Mixed-Ligand Targeting of a Nano-Pharmaceutical Against GBM Stem Cells

描述(申请人提供)：在这个第一阶段的SBIR项目中，Parabon NanoLabs，Inc.(PNL)将生产一种新型纳米药物化合物，该化合物优先选择和摧毁脑肿瘤干细胞(BTSCs)，以帮助治疗最致命的脑癌之一--多形性胶质母细胞瘤(GBM)。骨髓间充质干细胞是一种高度致瘤的细胞亚群，可促进肿瘤血管生成和治疗耐药。例如，在一个小鼠模型中，只有100个BTSC可以启动肿瘤生长，而同一肿瘤中的100万个非干细胞则不能。在目前的治疗标准下，无法消除足够的BTSCs可能是GBM 90%的复发率和不良预后的原因。使用Parabon的EsSemblix药物开发平台，先导化合物及其实验变体将在一种名为PNL24的专有“分子面包板”上开发，该面板可以以“即插即用”的方式使用不同的靶向配体和细胞毒性有效载荷来实现功能化。这些化合物将被用来检验这样一个假设，即混合配体、低亲和力靶向可以实现比单一配体替代方案更好的BTSC靶向特异性。为了测试BTSC的特异性，将通过用两种不同的靶向配体之一和两种不同的靶向配体的组合来功能化PNL24来创建三种靶向化合物。每种化合物的染料标记将用于测试通过荧光共聚焦显微镜测量的体外靶向性，针对BTSC和作为对照的正常人类细胞系，特别是神经干细胞、神经元和星形胶质细胞。三种靶向结构中最有选择性的(假设是混合配基结构)将进一步功能化 白喉毒素衍生物，并通过标准细胞毒性试验检测结果对BTSC的有效性和对三种正常细胞系的安全性进行了测试。最后，将通过对流增强递送(CED)在hBTSC颅内移植小鼠模型中测试该化合物的抗BTSC效果。如果发现既安全又有效，这种化合物将成为随后第二阶段项目未来研究的主要化合物，该项目检查系统毒性、PK和生物分布，为最终的IND应用做准备。 与公共卫生相关：这个第一阶段的SBIR项目将生产一种新的纳米药物化合物，该化合物可以主动靶向并摧毁多形性胶质母细胞瘤(GBM)的脑肿瘤干细胞(BTSCs)，GBM是最致命的脑癌形式之一。使用EsSemblix“药物开发平台”建造的药物开发平台实现了首个此类“即插即用”分子工程，将生产一种积极靶向的纳米化合物和具有不同靶向成分的实验性变体。这些化合物将在具有代表性的细胞系和小鼠模型上进行测试，以证明选择性靶向和破坏BTSCs，对正常脑细胞的毒性可以忽略不计。

DESCRIPTION (provided by applicant): In this Phase I SBIR project, Parabon NanoLabs, Inc. (PNL) will produce a novel, nano- pharmaceutical compound that preferentially selects and destroys brain tumor stem cells (BTSCs) to aid the treatment of glioblastoma multiforme (GBM), one of the most lethal brain cancers. BTSCs in GBM have been identified as a highly tumorigenic cell subpopulation that promotes tumor angiogenesis and therapeutic resistance. For example, as few as 100 BTSCs can initiate tumor growth in a mouse model, whereas 1 million non-stem cells from the same tumor cannot. The inability to eliminate sufficient BTSCs with the current standard of care may account for the >90% recurrence rate of GBM and its poor prognosis. Using Parabon's Essemblix" Drug Development Platform, the lead compound and its experimental variants will be developed upon a proprietary "molecular breadboard," called PNL24, that can be functionalized with different targeting ligands and cytotoxic payloads in "plug and play" fashion. These compounds will be used to test the hypothesis that mixed-ligand, low-affinity targeting can achieve superior BTSC targeting specificity versus single-ligand alternatives. To test BTSC specificity, three targeting compounds will be created by functionalizing PNL24 with one of two different targeting ligands and a combination of both. Dye-labeling of each compound will be used to test in vitro targeting specificity, measured via fluorescent confocal microscopy, against BTSC and normal human cell lines serving as controls, specifically, neural stem cells, neurons and astrocytes. The most selective of the three targeting structures (hypothetically the mix-ligand construct) wil be further functionalized with a diphtheria toxin derivative and the result tested for efficacy against BTSC and safety against three normal cell lines via standard cytotoxicity assay. Finally, the anti-BTSC efficacy of this compound will be tested in a hBTSC intracranial xenograft mouse model via convection-enhanced delivery (CED). If found to be both safe and effective, this compound will be the lead compound for future studies in a subsequent Phase II project that examines systematic toxicity, PK and biodistribution in preparation for an eventual IND application. PUBLIC HEALTH RELEVANCE: This Phase I SBIR project will produce a novel nano-pharmaceutical compound that actively targets and destroys brain tumor stem cells (BTSCs) from glioblastoma multiforme (GBM), one of the most lethal forms of brain cancer. Built using the Essemblix" Drug Development Platform, which enables first-of-its-kind "plug and play" molecular engineering, an actively targeted nano-compound and experimental variants with different targeting components, will be produced. The compounds will be tested against representative cell lines and a mouse model to demonstrate selective targeting and destruction of BTSCs, and negligible toxicity to normal brain cells.