MicroRNAs与癌症

MicroRNAs (miRNAs) belong to a class of noncoding, regulatory RNAs that are involved in oncogenesis and show remarkable tissue specificity. miRNAs are approximately 22 nt non-coding RNAs, which regulate gene expression in a sequence-specific manner via translational inhibition or messenger RNA (mRNA) degradation, thus affecting various cellular processes. Since the discovery of their fundamental mechanisms of action, the field of miRNAs has opened a new era in the understanding of small noncoding RNAs. Recent evidence has shown that miRNA controls cell growth, apoptosis, and differentiation. Cancer is a complex genetic disease caused by abnormalities in gene structure and expression, moreover, miRNA expression correlates with cancers and could have a crucial function in tumor progression. Bioinformatic data indicate that each miRNA can control hundreds of target genes, but identification of the accurate miRNA targets will be crucial to exploit the emerging knowledge of miRNA contribution to cancer process.     

MicroRNAs as prognostic indicators and therapeutic targets: potential effect on breast cancer management.

The discovery of microRNAs (miRNA) as novel modulators of gene expression has resulted in a rapidly expanding repertoire of molecules in this family, as reflected in the concomitant expansion of scientific literature. MiRNAs are a category of naturally occurring RNA molecules that play important regulatory roles in plants and animals by targeting mRNAs for cleavage or translational repression. Characteristically, miRNAs are noncoding, single-stranded short (18-22 nucleotides) RNAs, features which possibly explain why they had not been intensively investigated until recently. Accumulating experimental evidence indicates that miRNAs play a pivotal role in many cellular functions via the regulation of gene expression. Furthermore, their dysregulation and/or mutation has been shown in carcinogenesis. We provide a brief review of miRNA biogenesis and discuss the technical challenges of modifying experimental techniques to facilitate the identification and characterization of these small RNAs. MiRNA function and their involvement in malignancy, particularly their putative role as oncogenes or tumor suppressors is also discussed, with a specific emphasis on breast cancer. Finally, we comment on the potential role of miRNAs in breast cancer management, particularly in improving current prognostic tools and achieving the goal of individualized cancer treatment.     

循环microRNA在胃癌临床诊断及预后中的研究进展

microRNAs（miRNAs）是一类长约22个核苷酸的内源性非编码RNA分子,通过与靶基因mRNA 3'-非编码区相互作用引起靶基因mRNA降解或翻译抑制,在转录后水平发挥着重要的调控功能。有关miRNA在癌症中的功能已经进行了广泛研究,最近发现外周血等体液中存在miRNA,并且多种癌症患者的外周血miRNA表达谱发生特异性改变。越来越多证据表明循环miRNA可作为一种新颖的分子标志物应用于癌症诊断和预后评估。本文针对循环miRNA在胃癌诊断、评估和预后等方面的研究进展进行综述。     

Molecular pathways: microRNAs as cancer therapeutics

MicroRNAs (miRNA) are approximately 18 to 25 nucleotides in length and affect gene expression by silencing the translation of messenger RNAs. Because each miRNA regulates the expression of hundreds of different genes, miRNAs can function as master coordinators, efficiently regulating and coordinating multiple cellular pathways and processes. By coordinating the expression of multiple genes, miRNAs are responsible for fine-tuning the cell's most important processes, like the ones involved in cellular growth and proliferation. Dysregulation of miRNAs appears to play a fundamental role in the onset, progression and dissemination of many cancers, and replacement of downregulated miRNAs in tumor cells results in a positive therapeutic response. Thus, in theory, inhibition of a particular miRNA linked to cancer onset or progression can remove the inhibition of the translation of a therapeutic protein-and conversely, administration of a miRNA mimetic can boost the endogenous miRNA population repressing the translation of an oncogenic protein. Although several basic questions about their biologic principles still remain to be answered, and despite the fact that all data with respect to miRNAs and therapy are still at the preclinical level, many specific characteristics of miRNAs in combination with compelling therapeutic efficacy data have triggered the research community to start exploring the possibilities of using miRNAs as potential therapeutic candidates.     

微小RNA与人类肿瘤

微小RNA(microRNA,miRNA)是一类对基因具有调控功能的内源性非编码小分子RNA.目前认为miRNA在多种生物学过程中起着至关重要的作用,包括细胞增殖、分化、凋亡等.近年研究表明miRNA表达异常能导致疾病甚至肿瘤的发生,有类似于抑癌基因或癌基因的功能.因此,对miRNA的进一步研究为肿瘤的诊断和治疗开辟了...     

微小RNA与人类肿瘤

微小RNA（microRNA,miRNA）是一类对基因具有调控功能的内源性非编码小分子RNA。目前认为miRNA在多种生物学过程中起着至关重要的作用,包括细胞增殖、分化、凋亡等。近年研究表明miRNA表达异常能导致疾病甚至肿瘤的发生,有类似于抑癌基因或癌基因的功能。因此,对miRNA的进一步研究为肿瘤的诊断和治疗开辟了新的路径。     

The microRNA-17-92 family of microRNA clusters in development and disease

Overwhelming experimental evidence accumulated over the past decade indicates that microRNAs (miRNAs) are key regulators of gene expression in animals and plants and play important roles in development, homeostasis, and disease. The miR-17-92 family of miRNA clusters is composed of 3 related, highly conserved, polycistronic miRNA genes that collectively encode for a total of 15 miRNAs. We discuss recent studies demonstrating that these miRNAs are essential for vertebrate development and homeostasis. We also show how their mutation or deregulation contributes to the pathogenesis of a variety of human diseases, including cancer and congenital developmental defects. Finally, we discuss the current evidence suggesting how the different miRNAs encoded by these 3 clusters can functionally cooperate to fine-tune signaling and developmental pathways.     

microRNA及其在淋巴瘤中的表达

 micro RNA（miRNA）是一类长度大约为22 nt的非编码小片段RNA，其进化保守，通过与mRNA的3'UTR相互作用进而调控mRNA的翻译，广泛作用于发育、炎症、凋亡和肿瘤等各个生物学过程。在T淋巴瘤中发现miR-106a和miR-17-92过度表达；在弥漫性大B细胞淋巴瘤和滤泡细胞淋巴瘤中的miR-155，miR-221和miR-21表达上调，并与肿瘤的亚型有关。miR-17 簇过度表达可使凋亡水平下降，表明这些miRNA的主要作用是抑制细胞的死亡。miRNA既可促进肿瘤的发生，又能抑制肿瘤，但其确切机制尚不明。随着研究的深入，miRNA的遗传表型调节功能将会越来越清楚。     

MicroRNA与膀胱癌的研究进展

微小RNA(MicroRNA,miRNA)是一类小分子RNA,在转录后水平对基因的表达进行调控.目前研究证明,miRNA可通过不同信号通路直接参与人类多种肿瘤的形成与发展.本文就miRNA的形成、作用机制及其与肿瘤的关系等方面予以综述,并着重介绍了miRNA在膀胱癌中的研究进展.     

A role for microRNAs in the development of the immune system and in the pathogenesis of cancer

MicroRNAs are a growing class of endogenous small non-coding RNAs that regulate gene expression by binding to target messenger RNAs and inducing translational repression, cleavage or destabilization of the target. Because each miRNA potentially can regulate expression of a distinct set of genes, it is conceivable that the differential expression of different miRNAs might profoundly influence the repertoire of genes that are expressed during development, differentiation or disease. Here, we provide background on the biogenesis and function of miRNAs, and discuss how miRNA-mediated regulation can influence tumorigenesis as well as normal development and function of cells of the immune system.