MicroRNA-181b Inhibits Cellular Proliferation and Invasion of Glioma Cells via Targeting Sal-Like Protein 4

Oncol Res. 2017 Jul 5;25(6):947-957. doi: 10.3727/096504016X14791732531006. Epub 2016 Nov 17.

Abstract

MicroRNAs (miRs), a class of noncoding RNAs that are 18-25 nucleotides in length, are able to suppress gene expression by targeting complementary regions of mRNAs and inhibiting protein translation. Recently, miR-181b was found to play a suppressive role in glioma, but the regulatory mechanism of miR-181b in the malignant phenotypes of glioma cells remains largely unclear. In this study, we found that miR-181b was significantly downregulated in glioma tissues when compared with normal brain tissues, and decreased miR-181b levels were significantly associated with high-grade pathology and a poor prognosis for patients with glioma. Moreover, miR-181b was downregulated in glioma cell lines (U87, SHG44, U373, and U251) compared to normal astrocytes. Overexpression of miR-181b significantly decreased the proliferation, migration, and invasion of glioma U251 cells. Sal-like protein 4 (SALL4) was identified as a novel target gene of miR-181b in U251 cells. The expression of SALL4 was significantly upregulated in glioma tissues and cell lines, and an inverse correlation was observed between the miR-181b and SALL4 expression levels in glioma. Further investigation showed that the protein expression of SALL4 was negatively regulated by miR-181b in U251 cells. Knockdown of SALL4 significantly inhibited the proliferation, migration, and invasion of U251 cells, while overexpression of SALL4 effectively reversed the suppressive effects of miR-181b on these malignant phenotypes of U251 cells. In conclusion, our study demonstrates that miR-181b has a suppressive effect on the malignant phenotypes of glioma cells, at least partly, by directly targeting SALL4. Therefore, the miR-181b/SALL4 axis may become a potential therapeutic target for glioma.

MeSH terms

  • Brain Neoplasms / genetics
  • Brain Neoplasms / mortality
  • Brain Neoplasms / pathology*
  • Cell Line, Tumor
  • Cell Movement / genetics
  • Cell Proliferation / genetics
  • Female
  • Gene Expression Regulation, Neoplastic
  • Glioma / genetics
  • Glioma / mortality
  • Glioma / pathology*
  • Humans
  • Male
  • MicroRNAs / genetics*
  • Middle Aged
  • Prognosis
  • Transcription Factors / genetics*
  • Transcription Factors / metabolism
  • Up-Regulation

Substances

  • MIrn181 microRNA, human
  • MicroRNAs
  • SALL4 protein, human
  • Transcription Factors