癌症相关microRNA与靶基因的生物信息学分析

MicroRNAs(miRNAs)是一类长度约为22nt的内源性非编码RNA,通过与靶基因转录本互补结合调控基因的表达。近年来,研究发现miRNA与癌症发生密切相关,miRNA可以直接充当癌基因或者抑癌基因而影响肿瘤的发生和生长。为更进一步揭示癌症相关miRNA的特征及靶基因的功能,文章通过数据库搜索及文献检索,在人类基因组中发现了475个癌症相关miRNA,系统地比较了癌症相关miRNA与非癌症miRNA以及基因内和基因间区癌症相关miRNA在保守性、SNP位点分布、癌谱及转录调控等特性。研究发现,癌症相关miRNA比非癌症miRNA保守性要强,发生SNP概率比较低,同时发现miRNA所涉及癌症数目与保守性成正相关。基因组定位分析发现,癌症相关miRNA比非癌症miRNA更倾向于成簇存在。进一步对宿主基因、癌症相关miRNA及作用的靶基因与癌症发生进行关联分析,发现一些非癌症miRNA的宿主基因倾向于被癌症miRNA作用。本研究结果为深入理解miRNA与癌症之间的关系,以及进一步为miRNA作为癌症诊断指示物提供理论依据。     

循环microRNAs的外泌形成机制及其对乳腺癌侵袭和转移的影响

目前乳腺癌的临床诊疗主要依赖影像学和相对较少的预后/预测指标(如雌激素受体、孕激素受体、HER2等).这些生物标志物主要是基于原发肿瘤病灶的生物学检测,可用于转移或复发的检测指标很少,尤其是在切除肿瘤原发灶后,复发监测很困难.循环cell-free microRNAs(circulating cf-miRNAs,或简称circulating miRNAs)的发现为改变现有乳腺癌临床诊疗模式提供了可能.Cell-free miRNA通过外泌体、微囊或转运蛋白的主动外泌机制,可能在循环miRNA的形成中起着重要作用.Cell-free miRNA特别是circulating miRNA不仅自身可以作为信号分子影响肿瘤细胞和组织微环境,而且还可以与其他信号通路发生交互通讯来调控肿瘤部位新生血管的形成和肿瘤细胞表型的上皮-间质转换,影响乳腺癌的侵袭和转移.本文综述了循环miRNA的特征与分泌机制,特别是乳腺癌相关的循环miRNA参与作为一种液体活检生物标志物在乳腺癌诊断、预后评价和疗效评估的临床意义.     

The role of inflammation and its related microRNAs in breast cancer: A narrative review

Breast cancer is recognized as the most common type of cancer among women with a high rate of mortality all over the world. Over the past years, growing attention has been regarded to realize more about the mechanisms underlying the disease process. It is revealed that the progression of breast cancer may be strongly linked to chronic inflammation owing to the role of inflammatory factors in genetic instability and subsequent cancer predisposition. Although the association between breast cancer and inflammatory pathways has been well-defined now, only recent evidence pointed towards the inflammation-related microRNAs (miRNAs) as potential biomarkers and therapeutic targets involved in the crosstalk of multiple pathways during breast cancer development. Moreover, the practical interactions between these miRNAs and inflammatory factors are also a little characterized. In this review, we intended to describe the effects of predominant inflammatory pathways such as cytokines, phosphoinositide 3-kinase/protein kinase B, and nuclear factor kappa B in association with tumor promoting and tumor suppressing miRNAs on breast cancer progression. Providing new studies in the field of combining biomarkers for early diagnosis, prognosis, and monitoring breast cancer are very important. Notably, understanding the underlying mechanisms of miRNAs as a possible link between inflammation and tumorigenesis may offer a novel insight for combating this epidemic.     

酶法合成槲皮素3-O-糖苷酰基化衍生物的研究进展

槲皮素3-O-糖苷是一类重要的槲皮素糖苷类化合物,具有抗氧化、抗炎、抗癌和抗病毒等多种药理活性,其代表性化合物芦丁和曲克芦丁已被开发成临床用药.由此可见,槲皮素3-O-糖苷已经成为创新药物的重要来源之一.然而,较低的生物利用度限制了槲皮素3-O-糖苷在食品、制药等行业中更广泛地应用.为提高这些化合物的生物利用度,选择性...     

