A functional screen identifies miRs that induce radioresistance in glioblastomas

Mol Cancer Res. 2014 Dec;12(12):1767-78. doi: 10.1158/1541-7786.MCR-14-0268. Epub 2014 Sep 25.


The efficacy of radiotherapy in many tumor types is limited by normal tissue toxicity and by intrinsic or acquired radioresistance. Therefore, it is essential to understand the molecular network responsible for regulating radiosensitivity/resistance. Here, an unbiased functional screen identified four microRNAs (miR1, miR125a, miR150, and miR425) that induce radioresistance. Considering the clinical importance of radiotherapy for patients with glioblastoma, the impact of these miRNAs on glioblastoma radioresistance was investigated. Overexpression of miR1, miR125a, miR150, and/or miR425 in glioblastoma promotes radioresistance through upregulation of the cell-cycle checkpoint response. Conversely, antagonizing with antagomiRs sensitizes glioblastoma cells to irradiation, suggesting their potential as targets for inhibiting therapeutic resistance. Analysis of glioblastoma datasets from The Cancer Genome Atlas (TCGA) revealed that these miRNAs are expressed in glioblastoma patient specimens and correlate with TGFβ signaling. Finally, it is demonstrated that expression of miR1 and miR125a can be induced by TGFβ and antagonized by a TGFβ receptor inhibitor. Together, these results identify and characterize a new role for miR425, miR1, miR125, and miR150 in promoting radioresistance in glioblastomas and provide insight into the therapeutic application of TGFβ inhibitors in radiotherapy.

Implications: Systematic identification of miRs that cause radioresistance in gliomas is important for uncovering predictive markers for radiotherapy or targets for overcoming radioresistance.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Cycle Checkpoints / radiation effects
  • Cell Line, Tumor
  • Gene Expression Regulation, Neoplastic / radiation effects
  • Glioblastoma / genetics*
  • Glioblastoma / radiotherapy
  • Humans
  • MicroRNAs / genetics*
  • Radiation Tolerance*
  • Signal Transduction / radiation effects
  • Transforming Growth Factor beta / metabolism


  • MIRN1 microRNA, human
  • MIRN125 microRNA, human
  • MIRN150 microRNA, human
  • MIRN425 microRNA, human
  • MicroRNAs
  • Transforming Growth Factor beta