Hu Ying, Sun Xiaoli, Li Bing Li, Xu Ruilling, Shao Jing, Zhao Lei, Liu Jingyang, Zhang Xu, Dandan Ning, Jin Shizhu
Department of Gastroenterology, The Second Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China.
Turk J Gastroenterol. 2024 Apr 5;35(7):577-586. doi: 10.5152/tjg.2024.23293.
Hepatocellular carcinoma (HCC) represents a common neoplasm that presents a substantial worldwide health challenge. Nevertheless, the involvement of HPN-AS1 in HCC remains unknown. The quantitative reverse transcription polymerase chain reaction (qRT-PCR) assay was utilized to measure HPN-AS1 expression in HCC. The GABPA effects on the HPN-AS1 promoter were analyzed through chromatin immunoprecipitation and luciferase reporter assays. Cell proliferation potential was determined by deploying CCK-8 assay, Ki-67 immunofluorescence staining, and colony formation assay. Cell apoptosis was detected using acridine orange/ethidium bromide staining and terminal deoxynucleotidyl transferase dUTP nick end labeling staining. Western blotting was utilized to measure the protein levels of proliferation factors and apoptosis regulators. HPN-AS1 binding to eIF4A3 was accessed by RNA-binding protein immunoprecipitation assay. HPN-AS1 was significantly downregulated in both HCC cells and tissues. Lower HPN-AS1 levels indicate a poorer HCC prognosis. Moreover, we found that GABPA functions as a transcription factor for HPN-AS1. Functional studies revealed that HPN-AS1 displayed inhibitory effects on HCC cell proliferation and promoted apoptosis. Mechanically, HPN-AS1 bound to and facilitated translation initiation factor eIF4A3 degradation. Loss of HPN-AS1 augmented eIF4A3 protein levels rather than eIF4A3 mRNA levels. Exogenous expression of eIF4A3 could restore eIF4A3 protein levels and reverse HPN-AS1 overexpression-induced cell proliferation inhibition and cell apoptosis. Our study elucidated that HPN-AS1 downregulation was mediated by GABPA. HPN-AS acted as a tumor suppressor within HCC through binding and facilitating eIF4A3 degradation. The study provides a novel insight into the biological function of HPN-AS1 in HCC, suggesting that HPN-AS1 could be a promising biomarker and a potential target for HCC diagnosis and treatment.
肝细胞癌（HCC）是一种常见的肿瘤，在全球范围内对健康构成了重大挑战。然而，HPN - AS1在HCC中的作用仍不清楚。采用定量逆转录聚合酶链反应（qRT - PCR）检测法来测定HCC中HPN - AS1的表达。通过染色质免疫沉淀和荧光素酶报告基因检测分析GABPA对HPN - AS1启动子的影响。采用CCK - 8检测法、Ki - 67免疫荧光染色和集落形成检测法来确定细胞增殖潜能。使用吖啶橙/溴化乙锭染色和末端脱氧核苷酸转移酶dUTP缺口末端标记染色来检测细胞凋亡。利用蛋白质免疫印迹法来测定增殖因子和凋亡调节因子的蛋白质水平。通过RNA结合蛋白免疫沉淀检测法来检测HPN - AS1与eIF4A3的结合情况。HPN - AS1在HCC细胞和组织中均显著下调。较低水平的HPN - AS1提示HCC预后较差。此外我们发现GABPA作为HPN - AS1的转录因子发挥作用。功能研究表明，HPN - AS1对HCC细胞增殖具有抑制作用，并促进细胞凋亡。机制上，HPN - AS1与翻译起始因子eIF4A3结合并促进其降解。HPN - AS1缺失增加了eIF4A3蛋白水平而非eIF4A3 mRNA水平。eIF4A3的外源性表达可恢复eIF4A3蛋白水平，并逆转HPN - AS1过表达诱导的细胞增殖抑制和细胞凋亡。我们的研究阐明了HPN - AS1的下调是由GABPA介导的。HPN - AS通过结合并促进eIF4A3降解，在HCC中发挥肿瘤抑制作用。该研究为HPN - AS1在HCC中的生物学功能提供了新的见解，表明HPN - AS1可能是一种有前景的生物标志物以及HCC诊断和治疗的潜在靶点。
