微小RNA与DNA甲基化相互调控在胃癌中的作用

表观遗传修饰在胃癌发生发展及预后中起重要作用.微小RNA( miRNA)和DNA甲基化是表观遗传学的两个重要调控机制.miRNA抑制靶基因信使RNA的翻译,参与基因转录后水平调控.基因启动子区CpG岛的异常甲基化与肿瘤的发生关系密切,可导致癌基因、抑癌基因或其他肿瘤相关基因的表达异常.胃癌中存在miRNA和DNA甲基化...     

MicroRNA对肿瘤基因的调控及其临床意义

微小RNA(microRNA,miRNA)通过调控基因的表达,参与细胞生命过程中一系列重要的进程,包括胚胎发育、细胞增殖和分化、细胞死亡与凋亡、体内生化代谢等。成熟miRNA通过RNA诱导的沉默复合体(RNA-induced silencing complex,RISC)结合到靶mRNA上,依赖于序列的互补性机制、剪切或阻遏靶mRNA、沉默基因的表达。miRNA与肿瘤等疾病的发生、发展密切相关。miRNA的表达谱在肿瘤细胞与正常细胞之间具有明显差异,起到类似于癌基因或抑癌基因的作用。miRNA通过沉默肿瘤侵袭转移相关基因的表达,参与肿瘤侵袭转移过程。肿瘤细胞在miRNA表达谱上的特异性为肿瘤的诊断提供了一项生物标志物,同时也为调控miRNA表达以治疗肿瘤提供了新的靶点。以miRNA为基础的抗肿瘤治疗还可与传统的化疗结合起来,提高肿瘤的治疗效果,为肿瘤的生物治疗开拓新视野。     

肿瘤相关成纤维细胞在胃癌侵袭和转移中的作用研究进展

摘 要：肿瘤相关成纤维细胞（cancer-associated fibroblasts,CAFs）是包括胃癌在内的多种肿瘤的重要组成部分,主要通过细胞外基质沉积、血管形成、代谢重编程和耐药性等方式在肿瘤侵袭和转移过程中发挥关键作用。然而,CAFs在胃癌侵袭和转移中的作用机制尚不明确,相关报道主要集中在考察CAFs中miRNA或细胞因子的变化上。miRNA是一种非编码小RNA分子,不仅在CAFs中控制多个目标基因的表达,而且在肿瘤细胞与CAFs的信号通路中具有重要作用。CAFs分泌的某些细胞活性因子也可促进肿瘤的发生、发展和转移。全文对CAFs中miRNA、细胞因子在胃癌侵袭和转移中的作用以及相关的信号通路进行概述,以期为寻找胃癌治疗的新靶点提供理论依据。     

微RNA与肿瘤

微RNA（miRNA）是一类非编码的小RNA分子,通过直接抑制基因转录或蛋白质的表达而在器官发育,细胞增殖、分化和凋亡等多种生理过程中发挥关键作用.miRNA异常表达往往导致包括肿瘤在内的多种疾病.研究发现,miRNA在肿瘤发生发展、侵袭转移及肿瘤的诊治中起着重要作用.     

微RNA与肿瘤

微RNA(miRNA)是一类非编码的小RNA分子,通过直接抑制基因转录或蛋白质的表达而在器官发育,细胞增殖、分化和凋亡等多种生理过程中发挥关键作用.miRNA异常表达往往导致包括肿瘤在内的多种疾病.研究发现,miRNA在肿瘤发生发展、侵袭转移及肿瘤的诊治中起着重要作用.     

微RNA与肿瘤

微RNA(miRNA)是一类非编码的小RNA分子,通过直接抑制基因转录或蛋白质的表达而在器官发育,细胞增殖、分化和凋亡等多种生理过程中发挥关键作用.miRNA异常表达往往导致包括肿瘤在内的多种疾病.研究发现,miRNA在肿瘤发生发展、侵袭转移及肿瘤的诊治中起着重要作用.     

