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Identification and characterization of a small inhibitory peptide that can target DNA-PKcs autophosphorylation and

Xiaonan Sun1, Chunying Yang, Hai Liu

  • 1Department of Radiation Oncology, Sir Run Run Shaw Hospital, Sir Run Run Shaw Institute of Clinical Medicine of Zhejiang University, Hangzhou, China.

International Journal of Radiation Oncology, Biology, Physics
|May 18, 2012
PubMed
Abstract

Insights

A novel peptide, BTW3, targets DNA-PKcs autophosphorylation to enhance radiosensitivity. This DNA damage repair inhibitor shows promise as a new radiosensitizer for cancer therapy.

Area of Science:

  • Molecular Biology
  • Biochemistry
  • Cancer Research

Background:

  • DNA protein kinase catalytic subunit (DNA-PKcs) is crucial for DNA damage repair.
  • Inhibiting DNA-PKcs can sensitize cancer cells to ionizing radiation (IR).
  • Targeted radiosensitizers are sought for improved cancer treatment.

Purpose of the Study:

  • To develop small inhibitory peptides targeting DNA-PKcs autophosphorylation.
  • To create peptides that specifically inhibit the enzymatic activation of DNA-PKcs in response to IR.

Main Methods:

  • Fusion peptides with internalization and DNA-PKcs inhibitory domains were generated.
  • Peptide internalization, toxicity, and radiosensitization were characterized.
  • Mechanisms of peptide inhibition on DNA-PKcs autophosphorylation and DNA repair were investigated.

Main Results:

  • The peptide BTW3 targets DNA-PKcs threonine 2647 autophosphorylation.
  • BTW3 abrogated IR-induced DNA-PKcs activation and prolonged γ-H2AX focus formation.
  • BTW3 exposure caused IR hypersensitivity in DNA-PKcs-proficient cells, but not deficient cells.

Conclusions:

  • The small inhibitory peptide BTW3 specifically targets DNA-PKcs autophosphorylation.
  • BTW3 enhances radiosensitivity, indicating its potential as a novel radiosensitizer.
  • Further development of BTW3 as a radiosensitizer is warranted.

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