Ali Taqveema, Degorre Charlotte, Tofilon Philip J
Radiation Oncology Branch, National Cancer Institute, 10 Center Drive-MSC 1002, Building 10, B3B69B, Bethesda, MD 20892, USA.
Int J Mol Sci. 2025 Sep 1;26(17):8483. doi: 10.3390/ijms26178483.
Alterations in gene expression induced by ionizing radiation (IR) were commonly explained by transcriptional activation. However, the weak correlation between mRNA and protein levels following IR indicates the significant role for post-transcriptional regulation. microRNAs (miRNAs) bound to AGO2 play a significant role in post-transcriptional regulation; however, their role in radiation response is not clear. miRNA sequencing was performed to analyze the miRNAome of glioma cells. The effect of IR on Let-7 miRNAs and their association with AGO2 was examined using RT-qPCR and RNA immunoprecipitation (RIP) assays. Clonogenic assays were performed to measure radiosensitivity following Let-7a overexpression or knockdown. DNA damage (γH2AX foci) and cell cycle distribution were analyzed by immunofluorescence and flow cytometry. Let-7 miRNA regulatory networks were identified through target prediction and pathway enrichment analysis. AGO2-Let-7 binding decreased post IR, indicating impaired RISC loading. Let-7 overexpression increased radiosensitivity, DNA damage and G2/M cell cycle arrest in glioma and other cells (HeLa and MDA-MB-231). Let-7 miRNAs mainly targeted cell cycle and DNA damage response (DDR) pathways. Our study showed radiation impairs AGO2-miRNA binding, while restoring Let-7-AGO2 interaction enhances radiosensitivity by modulating DNA repair and cell cycle checkpoint activation. Targeting AGO2-miRNA dynamics represents a promising approach to improve radiotherapy outcomes.
电离辐射（IR）诱导的基因表达变化通常被解释为转录激活。然而，IR后mRNA水平与蛋白质水平之间的弱相关性表明转录后调控起着重要作用。与AGO2结合的微小RNA（miRNA）在转录后调控中发挥重要作用；然而，它们在辐射反应中的作用尚不清楚。进行了miRNA测序以分析胶质瘤细胞的miRNA组。使用RT-qPCR和RNA免疫沉淀（RIP）试验检测IR对Let-7 miRNAs的影响及其与AGO2的关联。进行克隆形成试验以测量Let-7a过表达或敲低后的放射敏感性。通过免疫荧光和流式细胞术分析DNA损伤（γH2AX焦点）和细胞周期分布。通过靶标预测和通路富集分析确定Let-7 miRNA调控网络。IR后AGO2-Let-7结合减少，表明RISC装载受损。Let-7过表达增加了胶质瘤和其他细胞（HeLa和MDA-MB-231）的放射敏感性、DNA损伤和G2/M细胞周期阻滞。Let-7 miRNAs主要靶向细胞周期和DNA损伤反应（DDR）通路。我们的研究表明，辐射会损害AGO2-miRNA结合，而恢复Let-7-AGO2相互作用可通过调节DNA修复和细胞周期检查点激活来增强放射敏感性。靶向AGO2-miRNA动态变化是改善放疗效果的一种有前景的方法。
