Guo Xiong, Liu Ling, Zhang Qi, Yang Weiming, Zhang Yang
Department of Colorectal and Anal Surgery, Hepatobiliary and Enteric Surgery Center, Xiangya Hospital, Central South University, Changsha, China.
Hepatobiliary & Enteric Surgery Research Center, Xiangya Hospital of Central South University, Changsha, China.
Front Oncol. 2021 Jan 7;10:565449. doi: 10.3389/fonc.2020.565449. eCollection 2020.
microRNAs (miRNAs) can modulate the expression level of genes in a post-transcription manner, which are closely related to growth and metastasis of colon cancer. Herein, we aimed to explore how miR-199b influences colon cancer and to characterize its underlying molecular mechanism associating with E2F transcription factor 7 (E2F7). Assays of RT-qPCR, Western blot, and immunohistochemistry were utilized to detect the expression of E2F7 in the tissue samples collected from 30 patients diagnosed with colon cancer. Flow analysis was utilized to detect the ratio of ALDH1 and CD133 colon cancer stem cells. The interaction between E2F7, miR-199b, USP47, and MAPK was identified by ChIP-Seq analysis, luciferase reporter, RNA pull-down, co-immunoprecipitation, as well as glutathione-S-transferase (GST) pull-down experiments. Based on the gain- and loss-of-function approaches, the cellular functions of colon cancer cells by the E2F7-regulated miR-199b/USP47/MAPK axis were assessed. It was identified that E2F7 are expressed highly in the collected colon cancer tissues. E2F7 silencing reduced the production of ALDH1 and CD133 colon cancer stem cells and antagonized the effects of 5-fluorouracil (5-FU) treatment. Besides, the silencing of E2F7 was observed to suppress the oxidative stress, proliferation, migration, as well as invasion of ALDH1 cells and tumorigenesis of colon cancer cells . Our findings reveal the pro-oncogenic effect of E2F7 on colon cancer development, highlighting E2F7 as a novel target for therapeutic strategy for colon cancer.
微小RNA（miRNA）可以通过转录后方式调节基因的表达水平，这与结肠癌的生长和转移密切相关。在此，我们旨在探讨miR-199b如何影响结肠癌，并阐明其与E2F转录因子7（E2F7）相关的潜在分子机制。采用RT-qPCR、蛋白质免疫印迹和免疫组织化学分析方法检测30例结肠癌患者组织样本中E2F7的表达。利用流式分析检测ALDH1和CD133结肠癌干细胞的比例。通过染色质免疫沉淀测序分析、荧光素酶报告基因检测、RNA下拉实验、免疫共沉淀以及谷胱甘肽-S-转移酶（GST）下拉实验确定E2F7、miR-199b、USP47和丝裂原活化蛋白激酶（MAPK）之间的相互作用。基于功能获得和功能缺失方法，评估E2F7调控的miR-199b/USP47/MAPK轴对结肠癌细胞功能的影响。结果发现，收集的结肠癌组织中E2F7高表达。E2F7沉默可减少ALDH1和CD133结肠癌干细胞的产生，并拮抗5-氟尿嘧啶（5-FU）治疗的效果。此外，观察到E2F7沉默可抑制ALDH1细胞的氧化应激、增殖、迁移和侵袭以及结肠癌细胞的肿瘤发生。我们的研究结果揭示了E2F7对结肠癌发展的促癌作用，突出了E2F7作为结肠癌治疗策略新靶点的地位。
