Increasing lines of evidence indicate the role of long non-coding RNAs (LncRNAs) in gene regulation and tumor development. Hence, it is important to elucidate the mechanisms of LncRNAs underlying the proliferation, metastasis, and invasion of lung adenocarcinoma (LUAD). We employed microarrays to screen LncRNAs in LUAD tissues with and without lymph node metastasis and revealed their effects on LUAD. Among them, Linc00426 was selected for further exploration in its expression, the biological significance, and the underlying molecular mechanisms. Linc00426 exhibits ectopic expression in LUAD tissues and cells. The ectopic expression has been clinically linked to tumor size, lymphatic metastasis, and tumor differentiation of patients with LUAD. The deregulation of Linc00426 contributes to a notable impairment in proliferation, invasion, metastasis, and epithelial–mesenchymal transition (EMT) in vitro and in vivo. Mechanistically, the deregulation of Linc00426 could reduce cytoskeleton rearrangement and matrix metalloproteinase expression. Meanwhile, decreasing the level of Linc00426 or increasing miR-455-5p could down-regulate the level of UBE2V1. Thus, Linc00426 may act as a competing endogenous RNA (ceRNA) to abate miR-455-5p-dependent UBE2V1 reduction. We conclude that Linc00426 accelerates LUAD progression by acting as a molecular sponge to regulate miR-455-5p, and may be a potential novel tumor marker for LUAD.

Background: Many studies have shown that microRNAs (miRNAs) play an essential role in gene regulation and tumor development. This study aimed to explore the expression of miR‐379‐5p and its mechanisms of affecting proliferation, migration, and invasion in breast cancer (BC).Methods: MiRNAs and mRNAs expression data of BC and normal breast tissue samples were downloaded from the TCGA and GEO databases. qRT‐PCR was used to detect the expression of miR‐379‐5p in human normal breast epithelial cell lines and human BC cell lines. The proliferation ability of transfected cells was detected by colony formation and EdU assays. The mobility and invasion ability of transfected cells was measured by wound healing and transwell assays. The relative protein expression of transfected cells was detected by western blot. Dual luciferase reporter assay was performed to identify the targeted binding of miR‐379‐5p and KIF4A.Results: MiR‐379‐5p was lowly expressed in BC tissue samples and BC cell lines. The target genes of miR‐379‐5p were involved in many cancer‐related signaling pathways. PPI analysis and the cytoHubba algorithm of Cytoscape identified 10 genes as the hub genes. Survival analysis showed that only KIF4A expression in 10 hub genes was significantly associated with the prognosis of BC patients and was significantly upregulated in BC. Overexpression of miR‐379‐5p inhibited proliferation, migration, and invasion in the BC cell line MDA‐MB‐231, which could be reversed by KIF4A.Conclusions: MiR‐379‐5p inhibits proliferation, migration, and invasion of BC by targeting KIF4A.

The roles of microRNAs (miRNAs) in the occurrence, metastasis, and prognosis of lung adenocarcinoma (LUAD) have been drawing extensive attention from researchers. The aim of this study is to identify the effects of miR-4732-5p on the migration, invasion, and metastasis of LUAD. In this study, we found that the expression of miR-4732-5p was decreased in LUAD based on the data derived from The Cancer Genome Atlas (TCGA) database, tissues, and cell lines. LUAD patients with a low expression of miR-4732-5p exhibited a lower survival rate. Meanwhile, miR-4732-5p could directly target xenotropic and polytropic retrovirus receptor 1 (XPR1), and elevated XPR1 was observed in LUAD mRNA microarrays, Gene Expression Omnibus (GEO), and The Human Protein Atlas (HPA) database. Overexpression of miR-4732-5p significantly inhibits the migration, invasion, and metastasis of LUAD in vitro and in vivo, which can be reversed by overexpression of XPR1. We also found that the PI3K/Akt/GSK3β/Snail pathway induced by EGF induced EMT could be inhibited by miR-4732-5p overexpression and XPR1 knockdown. The migration and invasion of LUAD could be converted by cytoskeletal rearrangements, and the polymerization of EGF induced F-actin in A549 cells could be inhibited by elevated miR-4732-5p. Our results suggest that miR-4732-5p exerts anti-tumor effects on the invasion and metastasis of LUAD by regulating XPR1 in vivo and in vitro, indicating that the miR-4732-5p/XPR1 axis may be a potential target for LUAD therapeutic intervention.

MicroRNAs（miRNAs）是短的非编码RNA，是能够调控基因表达、影响细胞过程、促进疾病发展的重要分子。在许多疾病中可以观察到miRNA表达的变化，包括肝炎、心血管疾病和癌症。本研究旨在探讨miR-144-3p靶向调控胰岛素受体底物1（insulin receptor substrate 1, IRS1）对肺腺癌细胞侵袭和转移的影响。 通过生物信息学数据库查询miR-144-3p在肺腺癌患者中的表达情况；利用mirTarPathway对miRNA进行KEGG通路富集分析；定量逆转录聚合酶链式反应（quantitative reverse transcription polymerase chain reaction, qRT-PCR）检测miR-144-3p在肺腺癌细胞系中的表达情况与质粒转染效率；Transwell实验检测不同组细胞侵袭迁移能力的变化。生物信息学确定miR-144-3p的关键基因（Hub基因）；双荧光素酶靶标实验检测miR-144和IRS1的相互结合情况；Western blot实验检测IRS1在不同细胞系的表达及过表达miR-144后IRS1的表达情况。 miR-144-3p在肺腺癌组织中表达降低，qRT-PCR结果提示miR-144-3p在肺腺癌细胞A549中的表达显著降低（P < 0.05）且过表达质粒转染成功（P < 0.05）；过表达miR-144后，细胞的迁移、侵袭和增殖能力下降（P < 0.05）；IRS1在肺腺癌组织中表达上调；生存分析表明高表达IRS1的肺腺癌患者预后不良（P < 0.05）；双荧光素酶实验结果显示，miR-144可特异识别IRS1的3’-UTR抑制报告酶的表达（P < 0.05）；Western blot结果提示IRS1在A549细胞中表达升高（P < 0.05），过表达miR-144后，IRS1蛋白表达水平下降（P < 0.05）；Transwell实验证明，miR-144-3p可通过靶向调控IRS1抑制肺腺癌细胞的侵袭和转移（P < 0.05）。 miR-144-3p通过靶向调控IRS1抑制A549细胞的侵袭和迁移能力，进而在肿瘤中发挥抑癌作用。

