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SMAD3 silencing enhances DNA damage in radiation therapy by interacting with MRE11-RAD50-NBS1 complex in glioma

Zheng Jiang1, Yan Guo2, Lifeng Miao3

  • 1Department of Neurosurgery, Qilu Hospital of Shandong University, No. 107 Wenhua West Road, Lixia District, Jinan, Shandong Province, P. R. China.

Journal of Biochemistry
|December 12, 2018
PubMed

Insights

Silencing Mothers against decapentaplegic homologue 3 (SMAD3) enhances radiotherapy effectiveness in malignant glioma. This occurs by SMAD3 silencing inhibiting the MRE11-RAD50-NBS1 complex, improving treatment outcomes.

Area of Science:

  • Oncology
  • Molecular Biology
  • Radiotherapy Research

Background:

  • Radiotherapy is a primary treatment for malignant glioma, but resistance limits its efficacy.
  • Understanding molecular mechanisms of radioresistance is crucial for improving glioma treatment outcomes.

Purpose of the Study:

  • To investigate the role of Mothers against decapentaplegic homologue 3 (SMAD3) in modulating malignant glioma response to radiotherapy.
  • To elucidate the mechanism by which SMAD3 influences glioma radioresistance.

Main Methods:

  • Malignant glioma cells were treated with small-interfering RNAs (siRNAs) targeting SMAD3 or SMAD3 expression plasmids.
  • Cell sensitivity to radiation was assessed using clonogenic assays.
  • MRE11-RAD50-NBS1 (MRN) complex mRNA and protein levels were quantified via qPCR and Western blot.
  • Chromatin immunoprecipitation (ChIP) assays were employed to confirm SMAD3 interaction with the MRN complex.

Main Results:

  • SMAD3 silencing significantly increased the sensitivity of glioma cells to radiotherapy.
  • Radiotherapy-induced overexpression of MRE11, RAD50, and NBS1 was attenuated by SMAD3 silencing and enhanced by SMAD3 overexpression.
  • ChIP analysis confirmed that SMAD3 interacts with the MRN complex under radiotherapy conditions, and this interaction is inhibited by SMAD3 silencing.

Conclusions:

  • SMAD3 silencing is a viable strategy to enhance radiotherapy efficacy in malignant glioma.
  • The mechanism involves SMAD3 interaction with the MRE11-RAD50-NBS1 complex, modulating the cellular response to radiation.
Keywords:
SMAD3DNA damageRAD50gliomaradiation therapy

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