E2F8 exerts cancer-promoting effects by transcriptionally activating RRM2 and E2F8 knockdown synergizes with WEE1 inhibition in suppressing lung adenocarcinoma.
E2F8 exerts cancer-promoting effects by transcriptionally activating RRM2 and E2F8 knockdown synergizes with WEE1 inhibition in suppressing lung adenocarcinoma.
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DOI：
10.1016/j.bcp.2023.115854
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发表时间：
2023-10
影响因子：
5.8
通讯作者：
Kaiping Liu;Ling Wang;Zhiyuan Lou;Lijuan Guo;Yuanling Xu;Hongyan Qi;Zejun Fang;Lingming Mei;Xiang Chen;Xiaomin Zhang;Jimin Shao;Xueping Xiang
中科院分区：
文献类型：
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作者：
Kaiping Liu;Ling Wang;Zhiyuan Lou;Lijuan Guo;Yuanling Xu;Hongyan Qi;Zejun Fang;Lingming Mei;Xiang Chen;Xiaomin Zhang;Jimin Shao;Xueping Xiang
核糖核苷酸还原酶(RR)是一种限速酶，通过将核苷酸二磷酸(NDPs)还原为脱氧核糖核酸二磷酸(DNDPs)来促进DNA复制和修复，因此对细胞增殖和癌症的发展至关重要。E2F转录因子家族包括参与细胞周期控制的基因表达的关键调控因子。在本研究中，E2F8在大多数肺腺癌(LUAD)患者的癌组织中的表达显著增加，并且通过数据库和临床样本分析，E2F8与RRM2的表达存在相关性。E2F8和RRM2的蛋白表达与肿瘤转移(TNM)病理分期呈正相关，且E2F8和RRM2的高表达预示LUAD患者的5年总生存率较低。过表达和敲除实验表明，E2F8对LUAD细胞的增殖、DNA合成和细胞周期进程是必不可少的，这些都是RRM2依赖的。报告基因、芯片-定量聚合酶链式反应和DNA下拉-Western印迹分析表明，E2F8通过直接与RRM2启动子结合而激活了RRM2基因的转录。以往的研究表明，抑制WEE1激酶可以抑制CDK1/2的磷酸化，促进RRM2的降解。我们进一步证明，E2F8基因敲除与临床试验中的WEE1抑制剂MK-1775联合使用，在体外和体内都能协同抑制LUAD细胞的增殖和促进细胞凋亡。因此，本研究揭示了E2F8作为原癌转录激活剂通过激活RRM2在LUAD中的表达而发挥的新作用，并且针对RRM2的转录和降解机制可以在常规抑制RR酶活性的基础上对LUAD治疗产生协同抑制作用。
Ribonucleotide reductase (RR) is a rate-limiting enzyme that facilitates DNA replication and repair by reducing nucleotide diphosphates (NDPs) to deoxyribonucleotide diphosphates (dNDPs) and is thereby crucial for cell proliferation and cancer development. The E2F family of transcription factors includes key regulators of gene expression involved in cell cycle control. In this study, E2F8 expression was significantly increased in most cancer tissues of lung adenocarcinoma (LUAD) patients and was correlated with the expression of RRM2 through database and clinical samples analysis. The protein expression of E2F8 and RRM2 were positively correlated with tumor–node–metastasis (TNM) pathological stage, and high expression of E2F8 and RRM2 predicted a low 5-year overall survival rate in LUAD patients. Overexpression and knockdown experiments showed that E2F8 was essential for LUAD cell proliferation, DNA synthesis, and cell cycle progression, which were RRM2-dependent. Reporter gene, ChIP-qPCR, and DNA pulldown–Western blot assays indicated that E2F8 activated the transcription of the RRM2 gene by directly binding with the RRM2 promoter in LUAD cells. Previous studies indicated that inhibition of WEE1 kinase can suppress the phosphorylation of CDK1/2 and promote the degradation of RRM2. We further showed here that the combination of E2F8 knockdown with MK-1775, an inhibitor of WEE1 being evaluated in clinical trials, synergistically suppressed proliferation and promoted apoptosis of LUAD cells in vitro and in vivo. Thus, this study reveals a novel role of E2F8 as a proto-oncogenic transcription activator by activating RRM2 expression in LUAD, and targeting both the transcription and degradation mechanisms of RRM2 could produce a synergistic inhibitory effect for LUAD treatment in addition to conventional inhibition of RR enzyme activity.