Targeted Photoactivable Nanocells: Image-based Drug Delivery and Dosimetry in GBM

描述（由申请人提供）：该合作申请旨在通过将使用新型纳米结构的药物递送与我们独特的用于图像分析的磁共振引导光学成像定量（MROQ）系统相结合来创建用于治疗多形性胶质母细胞瘤（GBM）的图像引导平台。我们使用靶向光动力疗法（PDT），一种基于光化学的技术来有效治疗GBM。PDT用于GBM治疗的临床研究中，并且PDT试剂也可以发荧光，从而使得能够进行用于图像引导药物递送（IGDD）和光剂量测定（IGLD）的药物的在线成像。这里测试的基本论点是，当治疗和成像剂的靶向递送与定量成像相结合以提供指导PDT治疗计划的药代动力学结合（PKB）模型时，治疗结果是上级的。该策略是制造基于纳米技术的表皮生长因子受体（EGFR）靶向荧光纳米细胞（TNC），其包含PDT试剂（苯并卟啉衍生物，BPD），生物试剂，Avastin和表面缀合的MRI造影剂钆-DTPA（Gd-DTPA）。使用单克隆抗体（Mab）西妥昔单抗C225靶向EGFR，C225用NIR染料LICOR 800 CW荧光标记，用于实现IGDD和随后开发成像剂和治疗剂与肿瘤细胞结合的PK模型。BPD荧光将为IGLD提供基础。在>50%的GBM中过表达的EGFR被用作主要用于递送高有效载荷探针的分子靶标。将TNC与非特异性靶向纳米细胞（NNC）进行比较，其中C225被靶向U87 GBM细胞上不表达的前列腺特异性膜抗原（PSMA）的不相关Mab替代。研究目标将在4个具体目标中实现，包括TNC/NNC制造、2D细胞培养、新开发的3D GBM模型（重现肿瘤结构）和结合使用MROQ定量成像的体内原位肿瘤模型。目的1合成和表征TNC和NNC。目标二：将在体外GBM（U87细胞）的3D细胞模型中测试TNC/NNC选择性和光毒性，以通过确定细胞相关分数来建立IGDD/IGLD的基础。目标3将使用我们的MROQ系统开发体内预测性PKB模型，用于定量药物递送和建立体内TNC的细胞相关部分，以指导目标4，这将在短期（肿瘤负荷）和长期（生存）研究中建立体内定量IGDD/IGLD和PKB模型对GBM原位小鼠模型治疗结果的影响。本研究的意义在于，它提供了新的多功能药物递送结构，新的3D GBM模型，用于定量成像的双模态系统，建立了IGDD/IGLD对治疗结果的影响，并通过与TNC和NNC的直接比较研究解决了大分子载体靶向价值的争议。如果IGDD/IGLD显示出上级结果，则该研究形成患者定制治疗的基础，其中根据个人调整照明的时间和量。

DESCRIPTION (provided by applicant): This collaborative application seeks to create an image-guided platform for the treatment of glioblastoma multiforme (GBM) by combining drug delivery using novel nanoconstructs with our unique magnetic resonance guided optical imaging quantification (MROQ) system for image analysis. We use targeted photodynamic therapy (PDT), a photochemistry-based technology to effectively treat GBM. PDT is in clinical studies for GBM treatment and PDT agents can also fluoresce thus enabling online imaging of drug for both image-guided drug delivery (IGDD) and light dosimetry (IGLD). The basic thesis being tested here is that treatment outcomes are superior when targeted delivery of therapeutic and imaging agents is combined with quantitative imaging to provide pharmacokinetic binding (PKB) models that guide treatment planning for PDT. The strategy is to fabricate nanotechnology-based, epidermal growth factor receptor (EGFR) targeting, fluorescent nanocells (TNC) that incorporate a PDT agent (benzoporphyrin derivatve, BPD), a biologic agent, Avastin and a surface conjugated MRI contrast agent Gadolinium-DTPA (Gd-DTPA). The EGFR is targeted using the monoclonal antibody (Mab) Cetuximab, C225, which is fluorescently labeled with an NIR dye LICOR 800CW for enabling IGDD and subsequent development of PK models of binding of the imaging and therapeutic agents to tumor cells. BPD fluorescence will provide the basis for IGLD. EGFR, overexpressed in >50% of GBMs is used as a molecular target primarily for delivering high payloads of probes. The TNC will be compared with non-specifically targeted nanocells (NNC) where the C225 is replaced by an irrelevant Mab targeted to prostate specific membrane antigen (PSMA) not expressed on U87 GBM cells. The study goals will be achieved in 4 specific aims that include TNC/NNC fabrication, 2D cell culture, newly developed 3D GBM models (recapitulating tumor architecture) and in vivo orthotopic tumor models combined with quantitative imaging using MROQ. Aim 1 will synthesize and characterize TNC and NNC. Aim 2: will test the TNC/NNC selectivity and phototoxicity in 3D cellular models of GBM (U87 cells) in vitro for establishing the basis for IGDD/IGLD by determining cell associated fractions. Aim 3 will develop predictive PKB models in vivo using our MROQ system for quantifying drug delivery and establishing cell-associated fractions of TNC in vivo to guide Aim 4, which will establish the impact of quantitative IGDD/IGLD and PKB models in vivo on treatment outcomes in orthotopic murine models of GBM in short-term (tumor burden) and long-term (survival) studies. The significance of this study is that it provides new multifunctional drug delivery constructs, new 3D GBM models, a dual modality system for quantitative imaging, establishes the impact of IGDD/IGLD on treatment outcome and resolves the controversy of the value of targeting of macromolecular carriers by direct comparative studies with TNC and NNC. If IGDD/IGLD show superior outcomes, the study forms the basis for patient-customized treatments where the timing and amount of illumination is adjusted to individuals.