。XIST 竞争性结合 miR-424-5p 以增加 OGT 表达。XIST 沉默抑制肝癌细胞的恶性表型，而 miR-424-5p 下调则消除了其作用。miR-424-5p 通过负调控 OGT 表达抑制 RAF1 糖基化，促进其泛素化/降解。此外，XIST 敲低抑制裸鼠肿瘤生长和转移，而过表达 OGT 则逆转了其作用。
这些结果揭示了 XIST/miR-424-5p/OGT 相互作用参与肝癌恶性和转移的新机制。
