a Department of Otorhinolaryngology , Henan Provincial People's Hospital , 7 WeiWu Road, Zhengzhou , China.
Cancer Biol Ther. 2018 Jun 3;19(6):534-542. doi: 10.1080/15384047.2018.1450119. Epub 2018 Apr 9.
The long non-coding RNA nuclear paraspeckle assembly transcript 1 (NEAT1) was reported to be upregulated and be involved in oncogenic growth and drug resistance in nasopharyngeal carcinoma (NPC). However, the exact roles of NEAT1 and its underlying mechanisms in the drug resistance of NPC remain largely unclear. In this study, the expressions of NEAT1, let-72-5p and Rsf-1 mRNA were detected by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The effects of NEAT1 and let-72-5p on cell proliferation and cisplatin resistance of NPC cells were investigated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay and 5-ethynyl-20-deoxyuridine (EdU) assay. Western blot analysis was performed to detect the protein levels of Rsf-1, Ras, p-Raf1, Raf1, p-MEK1, MEK1, p-ERK1/2 and ERK1/2. Xenograft tumor assay was done to elucidate the role of NEAT1 involved in NPC tumor growth in vivo. We found that NEAT1 was upregulated and let-7a-5p was downregulated in NPC tissues, as well as NPC cell lines. Inhibition of NEAT1 markedly repressed the cisplatin resistance of NPC cells. NEAT1 was demonstrated to interact with let-7a-5p. Besides, a negative correlation between NEAT1 and let-7a-5p expression was observed in NPC tissues. Rsf-1 was confirmed as a target of let-7a-5p. NEAT1 remarkably reversed the inhibitory effect of let-7q-5p on the cisplatin resistance of NPC cells in vitro. Additionally, NEAT1 knockdown inhibited the Ras-MAPK pathway in NPC cells. NEAT1 knockdown suppressed tumor growth in the presence of cisplatin in vivo. Overall, these findings suggest that NEAT1/let-7a-5p axis regulates the cisplatin resistance in NPC by targeting Rsf-1 and modulating the Ras-MAPK signaling pathway.
长链非编码 RNA 核斑浆组装转录本 1（NEAT1）被报道上调，并参与鼻咽癌（NPC）的致癌生长和耐药性。然而，NEAT1 及其在 NPC 耐药性中的潜在机制的确切作用在很大程度上仍不清楚。在这项研究中，通过逆转录定量聚合酶链反应（RT-qPCR）检测 NEAT1、let-72-5p 和 Rsf-1mRNA 的表达。通过 3-(4,5-二甲基噻唑-2-基）-2,5-二苯基四唑溴盐（MTT）测定和 5-乙炔基-20-脱氧尿苷（EdU）测定研究 NEAT1 和 let-72-5p 对 NPC 细胞增殖和顺铂耐药性的影响。Western blot 分析用于检测 Rsf-1、Ras、p-Raf1、Raf1、p-MEK1、MEK1、p-ERK1/2 和 ERK1/2 的蛋白水平。异种移植肿瘤实验用于阐明 NEAT1 在体内 NPC 肿瘤生长中的作用。我们发现，在 NPC 组织和 NPC 细胞系中，NEAT1 上调，而 let-7a-5p 下调。抑制 NEAT1 可显著抑制 NPC 细胞的顺铂耐药性。证明 NEAT1 与 let-7a-5p 相互作用。此外，在 NPC 组织中观察到 NEAT1 和 let-7a-5p 表达之间存在负相关。Rsf-1 被确认为 let-7a-5p 的靶标。NEAT1 可显著逆转 let-7a-5p 在体外对 NPC 细胞顺铂耐药性的抑制作用。此外，NEAT1 敲低抑制 NPC 细胞中 Ras-MAPK 通路。体内，在顺铂存在的情况下，NEAT1 敲低抑制肿瘤生长。总之，这些发现表明，NEAT1/let-7a-5p 轴通过靶向 Rsf-1 调节 Ras-MAPK 信号通路来调节 NPC 中的顺铂耐药性。
