Rødland Gro Elise, Temelie Mihaela, Eek Mariampillai Adrian, Serban Ana Maria, Edin Nina Frederike Jeppesen, Malinen Eirik, Lindbergsengen Lilian, Gilbert Antoine, Chevalier François, Savu Diana I, Syljuåsen Randi G
Department of Radiation Biology, Institute for Cancer Research, Norwegian Radium Hospital, Oslo University Hospital, 0379 Oslo, Norway.
Department of Life and Environmental Physics, Horia Hulubei National Institute for R&D in Physics and Nuclear Engineering, 077125 Magurele, Romania.
Radiother Oncol. 2025 Feb;203:110669. doi: 10.1016/j.radonc.2024.110669. Epub 2024 Dec 13.
Interferon (IFN) signaling plays an important role in antitumor immune responses. Inhibitors of the DNA damage response, such as ATR inhibitors, can increase IFN signaling upon conventional radiotherapy with X-rays. However, it is not known whether such inhibitors also enhance IFN signaling after irradiation with high linear energy transfer (LET) particles.
Human glioblastoma U-251 and T98G cells were irradiated with X-rays, protons (LET: 4.8 and 41.9 keV/µm) and carbon ions (LET: 28 and 73 keV/µm), with and without ATR inhibitor (VE-822) or ATM inhibitor (AZD1390). DNA damage signaling and cell cycle distribution were analyzed by immunoblotting and flow cytometry, and radiosensitivity was assessed by clonogenic survival assay. IFN-β secretion was measured by ELISA, and STAT1 activation was examined by immunoblotting.
High-LET protons and carbon ions caused stronger activation of the DNA damage response compared to low-LET protons and X-rays at similar radiation doses. G2 checkpoint arrest was abrogated by the ATR inhibitor and prolonged by the ATM inhibitor after all radiation types. The inhibitors increased radiosensitivity, as measured after X- and carbon ion irradiation. ATR inhibition increased IFN signaling following both low-LET and high-LET irradiation. ATM inhibition also increased IFN signaling, but to a lesser extent. Notably, both cell lines secreted significantly more IFN-β when the inhibitors were combined with high-LET compared to low-LET irradiation.
These findings indicate that DNA damage response inhibitors can enhance IFN signaling following X-, proton and carbon ion irradiation, with a strong positive dependency on LET.
干扰素（IFN）信号传导在抗肿瘤免疫反应中起重要作用。DNA损伤反应抑制剂，如ATR抑制剂，在传统X线放疗时可增强IFN信号传导。然而，尚不清楚此类抑制剂在高传能线密度（LET）粒子照射后是否也能增强IFN信号传导。
用人胶质母细胞瘤U-251和T98G细胞，在有或无ATR抑制剂（VE-822）或ATM抑制剂（AZD1390）的情况下，分别接受X线、质子（LET：4.8和41.9keV/μm）和碳离子（LET：28和73keV/μm）照射。通过免疫印迹和流式细胞术分析DNA损伤信号传导和细胞周期分布，通过克隆形成存活试验评估放射敏感性。用ELISA法检测IFN-β分泌，通过免疫印迹检测STAT1激活情况。
在相似辐射剂量下，与低LET质子和X线相比，高LET质子和碳离子引起更强的DNA损伤反应激活。所有辐射类型后，ATR抑制剂消除了G2期检查点阻滞，而ATM抑制剂则延长了该阻滞。如在X线和碳离子照射后所测，这些抑制剂增加了放射敏感性。ATR抑制在低LET和高LET照射后均增加了IFN信号传导。ATM抑制也增加了IFN信号传导，但程度较小。值得注意的是，与低LET照射相比，当抑制剂与高LET照射联合时，两种细胞系分泌的IFN-β均显著增多。
这些发现表明，DNA损伤反应抑制剂在X线、质子和碳离子照射后可增强IFN信号传导，且对LET有强烈的正依赖性。