Lung adenocarcinoma (LUAD) is the most common clinical histological subtype of lung cancer and microRNAs (miRNAs) are a type of small non-coding RNAs which play a central role in cells. miR-30b-3p plays a key effect in many types of carcinoma, but there is still very little research on how it works in lung adenocarcinoma. The role and mechanism of miR-30b-3p in the proliferation and invasion of LUAD were explored in this study, to provide new targets for inhibiting the proliferation and invasion of LUAD. NCBI database was used to screen out miRNA with obvious differential expression, and the differential expression and survival curve were searched by StarBase database. Real-time fluorescence quantitative polymerase chain reaction (qRT-PCR) was used to detect the relative expression of miR-30b-3p in each lung adenocarcinoma cell line. 5-ethynyl-2'-deoxyuridine (EdU) cell proliferation assay and Transwell invasion assay were used to detect the proliferation and invasion of A549 cells in each group. The target genes of miR-30b-3p were determined by the target gene prediction websites. Western blot assay was used to detect the expression of COX6B1 in each group of A549 cells. Double luciferase assay was used to verify the targeted binding relationship between miR-30b-3p and COX6B1. The expression of miR-30b-3p in lung adenocarcinoma tissues and lung adenocarcinoma cells was downregulated (P<0.05). Low expression levels of miR-30b-3p were associated with poor prognosis in patients with lung adenocarcinoma (P=0.005,8). Overexpression of miR-30b-3p could inhibit the proliferation and the invasion of lung adenocarcinoma cells (P<0.05). Double luciferase assay proved that miR-30b-3p could target and bind to COX6B1 (P<0.05). Western blot analysis showed that the overexpression of miR-30b-3p could downregulate the expression of COX6B1 in A549 cells (P<0.05). EdU cell proliferation assay and Transwell invasion assay showed that the overexpression of miR-30b-3p could reverse the promoting effect of upregulation of COX6B1 on proliferation and invasion in lung adenocarcinoma cells (P<0.05). miR-30b-3p acts as a tumor suppressor gene in lung adenocarcinoma, and it can inhibit the proliferation and invasion of lung adenocarcinoma by targeting the expression of COX6B1.

肺腺癌是最常见的非小细胞肺癌组织学类型，miRNAs作为基因表达的调控分子调控细胞增殖、凋亡和分化，从而影响细胞内稳态。本研究通过实验验证miR-186-5p通过调控其下游靶蛋白PRKAA2影响铁死亡途径从而抑制肺腺癌细胞增殖、迁移和侵袭能力。 前期研究获得肺癌中表达显著下调miRNA，即miR-186-5p；生物信息学方法预测其下游铁死亡相关靶蛋白并查询其在肺腺癌中的表达水平及对患者生存预后的影响；双荧光素酶验证两者结合位点；实时荧光定量聚合酶链式反应（quantitative real-time polymerase chain reaction, qRT-PCR）和Western blot检测过表达miR-186-5p后PRKAA2的基因和蛋白表达情况；EdU、Transwell、划痕实验验证miR-186-5p在A549、H1299细胞中的增殖、侵袭迁移能力的影响以及miR-186-5p对Fer-1抑制铁死亡敏感性的作用机制；活性氧（reactive oxygen species, ROS）实验检测miR-186-5p对肺腺癌细胞ROS含量的影响；丙二醛（malondialdehyde, MDA）、谷胱甘肽（glutathione, GSH）实验检测miR-186-5p、PRKAA2对肺腺癌细胞铁死亡指标变化的影响；脂质ROS（lipid ROS, L-ROS）实验检测miR-186-5p、PRKAA2对肺腺癌细胞L-ROS含量的影响。 PRKAA2在肺腺癌中表达上调；过表达miR-186-5p使PRKAA2的基因和蛋白表达量下降；过表达miR-186-5p通过调控PRKAA2促进铁死亡抑制肺腺癌细胞增殖、侵袭迁移能力；miR-186-5p能够增加A549细胞ROS含量；过表达miR-186-5p和敲低PRKAA2上调肺腺癌细胞MDA含量，下调还原型GSH含量；miR-186-5p通过靶向PRKAA2增加肺腺癌细胞L-ROS含量，促进肺腺癌细胞铁死亡敏感性。 miR-186-5p通过靶向调控PRKAA2促进肺腺癌A549、H1299细胞铁死亡，从而抑制肺腺癌增殖、侵袭和迁移能力。