胃癌相关的竞争内源性RNA调控网络的构建和分析

目的构建胃癌相关竞争内源性RNA(ceRNA)网络, 探索胃癌发生、发展的分子机制。方法应用生物芯片技术测定胃癌及对应癌旁组织的信使RNA(mRNA)、微小RNA(miRNA)和长链非编码RNA(lncRNA)表达谱, 应用R软件中的edgeR包筛选差异表达基因并绘制火山图, 基于miRNA-lncRNA在线预测工具lncBase数据库和miRNA靶基因预测数据库预测mRNA、miRNA和lncRNA的相互作用关系, 采用Cytoscape软件构建胃癌lncRNA-miRNA-mRNA ceRNA网络, 根据cytohubba计算各节点degree得分筛选关键基因(hub基因)。运用注释、可视化和集成发现数据库(DAVID), 对差异表达的mRNA进行基因本体论(GO)功能富集和京都基因与基因组百科全书(KEGG)通路富集分析。在OncoLnc数据库中, 选择肿瘤基因组计划(TCGA)数据集的胃癌项目, 输入hub基因, 以标准化后基因表达量中位数为界值, 将样本分为高表达组和低表达组, 并进行生存分析。结果共筛出差异表达的mRNA 766个, miRNA 10个, lncRNA 11...     

microRNA与胃癌肿瘤干细胞研究进展

胃癌肿瘤干细胞是胃癌细胞中能够引起肿瘤生长和维持自我更新及分化潜能的一小群细胞,常用的化疗、放疗等治疗措施难以将其杀灭.胃癌肿瘤干细胞能够有选择地启动肿瘤的生长等生物学行为,与胃癌的复发、转移及耐药性等密切相关,影响胃癌患者的治疗及预后.而在胃癌发生、发展过程中存在多种类型微RNA(miRNA)的异常表达(过表达或表达缺失),这些miRNA对胃癌细胞具有重要调控作用.同时,这些miRNA对胃癌肿瘤干细胞的生物学行为更是起到关键调控作用.本文综述了miRNA与胃癌肿瘤干细胞的研究进展,为未来胃癌治疗新策略的发展提供有力支持.     

外泌体中circRNA-miRNA-mRNA网络在胃癌发生发展及其治疗中的作用

复杂的肿瘤微环境（TME）是导致胃癌高度异质性的主要原因之一。外泌体是多囊泡体和质膜融合后释放到体液中形成的纳米级生物囊泡，是TME中的重要组成部分。外泌体携带的生物分子通过促进细胞间的信号交流，在一定程度上参与调控癌症的发生和转移。环状RNA（circRNA）是稳定存在于外泌体中的非编码RNA，其作为miRNA 分子海绵，抑制miRNA 与mRNA 的结合，进而调节下游靶基因mRNA 的表达，并由此形成circRNA-miRNA-mRNA 网络。外泌体中circRNA-miRNA-mRNA网络通过参与调节胃癌的增殖、迁移和侵袭，诱导胃癌细胞上皮间质转化（EMT），介导胃癌血管生成，调节胃癌转移，调控胃癌的化疗耐药以及放射敏感性，在胃癌的发生发展中发挥重要作用。此外，以外泌体中circRNA 为靶点或者靶向circRNA-miRNA-mRNA网络可能为胃癌的治疗提供新的治疗选择。     

微小RNA与肿瘤转移

微小RNA（miRNA）是一种内源性非编码小RNA,可在转录水平负调节靶基因的表达。在肿瘤中miRNA可起到癌基因和抑癌基因的作用,其在肿瘤中的功能失调可能是肿瘤发生、发展的重要原因,研究表明miRNA可望成为肿瘤转移治疗的新靶点。     

Identification of new aberrantly expressed miRNAs in intestinal-type gastric cancer and its clinical significance

miRNAs are small 19 to 22 nucleotide sequences of RNA that negatively regulate gene expression. miRNA expression profiles may become useful biomarkers for diagnostics, prognosis and prediction of response to treat, and it could be a powerful tool for cancer prevention and therapeutics. Several miRNA expression profiles of miRNAs in gastric cancer have been reported, but these studies screened only few miRNAs and samples used in experiments include several different subtypes of gastric cancers, which decrease the sensitivity to identify new aberrant miRNAs. In this study, a miRNA expression profile was identified by miRCURY LNA Array (v.14.0) between intestinal-type gastric cancers and normal tissues. Forty miRNA precursors were up-regulated and thirty-six miRNA were down-regulated in intestinal-type gastric cancers (p<0.01). Sixteen new miRNAs were found in intestinal-type gastric cancers. Seventeen new miRNAs were found in intestinal-type gastric cancers. miR-145, miR-27a, miR-494 are differently expressed between intestinal-type and diffuse-type gastric cancers. miR-32, miR-182 and miR-143 dysregulated expression levels are related with different pathological stages of intestinal-type gastric cancers (p<0.01). Taken together, aberrantly expressed miRNAs may offer new clues to tumorigenesis of gastric cancers. miR-32, miR-182 and miR-143 may be potential diagnostic biomarkers for intestinal-type gastric cancers.     

