Irreversible Inhibtion of Cerebellar Gli Transcription Factors by Cobalt (III) Complexes

刺猬（Hh）信号通路的异常表达与这种形成密切相关， 髓母细胞瘤（MB）肿瘤亚组的增殖。MB主要是儿科脑癌， 70%的病例发生在10岁以下的儿童中。由Hh信号驱动的SHH亚组是 在遗传病因和组织学上具有广泛的异质性，使得有效的治疗具有挑战性，并导致 令人沮丧的结果。目前的治疗策略包括肿瘤切除，颅脊髓放射治疗， 化疗，但遭受短期和长期的不良反应。为了抑制Hh通路， 研究已经针对蛋白Smoothened（Smo），但受到下游突变的阻碍， 导致癌症复发，且具有更高致死率。因此，该项目旨在靶向Gli蛋白， 属于锌指转录因子（TF）家族，并且是Hh途径的最终效应物。的 米德实验室开发了一系列与TF共有结构偶联的钴（III）-席夫碱配合物（Co（III）-sb 特异性和不可逆地抑制感兴趣的锌指TF的序列。该提案旨在重塑 将Co（III）-sb与Gli共有序列缀合以产生Co（III）-Gli的方法， 和Gli蛋白的不可逆抑制剂。该抑制剂将与Gd（III）标记的金纳米颗粒缀合 在一些实施方案中，使用金纳米粒子（AuNP）递送平台来评估和成像体外和体内Gli抑制的有效性。 该提议的第一个目标是重新设计用于将DNA偶联至Co（III）-Sb的合成路线。 Co（III）-sb的赤道配体骨架将用炔部分官能化以允许可点击 缀合至叠氮化物官能化的Gli共有序列，产生Co（III）-Gli。预计这将 显著提高了现有缀合方法的产率和可扩展性。第二和第三 目的集中于评价Co（III）-Gli对Gli抑制肿瘤生长的效力。Co（III）-Gli 将与DNA加帽的AuNP杂交，以产生优化的去杂交序列，从而释放 生理温度下的药剂。Co（III）-Gli AuNP将用Gd（III）磁共振成像标记 (MRI)造影剂以提供用于体外和体内对缀合物进行命运作图的平台。的能力 将使用人胚肾细胞在体外和体内评估Co（III）-Gli抑制外源性Gli的能力。 使用天然发展SHH亚型MB肿瘤的鼠模型。Co（III）-Gli预期可抑制Gli 具有高度特异性，从而抑制肿瘤生长。 该项目在短期和长期影响方面完全符合NIH的使命。它 将在短期内进一步发展有关抑制小脑Gli转录因子的知识， 生成一个平台，用于增强目前对SHH亚型髓母细胞瘤的长期治疗选择。的 该项目的成功将为提高成活率和质量提供一个独特的机会 最恶性的儿童脑癌的生命。

Aberrant expression of the Hedgehog (Hh) signaling pathway is heavily implicated in the formation and proliferation of a subgroup of medulloblastoma (MB) tumors. MB is predominantly a pediatric brain cancer, with 70% of occurrences appearing in children under the age of 10. The SHH subgroup, driven by Hh signaling, is widely heterogeneous in genetic cause and histology, making effective treatment challenging and resulting in dismal outcomes. Current treatment strategies involve tumor resection, craniospinal irradiation, and chemotherapy, but suffer from short-term and long-term adverse effects. In efforts to inhibit the Hh pathway, research has targeted the protein Smoothened (Smo), but has been stunted by downstream mutations that lead to cancer recurrence with a much higher lethality. Thus, this project seeks to target Gli proteins, which belong to a family of zinc finger transcription factors (TFs) and are the final effectors of the Hh pathway. The Meade lab has developed a series of Cobalt (III)-Schiff base complexes (Co(III)-sb) coupled to TF consensus sequences that specifically and irreversibly inhibit zinc finger TFs of interest. This proposal seeks to reinvent the method for conjugating Co(III)-sb to the Gli consensus sequence to generate Co(III)-Gli, a highly specific and irreversible inhibitor of Gli proteins. This inhibitor will be conjugated to a Gd(III)-labeled gold nanoparticle (AuNP) delivery platform to evaluate and image the effectiveness of Gli inhibition both in vitro and in vivo. The first objective of this proposal is to redesign the synthetic route for coupling DNA to Co(III)-sb. The equatorial ligand scaffold of Co(III)-sb will be functionalized with an alkyne moiety to allow for clickable conjugation to an azide functionalized Gli consensus sequence, generating Co(III)-Gli. This is anticipated to significantly improve yields and scalability from the current conjugation method. The second and third objectives focus on evaluating the potency of Co(III)-Gli against Gli for the inhibition of tumor growth. Co(III)-Gli will be hybridized to a DNA capped AuNP to generate an optimized dehybridization sequence to release the agent at physiological temperature. Co(III)-Gli AuNPs will be labeled with Gd(III) magnetic resonance imaging (MRI) contrast agents to provide a platform for fate mapping the conjugates both in vitro and in vivo. The ability of Co(III)-Gli to inhibit exogenous Gli will be evaluated in vitro using human embryonic kidney cells and in vivo using a murine model that natively develops SHH subtype MB tumors. Co(III)-Gli is anticipated to inhibit Gli with high specificity, resulting in suppressed tumor growth. This project fully aligns with the mission of the NIH both in its short-term and long-term implications. It will further develop knowledge about inhibition of cerebellar Gli transcription factors in the short-term, and generate a platform for enhancing current treatment options for SHH subtype medulloblastoma long-term. The success of this project would present a unique opportunity for improving the survival rate and resulting quality of life for the most malignant childhood brain cancer.