PO.ET06.02 · 实验与分子治疗
碱基切除修复抑制剂TRC102在DNA损伤应答过度激活的胶质母细胞瘤中的选择性细胞毒性
Selective Cytotoxicity of Base Excision Repair Inhibitor, TRC102, in DNA Damage Response Hyperactivated Glioblastoma
作者与单位 Authors & Affiliations
摘要 Abstract
中文摘要
背景：胶质母细胞瘤是最具侵袭性和致死性的脑肿瘤类型。肿瘤异质性和DNA修复通路对不良预后有很大影响，突显了对更加个体化方法的需求。TRC102（甲氧胺盐酸盐）是一种碱基切除修复的小分子抑制剂，其作用机制是共价结合于无碱基位点并阻止下游修复酶修复该损伤。在胶质母细胞瘤中使用TRC102的临床研究已在特殊应答者中鉴定出过度激活的DNA损伤应答（DDR）基因特征，提示DDR过度激活可能作为一种潜在的临床生物标志物。在此，我们评估了依赖DDR信号传导的胶质母细胞瘤细胞是否对TRC102治疗特别易感。方法：我们利用NCI神经肿瘤学分部数据库中24个胶质母细胞瘤细胞系的RNA-seq数据进行了基因集富集分析，鉴定出三个具有过度激活DDR特征的患者来源细胞系（L0、L1、GSC627）。使用细胞活力、集落形成、DNA损伤、修复及免疫荧光测定评估治疗疗效。结果：单独使用TRC102治疗在DDR过度激活的胶质母细胞瘤细胞系中诱导了显著的DNA损伤和细胞死亡，而DDR低激活的细胞则表现出极低的敏感性。在L0和L1细胞系中，TRC102治疗在72小时治疗过程中显著抑制了集落形成和细胞增殖。通过蛋白质印迹进行的机制研究揭示，TRC102导致CHK2活性的显著抑制，CHK2是DDR中一种控制细胞周期进程的关键激酶。通过CHK2耗竭消除细胞周期检查点阻断，可能使胶质母细胞瘤细胞在未完全解决DNA损伤的情况下启动有丝分裂，导致有丝分裂灾难和细胞死亡。有趣的是，TRC102在缺氧条件下还抑制了HIF蛋白表达，最终导致细胞死亡。结论：TRC102的抗肿瘤效应似乎是通过靶向新鉴定的ATM-CHK2-HIF轴介导的，从而在DDR过度激活的胶质母细胞瘤中实现选择性细胞毒性。这些结果提示，通常对常规化疗和放疗耐药的DDR过度激活胶质母细胞瘤对TRC102存在特定的易感性，支持在未来临床研究中进行生物标志物驱动的患者选择。
查看英文原文 English abstract
Background Glioblastoma is the most aggressive and lethal type of brain tumor. Tumor heterogeneity and DNA repair pathways contribute strongly to poor outcomes, highlighting the need for more personalized approaches. TRC102 (methoxyamine hydrochloride) is a small-molecule inhibitor of base excision repair that acts by covalently binding to abasic sites and preventing downstream repair enzymes from repairing the lesion. Clinical studies utilizing TRC102 in glioblastoma have identified hyperactivated DNA damage response (DDR) gene signature among exceptional responders, suggesting DDR-hyperactivity as a potential clinical biomarker. Here, we evaluated whether glioblastoma cells reliant on DDR signaling are particularly vulnerable to TRC102 treatment. Methods We performed gene set enrichment analysis using RNA-seq data across 24 glioblastoma cell lines within the NCI, Neuro Oncology Branch database and identified three patient-derived cell lines (L0, L1, GSC627) with hyperactivated DDR signature. Treatment efficacy was evaluated using cell viability, colony formation, DNA damage, repair and immunofluorescence assays. Results TRC102 treatment alone induced significant DNA damage and cell death in DDR-hyperactivated glioblastoma cell lines, whereas DDR-hypoactivated cells showed minimal sensitivity. In L0 and L1 cell lines, TRC102 treatment significantly inhibited colony formation and cell proliferation over 72-hour treatment. Mechanistic studies through western blotting revealed that TRC102 led to significant suppression of CHK2 activity, a key kinase involved in the DDR that controls cell cycle progression. Abrogation of cell cycle checkpoint blockades through CHK2 depletion may allow glioblastoma cells to initiate mitosis without fully resolving DNA damage, leading to mitotic catastrophe and cell death. Interestingly, TRC102 also suppressed HIF protein expression in hypoxic conditions, leading to eventual cell death. Conclusions The antitumor effect of TRC102 appears to be mediated through targeting of the newly identified ATM-CHK2-HIF axis, allowing for selective cytotoxicity in DDR-hyperactivated glioblastoma. These results suggest a specific vulnerability to TRC102 in DDR-hyperactivated glioblastoma that are typically resistant to conventional chemotherapy and radiation therapy, supporting biomarker-driven patient selection in future clinical studies.
利益披露 Disclosure
S. Sathe, None..
Q. Li, None..
J. Jung, None..
P. Lu, None..
Z. Sergi, None..
H. Wang, None..
J. Wu, None.