MicroRNA - Volume 3, Issue 2, 2014

MicroRNAs (miRNAs) are small noncoding regulatory RNAs that control essential cellular activities. Many viruses use these regulators to help infect host cells and maintain their presence in those cells. Therefore, virus-encoded miRNAs are important tools for viruses in the battle with their hosts. Knowledge of these miRNAs is essential for the development of new drugs to treat viral diseases and virus-associated cancers. In this minireview, the miRNAs encoded in viral genomes, their expression and functions, the interactions between viral and cellular miRNAs in viral diseases and virus- associated cancers, and the use of miRNAs for therapy are described.

Type 2 Diabetes is a complex disease with multifactorial pathogenesis. The interplay between genes and lifestyle changes complicates the etiology of the disease. In spite of growing number of attempts to unravel the mechanism of this metabolic disease, the molecular nature of type 2 Diabetes is not fully understood. The discovery of a new class of non-coding RNAs, micro RNAs and their role in regulation of gene expression have paved the way for better understanding of disease pathogenesis. Increasing number of evidences suggest crucial role of miRNAs in insulin resistance and β cell dysfunction, which are the two main features of type 2 Diabetes. This review summarizes the role of miRNA in elicitation and progression of type 2 Diabetes.

MicroRNAs (miRNA) are small (~22 nucleotide] non-coding RNA molecules originally characterised as nonsense or junk DNA. Emerging research suggests that these molecules have diverse regulatory roles in an array of molecular, cellular and physiological processes. MiRNAs are versatile and highly stable molecules, therefore, they are able to exist as intracellular or extracellular miRNAs. The purpose of this paper is to review the function and role of miRNAs in the intracellular space with specific focus on the interactions between miRNAs and organelles such as the mitochondria and the rough endoplasmic reticulum. Understanding the role of miRNAs in the intracellular space may be vital in understanding the mechanism of certain diseases.

MicroRNAs (miRNAs) are a class of small noncoding RNAs that regulate gene expression by targeting mRNAs and leading to either translation repression or RNA degradation. miRNAs have fundamental effects in the regulation of intracellular processes, and their importance during malignant transformation and metastasis is becoming increasingly well understood. The epithelial-mesenchymal transition (EMT), which reprograms tumor cells transcription, has been highlighted as a powerful process in tumor invasion, metastasis and tumorigenicity. In recent years, many studies have significantly enhanced our knowledge of EMT by the characterization of miRNAs that influence the signaling pathways and downstream events that define EMT on a molecular level. In this review, we detail the miRNAs and signal transduction pathways involved in the EMT process and demonstrate their importance in the study of cancer progression. We believe that this information will improve prognostication and reveal new opportunities for therapeutic intervention.

Metabolic rates of cancer cells are faster compared to normal cells. This faster rate yields aberrant protein folding and causes loss of protein function. Therefore, cancer cells need more Heat Shock Proteins (HSPs) for proper substrate- protein folding on oncogenic pathways. Pseudogenes regulate tumor suppressors and oncogenes, and pseudogenes are deregulated in cancer progression. Further, alterations in miRNA expression have been identified in different cancer types. MiRNAs also have both oncogenic and tumour-suppressive roles in breast cancer post-transcriptional gene regulation. Breast cancer is a genetic disease and we performed miRNA analysis in human breast cancer cell lines to identify miRNAs in association with HSPs and pseudogenes by employing CellMiner; a web-based suite. CellMiner integrates several databases and help analysing microarray metadata. The experimental data provide a platform for researchers to compare macromolecules’ relationships in NCI-60 cell lines. Breast cancer associated miRNAs gathered from literature and analyzed by employing this suite, significantly correlated HSP genes and pseudogenes in the breast cancer are determined as; HSPA13, HSP90AB1, TRAP1, HSPB1, DNAJB4, HSPD1 and HSP90AA4P, HSPB1P1, DNAJC8P1, HSPD1P9 respectively. HSPs involved in breast cancer are regulated by several miRNAs and miRNA regulators from CellMiner data found as hsa-miR-17, hsa-miR-22, hsa-miR-93, hsa-miR-106a, hsa-miR-125b, hsa-miR-130a, and hsamiR- 141. Cross check of the determined miRNAs and target HSPs was performed by target site prediction software. Comparison of the experimental data from CellMiner and software predicted data indicate differences. CellMiner data provide a vast miRNA types compared to prediction softwares-web tools data and reported miRNAs in the literature. Therefore, reported key miRNAs in this work that are not studied earlier may help cancer researchers to uncover novel posttranslational regulation mechanisms. Cancer cells use HSP network as an escape mechanism from apoptosis, therefore inhibition of associated HSPs by modulating miRNAs may provide a novel therapy for the tumorigenesis.