Dynamic Magnetic Targeting of Activated Brain Macrophages for Glioma Therapy

描述（由申请人提供）：即使采用目前积极的治疗方法，大多数原发性恶性脑肿瘤患者存活时间也不到两年。我们的目标是开发基于激活和靶向肿瘤相关巨噬细胞（tam）到胶质瘤的恶性胶质瘤的新型免疫疗法。虽然免疫疗法正在作为一种潜在的治疗方法进行研究，但血脑屏障和局部肿瘤免疫抑制环境经常阻止细胞毒性抗体或免疫细胞渗透到大脑中。局部递送免疫刺激分子如CpG可以克服这种抑制环境，然而，高剂量的CpG可能导致中毒性脑炎症。因此，迫切需要一种更安全、更有效、更有针对性的策略来增强中枢神经系统对恶性脑肿瘤的免疫反应。我们最近利用tam固有的吞噬特性，利用碳纳米颗粒增强细胞对CpG的吸收，并在治疗的胶质瘤小鼠中证明了60%的治愈率。然而，在这些实验中，激活的tam在第一次纳米颗粒注射后7天内从肿瘤环境中清除，这可能是导致一些未治愈肿瘤的小鼠治疗失败的原因。我们假设，延长脑肿瘤内活化tam存在的方法应该可以增强这种基于纳米颗粒的治疗的抗肿瘤功效。本研究的目的是测试动态可编程的低强度磁场（DPMF）对经过CpG与氧化铁纳米颗粒（IONP-CpG）结合处理的脑小胶质细胞和巨噬细胞的选择性路径和传输能力。与目前产生磁场的方法不同，我们的网格生成的DPMF允许我们对磁场的空间和时间轮廓进行广泛的控制，这可能会增强TAM到胶质瘤的路径。我们将首先定义dpmf介导的ionp处理的小胶质细胞的体外运动条件。在优化DPMF编程和IONP功能化之后，我们将开发我们的技术来调节正常小鼠大脑中小胶质细胞和巨噬细胞的运输和保留。最后，我们将确定DPMF-IONP治疗颅内胶质瘤小鼠的体内疗效。我们期望DPMF能够保留和运输活化的巨噬细胞和小胶质细胞到肿瘤，从而提高这种新疗法的治疗效果。这些研究的结果不仅将显著影响胶质瘤的治疗，还将影响其他中枢神经系统病理的治疗，如中风或创伤，其中小胶质细胞和巨噬细胞已知参与疾病过程和/或中枢神经系统修复。最后，联合使用IONP和DPMF有可能调节和指导中枢神经系统移植后的神经干细胞运输。

DESCRIPTION (provided by applicant): Even when treated with aggressive current therapies, most patients with primary malignant brain tumors survive less than two years. Our goal is to develop novel immunotherapies against malignant glioma that are based on activating and targeting tumor-associated macrophages (TAMs) to the glioma. Although immunotherapy is being studied as a potential treatment, the blood-brain barrier and local tumor immunosuppressive milieu often prevent penetration of cytotoxic antibodies or immune cells into the brain. The local delivery of immunostimulatory molecules such as CpG can overcome this suppressive environment, However, high CpG doses could cause toxic brain inflammation. Therefore, there is a pressing need for a safer, more effective, targeted strategy that will enhance the CNS immune response to malignant brain tumors. We recently took advantage of the inherent phagocytic properties of TAMs to enhance CpG uptake by the cells using carbon nanoparticles and demonstrated a 60% cure rate in treated mice bearing gliomas. In these experiments however, the activated TAMs cleared from the tumor environment within seven days of the first nanoparticle injection, which might have contributed to the treatment failure in some mice that were not cured of their tumors. We hypothesize that methods which prolong the presence of activated TAMs within brain tumors should enhance the anti-tumor efficacy of this nanoparticle-based therapy. The objective of this proposal is to test a dynamically programmable, low-intensity magnetic field (DPMF) for its ability to selectively route and traffic brain microglia and macrophages that have been treated with CpG conjugated to iron oxide nanoparticles (IONP-CpG). Unlike current methods of generating magnetic fields, our grid-generated DPMF allow us a broad range of control over the spatial and temporal profile of the magnetic field, which should potentially enhance TAM routing to gliomas. We will first define conditions for DPMF-mediated motility of IONP-treated microglia cells in vitro. After optimizing the DPMF programming and functionalization of IONP, we will then develop our technique to modulate the trafficking and retention of microglia and macrophage in normal mouse brains. Finally, we will determine the in vivo efficacy of DPMF-IONP therapy in mice with intracranial gliomas. We expect DPMF to retain and traffic the activated macrophage and microglia to the tumors, thereby enhancing the therapeutic efficacy of this novel therapy. The results from these studies will not only significantly impact the treatment of gliomas, but should also impact treatment of other CNS pathologies such as stroke or trauma, in which microglia and macrophages are known to participate in the disease process and/or CNS repair. Finally, combined use of IONP and DPMF has the potential to modulate and direct neural stem cell trafficking following CNS transplantation.