Hu Yan, Li Qing, Yi Ke, Yang Chi, Lei Qingjun, Wang Guanghui, Wang Qianyun, Xu Xiaohui
Central Laboratory, The First People's Hospital of Taicang, Taicang Affiliated Hospital of Soochow University, Taicang, China.
Department of Gastroenterology, The First People's Hospital of Taicang, Taicang Affiliated Hospital of Soochow University, Taicang, China.
Front Oncol. 2022 May 19;12:883444. doi: 10.3389/fonc.2022.883444. eCollection 2022.
We previously found that Hu antigen R (HuR) can regulate the proliferation and metastasis of esophageal cancer cells. This study aims to explore the effects of HuR on the radiosensitivity of esophageal cancer.
Analyses of CCK-8, colony formation assay, Western blot, immunofluorescence, flow cytometry, reactive oxygen species (ROS), and mitochondrial membrane potential were conducted to characterize the esophageal cancer cells. Nude mouse models were used to detect the effects of HuR in a combination of X-ray treatment on the subcutaneous xenografts of esophageal cancer. In addition, a luciferase assay was used to detect the direct interaction of HuR with Snail mRNA 3'-UTR.
The down-regulation of HuR combined with X-ray can significantly inhibit the proliferation and colony formation of esophageal cancer cells. Flow cytometry data showed that the down-regulation of HuR could induce a G1 phase cell cycle block in esophageal cancer cells, and aggravate X-ray-induced apoptosis, indicated by the increases of apoptosis-related proteins Bax, caspase-3 and caspase-9. Moreover, the down-regulation of HuR could significantly impair the mitochondrial membrane potential and increase the ROS production and DNA double-strand break marker γH2AX expression in esophageal cancer cells that were exposed to X-rays. data showed that the down-regulation of HuR combined with radiation significantly decreased the growth of subcutaneous xenograft tumors. Furthermore, HuR could interact with Snail. Up-regulation of Snail can reverse the EMT inhibitory effects caused by HuR down-regulation, and attenuate the tumor-inhibiting and radiosensitizing effects caused by HuR down-regulation.
In summary, our data demonstrate that HuR effectively regulates the radiosensitivity of esophageal cancer, which may be achieved by stabilizing Snail. Thus, HuR/Snail axis is a potentially therapeutic target for the treatment of esophageal cancer.
我们之前发现Hu抗原R（HuR）可调节食管癌细胞的增殖和转移。本研究旨在探讨HuR对食管癌放射敏感性的影响。
采用CCK-8分析、集落形成试验、蛋白质免疫印迹法、免疫荧光法、流式细胞术、活性氧（ROS）检测及线粒体膜电位检测等方法对食管癌细胞进行表征。利用裸鼠模型检测HuR联合X射线治疗对食管癌皮下异种移植瘤的影响。此外，采用荧光素酶报告基因检测法检测HuR与Snail mRNA 3'-UTR的直接相互作用。
HuR下调联合X射线可显著抑制食管癌细胞的增殖和集落形成。流式细胞术数据显示，HuR下调可诱导食管癌细胞G1期细胞周期阻滞，并加重X射线诱导的细胞凋亡，凋亡相关蛋白Bax、caspase-3和caspase-9表达增加表明了这一点。此外，HuR下调可显著损害暴露于X射线的食管癌细胞的线粒体膜电位，增加ROS产生及DNA双链断裂标志物γH2AX的表达。数据显示，HuR下调联合放疗可显著降低皮下异种移植瘤的生长。此外，HuR可与Snail相互作用。Snail上调可逆转HuR下调引起的上皮-间质转化（EMT）抑制作用，并减弱HuR下调引起的肿瘤抑制和放射增敏作用。
总之，我们的数据表明，HuR可有效调节食管癌的放射敏感性，这可能是通过稳定Snail来实现的。因此，HuR/Snail轴是食管癌治疗的一个潜在治疗靶点。
