Long non-coding RNA nuclear enriched abundant transcript 1 (NEAT1) modulates inhibitor of DNA binding 1 (ID1) to facilitate papillary thyroid carcinoma development by sponging microRNA-524-5p

Long non-coding RNA (lncRNA) nuclear-enriched abundant transcript 1 (NEAT1) exerts a pro-oncogenic role in several cancers, whereas its underlying regulatory mechanism in papillary thyroid carcinoma (PTC) progression remains unknown. This research mainly explored the roles of NEAT1 in PTC development. Quantitative real-time polymerase-chain reaction (qRT-PCR) was applied to measure NEAT1, miR-524-5p, and inhibitor of DNA binding 1 (ID1) expression in PTC tissues and cells. Western blot was conducted for detecting the protein levels. MTT, transwell, and flow cytometry assays were applied to assess cell proliferation, metastasis, and apoptosis in PTC cells in vitro. The PTC xenograft tumor model was used for investigating the role of NEAT1 in vivo. Dual-luciferase reporter assay was utilized for confirming the interaction between miR-524-5p and NEAT1 or ID1. In PTC tissues and cells, NEAT1 was significantly up-regulated. NEAT1 silencing blocked cell proliferation, metastasis, and facilitated apoptosis in vitro and impeded xenograft tumor growth in vivo. Bioinformatics prediction revealed the existence of binding sites between NEAT1 and miR-524-5p. Besides, ID1 was confirmed as a direct target to miR-524-5p, and the enhancement of ID1 reversed the regulation of miR-524-5p upregulation on cell progression. In addition, NEAT1 promoted PTC development by regulating ID1 expression via sponging miR-524-5p in PTC. In summary, we demonstrate that NEAT1 advanced the process of PTC by miR-524-5p/ID1 axis, which may enhance our comprehension of PTC pathogenesis.

长链非编码RNA（long non-coding RNA，lncRNA）核富集转录本1（nuclear-enriched abundant transcript 1，NEAT1）在多种癌症中发挥促癌作用，但其在甲状腺乳头状癌（papillary thyroid carcinoma，PTC）进展中的潜在调控机制仍未阐明。本研究主要探讨NEAT1在PTC发生发展中的作用。采用实时定量聚合酶链式反应（quantitative real-time polymerase-chain reaction，qRT-PCR）检测PTC组织与细胞中NEAT1、miR-524-5p及DNA结合抑制因子1（inhibitor of DNA binding 1，ID1）的表达水平；采用蛋白质印迹法（Western blot）检测蛋白表达水平。通过MTT法、Transwell实验及流式细胞术分别评估PTC细胞的体外增殖、迁移侵袭与凋亡情况；采用PTC异种移植瘤模型探究NEAT1在体内的生物学功能。采用双荧光素酶报告基因实验验证miR-524-5p与NEAT1或ID1之间的靶向互作关系。实验结果显示，在PTC组织及细胞中，NEAT1的表达水平显著上调；沉默NEAT1可在体外阻滞PTC细胞的增殖与迁移侵袭，并促进细胞凋亡，同时在体内抑制异种移植瘤的生长。生物信息学预测结果表明，NEAT1与miR-524-5p存在特异性结合位点；此外，ID1被证实为miR-524-5p的直接靶基因，而过表达ID1可逆转miR-524-5p上调对细胞进程的调控效应。进一步机制研究发现，NEAT1可通过海绵吸附miR-524-5p调控ID1的表达，进而促进PTC的发生发展。综上，本研究证实NEAT1通过调控miR-524-5p/ID1轴加速PTC进程，该发现有助于加深我们对PTC发病机制的理解。