MiR-122-5p increases radiosensitivity and aggravates radiation-induced rectal injury through CCAR1
MiR-122-5p increases radiosensitivity and aggravates radiation-induced rectal injury through CCAR1
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MiR-122-5p通过CCAR1增加放射敏感性并加重放射引起的直肠损伤
DOI：
10.1016/j.taap.2020.115054
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发表时间：
2020-07-15
影响因子：
3.8
通讯作者：
Liu, Yong
中科院分区：
文献类型：
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作者：
Ge, Yulong;Tu, Wenzhi;Liu, Yong
放射性直肠损伤是盆腔恶性肿瘤患者接受放射治疗的主要副作用。MicroRNA（miRNA）参与多种细胞生物学过程，可受到电离辐射（IR）的干扰。在这项研究中，我们研究了microRNA-122- 5 p（miR-122- 5 p）在辐射诱导的直肠损伤中的功能。采用实时荧光定量PCR（qRT-PCR）检测直肠癌患者血清和C57 BL/6小鼠直肠组织中miR-122- 5 p在IR前后的水平。我们发现IR后患者血清或小鼠直肠组织中miR-122- 5 p水平显著上调。miR-122- 5 p水平的升高在体外和体内均使人肠上皮隐窝（HIEC）细胞对IR敏感。将miR-122- 5 p模拟物转染至HIEC细胞，并通过生物信息学分析预测下游靶点。通过荧光素酶报告基因分析，发现miR-122- 5 p在细胞周期和凋亡调节因子1（CCAR 1）mRNA的3 'UTR处有两个可能的靶位点。与阴性对照组相比，过表达miR-122- 5 p或沉默CCAR 1联合IR可显著抑制细胞存活，增强放射敏感性，并增加细胞凋亡。IR后体内注射miR-122- 5 p阿托莫西米可显著减轻放射诱导的小鼠直肠损伤。这些结果表明，miR-122- 5 p通过靶向CCAR 1减轻辐射诱导的直肠损伤。
Radiation-induced rectal injury is a major side-effect observed in patients with pelvic malignancies who receive radiotherapy. MicroRNA (miRNA), involved in many cellular biological processes, can be disturbed by ionizing radiation (IR). In this study, we have investigated the function of microRNA-122-5p (miR-122-5p) in radiation-induced rectal injury. MiR-122-5p levels in the serum of rectal cancer patients or in the rectal tissues of C57BL/6 mice before and after IR were detected by quantitative real-time PCR (qRT-PCR). We found that the miR-122-5p levels were significantly up-regulated in patients' serum or in mice rectal tissues after IR. Elevation of miR-122-5p levels sensitized human intestinal epithelial crypt (HIEC) cells to IR both in vitro and in vivo. MiR-122-5p mimic was transfected to HIEC cells and the downstream targets were predicted by bioinformatic analysis. Two putative target sites of miR-122-5p in the 3'UTR of the cell cycle and apoptosis regulator 1 (CCAR1) mRNA were found and verified by luciferase reporter assay. Overexpression of miR-122-5p or silencing CCAR1 combined with IR significantly inhibited cell survival, enhanced radiosensitivity, and increased cell apoptosis compared to that in the negative control group in vitro. In vivo injection of miR-122-5p antagomir after IR significantly alleviated radiation-induced rectal injury in mice. These results suggest that miR-122-5p aggravates radiation-induced rectal injury through targeting CCAR1.