Life (Nov 2021)

The Effect of High-Dose-Rate Pulsed Radiation on the Survival of Clinically Relevant Radioresistant Cells

  • Shingo Terashima,
  • Hironori Yoshino,
  • Yoshikazu Kuwahara,
  • Hiro Sakuraba,
  • Yoichiro Hosokawa

DOI
https://doi.org/10.3390/life11121295
Journal volume & issue
Vol. 11, no. 12
p. 1295

Abstract

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We demonstrated that low dose pulsed radiation (0.25 Gy) at a high-dose-rate, even for very short intervals (10 s), decreases cell survival to a greater extent than single exposure to a similar total dose and dose rate. The objective of this study was to clarify whether high-dose-rate pulsed radiation is effective against SAS-R, a clinically relevant radioresistant cell line. Cell survival following high-dose-rate pulsed radiation was evaluated via a colony assay. Flow cytometry was utilized to evaluate γH2AX, a molecular marker of DNA double-strand breaks and delayed reactive oxygen species (ROS) associated with radiation-induced apoptosis. Increased cytotoxicity was observed in SAS-R and parent SAS cells in response to high dose rate pulsed radiation compared to single dose, as determined by colony assays. Residual γH2AX in both cells subjected to high-dose-rate pulsed radiation showed a tendency to increase, with a significant increase observed in SAS cells at 72 h. In addition, high-dose-rate pulsed radiation increased delayed ROS more than the single exposure did. These results indicate that high-dose-rate pulsed radiation was associated with residual γH2AX and delayed ROS, and high-dose-rate pulsed radiation may be used as an effective radiotherapy procedure against radioresistant cells.

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