Clinical implications of microRNAs in cancer

Abstract

MicroRNAs (miRNAs) are endogenously produced non-coding RNAs that serve as micromanagers by negatively regulating gene expression. MiRNAs are implicated in several biological pathways including development of neoplasia. Because altered miRNA expression is implicated in the pathobiology of various cancers, these molecules serve as potential therapeutic targets. Using miRNA mimics to restore levels of aberrantly down-regulated miRNAs or miRNA inhibitors to inactivate over-expressed miRNAs shows promise as the next generation of therapeutic strategies. Manipulation of miRNAs offers an alternative therapeutic approach for chemo- and radiation-resistant tumors. Similarly, miRNA expression patterns can be used for diagnosis and to predict prognosis and efficacy of therapy. We present here an overview of how miRNAs affect cancers, how they may be used as biomarkers, and the clinical implications of miRNAs in cancer.     

Regulation of cancer metastasis by microRNAs

MicroRNAs (miRNAs) are a class of endogenous small non-coding RNAs that have been found highly conserved among species. MiRNAs are able to negatively regulate gene expression through base pairing of 3’ UTRs of their target genes. Therefore, miRNAs have been shown to play an important role in regulating various cellular activities. Over the past decade, substantial evidences have been obtained to show that miRNAs are aberrantly expressed in human malignancies and could act as “OncomiRs” or “Tumor suppressor miRs”. In recent years, increasing number of studies have demonstrated the involvement of miRNAs in cancer metastasis. Many studies have shown that microRNAs could directly target genes playing a central role in epithelia-mesenchymal-transition (EMT), a cellular transformation process that allows cancer cells to acquire motility and invasiveness. EMT is considered an essential step driving the early phase of cancer metastasis. This review will summarize the recent findings and characterization of miRNAs that are involved in the regulation of EMT, migration, invasion and metastasis of cancer cells. Lastly, we will discuss potential use of miRNAs as diagnostic and prognostic biomarkers as well as therapeutic targets for cancer.     

基于右旋糖酐蔗糖酶转糖基作用的槲皮素葡萄糖苷的合成研究

右旋糖酐蔗糖酶是一种以蔗糖为唯一底物,将蔗糖分子中D-葡萄糖基催化转移到受体分子上的葡萄糖基转移酶。利用右旋糖酐蔗糖酶的转糖基作用,以蔗糖为葡萄糖糖基供体,槲皮素为糖基受体,对槲皮素糖苷的酶法合成进行了探索。通过对该酶催化反应体系、催化反应条件及产物分析的研究,结果表明：在25℃下,右旋糖酐蔗糖酶能够在30％DMSO-70％乙酸-乙酸钙（0.02 mol/L,pH值5.4）的反应体系中催化合成一种槲皮素葡萄糖苷,在这个反应体系下,以10％的蔗糖作为糖基供体,槲皮素为糖基受体,右旋糖酐蔗糖酶活力为40 U/mL,转速为150 r/min,槲皮素糖苷的转化率最高,可达39.5％。通过质谱分析确定是一种槲皮素单糖苷,分子量为464。该研究结果为黄酮类物质的糖基化修饰奠定了基础。     

成骨不全症血清中骨相关microRNAs的初步筛查

旨在初步筛选出成骨不全症(Osteogenesis imperfecta,OI)患者血清中差异表达的骨相关microRNAs(miRNAs),通过探讨其在该疾病中的可能作用,为进一步研究成骨相关miRNA的功能及miRNA在成骨不全症诊断中的应用奠定基础。首先用geNorm和NormFinder等程序挑选出适于血清miRNAs定量检测的内参基因,然后利用实时荧光定量PCR技术对miRanda,Targetscan和Pictar软件以及文献报道筛选出的骨形成相关miRNAs进行定量检测,最后用配对t检验统计学方法筛查出差异表达的骨相关miRNAs。结果显示6个候选内参基因在不同年龄、性别和用药情况的成骨不全症患者和健康个体血清中的表达稳定性良好(表达稳定值M<1.5),后经标准化因子配对差异(Pairwise variations)分析确定最适内参数目为4个(配对差异值V4/5=0.133<0.15),分别是miR-16、Let-7a、snRNAU6、miR-92a。通过在16个成骨不全症患者以及8个健康对照个体的血清中进一步检测miR-16、Let-7a、snRNAU6和miR-92a,发现其表达稳定性依然良好(M<1.5)。对100余种骨相关miRNAs进行实时荧光定量检测,发现11种miRNAs在成骨不全症患者血清中有差异表达(P<0.05),并且生物信息学分析显示这些差异表达的miRNAs很可能在成骨不全症的发生发展中起重要作用。以上实验结果表明成骨不全症患者血清中存在多种差异表达的骨相关miRNAs,而且这些miRNAs很可能成为一种用于成骨不全症血清学检查及诊断的生物标志物。     

