Department of Thyroid Surgery, The First Hospital of Jilin University, Changchun, Jilin 130020, P.R. China.
Oncol Rep. 2021 May;45(5). doi: 10.3892/or.2021.8015. Epub 2021 Mar 24.
Papillary thyroid carcinoma (PTC) is the most common type of cancer in the endocrine system. Long non‑coding RNAs (lncRNAs) are associated with PTC progression. Therefore, the present study aimed to identify a novel lncRNA involved in PTC. Herein, dysregulated lncRNAs were analyzed in The Cancer Genome Atlas (TCGA)‑thyroid cancer (THCA) data. Furthermore, the association between double homeobox A pseudogene 8 (DUXAP8) gene expression and disease stage, and prognosis of patients with PTC was evaluated using the GEPIA online database, while the correlation between DUXAP8 expression and the clinicopathological characteristics of patients with PTC was analyzed by Chi‑square test. In addition, the biological effect of DUXAP8 expression on cell proliferation and apoptosis was also investigated. The protein and mRNA/microRNA (miRNA)/lncRNA expression levels were assessed by western blot analysis and reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR), respectively. The interaction between miR‑20b‑5p and DUXAP8 was verified using bioinformatics analysis, RNA RIP assay, dual luciferase reporter assay, western blot analysis and RT‑qPCR. The analysis of the TCGA‑THCA data revealed that DUXAP8 was one of the most significantly upregulated lncRNAs in PTC. This finding was further confirmed in tissues from patients with PTC. Increased DUXAP8 expression was associated with higher grade and poorer prognosis in patients with PTC. In PTC cell lines, silencing of DUXAP8 expression with small interfering RNA‑DUXAP8 (si‑DUXAP8) induced cell apoptosis and attenuated cell proliferation. Additionally, transfection of PTC cells with si‑DUXAP8 decreased the phosphorylation levels of MEK1/2 and ERK1/2, as well as downregulated the expression of son of sevenless 1 (SOS1), cyclin D1 (CCND1) and c‑Myc. The results of the present study also revealed that miR‑20b‑5p could directly target DUXAP8. DUXAP8 expression was positively associated with that of SOS1, c‑Myc and CCND1 in the TCGA‑THCA data, and DUXAP8 level was positively correlated with that of SOS1 in PTC tumor tissues. Finally, transfection of PTC cells with the SOS1 overexpression plasmid, pcDNA3.1‑SOS1, rescued the effects of si‑DUXAP8 on cell proliferation and apoptosis. The present study was the first to identify DUXAP8 as a novel upregulated lncRNA in PTC, and provided new insights in understanding the effect of the lncRNA‑miRNA‑mRNA network in PTC.
甲状腺癌 (PTC) 是内分泌系统中最常见的癌症类型。长链非编码 RNA (lncRNA) 与 PTC 进展有关。因此，本研究旨在鉴定一种参与 PTC 的新型 lncRNA。在此，分析了癌症基因组图谱 (TCGA)-甲状腺癌 (THCA) 数据中的失调 lncRNA。此外，使用 GEPIA 在线数据库评估了 DUXAP8 基因表达与 PTC 患者疾病分期和预后之间的关联，并用卡方检验分析了 DUXAP8 表达与 PTC 患者临床病理特征之间的相关性。此外，还通过 Western blot 分析和逆转录-定量聚合酶链反应 (RT-qPCR) 分别评估了 DUXAP8 表达对细胞增殖和凋亡的生物学影响。通过生物信息学分析、RNA 免疫沉淀 (RIP) 测定、双荧光素酶报告基因测定、Western blot 分析和 RT-qPCR 验证了 miR-20b-5p 与 DUXAP8 之间的相互作用。TCGA-THCA 数据分析显示，DUXAP8 是 PTC 中上调最显著的 lncRNA 之一。这一发现在 PTC 患者的组织中得到了进一步证实。在 PTC 细胞系中，用小干扰 RNA-DUXAP8(si-DUXAP8) 沉默 DUXAP8 表达可诱导细胞凋亡并抑制细胞增殖。此外，转染 PTC 细胞的 si-DUXAP8 降低了 MEK1/2 和 ERK1/2 的磷酸化水平，并下调了 son of sevenless 1(SOS1)、细胞周期蛋白 D1(CCND1) 和 c-Myc 的表达。本研究的结果还表明，miR-20b-5p 可直接靶向 DUXAP8。在 TCGA-THCA 数据中，DUXAP8 的表达与 SOS1、c-Myc 和 CCND1 的表达呈正相关，而在 PTC 肿瘤组织中，DUXAP8 水平与 SOS1 的表达呈正相关。最后，转染 PTC 细胞的 SOS1 过表达质粒 pcDNA3.1-SOS1，挽救了 si-DUXAP8 对细胞增殖和凋亡的影响。本研究首次鉴定 DUXAP8 为 PTC 中一种新型上调的 lncRNA，为理解 lncRNA-miRNA-mRNA 网络在 PTC 中的作用提供了新的见解。
