Glioma Therapy Using Targeted Oncolytic HSV Vectors

多形性胶质母细胞瘤(Gbm)是一种毁灭性的疾病，尽管尽了最大努力，它几乎总是会导致患者死亡。 使用包括手术、放疗和化疗在内的标准疗法。需要新的治疗干预措施 它可以与标准的医疗实践结合使用。在这些治疗方法中，基因治疗可能 为治疗基底膜提供了希望，然而有效的基因传递的障碍仍然存在。高度衰减 具有复制能力的HSV-1载体提供了一个强大的机会来提供有效的基因传递除了 自然溶解特征(溶瘤)和早期人体试验支持这种方法的安全性。在这份提案中， 通过实验探索了通过改进载体来提高HSV溶瘤载体效力的方法 在肿瘤内的分布，测试额外的突变载体骨架，其性能可能是 通过增强和更特异的肿瘤内复制以及通过使用额外的转基因来改进，这些转基因可以 更有效地破坏肿瘤块，包括局部渗透到正常脑组织的肿瘤细胞。 在整个研究过程中，将结合放射外科对载体的性能和肿瘤杀伤进行评估。 我们将使用G207的性能作为基准来比较任何向量改进。 在四个相关的具体目标中，我们将：(I)利用胶原酶来增强肿瘤内载体的分布 如先进的生命显微镜所示；(Ii)检查HSV基因组中的新基因变化，以寻找更多 与目前用于早期相思患者的载体具有相同或更好安全性的活性突变溶瘤载体 研究(例如G207)；(3)制定重定目标策略，通过识别 肿瘤细胞受体；以及(Iv)将新的抗肿瘤转基因基因引入载体骨架，包括：(A)嘌呤 核苷磷酸化酶(PNP)与6-甲基嘌呤(MEP)联合治疗，(B)氯毒素(CLTX)，一种多肽 抑制肿瘤细胞迁移并可能诱导肿瘤细胞凋亡(C)肿瘤坏死因子(TNFoc)作用于 使肿瘤细胞和肿瘤血管对放射外科方法敏感。 这些研究的结果旨在发现新的载体、更有效的转基因和传递策略。 它们共同提供了一种有效的基因治疗方法，至少可以延长慢性阻塞性肺疾病患者的生存时间 复发的基底膜超过了目前可用的治疗方法。

Glioblastoma multiforme(GBM) is a devastating disease that almost invariably leads to patient death despite best efforts using standard therapies that include surgery, radiation and chemotherapy. New therapeutic interventionsare needed which may be used in combination with standard medical practice. Among these treatments, gene therapy potentially holds promise for treatment of GBM however impediments to effective gene delivery remain. Highly attenuated replication competent HSV-1 vectors providea powerful opportunityto provide effective gene delivery in additionto the natural lytic features (oncolysis) and early phase human trials support the safety of this approach. In this proposal, experiments are outlinedto explore methodsto enhancethe potency of HSV oncolyticvectors through improvedvector distribution within the tumor mass, the testing of additional mutant vector backbones whose performance may be improved by enhanced and more specific intra-tumoralreplicationand through the use of additionaltransgenes that may be more effective in destruction of the tumor mass including locally infiltrating tumor cells into normal brain tissue. Throughout this investigationvector performanceand tumor killing will be evaluated in combinationwith radiosurgery. We will use the performance of G207 as a benchmark with which to compare any vector improvements. In four related specific aims we will: (i) Exploit the use of collagenases to enhance intra-tumoral vector distribution as visualized by advanced vital microscopy; (ii) Examine new genetic alterations in the HSV genome in a search for more active mutant oncolytic vectors that have the same or better safety profiles as vectors currently used in early phasepatient studies (e.g. G207); (iii) Develop retargeting strategies to enable tumor-specific HSV infection through recognition of tumor-cell receptors; and (iv) Introduce novel anti-tumor transgenes into the vector backbone that include (a) purine nucleoside phosphorylase (PNP) in combination with 6-methylpurine(MeP) treatment, (b) chlorotoxin (CltX), a peptide that inhibits tumor cell migration and may induce tumor cell apoptosis (c) tumor necrosis factor (TNFoc)that acts to sensitize tumor cells and the tumor vasculature to radiosurgical methods. The outcome of these studies are intended to discover new vectors, more effective transgenes and delivery strategies which together may provide gene therapy as an effective approach to at least prolong the survival of patients with recurrent GBM over currently available treatment methods.