Gastric cancer (GC) remains one of prevalent causes of cancer‐related deaths worldwide. Long noncoding RNA is related to various cancers. Our study was conducted to explore the biological effects of LINC00240 on the tumorigenesis of GC and uncover its possible mechanisms. LINC00240 expression was determined in GC cell lines and samples through quantitative Real‐time Polymerase Chain Reaction (qRT‐PCR). The functional effects of LINC00240 were validated using in vitro and in vivo assays. Targets were assessed by AGO2‐dependent RNA immunoprecipitation assay and dual‐luciferase report assays. Our findings suggested higher LINC00240 expression in GC tissues and cells. Through downregulating LINC00240, cell proliferation, invasion and migration were retarded in vitro, and tumorigenesis of GC cells was notably suppressed in vivo. Further research showed that LINC00240 was a cytoplasmic lncRNA that shared miRNA response elements of microRNA (miR)‐124‐3p with DNMT3B, thus forming a LINC00240/miR‐124‐3p/DNMT3B axis explaining the functions of LINC00240. In a word, our study reveals that LINC00240 promotes GC tumorigenesis via a LINC00240/miR‐124‐3p/DNMT3B axis as an oncogene. These findings objectivise that LINC00240 may be a potential diagnostic biomarker for GC.

中文翻译：

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LINC00240通过miR-124-3p / DNMT3B轴促进胃癌细胞的增殖，迁移和EMT。

胃癌（GC）仍然是全球范围内与癌症相关的死亡的普遍原因之一。长的非编码RNA与多种癌症有关。我们的研究旨在探讨LINC00240对GC肿瘤发生的生物学作用，并揭示其可能的机制。通过定量实时聚合酶链反应（qRT-PCR）测定了GC细胞系和样品中的LINC00240表达。LINC00240的功能作用已通过体外和体内试验验证。通过AGO2依赖性RNA免疫沉淀测定法和双荧光素酶报告测定法对靶标进行了评估。我们的发现表明，LINC00240在GC组织和细胞中的表达更高。通过下调LINC00240，体外可抑制细胞增殖，侵袭和迁移，并且在体内可显着抑制GC细胞的肿瘤发生。进一步的研究表明，LINC00240是一种细胞质lncRNA，与DNMT3B共享microRNA（miR）124-3p的miRNA反应元件，因此形成了一条LINC00240 / miR-124-3p / DNMT3B轴，解释了LINC00240的功能。总之，我们的研究表明LINC00240通过LINC00240 / miR-124-3p / DNMT3B轴作为癌基因促进了GC的肿瘤发生。这些发现使LINC00240可能是GC的潜在诊断生物标志物。