MicroRNAs (miRNAs) are small non-coding RNAs found in eukaryotic organisms that regulate gene expression. Dismissed as “junk” until about a decade ago, it is now widely accepted that they play an important functional role in a wide array of cellular processes.
MiRNAs regulate gene expression by targeting individual or multiple messenger RNAs (mRNAs). Perfect or partial base pairing with the target mRNA promotes cleavage of the RNA in plants and inhibition of protein translation in animals. Many studies have demonstrated that dysregulation of these miRNAs is associated with various diseases suggesting there is potential for use of miRNAs in diagnosis and treatment.
Much of the study of miRNA and disease has focused on cancer and neurological disorders. Not surprising since cancer is the leading cause of death worldwide in 2010 and it is estimated that neurological disorders may affect as many as a billion people. There are urgent needs for early diagnosis and treatment in both areas.
Several miRNAs have been linked with various types of cancer due to their regulatory role in cellular development, including: differentiation, proliferation, and apoptosis. Neural miRNAs are known to be involved at various stages of synaptic development, including: dendritogenesis, synapse formation and synapse maturation. Since miRNAs exhibit specific expression profiles in tissues and tumor cells it makes sense that they could serve as biomarkers for these and other diseases.
The study of miRNA function to date has been performed mainly through collection of these tissues by invasive methods. In a clinical setting, more convenient and non-invasive methods are required, such as collection of peripheral blood or other bodily fluids. Recently, it has been demonstrated that miRNAs are present in circulating blood plasma, protected from degradation by inclusion in lipid or lipoprotein complexes. This represents a potential new approach for diagnostic screening in blood. Indeed, characteristic changes in the serum or plasma miRNA profiles of several cancers or other conditions have identified unique signatures that could be exploited as novel biomarkers in the clinic.
Pancreatic cancer (PC) has the poorest overall survival rate among all human cancers because of late diagnosis and absence of screening tools. Researchers at the Karmanos Cancer Institute, Wayne State University set out to develop novel, sensitive, and non-invasive biomarkers of PC using plasma samples1. Utilizing LC Sciences’ miRNA microarray service, they found many dysregulated miRNAs in the plasma of patients diagnosed with PC compared to healthy patients and that the expression of some miRNAs correlated well with survival. These results suggest that identifying and validating the expression of miRNAs in newly diagnosed patients could serve as potential biomarker for tumor aggressiveness. Such miRNAs could be useful for the screening of high-risk patients, and may also serve as targets for future drug development.
LC Sciences provides a genome-wide microRNA (miRNA) expression profiling microarray service using our innovative µParaflo® technology which enables highly sensitive and specific direct detection of miRNAs in plasma samples. We have standard arrays for mature miRNA of all species available in the latest version of the miRBase database (Release 16). Our service is comprehensive and includes sample preparation of your total RNA sample, single or dual color labeling, hybridization, image data processing and in-depth data analysis. Please see the application note: microRNA Profiling from Blood / Plasma Samples for information on collecting and extracting total RNA from your plasma samples.
(A) Box plot representing the expression of seven miRNAs as assessed by qRT-PCR. (B). The Kaplan-Meier curves and log-rank tests for miR-21 expression and survival; (C) The Kaplan-Meier curves and log-rank tests for let-7d expression and survival.
Related Service
miRNA Microarray Service – LC Sciences provides a microRNA (miRNA) expression profiling service using microarrays based on our in-house developed µParaflo® technology platform. We have standard arrays for all mature miRNAs of all species available in the latest version of the miRBase database (Release 21, July 2014). Our service is comprehensive and includes sample labeling, array hybridization, image data processing and in-depth data analysis. Two-three weeks after receiving your total RNA samples, we’ll send you both the raw and fully analyzed data. [Learn more…]
Reference
Ali S, Almhanna K, Chen W, Philip PA, Sarkar FH. (2010) Differentially expressed miRNAs in the plasma may provide a molecular signature for aggressive pancreatic cancer. Am J Transl Res 3(1):28-47. [article]