微RNA在炎症致癌化中的作用

炎症与肿瘤关系密切,约25%的肿瘤是直接由慢性感染与炎症导致。随着研究的深入,两者在分子水平的联系不断被阐明。微RNA(microRNA,miRNA)作为一类新发现的调节因子在一系列促肿瘤及抗肿瘤的炎症反应通路中起到至关重要的调控作用,对其加深了解将有助于探索出肿瘤预防、诊断、治疗的新思路。本文将就miRNA在炎症及肿瘤间的调控作用予以综述,为炎症相关性肿瘤的早期诊断、预防和治疗提供分子靶标。     

Interaction of quercetin with DNA

I n vitro experiments to study interaction of the mutagenic flavonoid quercetin with DNA are described. Calf thymus DNA treated with quercetin for various time periods was subjected to S₁ nuclease hydrolysis. Thermal melting profles of treated DNA were also determined using St nuclease. The rate of DNA hydrolyzed after 1 hr of pre-treatment with quercetin was found to be only about 50% of that in its absence. However, after 10 and 24hrs of treatment with the drug, the rate of S₁ nuclease hydrolysis was observed to be greater than that of native DNA. Thermal melting profiles of DNA, treated with quercetin for 10 and 24 hrs, indicated a slight decrease in melting temperatures. Gel filtration of native DNA, which had been digested with S₁ nuclease after preincubation with quercetin for 24 hrs, indicated the production of various sized degraded molecules. The results suggest that the initial interaction of quercetin with DNA may have a stabilizing effect on its secondary structure, but prolonged treatment leads to an extensive disruption of the double helix.     

槲皮素对B型烟粉虱羧酸酯酶和谷胱甘肽S-转移酶活性的影响

采用人工饲料添加法,研究植物防御性次生物质槲皮素对B型烟粉虱Bemisiatabaci(Gennadius)成虫主要解毒酶系羧酸酯酶(CarE)和谷胱甘肽S-转移酶(GSTs)影响的剂量效应和时间效应。用低剂量槲皮素(0.01%,wv)处理B型烟粉虱成虫24h后,其羧酸酯酶(CarE)和谷胱甘肽S-转移酶(GSTs)比活力分别为51.09mOD(min·头)和2.249OD(mgpro.min),是对照的1.233倍和2.20倍;而高剂量的槲皮素对2种解毒酶没有诱导增加作用,甚至还有抑制作用。低剂量的槲皮素短时间处理烟粉虱后,可诱导2种酶活性增加,谷胱甘肽S-转移酶(GSTs)在0.005%的槲皮素处理30min后,比活力值达到8.454OD(mgpro·min),为对照的8.30倍。     

Role of exosomal microRNAs in lung cancer biology and clinical applications

Exosomes, small extracellular vesicles ranging from 30 to 150 nm, are secreted by various cell types, including tumour cells. Recently, microRNAs (miRNAs) were identified to be encapsulated and hence protected from degradation within exosomes. These exosomal miRNAs can be horizontally transferred to target cells, in which they subsequently modulate biological processes. Increasing evidence indicates that exosomal miRNAs play a critical role in modifying the microenvironment of lung cancers, possibly facilitating progression, invasion, angiogenesis, metastasis and drug resistance. In this review, we summarize the novel findings on exosomal miRNA functions during lung cancer initiation and progression. In addition, we highlight their potential role and challenges as biomarkers in lung cancer diagnosis, prognosis and drug resistance and as therapeutic agents.     

Combination therapy for the treatment of pancreatic cancer through hyaluronic acid-decorated nanoparticles loaded with quercetin and gemcitabine: A preliminary in vitro study

Combination chemotherapy by means of two or more drugs is prone to suppressing or discouraging the inception of multidrug resistance, exploiting the fact that diverse drugs act in different points of the cellular cycle of amplifying tumor cells. For example, the combination of gemcitabine (GMC) with quercetin (QCT) showed a synergistic effect in inhibiting the migration of pancreatic cancer cells. Consequently, herein GMC and QCT have been loaded within biodegradable nanoparticles (NPs) based on poly(lactic-co-glycolic acid), externally decorated with hyaluronic acid (HA; viz., PPHA NPs), which plays a major role in drug targeting to tumors due to its ability to specifically interact with CD44 receptor, that is overexpressed in many tumors. The produced HA-decorated NPs loaded with GMC and QCT showed an improved cytotoxicity and cellular uptake toward two cell lines of pancreatic ductal adenocarcinoma, namely Mia-PaCa-2 and PANC-1, compared with both the bare drugs and the drugs loaded in NPs which do not expose HA on the surface. HA-decorated NPs were also able to improve the anti-inflammatory properties of QCT, therefore leading to a decrease of interleukin cellular levels in both cell lines, preliminarily stimulated with lipopolysaccharides. This result is of special interest also considering the crucial role of interleukins in progression, metastatic processes, and drug resistance of human pancreas cancer cells.