Department of Radiation Oncology, Medical Faculty Mannheim, University Medical Centre Mannheim, Heidelberg University, Theodor-Kutzer-Ufer 1-3, 68167, Mannheim, Germany.
Clinic for Urology and Paediatric Urology, University Hospital Bonn, Venusberg Campus 1, 53127, Bonn, Germany.
Radiat Oncol. 2024 Jan 30;19(1):16. doi: 10.1186/s13014-023-02395-1.
Ionotropic glutamate receptors α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor (AMPAR) and N-methyl-D-aspartate receptor (NMDAR) modulate proliferation, invasion and radioresistance in glioblastoma (GB). Pharmacological targeting is difficult as many in vitro-effective agents are not suitable for in patient applications. We aimed to develop a method to test the well tolerated AMPAR- and NMDAR-antagonist xenon gas as a radiosensitizer in GB.
We designed a diffusion-based system to perform the colony formation assay (CFA), the radiobiological gold standard, under xenon exposure. Stable and reproducible gas atmosphere was validated with oxygen and carbon dioxide as tracer gases. After checking for AMPAR and NMDAR expression via immunofluorescence staining we performed the CFA with the glioblastoma cell lines U87 and U251 as well as the non-glioblastoma derived cell line HeLa. Xenon was applied after irradiation and additionally tested in combination with NMDAR antagonist memantine.
The gas exposure system proved compatible with the CFA and resulted in a stable atmosphere of 50% xenon. Indications for the presence of glutamate receptor subunits were present in glioblastoma-derived and HeLa cells. Significantly reduced clonogenic survival by xenon was shown in U87 and U251 at irradiation doses of 4-8 Gy and 2, 6 and 8 Gy, respectively (p < 0.05). Clonogenic survival was further reduced by the addition of memantine, showing a significant effect at 2-8 Gy for both glioblastoma cell lines (p < 0.05). Xenon did not significantly reduce the surviving fraction of HeLa cells until a radiation dose of 8 Gy.
The developed system allows for testing of gaseous agents with CFA. As a proof of concept, we have, for the first time, unveiled indications of radiosensitizing properties of xenon gas in glioblastoma.
离子型谷氨酸受体 α-氨基-3-羟基-5-甲基-4-异恶唑丙酸受体（AMPA 受体）和 N-甲基-D-天冬氨酸受体（NMDAR）调节神经胶质瘤（GB）的增殖、侵袭和放射抗性。由于许多在体外有效的药物不适合患者应用，因此药物靶向治疗具有一定难度。我们旨在开发一种方法，以测试耐受性良好的 AMPAR 和 NMDAR 拮抗剂氙气作为 GB 的放射增敏剂。
我们设计了一种基于扩散的系统，在氙气暴露下进行集落形成测定（CFA），这是放射生物学的金标准。我们使用氧和二氧化碳作为示踪气体来验证稳定且可重复的气体氛围。通过免疫荧光染色检查 AMPAR 和 NMDAR 的表达后，我们用 U87 和 U251 神经胶质瘤细胞系以及非神经胶质瘤衍生的 HeLa 细胞系进行 CFA。氙气在照射后应用，并与 NMDAR 拮抗剂美金刚胺联合测试。
该气体暴露系统与 CFA 兼容，并产生 50%氙气的稳定气氛。在神经胶质瘤衍生细胞和 HeLa 细胞中存在谷氨酸受体亚基的存在迹象。在 U87 和 U251 中，在 4-8Gy 和 2、6 和 8Gy 的照射剂量下，氙气显著降低了克隆形成存活率（p<0.05）。在两种神经胶质瘤细胞系中，添加美金刚胺进一步降低了克隆形成存活率，在 2-8Gy 时均有显著效果（p<0.05）。在 8Gy 的辐射剂量下，氙气才对 HeLa 细胞的存活分数没有显著降低。
所开发的系统允许用 CFA 测试气态试剂。作为概念验证，我们首次揭示了氙气在神经胶质瘤中具有放射增敏作用的迹象。
