OTU deubiquitinase 4 is silenced and radiosensitizes non-small cell lung cancer cells via inhibiting DNA repair
OTU deubiquitinase 4 is silenced and radiosensitizes non-small cell lung cancer cells via inhibiting DNA repair
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OTU 去泛素酶 4 被沉默，并通过抑制 DNA 修复使非小细胞肺癌细胞放射增敏
DOI：
10.1186/s12935-019-0816-z
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发表时间：
2019-04-15
影响因子：
5.8
通讯作者：
Mi, Zeyun
中科院分区：
文献类型：
--
作者：
Wu, Zhiqiang;Qiu, Minghan;Mi, Zeyun
背景放射治疗已成为非小细胞肺癌（non-small cell lung cancer，NSCLC）的主要治疗手段之一。发现新的放射增敏剂将大大提高放射治疗的疗效，使更多的患者受益。OTU去泛素化酶4（OTUD 4）参与DNA损伤修复，可能成为化疗的潜在靶点。方法采用Western blotting和QRT-PCR方法检测OTUD 4、γ-H2 Ax和ATM/CHK 2/p53信号通路相关分子的表达。通过5-氮杂脱氧胞苷处理、甲基化特异性PCR和亚硫酸氢盐基因组测序分析来研究OTUD 4启动子的甲基化。通过克隆形成试验评估放射敏感性。流式细胞仪检测细胞周期、细胞凋亡。结果OTUD 4在NSCLC组织中表达明显下调，其表达下调与NSCLC患者的预后密切相关。启动子超甲基化是NSCLC细胞中OTUD 4表达丧失的原因。OTUD 4的过表达增加NSCLC细胞的放射敏感性，表现为克隆形成能力受损、细胞周期停滞增强和细胞凋亡增加。此外，分子机制研究表明OTUD 4通过ATM/CHK 2/P53信号通路和抑制电离辐射诱导的DNA双链断裂的同源定向修复而对NSCLC细胞产生放射增敏作用。
BackgroundRadiotherapy is becoming one major therapeutics for non-small cell lung cancer (NSCLC). Identifying novel radiosensitizers will greatly increase the efficacy of radiotherapy and benefit more patients. OTU deubiquitinase 4 (OTUD4) has been reported involved in DNA damage repair pathways and could be a potential target for chemotherapy therapy. This study aimed to investigate the roles of OTUD4 in regulation of radiosensitivity of NSCLC via modulating DNA repair.MethodsThe expression of OTUD4, γ-H2Ax and ATM/CHK2/p53 pathway-related signaling molecules were detected by Western blotting and QRT-PCR. The methylation of OTUD4 promoter was investigated by 5-aza-deoxycytidine treatment, methylation-specific PCR and bisulfite genomic sequencing assays. Radiosensitivity was assessed by the clonogenic formation assay. Cell cycle, cell apoptosis were analyzed by flow cytometry. DNA damage and repair were determined by comet assay, γ-H2Ax foci staining and flow cytometry.ResultsOTUD4 is dramatically downregulated in NSCLC and its downregulation significantly correlates with poor prognosis of NSCLC patients. Promoter hypermethylation is responsible for the loss of OTUD4 expression in NSCLC cells. Overexpression of OTUD4 increases radiosensitivity of NSCLC cells exhibiting as impaired clonogenic formation ability, enhanced cell cycle arrest and increased cell apoptosis. Moreover, molecular mechanism study reveals that OTUD4 radiosensitizs NSCLC cells via ATM/CHK2/P53 signaling and inhibiting homology-directed repair of DNA double strand breaks induced by ionizing radiation.ConclusionsThis study uncovers a tumor-suppressing role of OTUD4 and that OTUD4 is a potential radiosensitizer for NSCLC.