与卵巢癌转移有关的microRNA 研究进展

卵巢癌是女性生殖系统三大恶性肿瘤之一,其致死率居于各类妇科肿瘤之首,是严重影响妇女生命的重要疾患,卵巢癌的转移则是造成病人死亡的重要因素.近年来随着microRNA(又称miRNA或微RNA)作为一种小分子非编码RNA被发现,证实miRNA的作用与各类肿瘤有着重要的联系,这些肿瘤包括乳腺癌、食管癌、胰癌、口腔癌等.近几年的研究表明,miRNA可以影响卵巢癌的发生与发展,并与其转移也存在着紧密的关系.与卵巢癌转移有关的miRNA作用机制的揭示,将会为转移性卵巢癌的诊断及治疗提供新的途径.本综述在通过检索近年来最新文献的基础上,对于卵巢癌的转移机理进行了详尽的分析,并对miRNA在卵巢癌转移中的重要研究予以了详细的阐述.     

大豆microRNA基因GmMIR160A负调控植物叶片衰老进程

:叶片衰老是受内外多种因子影响的遗传发育进程.生长素、细胞分裂素和乙烯等多种植物激素是调 控叶片衰老的重要内部因子,它们通过长或短距离运输形成叶片组织内特定的区域分布和浓度梯度,从而直 接或间接参与植物叶片衰老过程.分子遗传学表明,细胞分裂素和乙烯分别是叶片衰老的抑制子和正调节 子,而生长素如何参与叶片衰老的分子机制目前还不清晰.植物体内成熟小分子RNA 由小RNA 基因转录 并通过特定酶加工形成的２１~２３bp的双链RNA分子.这些小分子通过不完全配对方式抑制其靶基因转录 和/或表达,参与植物生长发育多个过程,然而这类小RNA 分子如何调控植物叶片衰老发育过程目前则还鲜 有报告.大豆是重要的油料作物,具有典型的单次结实性衰老特征.研究大豆叶片衰老具有重要的科学意义 和深远的应用价值.该文采用实时荧光定量PCR(qPCR)技术分析大豆(Glycinemax)microRNA基因Gm- MIR１６０A 的表达模式,发现大豆第一复叶中GmMIR１６０A 表达受外源生长素和黑暗处理的诱导,暗示该基 因是生长素快速响应的叶片衰老相关基因.为进一步探究GmMIR１６０A 在大豆叶片发育中的功能,构建了 肾上腺皮质激素(Glucocorticoid,GR)类似物地塞米松(Dexamethasone,DEX)诱导表达GmMIR１６０A 双元表 达载体并通过农杆菌介导的子叶节方法转化野生型大豆.通过抗性筛选和基因组PCR 鉴定并结合表型分 析,共获得了４株诱导表达的稳定遗传转基因植株(株系OXＧ３、OXＧ５、OXＧ７和OXＧ８).GmMIR１６０A 过表达 植株根、茎、叶、花和果实在形态学上与野生型相比无显著差异,但叶片的叶绿素含量增加、最大光量子效率 (Fv/Fm)增强.进一步分子分析发现,转基因大豆叶片中GmARFs 和衰老标记基因(GmCYSP１)表达明显下 降,表明大豆Gma-miR１６０通过抑制靶基因GmARFs 的表达来负调控植物叶片的衰老进程.该文揭示了生 长素通过小分子RNA调控叶片发育一条新途径,为研究植物激素调控植物叶片衰老提供了新的思路.     

Reference genes for the relative quantification of microRNAs in renal cell carcinomas and their metastases

To obtain accurate results in miRNA expression changes between different sample sets using real-time quantitative polymerase chain reaction (RT-qPCR) analyses, normalization to reference genes that are stably expressed across the sample sets is generally used. A literature search of miRNA expression studies in renal cell carcinoma (RCC) proved that non-miRNAs such as small RNAs or mRNAs have most frequently been used without preceding validation of their suitability. In this study, the most stably expressed miRNAs were ascertained from microarray-based data of miRNA expression in nonmalignant and malignant samples from clear cell RCC and from corresponding distant RCC metastases using the geNorm and NormFinder algorithms. Validation experiments with RT-qPCR were performed for the four best-ranked miRNAs (miR-28, miR-103, miR-106a, miR-151) together with the small RNU6B, RNU44, and RNU48 mostly described in literature. miR-28, miR-103, miR-106a, and RNU48 were proved as the most stably expressed genes. miR-28 is recommended as normalizer if only a single reference gene can be used, while the combinations of miR-28 and miR-103 or of miR-28, miR-103, and miR-106a, respectively, are preferred. RNU6B most frequently used as normalizer in miRNA expression studies should be abandoned in order to avoid misleading results.     

miRNA Expression Analyses in Prostate Cancer Clinical Tissues

A critical challenge in prostate cancer (PCa) clinical management is posed by the inadequacy of currently used biomarkers for disease screening, diagnosis, prognosis and treatment. In recent years, microRNAs (miRNAs) have emerged as promising alternate biomarkers for prostate cancer diagnosis and prognosis. However, the development of miRNAs as effective biomarkers for prostate cancer heavily relies on their accurate detection in clinical tissues. miRNA analyses in prostate cancer clinical specimens is often challenging owing to tumor heterogeneity, sampling errors, stromal contamination etc. The goal of this article is to describe a simplified workflow for miRNA analyses in archived FFPE or fresh frozen prostate cancer clinical specimens using a combination of quantitative real-time PCR (RT-PCR) and in situ hybridization (ISH). Within this workflow, we optimize the existing methodologies for miRNA extraction from FFPE and frozen prostate tissues and expression analyses by Taqman-probe based miRNA RT-PCR. In addition, we describe an optimized method for ISH analyses formiRNA detection in prostate tissues using locked nucleic acid (LNA)- based probes. Our optimized miRNA ISH protocol can be applied to prostate cancer tissue slides or prostate cancer tissue microarrays (TMA).     

