Characterization of MET alteration using glioblastoma patient-derived xenograft models

项目摘要 胶质母细胞瘤（GBM）是对烷化剂和放射线具有抗性的最恶性的脑癌类型。 胶质瘤干细胞（GSC）是一种对辐射具有抗性的高度侵袭性GBM细胞亚群， 化疗是有效治疗的主要目标。识别和靶向分子决定簇 对于治疗恶性GBM是重要的。我们的长期目标是定义和部署具有良好特性的， 临床相关的MET驱动的GBM模型，以实现MET的有效治疗靶向。异常MET 受体酪氨酸激酶（RTK）激活，如MET扩增（METamp）、突变和PTPRZ 1-MET (ZM)融合，经常发现在原发性或继发性GBM。MET信号升高引起肿瘤侵袭 在GBM中，也负责GSC的维持和侵入性再增殖。临床上，贝伐珠单抗 诱导MET活化的治疗是具有更侵袭性表型的肿瘤复发的主要机制， 进一步证明了靶向MET途径在GBM中的重要性。虽然MET酪氨酸激酶 尽管TKI抑制剂（TKI）正在进入临床试验，但其治疗效果仍存在争议。此外，MET 单独的抑制剂治疗可能会被获得性耐药性击败。因此，使用临床相关的 GBM模型，以研究与治疗反应相关的分子机制，以改善治疗反应。 组合策略在本申请中，我们假设携带不同遗传MET的GBM PDX模型 这些变化表明了对MET靶向药物的明显治疗脆弱性以及逃逸机制 从MET TKI。我们对METamp和ZM融合模型特别感兴趣，因为这两种分子特征 表明对MET抑制剂敏感。对于此应用，我们将1）表征GBM PDX型号轴承 在患者中发现的各种MET改变，用于其MET途径活化和原位肿瘤生长。（二） 使用体外GSC和原位异种移植模型测定MET抑制剂的治疗反应， vivo.对于MET靶向试剂，我们将应用MET TKI和特异性MET靶向嵌合抗原受体 (CAR)T细胞在我们的实验室里发展。我们还将确定辐射或DNA修复抑制是否可以 增强MET TKI在这些模型中的疗效，以及MET TKI耐药GBM模型是否 可以继续对靶向MET的CAR T细胞作出反应。我们希望了解HGF/MET的改变如何 作为生物标志物来指示对MET抑制剂的治疗反应以及联合策略。 此外，本项目建立的GSC模型将成为研究MET介导的GSC的重要工具。 GBM生物学和治疗策略。

Project Summary Glioblastoma (GBM) is the most malignant type of brain cancer resistant to alkylating agents and radiation. Glioma stem cells (GSCs), a subpopulation of highly invasive GBM cells resistant to the irradiation and chemotherapy, are the major targets of effective therapeutics. Identifying and targeting molecular determinants of GSCs are important for treating malignant GBM. Our long-term goal is to define and deploy well-characterized, clinically relevant MET-driven GBM models to enable effective therapeutic targeting of MET. Aberrant MET receptor tyrosine kinase (RTK) activation, such as MET amplification (METamp), mutation, and PTPRZ1-MET (ZM) fusion, are frequently found in primary or secondary GBM. Elevated MET signaling provokes tumor invasion in GBM and is also responsible for GSC maintenance and invasive repopulation. Clinically, bevacizumab treatment inducing MET activation is a major mechanism of tumor recurrence with more aggressive phenotype, further demonstrating the significance of targeting MET pathway in GBM. Although MET tyrosine kinase inhibitors (TKIs) are entering clinical trials, their therapeutic efficacy remains controversial. Furthermore, MET inhibitor therapy alone can be defeated by acquired resistance. Therefore, it is important to use clinically relevant GBM models to study the molecular mechanisms in association to therapeutic response to improve the combination strategy. In this application, we hypothesize that GBM PDX models bearing different genetic MET alterations manifest distinct therapeutic vulnerability to MET-targeting agents as well as mechanisms of escape from MET TKIs. We are particularly interested in METamp and ZM fusion models as both molecular features indicate sensitivity to MET inhibitors. For this application, we will 1) Characterize the GBM PDX models bearing various MET alterations found in patients for their MET pathway activation and orthotopic tumor growth. 2) Determine the therapeutic response to MET inhibitors using GSCs in vitro and orthotopic xenograft models in vivo. For MET-targeting reagents we will apply MET TKIs and specific-MET targeting chimeric antigen receptor (CAR) T cells developed at our lab. We will also determine whether irradiation or DNA repair inhibition may enhance the therapeutic efficacy of MET TKIs in these models, and whether MET TKI resistant GBM models may continue respond to MET-targeting CAR T cells. We expect to understand how HGF/MET alteration may serve as biomarkers to indicate the therapeutic response to MET inhibitors as well as the combination strategies. In addition, the GSC models established from this project will become valuable tools for studying MET-mediated GBM biology and therapeutic strategies.