Fn14-targeted Therapeutics for Invasive Brain Cancer

描述（由申请人提供）：胶质母细胞瘤（GB）是最常见的原发性脑癌，即使采用最积极的治疗，5年生存率也<15%。恶性胶质瘤细胞是高度侵袭性的，其有效浸润到邻近的正常脑组织中 阻止了完全的手术切除并限制了放射和化疗药物的剂量。不幸的是，通过生物可降解聚合物植入物或对流增强输送提供的局部化疗的临床成功率有限;部分原因是输送效率低下 远距离侵入的肿瘤细胞的治疗方法。成纤维细胞生长因子诱导因子14（Fn 14）是肿瘤坏死因子（TNF）受体超家族成员之一，是一个有希望的GB治疗的分子靶点。Fn 14高表达与较高的脑肿瘤分级和较差的患者预后相关，并且在体外迁移的胶质瘤细胞和体内侵袭的胶质瘤细胞中均发现。因此，设计用于靶向Fn 14+肿瘤细胞的递送策略是用于治疗远端侵袭肿瘤细胞的有希望的方法。我们的试验数据表明，具有生物惰性表面的基因载体（通过极致密的PEG涂层）在脑组织中提供了更好的渗透和分布，最大限度地减少了非特异性结合，因此在脑中具有更大的细胞特异性靶向潜力。我们的总体假设是，Fn 14靶向基因载体将通过将治疗性基因构建体递送到含有浸润性肿瘤细胞的脑区域并有效抑制侵袭性Fn 14+胶质瘤细胞中的Fn 14信号传导来抑制脑癌侵袭。将在以下具体目标中检验这一假设：（1）合成和表征Fn 14靶向基因载体，并评估它们在Fn 14+神经胶质瘤细胞中的Fn 14靶向、细胞运输和体外基因表达，（2）使用来自Aim 1的优化的基因载体，评估体内脑组织渗透和颗粒分布，和（3）使用来自Aim 2的基因载体的治疗形式，评价离体和体内Fn 14信号传导的抑制和胶质瘤细胞侵袭的抑制。这些研究将为脑穿透递送技术的应用提供重要的下一步;具体地说，直接靶向治疗手术无法触及的关键浸润性肿瘤细胞。我们的下一步将包括：（1）鉴定最佳的治疗基因和细胞途径靶标，和（2）使用对流增强的局部递送和聚焦超声介导的全身递送来增强颗粒递送和分散。

DESCRIPTION (provided by applicant): Glioblastoma (GB) is the most common primary brain cancer with a 5 year survival rate of <15%, even with the most aggressive therapies. Malignant glioma cells are highly invasive and their efficient infiltration into adjacent normal brain tissue prevents complete surgical removal and limits the dosing of radiation and chemotherapeutic drugs. Unfortunately, local chemotherapy, provided by either biodegradable polymer implants or convection-enhanced delivery, has had limited clinical success; in part due to inefficient delivery of therapeutics to distant invading tumor cells. Fibroblast growth factor-inducible 14 (Fn14), a member of the tumor necrosis factor (TNF) receptor superfamily, is a promising molecular target for GB therapy. High Fn14 expression correlates with higher brain tumor grade and poor patient outcome, and is found in both migrating glioma cells in vitro and invading glioma cells in vivo. Hence, a delivery strategy designed to target Fn14+ tumor cells is a promising approach for treating distant invading tumor cells. Our pilot data show that gene vectors with bio-inert surfaces (via extremely dense PEG coatings) provide improved penetration and distribution in brain tissue, minimize non-specific binding, and therefore have a greater potential for cell-specific targeting in the brain. Our overall hypothesis is that Fn14-targeted gene vectors will suppress brain cancer invasion by delivering therapeutic gene constructs into the regions of the brain that contain infiltrating tumor cells and effectively inhibiting Fn14 signaling in invading Fn14+ glioma cells. This hypothesis will be tested in the following specific aims: (1) synthesize and characterize Fn14-targeting gene vectors and assess their Fn14 targeting, cellular trafficking, and in vitro gene expression in Fn14+ glioma cells, (2) using optimized gene vectors from Aim 1, evaluate brain tissue penetration and particle distribution in vivo, and (3) using therapeutic version of gene vectors from Aim 2, evaluate inhibition of Fn14 signaling and suppression of glioma cell invasion ex vivo and in vivo. These studies will provide an important next step in the application of brain- penetrating delivery technologies; specifically, directly targeting treatments to the key infiltrating tumor cells not accessible with surgery. Our next step would include: (1) identifying optimum therapeutic gene and cellular pathway targets, and (2) augmenting particle delivery and dispersion using convection-enhanced local delivery and focused ultrasound mediated systemic delivery.