Targeting EphA2 in Glioblastoma

胶质母细胞瘤中的靶向 EphA2

• 批准号: 9128090
• 负责人: Bingcheng Wang
• 金额: $ 55.29万
• 依托单位: CASE WESTERN RESERVE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-03-15 至 2020-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9128090
• 关键词: Address; Adrenergic Receptor; Affect; Affinity; Agonist; Biological Assay; Blood - brain barrier anatomy; Cells; Clinical; Complement; Complex; Development; Disease; Doxazosin; EphA2 Receptor; Ephrins; Etiology; Genetically Engineered Mouse; Glioblastoma; Glioma; Gliomagenesis; Goals; Heterogeneity; Human; Hypertension; Implant; In Vitro; Knockout Mice; Lead; Ligand Binding Domain; Ligands; Malignant - descriptor; Mesenchymal; Modeling; Molecular; Mus; Neoplasm Metastasis; Oncogenic; Pathway interactions; Pharmaceutical Chemistry; Pharmaceutical Preparations; Phosphoproteins; Phosphorylation; Phosphotransferases; Pre-Clinical Model; Preclinical Testing; Property; Proteins; Radiation; Radiation therapy; Regulation; Reporting; Roentgen Rays; Role; Series; Serine; Signal Transduction; Somatic Gene Therapy; Stem cells; Structure; Survival Rate; Testing; Therapeutic Agents; Therapeutic Intervention; Translating; Treatment Efficacy; Tumor Cell Invasion; Tumor Suppressor Proteins; Xenograft procedure; base; cell motility; chemotherapy; design; drug candidate; functional restoration; improved; in vivo; molecular subtypes; mouse model; neoplastic cell; next generation; novel; novel therapeutics; phosphoproteomics; pre-clinical; public health relevance; relating to nervous system; response; screening; small molecule; stem; stem cell differentiation; targeted treatment; temozolomide; transcriptome sequencing; tumor; tumorigenesis; virtual

 DESCRIPTION (provided by applicant) Glioblastoma (GBM) remains a largely incurable disease, with a 5 year survival rate of less than 10%. Effective targeted therapies to complement already maximal radiation and chemotherapy are urgently needed. Converging evidence shows that the EphA2 receptor is an attractive target for GBM. The PI's lab and others recently uncovered dual roles of EphA2 in tumor etiology and malignant progression. When engaged with ligands (ephrin-As), EphA2 is a tumor suppressor and inhibits both ERK and Akt activities in GBM cells. However, in the absence of ligands, EphA2 is phosphorylated by AGC kinases including Akt and p90-RSK on serine 897, and S897 phosphorylation converts EphA2 from a tumor suppressor into an oncogenic protein that promotes glioma cell migration in vitro and intracranial invasion of glioma stem cells (GSC) in vivo. Moreover level of pS897-EphA2 is correlated with tumor grades. Mechanistically pS897- EphA2 regulates the stem properties of GSCs and promotes gliomagenesis in the absence of ligands. In contrast, upon ligand stimulation, EphA2 induces GSC differentiation and inhibits tumor development. Based on this series of observations, we propose that ligand-mimicking small molecule agonists of EphA2 can be novel therapeutic agents for GBM. Such agonists are expected to i) restore the intrinsic tumor suppressor functions of EphA2, ii) disrupt the pro- oncogenic Akt/RSK-EphA2 signaling axis, and iii) induce differentiation of GSCs. Using structure- guided virtual screening and cell-based assays, we reported that doxazosin (DZ), an α1- adrenoceptor antagonist still in clinical use for hypertension, is a bona fide EphA2 agonist. DZ inhibits ERK and Akt and suppresses tumor cell dissemination in an EphA2-dependent manner. Much more potent derivatives of DZ have been characterized through medicinal chemistry, including BW27, which suppressed GBM in preclinical models and was capable of crossing the blood-brain barrier (BBB). The overarching goal of this proposal is to translate these basic and preclinical discoveries into nove GBM therapeutic agents. BW27 will be subject to systemic preclinical test across all four molecular subtypes of human GBM. The on-target effects of BW27 will be investigated using the genetically engineered mouse model. Finally the X-ray co-crystal structure of EphA2 in complex with BW27 will be determined to guide the design of next generation(s) of EphA2 agonists. Completion of the studies could lead to new mechanism-based small molecule drug(s) for therapeutic intervention of GBM.

 胶质母细胞瘤（GBM）仍然是一种基本上无法治愈的疾病，5年生存率低于10%。迫切需要有效的靶向治疗来补充已经最大的放射和化疗。越来越多的证据表明EphA 2受体是GBM的一个有吸引力的靶点。PI的实验室和其他人最近发现了EphA 2在肿瘤病因学和恶性进展中的双重作用。当与配体（肝配蛋白-As）接合时，EphA 2是肿瘤抑制剂并且抑制GBM细胞中的ERK和Akt活性。然而，在不存在配体的情况下，EphA 2被AGC激酶（包括丝氨酸897上的Akt和p90-RSK）磷酸化，并且S897磷酸化将EphA 2从肿瘤抑制因子转化为致癌蛋白，其促进体外神经胶质瘤细胞迁移和体内神经胶质瘤干细胞（GSC）的颅内侵袭。此外，pS 897-EphA 2的水平与肿瘤分级相关。pS 897-EphA 2在机制上调节GSC的干细胞特性并在配体不存在的情况下促进胶质瘤发生。相反，在配体刺激后，EphA 2诱导GSC分化并抑制肿瘤发展。基于这一系列的观察，我们提出EphA 2的配体模拟小分子激动剂可以是GBM的新型治疗剂。预期此类激动剂i）恢复EphA 2的内在肿瘤抑制功能，ii）破坏原癌Akt/RSK-EphA 2信号传导轴，和iii）诱导GSC的分化。我们采用结构导向的虚拟筛选和基于细胞的分析，报道了多沙唑嗪（DZ），一种仍在临床上用于高血压的α1-肾上腺素受体拮抗剂，是真正的EphA 2激动剂。DZ抑制ERK和Akt，并以EphA 2依赖性方式抑制肿瘤细胞播散。DZ的更有效的衍生物已经通过药物化学进行了表征，包括BW 27，其在临床前模型中抑制GBM并且能够穿过血脑屏障（BBB）。该提案的总体目标是将这些基础和临床前发现转化为新的GBM治疗剂。BW 27将在人GBM的所有四种分子亚型中进行全身临床前试验。将使用基因工程小鼠模型研究BW 27的中靶效应。最后，将确定与BW 27复合的EphA 2的X射线共晶体结构，以指导下一代EphA 2激动剂的设计。研究的完成可能导致新的基于机制的小分子药物用于GBM的治疗干预。