Tumor Targeted Corroles for Detection and Intervention

描述（由申请人提供）：该提案将测试非共价咔咯组装体在单个自组装复合物中同时介导肿瘤靶向检测和干预的假设。 磺化咔咯是水溶性大环化合物，可以金属化并能发出强烈的荧光。我们发现，咔咯自发地与载体蛋白组装，载体蛋白是促进细胞进入所必需的，一旦进入细胞，必须释放到细胞质中以引起细胞毒性，同时保持被排除在细胞核之外，因此暗示胞质因子是咔咯介导的毒性的目标。我们的靶向细胞渗透蛋白 HerPBK10 能够在体外和体内将 Corrole 摄取到 HER2 癌细胞中。 HerPBK10 由源自调蛋白的细胞靶向和内化配体以及源自腺病毒 (Ad) 衣壳五邻体碱基的膜穿透结构域组成。 Corrole 荧光能够实现体外和体内肿瘤细胞靶向的可视化，与直接肿瘤内递送化疗药物阿霉素相比，体内肿瘤靶向导致肿瘤生长干预的剂量减少近 300 倍。 HER2 癌症已成为我们实验室测试新靶向疗法的模型系统。由于 HER2（或 ErbB2）亚基的过度表达增强了受体亲和力，因此 HER2 细胞类型是测试配体导向疗法的理想模型。更重要的是，由于乳腺癌中 HER2 过度表达与侵袭性化疗耐药肿瘤相关，并预示着不良预后，因此标准治疗方案的替代疗法可能对这部分乳腺癌更有效，这些乳腺癌虽然不占大多数病例，但却是最致命的乳腺癌之一。尽管如此，我们已经确定了我们的调蛋白导向疗法的其他潜在靶点，包括表达高水平不同 HER 亚基的卵巢癌细胞、神经胶质瘤细胞和前列腺癌细胞。因此，这里提出的 HER 靶向系统可能对除 HER2 乳腺癌之外的几种不同肿瘤类型有更广泛的应用。 该提案结合了多个合作者的专业知识，进一步将corrole组件开发成可成像的肿瘤靶向剂。我们将评估靶细胞和免疫与载体蛋白的相互作用，以指导引入可能增强治疗功效和安全性的修饰的努力。我们将探索的一个令人兴奋的方向是应用定向进化来选择载体蛋白结构域，以改善靶细胞相互作用和免疫逃避。我们将在体外和体内测试这些修饰用于咔咯递送，并利用咔咯独特的光电发射特性来检测体内肿瘤靶向。 公共健康相关性：该研究项目与公共健康相关，因为它将导致一种新型自组装疗法的开发，该疗法可以专门针对 HER2 肿瘤（包括 HER2 乳腺癌），且与非靶向标准化疗相比，剂量要低得多，因此更安全。此外，这种治疗方法可以在治疗过程中进行成像，从而可以检测到肿瘤靶向。因此，该技术将检测和干预结合在一个自组装的靶向复合物中。

DESCRIPTION (provided by applicant): This proposal will test the hypothesis that noncovalent corrole assemblies simultaneously mediate both tumor targeted detection and intervention in a single self-assembled complex. Sulfonated corroles are water soluble, macrocyclic compounds that may be metallated and can emit an intense fluorescence. We have found that corroles spontaneously assemble with carrier proteins, which are required to facilitate cel entry, and once entering cels, must be released into the cytoplasm to elicit cytotoxicity while remaining excluded from the nucleus, thus implicating cytosolic factors as the targets of corrole-mediated toxicity. Our targeted cell penetration protein, HerPBK10, enables corrole uptake into HER2+ cancer cells in vitro and in vivo. HerPBK10 is comprised of a cell-targeting and internalizing ligand derived from the heregulin protein, and membrane penetration domain derived from the adenovirus (Ad) capsid penton base. Corrole fluorescence enables visualization of tumor cell targeting in vitro and in vivo, and tumor targeting in vivo results in tumor growth intervention at nearly 300x less dosage in comparison to direct intratumoral delivery of the chemotherapy agent, doxorubicin. HER2+ cancer has served as a model system for testing new targeted therapeutics in our lab. As the overexpression of the HER2 (or ErbB2) subunit enhances receptor affinity, the HER2+ cell type is an ideal model for testing ligand-directed therapies. More importantly, as HER2 overexpression in breast cancer correlates with aggressive chemoresistant tumors and predicts a poor prognosis, alternative treatments to standard regimens may prove more effective on this subset of breast cancers that, while not comprising a majority of cases, are among the most deadly of breast cancers. Nevertheless, we have identified additional potential targets of our heregulin-directed therapeutics, including ovarian, glioma, and prostate cancer cells that express high levels of different HER subunits. Thus, the HER-targeted system presented here may have a broader application to several different tumor types in addition to HER2+ breast cancer. This proposal combines the expertise of multiple collaborators to further develop corrole assemblies into image-able tumor targeting agents. We will assess target cell and immune interactions with the carrier protein to direct efforts in introducing modifications that may enhance therapeutic efficacy and safety. One exciting direction we will explore is to apply directed evolution to select carrier protein domains to improve target cell interactions and immune evasion. We will test these modifications for corrole delivery in vitro and in vivo, and utilize the unique photoemission properties of corroles to detect in vivo tumor targeting. PUBLIC HEALTH RELEVANCE: This research project is relevant to public health because it will result in the development of a novel self-assembled therapeutic that can specifically target HER2+ tumors (which includes HER2+ breast cancer) at substantially lower, and thus safer doses compared to untargeted standard chemotherapy. Moreover, this therapeutic can be imaged during treatment so that tumor targeting can be detectable. Thus, this technology combines both detection and intervention in a single self-assembled targeted complex.