Carandang Beatriz Allyne D, Sy-Ortin Teresa, Cabahug John Paul C, Feliciano Chitho P
University of the Philippines - Manila, Padre Faura Manila, Metro Manila, 1000, Philippines; University of Santo Tomas, Sampaloc Manila, Metro Manila, 1008, Philippines.
University of Santo Tomas, Sampaloc Manila, Metro Manila, 1008, Philippines.
Appl Radiat Isot. 2025 Nov;225:112065. doi: 10.1016/j.apradiso.2025.112065. Epub 2025 Jul 22.
Emerging evidence shows that exposure of cancer cells to ionizing radiation may trigger signal-mediated events in unirradiated cells called the radiation-induced bystander effects (RIBE). Manifestation of the effect is highly variable, dependent on the treatment parameters such as methodology, radiation type, LET, or cell lines. This study aims to investigate RIBE in MCF-7 after irradiation using an X-ray benchtop irradiator. MCF-7 cells were cultured at 2 × 10 cells per T25 flask and irradiated using a CellRad™ bench-top irradiator at 130 kV, 5 mA, with an additional 0.5 mm aluminum filter. The irradiation setup placed the flask within a circular field size of 19.8 cm, delivering a dose rate of 2.096 Gy/min. Acute doses investigated included 0 Gy (sham), 0.5 Gy, 1.5 Gy, 3.36 Gy, 8 Gy, and 12 Gy. Twenty-four hours post-irradiation, medium transfer from irradiated cells (ICM) was performed to initiate radiation-induced bystander effects in non-irradiated cells. Subsequent assessments included viability assays and colony formation assays to validate observed effects, with relative survival calculated relative to sham-irradiated cells. Results show that exposure of the cells to the irradiated cell medium resulted in a significant decrease in cell viability and clonogenic ability, demonstrating bystander effects. This decrease in survival is dose-dependent where the effect is more significant at higher doses 3.36 Gy-12 Gy.
新出现的证据表明，癌细胞暴露于电离辐射可能会在未受辐射的细胞中引发信号介导的事件，即辐射诱导旁观者效应（RIBE）。该效应的表现高度可变，取决于诸如方法、辐射类型、传能线密度或细胞系等治疗参数。本研究旨在使用X射线台式辐照仪研究MCF-7细胞受辐照后的辐射诱导旁观者效应。MCF-7细胞以每T25培养瓶2×10个细胞的密度进行培养，并使用CellRad™台式辐照仪在130 kV、5 mA条件下进行辐照，附加0.5 mm铝滤片。辐照装置将培养瓶置于直径19.8 cm的圆形照射野内，剂量率为2.096 Gy/min。研究的急性剂量包括0 Gy（假照射）、0.5 Gy、1.5 Gy、3.36 Gy、8 Gy和12 Gy。辐照后24小时，进行从辐照细胞的培养基转移（ICM），以在未辐照细胞中引发辐射诱导旁观者效应。随后的评估包括活力测定和集落形成测定，以验证观察到的效应，相对于假照射细胞计算相对存活率。结果表明，细胞暴露于辐照细胞培养基导致细胞活力和克隆形成能力显著降低，表明存在旁观者效应。这种存活率的降低是剂量依赖性的，在较高剂量3.36 Gy - 12 Gy时效应更显著。
