BACKGROUND LncRNA LINC00662 is closely related to the occurrence and development of cancer. This study aims to explore the effect of LINC00662 on colon cancer tumor growth and metastasis and its molecular mechanism. METHODS CCK8, colony formation, transwell, scratch wound, TUNEL, flow cytometry, RT-PCR, western blotting and immunohistochemistry assays were used to detect the proliferation, apoptosis, invasion and migration of colon cancer cell and mRNA and protein expressions. Luciferase reporter and RNA pull down assays were used to detect the combination of LINC00662 and miR-340-5p or IL22 and the combination of miR-340-5p and CLDN8/IL22. Co-immunoprecipitation were used to detect the co-expression of CLDN8 and IL22 in colon cell lines. The targets of LINC00662 were predicated by Starbase v2.0. The target genes of miR-340-5p were predicated by miRDB and TargetScan. GO and KEGG enrichment analysis were performed by DAVID website. RESULTS LINC00662 was up-regulation in colon cancer tissues and cell lines. Univariate Cox regression analysis showed that the LINC00662 expression level was related to the poor prognosis. LINC00662-WT and miR-340-5p mimics co-transfection depressed luciferase activity and IL22/CLDN8-WT and miR-340-5p inhibitors co-transfection memorably motivated luciferase activity. LINC00662 overexpression promoted cell proliferation, invasion and migration, and inhibited cell apoptosis in colon cancer. In vivo xenograft studies in nude mice manifested that LINC00662 overexpression prominently accelerate tumor growth. There was an opposite reaction in the biological functions of colon cells and tumor growth between LINC00662 overexpression and LINC00662 inhibition in vitro and in vivo. The functions of miR-340-5p mimics regulating the biological functions of colon cells and tumor growth were consistent with those of LINC00662 inhibition. CLDN8 and IL22, as target genes of miR-340-5p, reversed the functions of LINC00662 affecting the biological functions of colon cells and the protein levels of Bax, Bcl-2, XIAP, VEGF, MMP-2, E-cadherin and N-cadherin. Co-immunoprecipitation experiments indicated that CLDN8 directly interact with IL22 in colon cell lines. LINC00662 regulated CLDN8 and IL22 expressions and the activation of ERK signaling pathway via targeting miR-340-5p. CONCLUSION LINC00662 overexpression promoted the occurrence and development of colon cancer by competitively binding with miR-340-5p to regulate CLDN8/IL22 co-expression and activating ERK signaling pathway.

中文翻译：

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LncRNA LINC00662通过与miR-340-5p竞争性结合调节CLDN8/IL22共表达并激活ERK信号通路来促进结肠癌肿瘤生长和转移。

背景LncRNA LINC00662与癌症的发生、发展密切相关。本研究旨在探讨LINC00662对结肠癌肿瘤生长和转移的影响及其分子机制。方法采用CCK8、集落形成、Transwell、划痕、TUNEL、流式细胞术、RT-​​PCR、Western blotting、免疫组化等方法检测结肠癌细胞的增殖、凋亡、侵袭和迁移以及mRNA和蛋白的表达。使用荧光素酶报告基因和RNA Pull down测定来检测LINC00662与miR-340-5p或IL22的组合以及miR-340-5p与CLDN8/IL22的组合。采用免疫共沉淀法检测结肠细胞系中CLDN8和IL22的共表达。LINC00662 的目标由 Starbase v2.0 预测。通过miRDB和TargetScan预测miR-340-5p的靶基因。DAVID网站进行GO和KEGG富集分析。结果 LINC00662 在结肠癌组织和细胞系中表达上调。单变量Cox回归分析显示LINC00662表达水平与不良预后相关。LINC00662-WT 和 miR-340-5p 模拟共转染降低的荧光素酶活性，而 IL22/CLDN8-WT 和 miR-340-5p 抑制剂共转染显着激发荧光素酶活性。LINC00662过表达促进结肠癌细胞增殖、侵袭和迁移，并抑制细胞凋亡。裸鼠体内异种移植研究表明，LINC00662 过表达显着加速肿瘤生长。LINC00662过表达和LINC00662体外和体内抑制在结肠细胞生物学功能和肿瘤生长方面存在相反的反应。miR-340-5p模拟物调节结肠细胞生物学功能和肿瘤生长的功能与LINC00662抑制作用一致。CLDN8和IL22作为miR-340-5p的靶基因，逆转LINC00662的功能，影响结肠细胞的生物学功能以及Bax、Bcl-2、XIAP、VEGF、MMP-2、E-cadherin和N的蛋白水平-钙粘蛋白。免疫共沉淀实验表明，CLDN8 与结肠细胞系中的 IL22 直接相互作用。LINC00662 通过靶向 miR-340-5p 调节 CLDN8 和 IL22 表达以及 ERK 信号通路的激活。结论 LINC00662过表达可能通过与miR-340-5p竞争性结合调节CLDN8/IL22共表达并激活ERK信号通路促进结肠癌的发生和发展。