Keck School of Medicine, University of Southern California, Los Angeles, CA, USA.
Oxid Med Cell Longev. 2020 Jun 27;2020:2067959. doi: 10.1155/2020/2067959. eCollection 2020.
Upregulation of Brf1 (TFIIB-related factor 1) and Pol III gene (RNA polymerase III-dependent gene, such as tRNAs and 5S rRNA) activities is associated with cell transformation and tumor development. Alcohol intake causes liver injury, such as steatosis, inflammation, fibrosis, and cirrhosis, which enhances the risk of HCC development. However, the mechanism of alcohol-promoted HCC remains to be explored. We have designed the complementary research system, which is composed of cell lines, an animal model, human samples, and experiments and , to carry out this project by using molecular biological, biochemical, and cellular biological approaches. It is a unique system to explore the mechanism of alcohol-associated HCC. Our results indicate that alcohol upregulates Brf1 and Pol III gene (tRNAs and 5S rRNA) transcription in primary mouse hepatocytes, immortalized mouse hepatocyte-AML-12 cells, and engineered human HepG2-ADH cells. Alcohol activates MSK1 to upregulate expression of Brf1 and Pol III genes, while inhibiting MSK1 reduces transcription of Brf1 and Pol III genes in alcohol-treated cells. The inhibitor of MSK1, SB-747651A, decreases the rates of cell proliferation and colony formation. Alcohol feeding promotes liver tumor development of the mouse. These results, for the first time, show the identification of the alcohol-response promoter fragment of the Pol III gene key transcription factor, Brf1. Our studies demonstrate that Brf1 expression is elevated in HCC tumor tissues of mice and humans. Alcohol increases cellular levels of Brf1, resulting in enhancement of Pol III gene transcription in hepatocytes through MSK1. Our mechanism analysis has demonstrated that alcohol-caused high-response fragment of the Brf1 promoter is at p-382/+109bp. The MSK1 inhibitor SB-747651A is an effective reagent to repress alcohol-induced cell proliferation and colony formation, which is a potential pharmaceutical agent. Developing this inhibitor as a therapeutic approach will benefit alcohol-associated HCC patients.
Brf1（TFIIB 相关因子 1）和 Pol III 基因（RNA 聚合酶 III 依赖性基因，如 tRNA 和 5S rRNA）活性的上调与细胞转化和肿瘤发展有关。饮酒会导致肝损伤，如脂肪变性、炎症、纤维化和肝硬化，从而增加 HCC 发展的风险。然而，酒精促进 HCC 的机制仍有待探索。我们设计了互补的研究系统，该系统由细胞系、动物模型、人类样本和实验组成，通过分子生物学、生物化学和细胞生物学方法开展本项目。这是一个独特的系统，用于探索与酒精相关的 HCC 机制。我们的研究结果表明，酒精在原代小鼠肝细胞、永生化小鼠肝细胞 AML-12 细胞和工程化人 HepG2-ADH 细胞中上调 Brf1 和 Pol III 基因（tRNA 和 5S rRNA）的转录。酒精激活 MSK1 上调 Brf1 和 Pol III 基因的表达，而抑制 MSK1 则降低酒精处理细胞中 Brf1 和 Pol III 基因的转录。MSK1 的抑制剂 SB-747651A 降低细胞增殖和集落形成的速率。酒精喂养促进小鼠肝脏肿瘤的发展。这些结果首次表明，鉴定出了 Pol III 基因关键转录因子 Brf1 的酒精反应启动子片段。我们的研究表明，Brf1 在小鼠和人类 HCC 肿瘤组织中的表达升高。酒精增加细胞内 Brf1 的水平，通过 MSK1 增强肝细胞中 Pol III 基因的转录。我们的机制分析表明，酒精引起的 Brf1 启动子高反应片段位于 p-382/+109bp。MSK1 抑制剂 SB-747651A 是一种有效的抑制酒精诱导的细胞增殖和集落形成的试剂，是一种有潜力的药物。将这种抑制剂开发为治疗方法将使酒精相关 HCC 患者受益。
