RNA-seq for HepG2 cell line with AUF1 knockdown.. RNA-seq for HepG2 cell line with AUF1 knockdown.

Although several studies indicate that ARE-specific RNA binding proteins (ARE-BPs) contribute to the development of cancer, the detailed functions and mechanisms of ARE-BPs have not been fully elucidated. By using a bioinformatics analysis of two well-established hepatocellular carcinoma (HCC) datasets, we identified the AU-rich binding factor 1(AUF1), one of the well-known ARE-BPs, was abnormally highly expressed in HCC and the high expression of AUF1 was correlated with poor prognosis of HCC patients. The prognostic value of AUF1 expression was also confirmed in our HBV-related HCC cohorts. Gain and loss of function analyses demonstrated that AUF1 promoted HCC tumorigenesis both in vitro and in vivo. Mechanistically, we found that aldoketo reductase family 1 member B 10(AKR1B10) was a critical target of AUF1 and was essential for sustaining the AUF1-induced proliferation of HCC cells. AUF1 stabilized AKR1B10 mRNA by binding to the 3'UTR region of AKR1B10. Additionally, we confirmed that E2F1 enhanced AUF1 expression in HCC through the transcription level, and in HBV-related HCC, HBx could up-regulate E2F1 expression and promote the expression of AUF1. Our study reveals a novel role of AUF1 in promoting hepatocarcinogenesis via the post-transcriptional regulation of AKR1B10 expression and proposes that the HBx/E2F1/AUF1/AKR1B10 pathway may serve as a potential therapeutic target in HCC. Overall design: AUF1 was knock down by siRNA in HepG2 cell lines for 48 hours.

尽管多项研究表明，富含AU元件的RNA结合蛋白（ARE-specific RNA binding proteins, ARE-BPs）在癌症发生发展中具有促进作用，但目前ARE-BPs的具体功能与作用机制尚未完全阐明。本研究通过对两套已被广泛验证的肝细胞癌（hepatocellular carcinoma, HCC）数据集开展生物信息学分析，鉴定出AU富集结合因子1（AU-rich binding factor 1, AUF1）——一类经典的ARE-BPs——在肝细胞癌组织中呈现异常高表达，且AUF1高表达与肝细胞癌患者的不良预后显著相关。AUF1表达的预后价值在本研究的HBV相关肝细胞癌队列中同样得到了验证。功能获得与功能缺失实验证实，AUF1可在体内外促进肝细胞癌的肿瘤发生进程。机制层面研究显示，醛酮还原酶家族1成员B10（aldoketo reductase family 1 member B 10, AKR1B10）是AUF1的关键靶标，且其对于维持AUF1诱导的肝细胞癌细胞增殖能力至关重要。AUF1可通过结合AKR1B10的3'非翻译区（3'UTR）稳定其mRNA分子。此外，本研究证实E2F1可在转录水平上调肝细胞癌中AUF1的表达；而在HBV相关肝细胞癌中，HBx可通过上调E2F1的表达进而促进AUF1的表达。本研究揭示了AUF1通过转录后调控AKR1B10表达从而促进肝细胞癌发生的全新作用，并提出HBx/E2F1/AUF1/AKR1B10通路可作为肝细胞癌潜在的治疗靶点。整体实验设计：利用小干扰RNA（siRNA）敲低HepG2细胞系中的AUF1，处理时长为48小时。