An In Vitro Protocol for Evaluating MicroRNA Levels, Functions, and Associated Target Genes in Tumor Cells

J Vis Exp. 2019 May 21:(147). doi: 10.3791/59628.

Abstract

MicroRNAs (miRNAs) are small regulatory RNAs which are recognized to modulate numerous intracellular signaling pathways in several diseases including cancers. These small regulatory RNAs mainly interact with the 3' untranslated regions (3' UTR) of their target messenger RNAs (mRNAs) ultimately resulting in the inhibition of decoding processes of mRNAs and the augmentation of target mRNA degradations. Based on the expression levels and intracellular functions, miRNAs are able to serve as regulatory factors of oncogenic and tumor-suppressive mRNAs. Identification of bona fide target genes of a miRNA among hundreds or even thousands of computationally predicted targets is a crucial step to discern the roles and basic molecular mechanisms of a miRNA of interest. Various miRNA target prediction programs are available to search possible miRNA-mRNA interactions. However, the most challenging question is how to validate direct target genes of a miRNA of interest. This protocol describes a reproducible strategy of key methods on how to identify miRNA targets related to the function of a miRNA. This protocol presents a practical guide on step-by-step procedures to uncover miRNA levels, functions, and related target mRNAs using the probe-based real-time polymerase chain reaction (PCR), sulforhodamine B (SRB) assay following a miRNA mimic transfection, dose-response curve generation, and luciferase assay along with the cloning of 3' UTR of a gene, which is necessary for proper understanding of the roles of individual miRNAs.

Publication types

  • Research Support, Non-U.S. Gov't
  • Video-Audio Media

MeSH terms

  • 3' Untranslated Regions / genetics
  • Cell Line, Tumor
  • Gene Expression Regulation, Neoplastic
  • Genes, Neoplasm*
  • Humans
  • Luciferases / genetics
  • MicroRNAs / genetics
  • MicroRNAs / metabolism*
  • Neoplasms / genetics*
  • RNA, Messenger / genetics

Substances

  • 3' Untranslated Regions
  • MicroRNAs
  • RNA, Messenger
  • Luciferases