Elucidating the Role of Epigenetic Plasticity in anti-GD2 Immunotherapy Response

项目摘要(来自已获资助的申请) 神经节苷脂GD2在许多儿科癌症的细胞表面表达，包括尤文肉瘤， 骨肉瘤和神经母细胞瘤。2015年，FDA批准了抗GD2免疫疗法迪努昔单抗 通过显著降低肿瘤的发病率，代表了神经母细胞瘤治疗的范式转变 复发。尽管地努西单抗取得了成功，但大约30%的神经母细胞瘤患者对地努西单抗无效。报告 提示细胞表面GD2的表达程度与临床对地诺昔单抗的疗效相关。然而， 肿瘤细胞中GD2调控的细胞机制尚不清楚。地面GD2的相关性 RNA测序表明，GD2在大量神经母细胞瘤细胞系中的表达是 与间充质表观遗传程序相关。上皮向间充质转化(EMT)已被 因其在化疗耐药中的作用而在上皮性实体肿瘤中被广泛研究。然而，已经有了 没有报道将肾上腺素能到间充质转化(AMT)的表观遗传学程序与表面调节联系起来 抗原GD2，使这种关系引起神经母细胞瘤社区的强烈兴趣。在这份提案中， 目的1通过严格测试AMT和GD2表达的充分性来阐明两者之间的关系 神经母细胞瘤特异性AMT转录因子Prrx1调控GD2的必要性。此外，损失 通过AMT表达GD2将在体外和体内测试对地努昔单抗的反应丧失。目标2将 评估GD2表达缺失的潜在途径。初步数据显示间充质细胞 细胞系和肿瘤通过基因启动子的表观遗传沉默表达显著降低的GD3合成酶。我们 将评估AMT是否直接调节GD3合酶，以及恢复其表达是否拯救 对迪努西单抗的反应。这些发现将直接将表观遗传状态与肿瘤的下调联系起来。 抗原GD2和对地诺昔单抗的反应。此外，这些研究可能有助于了解有理组合 加强神经母细胞瘤抗GD2治疗的策略，并可能为未来的研究提供一个框架 在其他表达GD2的儿童癌症中。

Project Summary (from the funded application) Ganglioside GD2 is expressed on the cell surface of numerous pediatric cancers, including Ewing sarcoma, osteosarcoma, and neuroblastoma. In 2015, FDA approval of the anti-GD2 immunotherapy dinutuximab represented a paradigm shift in the treatment of neuroblastoma by significantly reducing the incidence of tumor recurrence. Despite dinutuximab's success, dinutuximab fails ~30% of neuroblastoma patients. Reports suggest that the degree of surface GD2 expression correlates with clinical response to dinutuximab. However, the cellular mechanisms governing GD2 regulation in tumor cells remain unknown. Correlation of surface GD2 expression with RNA-sequencing in a large cohort of neuroblastoma cell lines revealed that GD2 expression is associated with a mesenchymal epigenetic program. Epithelial-to-Mesenchymal Transition (EMT) has been widely studied in epithelial solid tumors for its purported role in chemoresistance. However, there have been no reports linking an adrenergic-to-mesenchymal transition (AMT) epigenetic program to regulation of surface antigen GD2, making this relationship of intense interest to the neuroblastoma community. In this proposal, AIM 1 will elucidate the relationship between AMT and GD2 expression by rigorously testing the sufficiency and necessity of the neuroblastoma-specific AMT transcription factor PRRX1 to regulate GD2. Further, loss of GD2 expression via AMT will be tested in vitro and in vivo for loss of response to dinutuximab. Aim 2 will evaluate the pathways underlying loss of GD2 expression. Preliminary data suggest that mesenchymal cell lines and tumors express markedly reduced GD3 synthase via epigenetic silencing at the gene promoter. We will evaluate whether AMT directly regulates GD3 synthase, and whether restoration of its expression rescues response to dinutuximab. These findings will directly link epigenetic state to the downregulation of tumor antigen GD2 and response to dinutuximab. Further, these studies may help inform rational combinatorial strategies to enhance anti-GD2 therapies in neuroblastoma, and could provide a framework for future studies in other GD2-expressing pediatric cancers.