Magnetofluorescent nanoplatform for glioblastoma therapy

摘要： 多形性胶质母细胞瘤(GBM)是最致命和侵袭性最强的癌症之一。护理标准始于 手术，以消除大部分肿块，然后结合化疗和放射治疗 以根除残留的肿瘤组织。然而，这些肿瘤的浸润性使其几乎不可能 切除所有肿块，同时保留能言善辩的脑组织。当前面临的主要挑战 治疗GBM的化疗药物缺乏有效穿越脑血屏障(BBB)的能力， 防止足够的药物到达肿瘤区域，这往往会导致肿瘤的复发。在此，我们 建议研制一种跨血脑屏障、靶向脑胶质瘤细胞的磁荧光纳米探针，用于图像引导 通过血脑屏障向基底膜肿瘤输送药物。我们平台技术的核心是Feraheme(FH)， FDA批准的超顺磁性氧化铁纳米颗粒(SPION)。对于FH，我们结合了七甲基甲胺 花菁(HMC)，一种独特的近红外荧光配体，专门针对有机阴离子转运体 蛋白(OATP)在多种肿瘤中高表达，包括基底膜微血管。HMC跨越大西洋的能力 OATP亚型OATP1A2和OATP2B介导BBB和内化到GBM癌细胞。vt.在.的基础上 HMC与FH的偶联，得到的HMC-FH纳米探针具有以下独特的组合 性质：(1)双磁(MRI)和近红外荧光性质；(2)血脑屏障交叉和特异性 胶质瘤靶向能力，在健康的大脑中没有积聚，以及(3)通过特定的血脑屏障给药 在脑肿瘤中蓄积，作为神经胶质瘤特异性的图像引导递送纳米片。我们的预赛 研究表明，HMC-FH选择性地聚集在裸鼠颅内人GBM肿瘤移植瘤中， 尤其是在大脑的浸润区。此外，研究表明，HMC-FH在 肿瘤区域，并与肿瘤内的GBM细胞相关联，促进药物输送，缩小肿瘤大小 在小鼠中，当紫杉醇被包裹在HMC-FH中时。因此，我们假设HMC-FH可以 促进药物通过血脑屏障进入胶质瘤细胞，导致肿瘤缓解和 提高原位颅内基底细胞瘤小鼠的存活率。此外，生物分布和肿瘤摄取研究 将在自发性高级别脑胶质瘤犬模型中进行实验。为了检验我们的假设，以下是具体的 1)优化HMC-FH的载药量；2)研究血脑屏障的穿透机制 3)研究HMC-FH的生物分布、肿瘤摄取、滞留 以及使用人和狗的GBM细胞在颅内肿瘤小鼠模型中给药的能力， 4)研究HMC-FH在犬GBM模型中的生物分布、肿瘤摄取和滞留

ABSTRACT: Glioblastoma multiforme (GBM) is among the most lethal and aggressive cancers. Standard of care starts with surgery, to eliminate most of the tumor mass, followed by a combination of chemotherapy and radiation therapy to eradicate residual tumor tissue. However, the infiltrating nature of these tumors renders it almost impossible to resect all of the tumor mass, while preserving eloquent brain tissue. A major challenge with current chemotherapeutic drugs to treat GBM are their lack of efficient crossing across the brain blood barrier (BBB), preventing enough drug to reach the tumor area, which often results in recurrence of the tumor. Herein, we propose to develop a BBB-crossing, glioma cell targeting magnetofluorescent nanoprobe for the image-guided delivery of drugs across the BBB and into GBM tumors. At the core of our platform technology is Feraheme (FH), an FDA-approved superparamagnetic iron oxide nanoparticle (SPION). To FH, we conjugate hepthamethine cyanine (HMC), a unique near infrared fluorescent ligand that specifically targets the organic anion transporter protein (OATP) overexpressed in various tumors, including GBM microvasculature. HMC’s ability to cross the BBB and internalize into GBM cancer cells is mediated by the OATP subtypes OATP1A2 and OATP2B. Upon conjugation of HMC to FH, the resulting HMC-FH nanoprobe has a unique combination of the following properties: (1) dual magnetic (MRI) and near infrared fluorescent properties, (2) BBB-crossing and specific glioma targeting ability, with no accumulation in heathy brain, and (3) delivery of drugs across BBB with specific accumulation in brain tumors, acting as a glioma-specific image-guided delivery nanodrug. Our preliminary studies show that HMC-FH selectively accumulates in intracranial human GBM tumor xenographs in nude mice, particularly in in infiltrating areas within the brain. In addition, studies show that HMC-FH crosses the BBB in the tumor area and associates with the GBM cells within the tumor, facilitating drug delivery and reducing tumor size in mice when paclitaxel is encapsulated within the HMC-FH. Therefore, we hypothesize that HMC-FH can facilitate the delivery of drugs across the BBB and into glioma tumor cells, causing tumor remission and increasing survival in mice with orthotopic intracranial GBM. In addition, biodistribution and tumor uptake studies will be done in a spontaneous high-grade glioma canine model. To test our hypothesis, the following specific aims will be pursued: 1) Optimization of drug loading into HMC-FH, 2) Study the mechanism of BBB crossing and GBM cancer cell internalization of HMC-FH, 3) Investigate HMC-FH biodistribution, tumor uptake, retention and ability to deliver drugs in an intracranial tumor mouse models using human and canine derived GBM cells, 4) Investigate the biodistribution, tumor uptake and retention of HMC-FH in a canine GBM model