Drugging MYCN Oncogenic Signaling through the MYCN-PA2G4 Binding Interface
Drugging MYCN Oncogenic Signaling through the MYCN-PA2G4 Binding Interface
复制标题
DOI：
10.1158/0008-5472.can-19-1112
复制
发表时间：
2019-11-01
期刊：
影响因子：
11.2
通讯作者：
Marshall, Glenn M.
中科院分区：
文献类型：
--
作者：
Koach, Jessica;Holien, Jessica K.;Marshall, Glenn M.
MYCN 是儿童癌症、神经母细胞瘤的主要驱动因素，但是，没有针对该靶点的抑制剂。增强的 MYCN 蛋白稳定性是 MYCN 肿瘤发生的关键组成部分，并由涉及 MYCN 反式激活靶基因的多个前馈表达环维持。在这里，我们揭示了一种新的 MYCN 靶点和结合蛋白——增殖相关 2AG4 (PA2G4) 的致癌作用。染色质免疫沉淀研究表明，MYCN 占据 PA2G4 基因启动子，刺激转录。 PA2G4 与 MYCN 蛋白的直接结合可阻断 MYCN 的蛋白水解，并以 MYCN 依赖性方式增强集落形成。利用分子建模、表面等离子体共振和诱变研究，我们将 MYCN-PA2G4 相互作用位点映射到 14 个氨基酸的 MYCN 序列和 PA2G4 的表面裂缝。 MYCN-PA2G4蛋白-蛋白界面的竞争性化学抑制对体内神经母细胞瘤的肿瘤发生具有有效的抑制作用。治疗后的肿瘤显示 MYCN 和 PA2G4 水平降低。我们的研究结果证明了 PA2G4 作为 MYCN 驱动的神经母细胞瘤中的辅助因子的关键作用，并强调了 PA2G4-MYCN 蛋白结合的竞争性抑制作为该疾病的一种新型治疗策略。意义：PA2G4-MYCN 蛋白界面的竞争性化学抑制为针对 MYC 家族癌蛋白驱动的恶性肿瘤中的 MYC 和 MYCN 结合伴侣的小分子药物设计提供了基础。
MYCN is a major driver for the childhood cancer, neuroblastoma, however, there are no inhibitors of this target. Enhanced MYCN protein stability is a key component of MYCN oncogenesis and is maintained by multiple feedforward expression loops involving MYCN transactivation target genes. Here, we reveal the oncogenic role of a novel MYCN target and binding protein, proliferation-associated 2AG4 (PA2G4). Chromatin immunoprecipitation studies demonstrated that MYCN occupies the PA2G4 gene promoter, stimulating transcription. Direct binding of PA2G4 to MYCN protein blocked proteolysis of MYCN and enhanced colony formation in a MYCN-dependent manner. Using molecular modeling, surface plasmon resonance, and mutagenesis studies, we mapped the MYCN-PA2G4 interaction site to a 14 amino acid MYCN sequence and a surface crevice of PA2G4. Competitive chemical inhibition of the MYCN-PA2G4 protein-protein interface had potent inhibitory effects on neuroblastoma tumorigenesis in vivo. Treated tumors showed reduced levels of both MYCN and PA2G4. Our findings demonstrate a critical role for PA2G4 as a cofactor in MYCN-driven neuroblastoma and highlight competitive inhibition of the PA2G4-MYCN protein binding as a novel therapeutic strategy in the disease.Significance: Competitive chemical inhibition of the PA2G4-MYCN protein interface provides a basis for drug design of small molecules targeting MYC and MYCN-binding partners in malignancies driven by MYC family oncoproteins.