MicroRNAs in cell proliferation, cell death, and tumorigenesis

MicroRNAs (miRNAs) are a recently discovered class of approximately 18-24 nucleotide RNA molecules that negatively regulate target mRNAs. All studied multicellular eukaryotes utilise miRNAs to regulate basic cellular functions including proliferation, differentiation, and death. It is now apparent that abnormal miRNA expression is a common feature of human malignancies. In this review, we will discuss how miRNAs influence tumorigenesis by acting as oncogenes and tumour suppressors.     

microRNAs与胃癌治疗

microRNAs（miRNAs）是真核生物中一类小分子非编码单链RNA,在转录后水平上调控靶mRNA的表达。目前,miRNA功能学研究发现miRNA与胃癌的侵袭转移、化疗耐药、放疗增敏、血管形成、基因甲基化、诊断和预后有直接关系,提示miRNA有可能成为肿瘤治疗的新思路。本文将阐述miRNA和胃癌放化疗的关系及其作为诊断、预后因子和基因治疗靶点基础研究方面的新进展。     

MicroRNAs相关的胃癌研究进展

MicroRNAs（miRNAs）是一类广泛存在于真核细胞中长22-25nt的单链、非蛋白编码RNA,具有转录后基因调控的功能,调节细胞增殖、凋亡以及分化等多种生物学过程。近年来研究发现,miRNAs与胃癌的发生、发展关系密切。本文就与胃癌相关的miRNAs及其在肿瘤发生、发展中的研究进展作一综述。     

MicroRNAs相关的胃癌研究进展

MicroRNAs(miRNAs)是一类广泛存在于真核细胞中长22-25nt的单链、非蛋白编码RNA,具有转录后基因调控的功能,调节细胞增殖、凋亡以及分化等多种生物学过程。近年来研究发现,miRNAs与胃癌的发生、发展关系密切。本文就与胃癌相关的miRNAs及其在肿瘤发生、发展中的研究进展作一综述。     

MicroRNAs involved in the EGFR/PTEN/AKT pathway in gliomas

Gliomas are the most common type of malignant primary brain tumor. Despite advances in surgery, radiation therapy, and chemotherapy, the prognosis of patients with gliomas has not significantly improved. MicroRNAs (miRNAs), a class of non-coding RNAs, 21–25 nucleotides long, negatively regulate the expression of target genes by interacting with specific sites in mRNAs, and play a critical role in the development of gliomas. The EGFR/PTEN/AKT pathway is a promising target for anti-glioma therapy. Recent studies have showed that regulation of the EGFR/PTEN/AKT pathway by miRNAs plays a major role in glioma progression, indicating a novel way to investigate the tumorigenesis, diagnosis, and therapy of gliomas. Here, we focus on recent findings of miRNAs with respect to the EGFR/PTEN/AKT pathway in gliomas.     

miR-27 promotes human gastric cancer cell metastasis by inducing epithelial-to-mesenchymal transition

microRNAs (miRNAs) play an important role in tumorigenesis. However, the mechanisms by which miRNAs regulate gastric cancer metastasis remain poorly understood. In the current study, we defined the target genes and biological functions of miR-27 with a luciferase reporter assay and Western blot analysis. We verified that miR-27 levels were increased in gastric cancer tissues. The overexpression of miR-27 promoted the metastasis of AGS cells, whereas its depletion decreased cell metastasis. Up-regulation of miR-27 increased the levels of the epithelial-mesenchymal transition (EMT)-associated genes ZEB1, ZEB2, Slug, and Vimentin, as well as decreased E-cadherin levels. We demonstrated that miR-27 promoted EMT by activating the Wnt pathway. Finally, the APC gene was identified as the direct and functional target of miR-27. These results suggest an important role of miR-27 in regulating metastasis of gastric cancer and implicate the potential application of miR-27 in gastric cancer therapy.