PO.ET06.02 · 实验与分子治疗
靶向复制应激促进脊索瘤中的免疫原性细胞死亡
Targeting replication stress promotes immunogenic cell death in chordoma
作者与单位 Authors & Affiliations
摘要 Abstract
中文摘要
脊索瘤是一种罕见的骨癌，复发率高且无获批的全身治疗。靶点发现工作揭示了复杂的基因组重排、DNA 损伤应答（DDR）和染色质重塑基因的改变，以及对稳定停滞复制叉的 DDR 通路的依赖。此外，一部分脊索瘤被多细胞免疫聚集体高度浸润，但驱动抗肿瘤免疫应答的潜在机制仍不清楚。我们假设复制应激是脊索瘤中一个可干预的治疗脆弱性，靶向该通路可诱导致死性 DNA 损伤和免疫原性细胞死亡。为评估加剧脊索瘤复制应激的效果，用 DNA 合成抑制剂 gemcitabine 或 ATR 抑制剂 elimusertib（BAY 1895344）处理由 14 个细胞系组成的组合。大多数细胞系高度敏感，14 个中有 9 个显示 EC₅₀ 值低于 10 nM（gemcitabine）或 100 nM（elimusertib）。生化分析显示 gemcitabine 诱导的 DNA 损伤以 ATR 依赖方式导致 Chk1 激活，DNA 纤维实验揭示 ATR 抑制（ATRi）后复制叉速度、对称性和稳定性下降。对 ATRi 或 gemcitabine 的敏感性在脊索瘤 PDX 模型中得到印证，ATRi 在敏感模型中促进 85-90% 的肿瘤生长抑制，而 gemcitabine 则驱动肿瘤消退。当这些疗法联合时，在体外观察到卓越的协同作用，细胞活力显著降低、DNA 双链断裂增强以及 S 期几近完全崩溃。此外，任一药物治疗都导致双链 DNA 在细胞质中积累，同时伴随 I 型干扰素、免疫调节趋化因子 CXCL10 和 CCL5 以及细胞表面 PD-L1 的上调。这些发现与以下模型一致：ATRi 或 gemcitabine 治疗促进脊索瘤中的致死性 DNA 损伤和免疫原性细胞死亡，而这可能通过 PD-1 检查点阻断进一步增强。
查看英文原文 English abstract
Chordoma is a rare bone cancer with a high rate of recurrence and no approved systemic therapies. Target discovery efforts have uncovered complex genomic rearrangements, alterations in DNA damage response (DDR) and chromatin-remodeling genes, and a reliance on DDR pathways that stabilize stalled replication forks. Additionally, a subset of chordomas is highly infiltrated by multicellular immune aggregates, but the underlying mechanisms driving an antitumor immune response remain unclear. We hypothesized that replication stress presents an actionable therapeutic vulnerability in chordoma and that targeting this pathway could induce lethal DNA damage and immunogenic cell death. To assess the effects of exacerbating replication stress in chordoma, a panel of 14 cell lines was treated with the DNA synthesis inhibitor gemcitabine or the ATR inhibitor elimusertib (BAY 1895344). Most lines were highly sensitive, with 9 of 14 showing EC₅₀ values below 10 nM (gemcitabine) or 100 nM (elimusertib). Biochemical analysis showed that gemcitabine-induced DNA damage leads to activation of Chk1 in an ATR-dependent manner, with DNA fiber assays revealing decreased replication fork speed, symmetry, and stability following ATR inhibition (ATRi). Sensitivity to ATRi or gemcitabine was mirrored in chordoma PDX models, with ATRi promoting 85-90% tumor growth inhibition in sensitive models and gemcitabine driving tumor regressions. Exceptional synergy was observed in vitro when these therapies were combined, with significant reductions in cell viability, enhanced DNA double-strand breaks, and near-complete S-phase collapse. Moreover, treatment with either drug resulted in the accumulation of double-stranded DNA in the cytoplasm, along with upregulation of type I interferon, immunomodulatory chemokines CXCL10 and CCL5, and cell surface PD-L1. These findings are consistent with a model where ATRi or gemcitabine treatment promotes lethal DNA damage and immunogenic cell death in chordoma, which may be further augmented by PD-1 checkpoint blockade.
利益披露 Disclosure
N. Punturi, None..
A. Ghosh, None..
W. Leung, None.