Table_1_MicroRNA-483-5p Predicts Poor Prognosis and Promotes Cancer Metastasis by Targeting EGR3 in Nasopharyngeal Carcinoma.docx

BackgroundMicroRNAs, as small non-coding RNAs, play an important role in tumorigenesis. MiR-483-5p was found to have a significant increase as a diagnostic biomarker of nasopharyngeal carcinoma (NPC), not only in plasma from NPC patients but also in tumor cell lines and biopsy tissues in our previous study. However, its function and mechanism in NPC are still unclear.
MethodsTissue microarray including 178 primary NPC and 35 adjacent non-cancerous nasopharyngeal mucosal tissues was used to further validate the overexpression of miR-483-5p. Wound healing and invasion assays were conducted to verify its biological function. RNA sequencing (RNA-seq) and dual-luciferase reporter assay was performed to explore its target, and it was verified in fresh biopsy tissues from 23 NPC patients and 9 patients with chronic nasopharyngitis.
ResultsMiR-483-5p was highly expressed in NPC tissues than in adjacent non-cancerous tissues. It was found to have a significant correlation with poor overall survival (OS) [hazard ratio (HR) = 2.89, 95% confidence interval (CI) = 1.00–8.35, p = 0.041] and progression-free survival (PFS) (HR = 1.95, 95%CI = 1.06–3.60, p = 0.029) of NPC patients. Silencing of its expression inhibited the migratory and invasive capacities of NPC cells in vitro. EGR3 (early growth response 3) was identified as a direct target, and inhibiting miR-483-5p expression markedly enhanced the expression of EGR3 at both the mRNA and protein levels. Besides, a significant decrease of EGR3 expression was found in fresh biopsy tissues from NPC patients, in contrast to miR-483-5p expression. Furthermore, directly decreasing the expression of EGR3 could enhance the migration and invasion of NPC cells.
ConclusionThe newly identified miR-483-5p/EGR3 pathway provides further insights into the development and metastasis of NPC and may provide a potential therapeutic target for NPC treatment in order to improve survival of NPC patients.

背景：微小RNA（MicroRNAs）作为一类小型非编码RNA，在肿瘤发生发展中发挥重要作用。本团队前期研究发现，miR-483-5p作为鼻咽癌（nasopharyngeal carcinoma, NPC）的诊断生物标志物存在显著高表达，不仅在鼻咽癌患者血浆中，还在肿瘤细胞系及活检组织中均有体现。然而，其在鼻咽癌中的具体功能与作用机制仍未明确。
方法：本研究采用包含178例原发性鼻咽癌组织及35例癌旁正常鼻咽黏膜组织的组织微阵列（Tissue microarray），进一步验证miR-483-5p的高表达特性。通过划痕愈合实验与侵袭实验验证其生物学功能；借助RNA测序（RNA-seq）及双荧光素酶报告基因实验探索其靶基因，并在23例鼻咽癌患者及9例慢性鼻咽炎患者的新鲜活检组织中进行验证。
结果：miR-483-5p在鼻咽癌组织中的表达量显著高于癌旁正常组织。分析显示，其表达水平与鼻咽癌患者的不良总生存期（overall survival, OS）[风险比（hazard ratio, HR）=2.89，95%置信区间（confidence interval, CI）=1.00–8.35，p=0.041]及无进展生存期（progression-free survival, PFS）（HR=1.95，95%CI=1.06–3.60，p=0.029）显著相关。体外实验表明，沉默miR-483-5p的表达可抑制鼻咽癌细胞的迁移与侵袭能力。本研究鉴定出早期生长应答因子3（early growth response 3, EGR3）为其直接靶基因，抑制miR-483-5p的表达可显著上调EGR3的mRNA及蛋白水平。此外，鼻咽癌患者新鲜活检组织中EGR3的表达水平显著降低，与miR-483-5p的表达呈负相关。进一步实验证实，直接下调EGR3的表达可增强鼻咽癌细胞的迁移与侵袭能力。
结论：本研究新发现的miR-483-5p/EGR3通路为鼻咽癌的发生发展及转移机制提供了新的见解，或可成为鼻咽癌治疗的潜在靶点，以期改善鼻咽癌患者的生存预后。