Development of anti-polo-box therapeutic agents

抗polo-box治疗剂的开发

• 批准号: 8157396
• 负责人: Kyung Lee
• 金额: $ 34.28万
• 依托单位: DIVISION OF BASIC SCIENCES - NCI
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/8157396
• 关键词: Boxing; Development; Therapeutic Agents

Development of a specific anti-Plk1 therapeutic agent is one of the most compelling missions in the field of anti-cancer therapy. Efforts to generate Plk1-specific inhibitors by targeting the catalytic activity of Plk1 have proven to be difficult due to similarities with the catalytic domains of other structurally related kinases. Here, we propose to develop a new class of mono-specific Plk1 inhibitors by employing a novel approach of targeting the non-catalytic, but functionally essential, PBD of Plk1. To this end, we will take advantage of the crystal structures of the Plk1 PBD in complex with a highly specific ligand, PLHSpT. The first aim of the project will be to develop PLHSpT-derived templates for drug design and subsequent modifications. Since the function of the N-terminal Pro-4 (number indicates the relative position of the residue from pT) residue of PLHSpT can be substituted by hydrophobic moieties and the side chain of the Leu-3 residue is not involved in interactions with surrounding PBD residues, we will first generate N-substituted glycine (Nsg)-containing LHSpT or HSpT peptoidpeptide hybrids and their respective cyclic forms. Then, the Nsg residue of the hybrids will be modified by covalently conjugating them with site-specifically synthesized hydrophobic moieties to fill in the intramolecular cavity present between the compound and the PBD. Since the His-2, Ser-1 and p-Thr residues are critical for the specificity and high affinity binding, these residues will not be modified. Peptide-derived inhibitors are commonly associated with problems in stability, lipophilicity, and transcellular permeability. Hence, the second aim of the project will be to enhance the stability, membrane permeability, and tumor-specific targeting of the above compounds by generating innovative prodrugs. Compounds with a high PBD-binding affinity and specificity will be converted to phosphatase-insensitive, non-hydrolyzable, p-Thr mimetic (Pmab) forms and then further modified to generate Ala- or Val-ester-conjugated phosphonic diamide prodrugs. The latter modification is not only to eliminate the electronegativity of the dianionic phosphonic acid moiety for better transcellular permeation but also to target the compound to the highly active PepT1 transporter for efficient cellular uptake. For the compounds that exhibit anti-Plk1 PBD activities at the cultured cell level, we will investigate whether the addition of a tumor-targeting RGD motif facilitates tumor-specific delivery of the compounds. As the third aim of the project, we will determine the potency and selectivity of the resulting compounds in the inhibition of Plk1-dependent cell proliferation activity in mouse tumor models. Because of the harsh chemical and enzymatic conditions of the gastrointestinal tract, intravenous injection into mouse-tail vein will be the choice of compound administration. Since peptide-derived inhibitors often exhibit physicochemical drawbacks, we will also take complementary approaches to isolate PBD-inhibitory compounds or moieties by screening the NCI natural products extract repository or by carrying out in silico screening. Structural analyses and computer modeling of the isolated small molecule compounds together with the above PLHSpT-derived inhibitors will allow us to perform site-specific replacements and modifications of the latter inhibitors to achieve enhanced in vivo stability and bioavailability. To this end, we will bring the expertise of our collaborators ranging from in vitro high throughput screening and cell-based assays (Dr. James McMahon), in silico screening and computer modeling (Dr. Marc Nicklaus), and X-ray crystallography (Drs. Alex Wlodawer and Michael Yaffe). The ultimate goal of this multifaceted approach is to generate a new class of mono-specific anti-Plk1 therapeutic agents that have potential to treat various cancers in humans.

特定抗PLK1治疗剂的开发是抗癌治疗领域中最具吸引力的任务之一。由于与其他相关激酶的催化域的相似性，因此很难通过靶向PLK1的催化活性来产生PLK1特异性抑制剂。在这里，我们建议通过采用一种新的靶向非催化性但在功能上必不可少的PLK1的PBD来开发新的单一特异性PLK1抑制剂。为此，我们将利用与高度特异性配体PLHSPT中PLK1 PBD的晶体结构。该项目的第一个目的是开发用于药物设计和随后修改的PLHSPT衍生模板。 Since the function of the N-terminal Pro-4 (number indicates the relative position of the residue from pT) residue of PLHSpT can be substituted by hydrophobic moieties and the side chain of the Leu-3 residue is not involved in interactions with surrounding PBD residues, we will first generate N-substituted glycine (Nsg)-containing LHSpT or HSpT peptoidpeptide hybrids and their各自的循环形式。然后，将通过与位点特异性合成的疏水部分共价结合杂种的NSG残基来修饰它们，以填充化合物和PBD之间存在的分子内腔。由于HIS-2，SER-1和P-THR残基对于特异性和高亲和力结合至关重要，因此不会修改这些残基。肽衍生的抑制剂通常与稳定性，亲脂性和跨细胞通透性的问题有关。因此，该项目的第二个目的是通过产生创新的前药来增强上述化合物的稳定性，膜渗透性和肿瘤特异性靶向。具有较高PBD结合亲和力和特异性的化合物将转换为对磷酸酶的敏感，非溶解度，p-thR Mimetic（PMAB）形式，然后进一步修饰以产生Ala-或val-酯偶联的磷酸化磷酸化糖尿病。后一种修饰不仅是为了消除狄安尼离子磷酸部分的电负性，以获得更好的跨细胞渗透，而且还靶向化合物到高度活性的PEPT1转运蛋白以有效的细胞摄取。对于在培养的细胞水平上表现出抗PLK1 PBD活性的化合物，我们将研究添加靶向肿瘤的RGD基序是否有助于化合物的肿瘤特异性递送。作为该项目的第三个目标，我们将确定在小鼠肿瘤模型中抑制PLK1依赖性细胞增殖活性中所得化合物的效力和选择性。由于胃肠道的化学和酶促条件恶劣，因此将静脉注射到小鼠尾静脉中，是化合物给药的选择。由于肽衍生的抑制剂经常表现出物理化学缺点，因此我们还将采用互补方法来通过筛选NCI天然产物提取库或进行硅胶筛选来分离PBD抑制性化合物或部分。与上述PLHSPT衍生的抑制剂一起对分离的小分子化合物的结构分析和计算机建模将使我们能够进行特定位点特异性替代品和后者抑制剂的修饰，从而实现增强的体内稳定性和生物可利用性。为此，我们将把合作者的专业知识从体外高吞吐量筛选和基于细胞的测定（James McMahon博士），硅筛选和计算机建模（Marc Nicklaus博士）和X射线晶体学（Drs。AlexWlodawer和Michael Yaffe）中提供。这种多方面方法的最终目标是生成一类新的单一特异性抗Plk1治疗剂，这些抗Plk1治疗剂具有治疗人类各种癌症的潜力。