Targeted MV-CEA as a Potent Antitumor Agent against GBM

多形性胶质母细胞瘤是最具侵袭性的胶质瘤组织学，是最致命的恶性肿瘤之一，尽管进行了多种治疗，但中位生存期不到一年。由于胶质瘤的转移能力有限，它是基因转移方法的一个有希望的靶点，但尽管有希望的临床前数据，到目前为止，重大的临床益处还没有实现。我们的团队已经开发出一种新的有效的抗肿瘤方法来攻击复发的胶质瘤，利用埃德蒙斯顿的麻疹病毒疫苗株，我们已经设计出产生标志肽CEA(MV-CEA)的疫苗株。CEA可作为病毒基因表达的可追踪标记物，可用于监测体内的病毒治疗。使用MV-CEA，我们在体外对几种胶质瘤株以及在皮下和原位U87异种移植瘤中显示了显着的抗肿瘤活性。我们现在建议进行更多的临床前工作，以优化基于MV-CEA的治疗复发胶质瘤的方法。 为了克服麻疹病毒受体CD46在胶质瘤中表达的变异性和CD46在正常脑中普遍存在的低水平表达所带来的挑战，我们建议利用EGFR途径的改变，可能结合与CD46和SLAM受体的自然结合来构建重定向MV-CEA衍生物。这些将在体外和体内进行比较测试，以决定临床翻译的最佳候选者。这项提议提出了两个新的概念：探索使用埃德蒙斯顿疫苗谱系的减毒麻疹病毒来治疗复发的胶质瘤，以及使用一种新的跟踪系统，该系统可以显著提高我们监测脑瘤病毒治疗试验的能力。我们的假设是，与MV-CEA相比，靶向MV-CEA衍生物将是治疗多形性胶质母细胞瘤的有效抗肿瘤药物，具有更好的疗效/毒性。因此，我们的建议有以下具体目标：1) 建立和鉴定麻疹病毒的衍生减毒疫苗株，通过扩大MV-CEA的趋向性来表达标志肽CEA，以便于进入过度表达EGFR和/或EGFRvlII突变体的胶质瘤细胞，并在或不去除对自然受体CD46和SLAM的趋向性的情况下；2)在四种不同的原位胶质母细胞瘤模型中，比较MV-CEA和EGFR靶向衍生病毒在体内外的疗效，并评估血清CEA作为病毒基因表达、病毒复制和抗肿瘤活性的相关性的价值；3)在敏感的灵长类动物中比较不同工程株的毒性 模型，并评估预先存在的麻疹病毒免疫和激素诱导的影响 免疫抑制治疗的安全性；4)在复发性多形性胶质母细胞瘤患者的I期临床试验中使用具有最佳安全性/有效性特征的病毒株。

Glioblastoma multiforme, the most aggressive glioma histology, is one of the most lethal malignancies with a medial survival of less than one year despite multimodality treatment. Gliomas represent a promising target for gene transfer approaches given their limited ability to metastasize, but despite promising preclinical data, significant clinical benefit has not been materialized to date. Our group has developed a novel potent antitumor approach to attack recurrent gliomas, by utilizing an Edmonston's vaccine strain of measles virus, which we have engineered to produce the marker peptide CEA (MV-CEA). CEA serves as a trackable marker of viral gene expression and can be used to monitor viral therapy in vivo. Using MV-CEA we have demonstrated significant antitumor activity in vitro against several glioma lines and in vivo in subcutaneous and orthotopic U87 xenografts. We now propose to perform additional preclinical work in order to optimize MV-CEA-based therapy for the treatment of recurrent gliomas. In order to overcome challenges associated with the variability of expression of the measles virus receptor CD46 in gliomas and the ubiquitous, although low level, expression of CD46 in normal brain, we propose to exploit alterations of the EGFR pathway, possibly in combination with ablation of the natural binding to the CD46 and SLAM receptors to construct retargeted MV-CEA derivatives. These will be comparatively tested in vitro and in vivo in order to decide on the optimal candidate for clinical translation. This proposal brings forward two novel concepts: exploring the use of an attenuated measles virus of the Edmonston vaccine lineage to treat recurrent gliomas and use of a novel tracking system that could significantly improve our ability to monitor virotherapy trials in brain tumors. Our hypothesis is that targeted MV-CEA derivatives will be potent antitumor agents against glioblastoma multiforme with a superior efficacy/toxicity profile as compared to MV-CEA. Therefore, our proposal has the following specific aims: 1) To generate and characterize derivative attenuated vaccine strains of measles virus, expressing the marker peptide CEA by expanding the MV-CEA tropism in order to facilitate entry in glioma cells overexpressing EGFR and/or the EGFRvlII mutant with or without ablation of the tropism to the natural receptors CD46 and SLAM; 2) To compare the efficacy of MV-CEA with the EGFR targeted derivative viruses in vitro and in vivo in four different orthotopic glioblastoma models that exhibit distinct alterations of the EGFR pathway and to assess the value of serum CEA as a correlate of viral gene expression, viral replication, and antitumor activity in this setting; 3) To compare toxicity of the different engineered strains, in a susceptible primate model, and to assess the impact of preexisting measles virus immunity and steroid induced immunosuppression on the safety of the treatment; 4) To use the viral strain with the optimal safety/efficacy profile in a phase I clinical trial in patients with recurrent glioblastoma multiforme.