Present studies report that high expression of GINS complex subunit 1 (GINS1) is notably pertinent to poor survival for hepatocellular carcinoma (HCC), but it remains unclear how GINS1 affects the progression of HCC. This study aims at investigating the mechanism by which GINS1 affects HCC cell proliferation and stemness. We performed bioinformatics analysis for determining GINS1 expression in HCC tissues, as well as the HCC patients' survival rate with different expression levels of GINS1. E2F transcription factor 1 (E2F1) was predicted as the upstream transcription factor of GINS1, and the binding relation between the two was verified by chromatin immunoprecipitation and dual-luciferase reporter assays. Quantitative real-time polymerase chain reaction was adopted to evaluate the expression of GINS1 and E2F1. The protein expression levels of GINS1, E2F1, and cell stemness-related genes (SOX-2, NANOG, OCT4, and CD133) were detected by Western blot. Afterward, the proliferative capacity and stemness of HCC tumor cells were determined through colony formation, cell counting kit-8, and sphere formation assays. Our study found the high expression of GINS1 and E2F1 in HCC, and overexpressed GINS1 markedly enhanced the sphere formation and proliferation of HCC cells, while silencing GINS1 led to the opposite results. Besides, E2F1 promoted the transcription of GINS1 by working as an upstream transcription factor. The results of the rescue experiment suggested that overexpressed E2F1 could offset the suppressive effect of GINS1 silencing on HCC cell stemness and proliferation. We demonstrated that the transcription factor E2F1 accelerated cell proliferation and stemness in HCC by activating GINS1 transcription. The results can provide new insight into the GINS1-related regulatory mechanism in HCC, which suggest that it may be an effective way for HCC treatment by targeting the E2F1/GINS1 axis.

中文翻译：

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转录因子E2F1通过激活GINS1增强肝细胞癌细胞增殖和干性

目前的研究报告称，GINS 复合物亚基 1 (GINS1) 的高表达与肝细胞癌 (HCC) 的生存率较低密切相关，但目前尚不清楚 GINS1 如何影响 HCC 的进展。本研究旨在探讨GINS1影响HCC细胞增殖和干性的机制。我们进行了生物信息学分析来确定GINS1在HCC组织中的表达，以及不同GINS1表达水平的HCC患者的生存率。E2F转录因子1（E2F1）被预测为GINS1的上游转录因子，并通过染色质免疫沉淀和双荧光素酶报告基因测定验证了两者之间的结合关系。采用实时定量聚合酶链式反应评价GINS1和E2F1的表达。采用Western blot检测GINS1、E2F1和细胞干性相关基因（SOX-2、NANOG、OCT4、CD133）的蛋白表达水平。随后，通过集落形成、细胞计数kit-8和球体形成测定来测定HCC肿瘤细胞的增殖能力和干性。我们的研究发现HCC中GINS1和E2F1高表达，过表达GINS1显着增强HCC细胞的球体形成和增殖，而沉默GINS1则导致相反的结果。此外，E2F1作为上游转录因子促进GINS1的转录。拯救实验的结果表明，过表达的E2F1可以抵消GINS1沉默对HCC细胞干性和增殖的抑制作用。我们证明转录因子 E2F1 通过激活 GINS1 转录来加速 HCC 中的细胞增殖和干性。该结果可以为HCC中GINS1相关调控机制提供新的见解，提示靶向E2F1/GINS1轴可能是治疗HCC的有效途径。