Background

Long non-coding RNAs (lncRNAs) are known to be frequently dysregulated in many types of human cancer. As yet, however, their roles in colon carcinogenesis have not been fully elucidated. In the current study, we assessed whether lncRNA LINC00858 may be involved in the progression of colon cancer and, in addition, investigated its downstream targets.

Methods

LINC00858 expression in patient-derived colon cancer tissues and in colon cancer cell lines was determined using RT-qPCR. Also, relationships between LINC00858 expression and various clinicopathological characteristics were analyzed. The subcellular localization of LINC00858 was determined using fluorescence in situ hybridization. Interactions between LINC00858 and its downstream targets were first predicted by bioinformatic analysis and, subsequently, confirmed by RNA pull-down, RNA immunoprecipitation, chromatin immunoprecipitation and dual luciferase reporter assays. After in vitro upregulation of LINC00858 and/or silencing of WNK2 and hepatocyte nuclear factor 4α (HNF4α), the biological behavior of colon cancer cells was assessed using 5-ethynyl-2′-deoxyuridine (EdU) incorporation, Transwell invasion and tube formation assays. In vivo cancer growth was evaluated in nude mice.

Results

We found that LINC00858 was highly expressed in primary colon cancer tissues and colon cancer cell lines, and was mainly located in the nucleus. High LINC00858 expression was found to correlate with a poor differentiation, advanced TNM stages and lymph node metastasis. Exogenous overexpression of LINC00858 promoted cell proliferation, invasion and migration of colon cancer cells, and facilitated angiogenesis and tumor growth. In addition, we found that LINC00858 can bind to and upregulate the nuclear transcription factor HNF4α, leading to WNK2 expression downregulation. This, in turn, resulted in the promotion of colon cancer cell growth.

Conclusions

From our data we conclude that LINC00858 acts as a tumor-promoting lncRNA in colon cancer by upregulating HNF4α and downregulating WNK2. Our results may provide novel targets for the treatment for colon cancer.

中文翻译：

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长非编码RNA LINC00858通过HNF4α和WNK2调控在结肠癌中发挥肿瘤促进作用

背景

长的非编码RNA（lncRNA）已知在许多类型的人类癌症中经常失调。然而，到目前为止，它们在结肠癌发生中的作用尚未完全阐明。在本研究中，我们评估了lncRNA LINC00858是否可能参与了结肠癌的进展，此外，还研究了其下游靶标。

方法

使用RT-qPCR确定患者来源的结肠癌组织和结肠癌细胞系中的LINC00858表达。此外，分析了LINC00858表达与各种临床病理特征之间的关系。使用荧光原位杂交确定LINC00858的亚细胞定位。LINC00858及其下游靶标之间的相互作用首先通过生物信息学分析进行预测，然后通过RNA下拉，RNA免疫沉淀，染色质免疫沉淀和双重萤光素酶报告基因分析进行确认。在LINC00858体外上调和/或WNK2和肝细胞核因子4α（HNF4α）沉默后，使用5-乙炔基-2'-脱氧尿苷（EdU）掺入，Transwell侵袭和管形成实验评估了结肠癌细胞的生物学行为。 。

结果

我们发现LINC00858在原发性结肠癌组织和结肠癌细胞系中高度表达，并且主要位于细胞核中。发现高LINC00858表达与差的分化，晚期TNM分期和淋巴结转移相关。LINC00858的外源性过表达促进结肠癌细胞的细胞增殖，侵袭和迁移，并促进血管生成和肿瘤生长。此外，我们发现LINC00858可以结合并上调核转录因子HNF4α，从而导致WNK2表达下调。反过来，这导致了结肠癌细胞生长的促进。

结论

根据我们的数据，我们得出结论，LINC00858通过上调HNF4α和下调WNK2在结肠癌中充当促进肿瘤的lncRNA。我们的结果可能为结肠癌的治疗提供新的靶标。