From the Guidelines
MicroRNAs are small, non-coding RNAs (∼18–22 nt) that play crucial roles in regulating gene expression by binding to mRNA to control protein expression. They are highly biologically stable both inside and outside cells 1. MicroRNAs have unique profiles when comparing extracellular vesicle (EV) isolation from diseased or normal organisms, making them promising novel biomarkers for liquid biopsy 1. Due to their roles in modulating gene expression, microRNAs may also be useful in development, cell proliferation and differentiation, apoptosis, and immune regulation, among other biological processes 1. Some key points about microRNAs include:
- They are involved in numerous biological processes, including development, cell proliferation, differentiation, and apoptosis
- Dysregulation of microRNAs has been implicated in various diseases, particularly cancer, where they can function as either tumor suppressors or oncogenes 1
- Their stability in body fluids makes them potential biomarkers for disease diagnosis and prognosis 1
- MicroRNAs can be used to distinguish histologic subtypes, such as miR-205, which is overexpressed in squamous cell carcinoma (SCC) compared with adenocarcinoma 1
- Some microRNAs, such as miR-21, have been consistently correlated with poor outcomes in cancer patients 1 The most recent and highest quality study suggests that microRNAs have promise as novel biomarkers for liquid biopsy and may be useful in development, cell proliferation and differentiation, apoptosis, and immune regulation 1.
From the Research
Definition and Characteristics of MicroRNAs
- MicroRNAs (miRNAs) are small RNA molecules that regulate gene expression in cells 2
- They comprise 17 to 25 nucleotides and recognize target messenger RNAs by sequence complementarity to regulate their protein translation 2
- There are over 2,500 microRNAs described in humans, involved in virtually all biological processes 2
Functions and Roles of MicroRNAs
- MicroRNAs play a key role in gene expression regulation and are involved in disease biology 3
- They can mediate posttranscriptional downregulation of expression, translational repression, and deadenylation-dependent decay of messages 4
- MicroRNAs can also function to posttranscriptionally stimulate gene expression by direct and indirect mechanisms 4
- They are powerful regulators of various cellular activities, including cell growth, differentiation, development, and apoptosis 5
MicroRNAs in Disease and Therapy
- The aberrant expression of specific miRNAs has been implicated in the development and progression of diverse diseases, including cancer and cardiovascular diseases 2, 6
- MicroRNAs have been proposed as biomarkers for disease diagnosis and monitoring of therapeutic responses 2
- MicroRNA-mediated clinical trials have shown promising results for the treatment of cancer and viral infections 5
- MicroRNA therapeutics has flourished, with genetic replacement or knockdown of target miRNAs by chemical molecules being used to reverse their abnormal expression and adverse biological effects 6