MicroRNA-17 induces epithelial-mesenchymal transition consistent with the cancer stem cell phenotype by regulating CYP7B1 expression in colon cancer

Int J Mol Med. 2016 Aug;38(2):499-506. doi: 10.3892/ijmm.2016.2624. Epub 2016 Jun 6.

Abstract

MicroRNA-17 (miRNA-17/miR‑17) expression has been confirmed to be significantly higher in colorectal cancer tissues than in normal tissues. However, its exact role in colorectal cancer has not yet been fully elucidated. In this study, we found that miR-17 not only promoted epithelial-mesenchymal transition (EMT), but also promoted the formation of a stem cell-like population in colon cancer DLD1 cells. We also wished to determine the role of cytochrome P450, family 7, subfamily B, polypeptide 1 (CYP7B1) in CRC. miR-17 was overexpressed using a recombinant plasmid and CYP7B1 was silenced by transfection with shRNA. Western blot analysis was used to determine protein expression in the DLD1 cells and in tumor tissues obtained from patients with colon cancer. Our results revealed that miR‑17 overexpression led to the degradation of CYP7B1 mRNA expression in DLD1 cells. In addition, we found that the silencing of CYB7B1 promoted EMT and the formation of a stem cell-like population in the cells. Thus, our findings demonstrate that miR‑17 induces EMT consistent with the cancer stem cell phenotype by regulating CYP7B1 expression in colon cancer.

MeSH terms

  • Base Sequence
  • Cell Line, Tumor
  • Colonic Neoplasms / genetics*
  • Colonic Neoplasms / pathology*
  • Cytochrome P450 Family 7 / genetics*
  • Cytochrome P450 Family 7 / metabolism
  • Epithelial-Mesenchymal Transition / genetics*
  • Gene Expression Regulation, Neoplastic*
  • Gene Silencing
  • Humans
  • MicroRNAs / genetics
  • MicroRNAs / metabolism*
  • Neoplastic Stem Cells / metabolism*
  • Neoplastic Stem Cells / pathology*
  • Phenotype
  • Proteolysis
  • Steroid Hydroxylases / genetics*
  • Steroid Hydroxylases / metabolism

Substances

  • MIRN17 microRNA, human
  • MicroRNAs
  • Steroid Hydroxylases
  • Cytochrome P450 Family 7
  • CYP7B1 protein, human