MicroRNA-143 targets DNA methyltransferases 3A in colorectal cancer

Br J Cancer. 2009 Aug 18;101(4):699-706. doi: 10.1038/sj.bjc.6605195. Epub 2009 Jul 28.

Abstract

Background: MicroRNAs (miRNAs) are 19-25-nucleotides regulatory non-protein-coding RNA molecules that regulate the expressions of a wide variety of genes, including some involved in cancer development. In this study, we investigated the possible role of miR-143 in colorectal cancer (CRC).

Methods: Expression levels of human mature miRNAs were examined using real-time PCR-based expression arrays on paired colorectal carcinomas and adjacent non-cancerous colonic tissues. The downregulation of miR-143 was further evaluated in colon cancer cell lines and in paired CRC and adjacent non-cancerous colonic tissues by qRT-PCR. Potential targets of miR-143 were defined. The functional effect of miR-143 and its targets was investigated in human colon cancer cell lines to confirm miRNA-target association.

Results: Both real-time PCR-based expression arrays and qRT-PCR showed that miR-143 was frequently downregulated in 87.5% (35 of 40) of colorectal carcinoma tissues compared with their adjacent non-cancerous colonic tissues. Using in silico predictions, DNA methyltranferase 3A (DNMT3A) was defined as a potential target of miR-143. Restoration of the miR-143 expression in colon cell lines decreased tumour cell growth and soft-agar colony formation, and downregulated the DNMT3A expression in both mRNA and protein levels. DNMT3A was shown to be a direct target of miR-143 by luciferase reporter assay. Furthermore, the miR-143 expression was observed to be inversely correlated with DNMT3A mRNA and protein expression in CRC tissues.

Conclusion: Our findings suggest that miR-143 regulates DNMT3A in CRC. These findings elucidated a tumour-suppressive role of miR-143 in the epigenetic aberration of CRC, providing a potential development of miRNA-based targeted approaches for CRC therapy.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Blotting, Western
  • Cell Line, Tumor
  • Colorectal Neoplasms / enzymology*
  • Colorectal Neoplasms / genetics*
  • DNA (Cytosine-5-)-Methyltransferases / metabolism*
  • DNA Methyltransferase 3A
  • Down-Regulation
  • Gene Expression Regulation, Neoplastic / genetics*
  • Gene Silencing
  • Humans
  • MicroRNAs / genetics
  • MicroRNAs / metabolism*
  • RNA, Small Interfering
  • Reverse Transcriptase Polymerase Chain Reaction

Substances

  • DNMT3A protein, human
  • MIRN143 microRNA, human
  • MicroRNAs
  • RNA, Small Interfering
  • DNA (Cytosine-5-)-Methyltransferases
  • DNA Methyltransferase 3A