Hui Beina, Pan Shupei, Che Shaomin, Sun Yuchen, Yan Yanli, Guo Jia, Gong Tuotuo, Ren Juan, Zhang Xiaozhi
Department of Radiation Oncology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi Province, 710061, People's Republic of China.
Department of Radiation Oncology, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi Province, 710004, People's Republic of China.
Cancer Manag Res. 2021 Jun 21;13:4841-4852. doi: 10.2147/CMAR.S311192. eCollection 2021.
Resistance to radiotherapy results in a high treatment failure rate for locally advanced esophageal squamous cell carcinoma (ESCC). Ubiquitin-like with plant homeodomain and ring-finger domains 1 (UHRF1), is associated with poor prognosis in ESCC. The present study aims to characterize the effect of UHRF1 silencing on the radiosensitivity of ESCC and its potential mechanism.
Both in vitro and in vivo experiments were conducted to observe the effects of UHRF1 silencing on the radiosensitivity of ESCC. The effects of UHRF1 silencing on the apoptosis of ESCC cells were assessed by flow cytometry. The expression of apoptosis-related factors (caspase-3 and Bcl-2), PI3K/Akt/mTOR signaling pathway-related factors (PTEN, p-Akt and Akt, p-mTOR and mTOR), and DNMT1 were measured via Western blot, and the status of PTEN methylation was detected by methylation-specific PCR. Immunohistochemistry was used to detect the expressions of PTEN, p-AKT, and p-mTOR in xenograft tumor tissues.
In vitro and in vivo experiments showed that UHRF1 knock-down inhibited ESCC cell growth and enhanced their radiosensitivity. shUHRF1 combined with radiation significantly increased ESCC cell apoptosis. Meanwhile, it activated the expression of caspase-3 and inhibited the expression of Bcl-2. shUHRF1 inhibited the expression of DNMT1 and reduced the methylation of PTEN, and then upregulated the expression of PTEN to inhibit the PI3K/Akt/mTOR signaling pathway. On the contrary, the PI3K/Akt/mTOR signaling pathway can be activated by upregulation of UHRF1.
Our findings provide a theoretical basis for UHRF1 as a target to improve the radiosensitivity of ESCC.
放疗抵抗导致局部晚期食管鳞状细胞癌（ESCC）的治疗失败率很高。含植物同源结构域和泛素样结构域1（UHRF1）与ESCC的不良预后相关。本研究旨在探讨UHRF1沉默对ESCC放射敏感性的影响及其潜在机制。
通过体外和体内实验观察UHRF1沉默对ESCC放射敏感性的影响。采用流式细胞术评估UHRF1沉默对ESCC细胞凋亡的影响。通过蛋白质免疫印迹法检测凋亡相关因子（caspase-3和Bcl-2）、PI3K/Akt/mTOR信号通路相关因子（PTEN、p-Akt和Akt、p-mTOR和mTOR）以及DNMT1的表达，并通过甲基化特异性PCR检测PTEN甲基化状态。采用免疫组织化学法检测移植瘤组织中PTEN、p-AKT和p-mTOR的表达。
体外和体内实验表明，UHRF1基因敲低抑制了ESCC细胞生长并增强了其放射敏感性。shUHRF1联合放疗显著增加了ESCC细胞凋亡。同时，它激活了caspase-3的表达并抑制了Bcl-2的表达。shUHRF1抑制了DNMT1的表达并降低了PTEN的甲基化，进而上调了PTEN的表达以抑制PI3K/Akt/mTOR信号通路。相反，UHRF1的上调可激活PI3K/Akt/mTOR信号通路。
我们的研究结果为将UHRF1作为提高ESCC放射敏感性的靶点提供了理论依据。
