Solution-phase detection of dual microRNA biomarkers in serum

Anal Bioanal Chem. 2012 Jan;402(1):543-50. doi: 10.1007/s00216-011-5357-9. Epub 2011 Sep 7.

Abstract

A strategy for the simultaneous detection of multiple microRNA (miRNA) targets was developed utilizing fluorophore/quencher-labeled oligonucleotide probe sets. Two miRNA targets (miR-155 and miR-103), whose misregulation has afforded them status as putative biomarkers in certain types of cancer, were detected using our assay design. In the absence of target, the complementary fluorophore-probe and quencher-probe hybridize, resulting in a fluorescence resonance energy transfer-based quenching of the fluorescence signal. In the presence of unlabeled target, however, the antisense quencher-probe can hybridize with the target, resulting in increased fluorescence intensity as the quencher-probe is sequestered beyond the Förster radius of the fluorescent-probe. The assay design was tested in multiple matrices of buffer, cellular extract, and serum; and detection limits were found to be matrix-dependent, ranging from 0.34 to 8.89 pmol (3.4-59.3 nM) for miR-155 and 2.90-11.8 pmol (19.3-79.0 nM) for miR-103. Single, double, and triple nucleotide selectivity was also tested. Additionally, miR-155 concentrations were assessed in serum samples obtained directly from breast cancer patients without the need for RNA extraction. This assay is quantitative, possesses a low detection limit, can be applied in multiple complex matrices, and can obtain single-nucleotide selectivity. This method can be employed for the multiplex detection of solution-phase DNA or RNA targets and, more specifically, for the direct detection of serum miRNA biomarkers.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Biomarkers / blood
  • Fluorescence Resonance Energy Transfer / methods*
  • Humans
  • Mice
  • MicroRNAs / blood*
  • Oligonucleotide Probes / blood*

Substances

  • Biomarkers
  • MicroRNAs
  • Oligonucleotide Probes