Department of Pediatrics, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania, USA.
Department of Ophthalmology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania, USA.
J Immunother Cancer. 2022 Apr;10(4). doi: 10.1136/jitc-2021-004399.
Anti-GD2 monoclonal antibody immunotherapy has significantly improved the overall survival rate for high-risk neuroblastoma patients. However, 40% of patients fail to respond or develop resistance to treatment, and the molecular mechanisms by which this occurs remain poorly understood. Tumor-derived small extracellular vesicles (sEVs) have emerged as critical regulators in modulating the response to immunotherapy. In this study, we investigated the role of neuroblastoma-derived sEVs in promoting resistance to the anti-GD2 monoclonal antibody dinutuximab. Moreover, to determine whether pharmacologic inhibition of sEV secretion sensitizes tumors to dinutuximab treatment, we combined dinutuximab with tipifarnib, a farnesyltransferase inhibitor that inhibits sEV secretion.
We investigated the role of neuroblastoma-derived sEVs in modulating the response to dinutuximab by utilizing the syngeneic 9464D-GD2 mouse model. The effect of neuroblastoma-derived sEVs in modulating the tumor microenvironment (TME) and host immune system were evaluated by RNA-sequencing and flow cytometry. Importantly, we used this mouse model to investigate the efficacy of tipifarnib in sensitizing neuroblastoma tumors to dinutuximab. The effect of tipifarnib on both the TME and host immune system were assessed by flow cytometry.
We demonstrated that neuroblastoma-derived sEVs significantly attenuated the efficacy of dinutuximab and modulated tumor immune cell infiltration upon dinutuximab treatment to create an immunosuppressive TME that contains more tumor-associated macrophages and fewer tumor-infiltrating NK cells. In addition, we demonstrated that neuroblastoma-derived sEVs suppress splenic NK cell maturation and dinutuximab-induced NK cell-mediated antibody-dependent cellular cytotoxicity . Importantly, tipifarnib drastically enhanced the efficacy of dinutuximab-mediated inhibition of tumor growth and prevented the immunosuppressive effects of neuroblastoma-derived sEVs .
These preclinical findings uncover a novel mechanism by which neuroblastoma-derived sEVs modulate the immune system to promote resistance to dinutuximab and suggest that tipifarnib-mediated inhibition of sEV secretion may serve as a viable treatment strategy to enhance the antitumor efficacy of anti-GD2 immunotherapy in high-risk neuroblastoma patients.
抗 GD2 单克隆抗体免疫疗法显著提高了高危神经母细胞瘤患者的总生存率。然而，仍有 40%的患者对治疗无反应或产生耐药性，而其发生的分子机制仍知之甚少。肿瘤衍生的小细胞外囊泡（sEVs）已成为调节免疫治疗反应的关键调节因子。在本研究中，我们研究了神经母细胞瘤衍生的 sEVs 在促进对抗 GD2 单克隆抗体 dinutuximab 耐药中的作用。此外，为了确定抑制 sEV 分泌是否使肿瘤对 dinutuximab 治疗敏感，我们将 dinutuximab 与法尼基转移酶抑制剂 tipifarnib 联合使用，该抑制剂可抑制 sEV 分泌。
我们利用同源 9464D-GD2 小鼠模型研究了神经母细胞瘤衍生的 sEVs 在调节 dinutuximab 反应中的作用。通过 RNA 测序和流式细胞术评估神经母细胞瘤衍生的 sEVs 对肿瘤微环境（TME）和宿主免疫系统的调节作用。重要的是，我们使用该小鼠模型研究了 tipifarnib 增强神经母细胞瘤肿瘤对 dinutuximab 敏感性的效果。通过流式细胞术评估了 tipifarnib 对 TME 和宿主免疫系统的影响。
我们证明神经母细胞瘤衍生的 sEVs 显著降低了 dinutuximab 的疗效，并在 dinutuximab 治疗时调节肿瘤免疫细胞浸润，从而产生含有更多肿瘤相关巨噬细胞和更少肿瘤浸润 NK 细胞的免疫抑制 TME。此外，我们证明神经母细胞瘤衍生的 sEVs 抑制脾 NK 细胞成熟和 dinutuximab 诱导的 NK 细胞介导的抗体依赖性细胞毒性。重要的是，tipifarnib 大大增强了 dinutuximab 抑制肿瘤生长的疗效，并防止了神经母细胞瘤衍生的 sEVs 的免疫抑制作用。
这些临床前发现揭示了神经母细胞瘤衍生的 sEVs 调节免疫系统促进对 dinutuximab 耐药的新机制，并表明 tipifarnib 介导的 sEV 分泌抑制可能是增强高危神经母细胞瘤患者抗 GD2 免疫治疗抗肿瘤疗效的可行治疗策略。
