Zhang Tian, Sun Quanquan, Liu Tongxin, Chen Jiarong, Du Shasha, Ren Chen, Liao Guixiang, Yuan Yawei
Department of Radiation Oncology, Nanfang Hospital, Southern Medical University, No. 1838 Guangzhou Da Dao Bei, Guangzhou, Guangdong, 510515, People's Republic of China,
Tumour Biol. 2014 Dec;35(12):12593-9. doi: 10.1007/s13277-014-2581-x. Epub 2014 Sep 9.
Radioresistance severely impedes the treatment of nasopharyngeal carcinoma (NPC). Recent evidence has shown that the abnormal expression of microRNAs (miRNAs) contributes to radiosensitivity. The aim of this study, therefore, was to investigate whether expression of the miRNAs correlated with radiosensitivity in the context of NPC. Quantitative reverse transcription polymerase chain reaction (RT-PCR) was used to quantify miR-451 expression in two representative NPC cell lines. The role of miR-451 in NPC radiosensitivity was analyzed using a colony formation assay and an immunofluorescence assay with overexpression of miR-451 in NPC cells. Luciferase reporter assays, RT-PCR, and Western blot were performed to confirm the target of miR-451. High levels of miR-451 expression enhanced radiosensitivity in NPC cells by inhibiting the repair of irradiation-induced double-strand breaks (DSBs) and increasing apoptosis. The results also demonstrated that miR-451 directly targeted ras-related protein 14 (RAB14). Downregulation of RAB14 partially replicated the miR-451-mediated DSBs induced by ionizing radiation (IR). MiR-451 could be a potential target for enhancing radiosensitivity of NPC cells by targeting RAB14.
放射抗性严重阻碍了鼻咽癌（NPC）的治疗。最近的证据表明，微小RNA（miRNA）的异常表达与放射敏感性有关。因此，本研究的目的是探讨在鼻咽癌背景下，miRNA的表达是否与放射敏感性相关。采用定量逆转录聚合酶链反应（RT-PCR）对两种具有代表性的NPC细胞系中的miR-451表达进行定量。通过集落形成试验和免疫荧光试验分析miR-451在NPC放射敏感性中的作用，其中NPC细胞中miR-451过表达。进行荧光素酶报告基因试验、RT-PCR和蛋白质免疫印迹法以确认miR-451的靶标。高水平的miR-451表达通过抑制辐射诱导的双链断裂（DSB）修复和增加细胞凋亡来增强NPC细胞的放射敏感性。结果还表明，miR-451直接靶向Ras相关蛋白14（RAB14）。RAB14的下调部分复制了电离辐射（IR）诱导的miR-451介导的DSB。通过靶向RAB14，miR-451可能成为增强NPC细胞放射敏感性的潜在靶点。
