Long non-coding RNAs (lncRNAs) play key roles in tumorigenesis. It has been reported that the lncRNA nuclear-enriched abundant transcript 1 (NEAT1) may act as an oncogenic regulator in several cancers. However, the biological mechanism of action of NEAT1, particularly the miRNA sponge role in colorectal cancer (CRC), has not been fully elucidated. In our study, the expression of NEAT1, miR-205-5p, and vascular endothelial growth factor A (VEGFA) in CRC cell lines were assessed by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) analysis. Cell proliferation was detected by Cell Counting Kit-8 (CCK-8) assay. Cell migration and invasion were examined by wound healing and transwell assays, respectively. RNA-binding protein immunoprecipitation (RIP), and dual-luciferase and RNA pull-down assays were conducted to determine the correlation between miR-205-5p and NEAT1 or VEGFA. VEGFA, matrix metalloproteinase (MMP)2, and MMP9 protein and mRNA expression were measured by western blotting and RT-qPCR analysis, respectively. Our results demonstrated high expression of NEAT1 and VEGFA and low expression of miR-205-5p in CRC cell lines. The RIP and dual-luciferase assays confirmed miR-205-5p as a target of NEAT1. In addition, VEGFA was identified as a direct target of miR-205-5p. Inhibition of NEAT1 or overexpression of miR-205-5p was able to repress VEGFA expression. Moreover, downregulation of NEAT1 and VEGFA inhibited cell proliferation, migration, and invasion. NEAT1 overexpression facilitated tumor growth by modulating miR-205-5p. Taken together, lncRNA NEAT1 was found to be upregulated in CRC cell lines, promoting CRC cell proliferation, migration, and invasion through regulating the miR-205-5p/VEGFA signaling pathway. These findings suggest that NEAT1 may be a promising biomarker in CRC diagnosis and treatment.

中文翻译：

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长链非编码 RNA NEAT1 通过调节 miR-205-5p/VEGFA 轴促进结直肠癌进展。

长链非编码 RNA (lncRNA) 在肿瘤发生中起关键作用。据报道，lncRNA 核富集的丰富转录物 1 (NEAT1) 可能在几种癌症中充当致癌调节剂。然而，NEAT1 的生物学作用机制，特别是 miRNA 海绵在结直肠癌 (CRC) 中的作用，尚未完全阐明。在我们的研究中，通过逆转录-定量聚合酶链反应 (RT-qPCR) 分析评估 CRC 细胞系中 NEAT1、miR-205-5p 和血管内皮生长因子 A (VEGFA) 的表达。通过 Cell Counting Kit-8 (CCK-8) 测定法检测细胞增殖。分别通过伤口愈合和 transwell 测定检查细胞迁移和侵袭。RNA结合蛋白免疫沉淀（RIP），并进行双荧光素酶和 RNA 下拉测定以确定 miR-205-5p 与 NEAT1 或 VEGFA 之间的相关性。分别通过蛋白质印迹和 RT-qPCR 分析测量 VEGFA、基质金属蛋白酶 (MMP)2 和 MMP9 蛋白和 mRNA 表达。我们的结果表明在 CRC 细胞系中 NEAT1 和 VEGFA 的高表达和 miR-205-5p 的低表达。RIP 和双荧光素酶测定证实 miR-205-5p 是 NEAT1 的靶标。此外，VEGFA 被鉴定为 miR-205-5p 的直接靶标。抑制 NEAT1 或过表达 miR-205-5p 能够抑制 VEGFA 表达。此外，NEAT1 和 VEGFA 的下调抑制了细胞增殖、迁移和侵袭。NEAT1 过表达通过调节 miR-205-5p 促进肿瘤生长。综合起来，发现 lncRNA NEAT1 在 CRC 细胞系中上调，通过调节 miR-205-5p/VEGFA 信号通路促进 CRC 细胞增殖、迁移和侵袭。这些发现表明，NEAT1 可能是 CRC 诊断和治疗中一个很有前景的生物标志物。