Direct identification of ready-to-use peptoid-DOTA theranostic systems

描述(由申请人提供)：直接鉴定即可使用的Peptoid-DOTA诊断系统将开发一种快速且具有成本效益的“诊断试剂”技术，用于抗癌治疗和实时治疗后续治疗。目前开发诊断试剂的两种基本方法包括将造影剂与治疗分子进行化学连接，或将这两种成分包装在大分子系统中，如脂质体。虽然化学修饰通常会削弱药物的原始活性，但大分子通常会表现出稳定性、生物分布和清除问题。努力 将治疗药物和造影剂等明显不同的成分结合在一起，作为最后一步，会造成大多数这些问题。我们的新方法包括合成单个分子，该分子结合了治疗和成像成分，从而从整个开发过程的第一步验证了感兴趣的靶点。我们的想法是开发已经与DOTA造影剂偶联的类肽组合文库，并使用我们独特的珠上双色细胞分析直接识别细胞表面受体的(类肽)3-DOTA分子。当某个(类肽)3-DOTA在筛选过程中被目标受体作为最佳结合配体时，该类肽上的DOTA支架已经看到了靶标，并有迹象表明它不会干扰所选择的类肽部分的结合。据报道，类肽是一种重要的蛋白质结合配体，具有自身的拮抗活性。此外，DOTA支架还可以与90Y络合，用于放射性核素治疗。诊断上，这种DOTA支架可以与68Ga或64Cu络合，用于PET成像，并与Gd3+络合，用于磁共振成像。为了建立这个文库，DOTA支架将通过其中一个臂加载到树脂珠上，其余3个臂将使用类肽残基进行多样化。该文库将与表皮生长因子受体(EGFR)和肾上腺素受体A2(EphA2)作为模型靶系统进行筛选，这些系统在许多癌症类型中过度表达，理想情况下在细胞表面形成多聚体簇。已鉴定的‘HIT’化合物[(Peptoid)3-DOTA]将被验证为结合，拮抗剂的潜力将通过标准的蛋白质印迹分析对EGFR和EphA2受体磷酸化的影响来评估。最后，Gd3+络合物将用于细胞水平的磁共振成像分析，以探索其成像潜力，体内PET应用是近期的目标。这项提议的主要概念进展是开发和验证作为“第一步的单一包装”的治疗不可知剂。由于类肽化学的多功能性，整个开发过程可以快速且经济有效地完成。此外，考虑到类肽的高度生物顺应性，如血清稳定性、非免疫原性和适度的清除性，人们可以预期这些类肽-DOTA制剂的药效增强等性质，从而确保在未来将台式水平的铅分子快速和经济地转化为临床适用的抗癌诊断试剂。

DESCRIPTION (provided by applicant): Direct identification of ready-to-use peptoid-DOTA theragnostic systems A rapid and cost effective technology for 'theragnostic agents' will be developed for use in anti-cancer therapy and real time treatment follow up. The two current basic approaches to develop theragnostic agents include the chemical linkage of a contrast agent to a therapeutic molecule, or to pack these two components inside a macromolecular system such as liposomes. While chemical modifications typically weaken the original activity of the drug, macromolecules generally exhibit stability, biodistribution and clearance issues. Efforts to combine significantly different components, such as therapeutics and contrast agents, as the last step create most of these problems. Our novel approach involves the synthesis of a single molecule that combines therapeutic and imaging components and thus validates the target of interest from the first step of the overall development process. The idea is to develop peptoid combinatorial libraries that are already coupled with a DOTA-contrast agent and directly identify '(peptoid)3-DOTA' molecules for cell surface receptors using our unique on-bead two-color cell assay. When a certain (peptoid)3-DOTA is picked up by the target receptor as the optimal binding ligand during the screen, the DOTA scaffold on that peptoid has already seen the target and signs that it would not interfere with the binding of the selected peptoid portion. Peptoids have been reported as great protein binding ligands with their own antagonist activities. In addition, the DOTA scaffold can be complexed with 90Y and used in radionuclide therapy. Diagnostically, this DOTA scaffold can be complexed with 68Ga or 64Cu for PET imaging and with Gd3+ for MR imaging applications. To build the library, DOTA scaffolds will be loaded on to the resin beads through one of its arms and the remaining 3 arms will be diversified using peptoid residues. This library will be screened against Epidermal Growth Factor Receptor (EGFR) and ephrin receptor A2 (EphA2) as model target systems that overexpress in many cancer types which ideally form multimeric clusters on the cell surface. Identified 'hit' compounds [(peptoid)3-DOTA] will be validated for binding and the antagonist potential will be evaluated by effects on EGFR and EphA2 receptor phosphorylation using standard western blot analysis. Finally, the Gd3+ complexes will be used in cellular level MR imaging assays to probe their imaging potential, leaving in vivo PET applications as the immediate future goals. The primary conceptual advancement of this proposal is the development and validation of a theragnostic agent as a 'single package from the first step'. Due to the versatility of peptoid chemistry, the overall development process can be completed rapidly and cost effectively. In addition, when considering the highly biological amenable features of peptoids, such as serum stability, non-immunogenicity and moderate clearance, one could expect enhanced pharamacokinetc properties of these peptoid-DOTA agents and therefore assure a rapid and economical conversion of bench level lead molecules into clinically applicable anti-cancer theragnostic agents in the future.