miR-124 and miR-506 inhibit colorectal cancer progression by targeting DNMT3B and DNMT1

Oncotarget. 2015 Nov 10;6(35):38139-50. doi: 10.18632/oncotarget.5709.

Abstract

miR-124 and miR-506 are reportedly down-regulated and associated with tumor progression in many cancers, but little is known about their intrinsic regulatory mechanisms in colorectal cancer (CRC). In this study, we found that the miR-124 and miR-506 levels were significantly lower in human CRC tissues than in controls, as indicated by qRT-PCR and in situ hybridization histochemistry. We also found that the overexpression of miR-124 or miR-506 inhibited tumor cell progression and increased sensitivity to chemotherapy in vitro. Increased miR-124 or miR-506 expression also inhibited tumor cell proliferation and invasion in vivo. Luciferase reporter assays and western blotting were used to determine the association between miR-124, miR-506 and their target genes, DNMTs. We further identified that miR-124 and miR-506 directly targeted DNMT3B and indirectly targeted DNMT1. The overexpression of miR-124 and miR-506 reduced global DNA methylation and restored the expression of E-cadherin, MGMT and P16. In conclusion, our data showed that miR-124 and miR-506 inhibit progression and increase sensitivity to chemotherapy by targeting DNMT3B and DNMT1 in CRC. These findings may provide novel avenues for the development of targeted therapies.

Keywords: DNMT1; DNMT3B; colorectal cancer; miR-124; miR-506.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antigens, CD
  • Antineoplastic Agents / pharmacology
  • Cadherins / genetics
  • Cadherins / metabolism
  • Cell Movement
  • Cell Proliferation
  • Colorectal Neoplasms / drug therapy
  • Colorectal Neoplasms / enzymology*
  • Colorectal Neoplasms / genetics
  • Colorectal Neoplasms / pathology
  • Cyclin-Dependent Kinase Inhibitor p16 / genetics
  • Cyclin-Dependent Kinase Inhibitor p16 / metabolism
  • DNA (Cytosine-5-)-Methyltransferase 1
  • DNA (Cytosine-5-)-Methyltransferases / genetics
  • DNA (Cytosine-5-)-Methyltransferases / metabolism*
  • DNA Methylation
  • DNA Methyltransferase 3B
  • DNA Modification Methylases / genetics
  • DNA Modification Methylases / metabolism
  • DNA Repair Enzymes / genetics
  • DNA Repair Enzymes / metabolism
  • Disease Progression
  • Dose-Response Relationship, Drug
  • Gene Expression Regulation, Enzymologic
  • Gene Expression Regulation, Neoplastic
  • Genes, Reporter
  • HCT116 Cells
  • Humans
  • Mice, Inbred BALB C
  • Mice, Nude
  • MicroRNAs / genetics
  • MicroRNAs / metabolism*
  • Neoplasm Invasiveness
  • Signal Transduction
  • Time Factors
  • Transfection
  • Tumor Burden
  • Tumor Suppressor Proteins / genetics
  • Tumor Suppressor Proteins / metabolism
  • Xenograft Model Antitumor Assays

Substances

  • Antigens, CD
  • Antineoplastic Agents
  • CDH1 protein, human
  • Cadherins
  • Cyclin-Dependent Kinase Inhibitor p16
  • MIRN124 microRNA, human
  • MIRN506 microRNA, human
  • MicroRNAs
  • Tumor Suppressor Proteins
  • DNA Modification Methylases
  • DNA (Cytosine-5-)-Methyltransferase 1
  • DNA (Cytosine-5-)-Methyltransferases
  • DNMT1 protein, human
  • Dnmt1 protein, mouse
  • MGMT protein, human
  • DNA Repair Enzymes