Chen Zhimin, Hao Weijie, Tang Jingzhi, Gao Wei-Qiang, Xu Huiming
State Key Laboratory of Oncogenes and Related Genes, Renji-Med X Clinical Stem Cell Research Center, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
Department of Ultrasound, Fudan University Shanghai Cancer Center, Shanghai, China.
Front Oncol. 2022 Jul 8;12:897804. doi: 10.3389/fonc.2022.897804. eCollection 2022.
The shortening of 3' untranslated regions (3'UTRs) of messenger RNAs(mRNAs) by alternative polyadenylation (APA) is an important mechanism for oncogene activation. Cleavage stimulation factor 2 (CSTF2), an important regulator of APA, has been reported to have a tumorigenic function in urothelial carcinoma of the bladder and lung cancers. However, the tumor-promoting role of CSTF2 in hepatocellular carcinoma (HCC) and its underlying molecular mechanism remains unclear.
Multiple databases were used to analyze the expression level and prognostic value of CSTF2 in HCC. Function enrichment analysis was used to investigate the molecular mechanism of CSTF2 for the occurrence and development of HCC. The biological function in HCC cell lines was determined by CCK8, colony formation, Transwell migration, and invasion assay. Moreover, the tumorigenic function of CSTF2 was measured by a subcutaneous tumor formation or injecting four plasmids into a mouse tail vein within 5-7 s in an immunocompetent HCC mouse model. In addition, aerobic glycolysis in HCC cells was determined by measuring the extracellular acid rate (ECAR) and extracellular glucose and lactate levels.
Bioinformatics analysis revealed that CSTF2 was overexpressed in HCC tissues. The high expression of CSTF2 was correlated with a poor prognosis and high histological grades. CSTF2 knockout inhibited the proliferation, migration, and invasion of HCC cells. In addition, CSTF2 knockout HCC cells failed to form tumors by a subcutaneous graft experiment. Furthermore, endogenous CSTF2 knockout attenuated hepatocarcinogenesis in an immunocompetent HCC mouse model. Function enrichment analysis suggested that the high expression of CSTF2 was associated with enhanced glycolysis. Moreover, we found that CSTF2 knockout reduced the level of the short 3' UTR isoform of hexokinase 2 and increased its level of long 3'UTR. Furthermore, CSTF2 knockout inhibited ECAR levels, glucose uptake, and lactate production.
Our results indicated that CSTF2 is highly expressed in HCC and is correlated with a poor prognosis and high histological grade. The knockout of CSTF2 inhibits the tumorigenesis and procession of HCC both and . Moreover, CSTF2 is associated with enhanced glycolysis. Therefore, this study suggests that CSTF2 might be a new prognostic biomarker and therapeutic target for HCC.
信使核糖核酸（mRNA）的3'非翻译区（3'UTR）通过可变聚腺苷酸化（APA）缩短是癌基因激活的重要机制。切割刺激因子2（CSTF2）作为APA的重要调节因子，已被报道在膀胱尿路上皮癌和肺癌中具有致瘤功能。然而，CSTF2在肝细胞癌（HCC）中的促肿瘤作用及其潜在分子机制仍不清楚。
使用多个数据库分析CSTF2在HCC中的表达水平和预后价值。功能富集分析用于研究CSTF2在HCC发生发展中的分子机制。通过CCK8、集落形成、Transwell迁移和侵袭实验确定其在HCC细胞系中的生物学功能。此外，通过皮下肿瘤形成实验或在免疫健全的HCC小鼠模型中于5至7秒内将四种质粒注射到小鼠尾静脉中来检测CSTF2的致瘤功能。另外，通过测量细胞外酸化率（ECAR）以及细胞外葡萄糖和乳酸水平来确定HCC细胞中的有氧糖酵解情况。
生物信息学分析显示CSTF2在HCC组织中高表达。CSTF2的高表达与预后不良和高组织学分级相关。CSTF2基因敲除抑制了HCC细胞的增殖、迁移和侵袭。此外，通过皮下移植实验发现CSTF2基因敲除的HCC细胞无法形成肿瘤。此外，在免疫健全的HCC小鼠模型中，内源性CSTF2基因敲除减弱了肝癌发生。功能富集分析表明CSTF2的高表达与糖酵解增强有关。此外，我们发现CSTF2基因敲除降低了己糖激酶2短3'UTR亚型的水平并增加了其长3'UTR的水平。此外，CSTF2基因敲除抑制了ECAR水平、葡萄糖摄取和乳酸生成。
我们的结果表明CSTF2在HCC中高表达，与预后不良和高组织学分级相关。CSTF2基因敲除抑制了HCC的肿瘤发生和进程。此外，CSTF2与糖酵解增强有关。因此，本研究表明CSTF2可能是HCC的一种新的预后生物标志物和治疗靶点。
