Characterization of MET alteration using glioblastoma patient-derived xenograft models

项目摘要 胶质母细胞瘤(GBM)是最恶性的脑癌类型，对烷化剂和辐射耐药。 胶质瘤干细胞(GSCs)，一种高侵袭性的GBM细胞亚群，耐受辐射和 化疗是有效治疗的主要靶点。识别和靶向分子决定因素 GSCs对恶性基底膜的治疗具有重要意义。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，以实现有效的MET靶向治疗。反常的MET 受体酪氨酸激酶(RTK)的激活，如MET扩增(METAMP)、突变和PTPRZ1-MET (ZM)融合，常见于原发或继发性基底膜。MET信号升高引发肿瘤侵袭 他还负责GSC的维护和侵袭性的再繁殖。临床上，贝伐单抗 诱导MET活化的治疗是肿瘤复发的主要机制，具有更具侵袭性的表型， 进一步论证了靶向MET通路在GBM中的意义。尽管MET酪氨酸激酶 抑制剂(TKI)正在进入临床试验，其治疗效果仍存在争议。此外，Met 仅用抑制剂治疗可能会被获得性耐药所击败。因此，重要的是使用临床相关的 用GBM模型研究与治疗反应相关的分子机制以改善 组合策略。在这个应用中，我们假设具有不同遗传条件的GBM PDX模型 改变表现出对MET靶向药物的明显的治疗易感性以及逃逸机制 来自大都会TKIS。我们对METAMP和ZM融合模型特别感兴趣，因为它们都是分子特征 表明对MET抑制剂的敏感性。对于此应用，我们将1)描述GBM PDX模型的特征，包括 在患者体内发现了多种MET变化，导致MET通路激活和原位肿瘤生长。2) 用体外GSCs和小鼠原位异种移植模型确定MET抑制剂的治疗反应 活着。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细胞是我们实验室培养的。我们还将确定辐射或DNA修复抑制是否可能 在这些模型中提高MET TKI的治疗效果，以及MET TKI耐药的GBM模型 可能会继续对MET靶向CAR T细胞的反应。我们希望了解HGF/MET的改变可能 作为生物标志物，指示对MET抑制剂的治疗反应以及联合策略。 此外，从这个项目建立的GSC模型将成为研究MET中介的有价值的工具 基底膜生物学和治疗策略。

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.