Digital detection of multiple minority mutants and expression levels of multiple colorectal cancer-related genes using digital-PCR coupled with bead-array

PLoS One. 2015 Apr 16;10(4):e0123420. doi: 10.1371/journal.pone.0123420. eCollection 2015.

Abstract

To simultaneously analyze mutations and expression levels of multiple genes on one detection platform, we proposed a method termed "multiplex ligation-dependent probe amplification-digital amplification coupled with hydrogel bead-array" (MLPA-DABA) and applied it to diagnose colorectal cancer (CRC). CRC cells and tissues were sampled to extract nucleic acid, perform MLPA with sequence-tagged probes, perform digital emulsion polymerase chain reaction (PCR), and produce a hydrogel bead-array to immobilize beads and form a single bead layer on the array. After hybridization with fluorescent probes, the number of colored beads, which reflects the abundance of expressed genes and the mutation rate, was counted for diagnosis. Only red or green beads occurred on the chips in the mixed samples, indicating the success of single-molecule PCR. When a one-source sample was analyzed using mixed MLPA probes, beads of only one color occurred, suggesting the high specificity of the method in analyzing CRC mutation and gene expression. In gene expression analysis of a CRC tissue from one CRC patient, the mutant percentage was 3.1%, and the expression levels of CRC-related genes were much higher than those of normal tissue. The highly sensitive MLPA-DABA succeeds in the relative quantification of mutations and gene expressions of exfoliated cells in stool samples of CRC patients on the same chip platform. MLPA-DABA coupled with hydrogel bead-array is a promising method in the non-invasive diagnosis of CRC.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Colorectal Neoplasms / genetics*
  • Cyclooxygenase 2 / genetics
  • DNA Mutational Analysis / instrumentation
  • DNA Mutational Analysis / methods
  • Gene Expression Regulation, Neoplastic*
  • Genes, myc
  • Genes, ras
  • Humans
  • Hyaluronan Receptors / genetics
  • Multiplex Polymerase Chain Reaction / instrumentation
  • Multiplex Polymerase Chain Reaction / methods*
  • Mutation Rate
  • Mutation*
  • Sensitivity and Specificity

Substances

  • CD44v6 antigen
  • Hyaluronan Receptors
  • Cyclooxygenase 2
  • PTGS2 protein, human

Grants and funding

The National Science Foundation of China (Grant No. 21305069 and 21275161) provided funding for the decision to publish and preparation of the manuscript. The Training project of Young talents in Jiangsu Province Maternal and Child Health Hospital (FRC201302) provided funding for data collection and analysis. Jiangsu Province's Clinical Science & Technology Special Project (SBL2012061) provided funding for study design.