Magnetofluorescent nanoplatform for glioblastoma therapy

摘要： 多形性胶质母细胞瘤 (GBM) 是最致命和最具侵袭性的癌症之一。护理标准始于 手术，消除大部分肿瘤块，然后结合化疗和放疗 以根除残留的肿瘤组织。然而，这些肿瘤的浸润性质使其几乎不可能 切除所有肿瘤块，同时保留能说话的脑组织。当前的一个重大挑战 治疗GBM的化疗药物缺乏有效穿过脑血屏障（BBB）的能力， 阻止足够的药物到达肿瘤区域，这通常会导致肿瘤复发。在此，我们 提议开发一种 BBB 交叉、神经胶质瘤细胞靶向磁荧光纳米探针，用于图像引导 将药物输送穿过 BBB 并进入 GBM 肿瘤。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，我们将七次甲基缀合 花青 (HMC)，一种独特的近红外荧光配体，专门针对有机阴离子转运蛋白 蛋白 (OATP) 在各种肿瘤中过度表达，包括 GBM 微血管系统。 HMC 的跨越能力 BBB 和内化到 GBM 癌细胞中是由 OATP 亚型 OATP1A2 和 OATP2B 介导的。之上 HMC 与 FH 的结合，所得的 HMC-FH 纳米探针具有以下独特的组合 特性：(1) 双磁性 (MRI) 和近红外荧光特性，(2) BBB 交叉和特异性 神经胶质瘤靶向能力，在健康大脑中不会积聚，以及（3）通过特定的血脑屏障递送药物 在脑肿瘤中积累，充当神经胶质瘤特异性图像引导递送纳米药物。我们的初步 研究表明，HMC-FH 在裸鼠颅内人 GBM 肿瘤异种移植图中选择性积累， 特别是在大脑内的浸润区域。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，促进药物输送并缩小肿瘤大小 当紫杉醇被封装在 HMC-FH 内时，在小鼠中。因此，我们假设 HMC-FH 可以 促进药物穿过血脑屏障并进入神经胶质瘤细胞，从而导致肿瘤缓解和 增加原位颅内 GBM 小鼠的存活率。此外，生物分布和肿瘤摄取研究 将在自发性高级别神经胶质瘤犬模型中进行。为了检验我们的假设，具体如下 将追求的目标：1）优化HMC-FH的载药量，2）研究BBB穿越机制 和 GBM 癌细胞对 HMC-FH 的内化，3) 研究 HMC-FH 的生物分布、肿瘤摄取、保留 以及使用人类和犬类 GBM 细胞在颅内肿瘤小鼠模型中递送药物的能力， 4) 研究 HMC-FH 在犬 GBM 模型中的生物分布、肿瘤摄取和保留

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