MicroRNAs in Solid Tumors

Abstract

MicroRNAs (miRNAs or miRs) are small, noncoding RNAs (∼20-22 nucleotides) that have critical functions in cell proliferation, apoptosis, and differentiation. These evolutionarily conserved RNA sequences are the result of a complex sequence of processing steps, which can regulate the expression of tens, and even hundreds, of genes. Their regulatory effect is based upon the degree of complementarity between the mature miRNA and the 3′ untranslated region region of the target mRNA resulting in either complete degradation or translational inhibition of the target mRNA. In vertebrates they are often tissue specific in their expression patterns and dysregulated in malignancies. Thus, miRNA profiling has been used to create signatures for many solid malignancies. These profiles have been used to not only classify tumors, but also to help predict survival and outcome. Herein, we review the role of miRNAs in the development and progression of solid tumors.

Changes in the expression of miRNAs at the pericentral and periportal regions of the rat liver in response to hepatocellular injury: Comparison with the changes in the expression of plasma miRNAs

“…miRNA expression varies from highly specific to ubiquitous. It has been demonstrated that the aberrant expression of miRNAs is associated with a variety of diseases, including cancer (Dillhoff et al, 2009), viral hepatitis (Ura et al, 2009, and heart disease (Ikeda et al, 2007). In 2008, it was reported that miRNAs stably exist in plasma (Chim et al, 2008, Mitchell et al, 2008 and serum (Lawrie et al, 2008, Mitchell et al, 2008.…”

Knockdown of microRNA-21 Inhibits Proliferation and Increases Cell Death by Targeting Programmed Cell Death 4 (PDCD4) in Pancreatic Ductal Adenocarcinoma

“…They function by binding to mRNA of target genes and prevent protein translation by the process of repression or degradation. 7,8 More than 5,000 miRNAs have been discovered in 58 different species, with each having the potential to regulate hundreds of target mRNA indicating that a large proportion of the transcriptome is subject to miRNA-mediated regulation. 9,10 miRNAs can therefore play a role in a range of biological processes and have been implicated in differentiation, transformation and carcinogenesis.…”

Up-regulation of microRNA in bladder tumor tissue is not common

“…It has been suggested that miRNA can act as oncogenes and/or tumor-suppressors [12,13], thereby playing an important role in oncogenesis [14]. Furthermore, miRNA expression is also tissue-specific in many human tissues [15,16], suggesting the possibility of creating the signature for different solid tumors [17]. However, few studies have been published in the attempt to understand the regulatory effects of specific miRNA on the tumorigenesis of bladder cancer.…”