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。标准治疗开始于 手术，以消除大部分的肿瘤肿块，其次是化疗和放疗的组合 来清除残留的肿瘤组织然而，这些肿瘤的浸润性使得几乎不可能 切除所有肿瘤同时保留功能脑组织当前的一个重大挑战是 治疗GBM的化疗药物缺乏有效的穿过脑血屏障（BBB）， 阻止足够的药物到达肿瘤区域，这通常导致肿瘤复发。在此我们 建议开发一种跨血脑屏障，胶质瘤细胞靶向磁荧光纳米探针，用于图像引导 通过BBB和GBM肿瘤递送药物。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，我们将七甲川 花青（HMC），一种独特的近红外荧光配体，特异性靶向有机阴离子转运蛋白 OATP蛋白（OATP）在各种肿瘤中过表达，包括GBM微血管。HMC穿越 BBB并内化到GBM癌细胞中是由OATP亚型OATP 1A 2和OATP 2B介导的。后 通过将HMC缀合至FH，所得HMC-FH纳米探针具有以下的独特组合： 特性：（1）双重磁性（MRI）和近红外荧光特性，（2）BBB交叉和特异性 具有胶质瘤靶向能力，在健康脑中无蓄积，和（3）具有特异性的药物穿过BBB递送 在脑肿瘤中积累，作为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选择性地在裸鼠的颅内人GBM肿瘤异种移植物中积累， 特别是在大脑的浸润区域。此外，研究表明，HMC-FH在血脑屏障中穿过血脑屏障。 肿瘤区域，并与肿瘤内的GBM细胞相关联，促进药物递送并减小肿瘤大小 当紫杉醇包封在HMC-FH中时，因此，我们假设HMC-FH可以 促进药物穿过BBB并进入神经胶质瘤肿瘤细胞，引起肿瘤缓解， 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。为了验证我们的假设，以下具体 本论文的主要目的是：1）优化HMC-FH的载药工艺; 2）研究HMC-FH的血脑屏障穿越机制 3）研究HMC-FH的生物分布、肿瘤摄取、滞留 以及使用人和犬来源的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