MicroRNA expression profiling of endocrine sensitive and resistant breast cancer cell lines

BackgroundMicroRNAs (miRs) regulate gene expression through translation inhibition of target mRNAs. One of the most promising approaches for cancer therapy is through mimicking or antagonizing the action of miRs. In this report, we analyzed the miRnome profile of several human breast cancer cell lines to determine the influence of estrogen receptor (ER) silencing previously shown to result in epithelial to mesenchymal transition (EMT) and enhanced tumor invasion.MethodsMicroRNA extracted from MDA-MB-231 (de novo ER-) and ER-silenced (acquired ER-) pII and IM-26 or ER-expressing (YS1.2) siRNA transfected derivatives of MCF7 cells was deep sequenced on Illumina NextSeq500. Respective miRnomes were compared with edgeR package in R and Venny2.1 and target prediction performed with miRTarBase. Mimics and inhibitors of selected differentially expressed miRs associated with EMT mediators (miR-200c-3p targeting ZEB1, miR-449a targeting δ-catenin and miR-29a-3p) were transfected into pII cells and mRNA targets, as well as E-cadherin and keratin 19 (epithelial and mesenchymal markers respectively) were measured using taqman PCR.ResultsEach cell line expressed about 20% of the total known human miRnome; There was a high degree of similarity between the 3 tested ER-lines. Out of these expressed miRs, 50–60% were significantly differentially expressed between ER- and ER + lines. Transfection of miR-200c-3p mimic into pII cells down regulated ZEB1 and vimentin, and increased E-cadherin and keratin 19 with accompanying morphological changes, and reduced cell motility, reflecting a reversal back into an epithelial phenotype. On the other hand, transfecting pII with miR-449a inhibitor reduced cell invasion but did not induce EMT. Transfecting pII cell line with the mimic or inhibitor of miR-29a-3p showed no change in EMT markers or cell invasion suggesting that the EMT induced by loss of ER function can be reversed by blocking some but not just any random EMT-associated genes.ConclusionsThese data suggest that differences in miR expression can be exploited not only as mediators (using mimics) and targets (using miR antagonists) for general cancer therapies aimed at regulating either individual or multiple mRNAs, but also to re-sensitize endocrine resistant breast cancers by turning them back into a type that will be susceptible to endocrine agents.     

MicroRNAs are tightly associated with RNA-induced gene silencing complexes in vivo

Previous work has shown that synthesized siRNA/miRNA is tightly associated with RNA-induced Gene Silencing Complexes (RISCs) in vitro. However, it is unknown if the endogenous miRNAs are also stably bound to RISC complexes in vivo in cells under physiological conditions. Here we describe the use of the looped real-time PCR-based method to trace the location of endogenous miRNAs in intact cells. We found that most of the endogenous miRNAs are tightly bound to RISC complexes, and only a very small proportion of them are free in cells. Furthermore, synthesized single-stranded mature miRNA or hairpin miRNA precursor cannot replace endogenous miRNAs already present in RISC complexes. However, we found that modified 2-O-Methyl-ribonucleotides were able to dissociate the target miRNA specifically from the RISC complex. These findings have important implications for understanding the basis for the stability and metabolism of miRNAs in living cells.     

血浆microRNA与HIV感染及治疗关系的研究

本次研究分析了Ⅰ型艾滋病病毒(HIV-1)感染者血浆中miRNA表达特点,探讨了血浆miRNA作为HIV-1感染及治疗监测生物学标志物的潜在可行性。选取2017年7月-2018年7月期间在昆明市第三人民医院就诊的HIV-1感染未经抗病毒治疗患者50例作为未治疗组,HIV-1感染经抗病毒治疗患者50例作为治疗组,选取同期本院健康体检者50例作为对照组,应用qPCR技术检测三组对象血浆miR-29a、miR-122,miR-155的相对表达量。结果显示,与健康对照组相比HIV-1感染未经抗病毒治疗组血浆miR-29a、miR-155、miR-122表达均升高,差异有统计学意义(P<0.05);未治疗组与治疗组相比较血浆miR-29a、miR-155和miR-122表达均升高,差异有统计学意义(P<0.05)。对未治疗组的研究显示,血浆miR-29a、miR-155表达水平与HIV-1RNA病毒载量呈正相关(P<0.05),miR-122与HIV-1RNA病毒载量无显著相关(P>0.05),miR-29a、miR-155表达水平与CD4;T细胞计数呈负相关(P<0.05)。本研究提示HIV-1感染后血浆miRNA有变化,血浆miR-29a、miR-122,miR-155与HIV-1感染相关,可能是HIV-1感染的潜在生物学标志物。而抗病毒治疗可以诱导miR-29a、miR-155和miR-122表达降低,这些miRNA可能具有成为监测HIV-1感染抗病毒治疗效果观察指标的潜在价值。未治疗组血浆miR-29a、miR-155与HIV-1RNA呈正相关,表明其与HIV-1病毒复制相关。