D-peptide activators of p53 as anticancer therapeutics

描述(申请人提供)：拟议的多学科研究结合了当代合成多肽/蛋白质化学、结构生物学、癌症生物学以及各种生化和生物物理技术，展示了一种强大的、创新的和综合的方法，以填补基于多肽的抗癌药物发现的重要空白。如果得到资助，该项目将为现有的抗癌库增加新的武器，并广泛影响用于许多其他人类疾病的靶向分子治疗的多肽疗法的发展。背景：P53作为一种转录因子被激活，在细胞应激状态下诱导强大的生长抑制和凋亡反应，但在正常细胞中受其负调控因子MDM2和MDMX的严格控制。P53途径的损伤是几乎所有人类肿瘤的标志，在这些肿瘤中，要么TP53基因发生突变，要么p53蛋白被MDM2和MDMX功能失活。MDM2和MDMX在许多肿瘤中的过度表达或扩增与P53的正常(野生型)状态相关，有助于对P53的强烈抑制和降解。最近的研究证实，抑制p53-MDM2/MDMX相互作用是治疗癌症的一种新的治疗模式。我们实验室已经开发出一系列高亲和力的MDM2和MDMX D肽拮抗剂(DPMI-？，？，d)，当通过脂质体载体输送时，能够通过激活P53途径在体外和体内杀死肿瘤细胞。目标：使用 以DPMI-d为母体分子(MDM2的Kd=220 PM，MDMX的Kd=200 nM)，我们寻求开发高亲和力、耐蛋白酶和细胞穿透的MDM2和MDMX的D-肽拮抗剂，用于潜在的抗癌治疗。具体目的：(1)设计能够穿透细胞膜的侧链交联型DPMI-d，稳定细胞内P53。我们将使用碳氢化合物装订技术来设计一系列DPMI-d的侧链交联类似物，并从-螺旋度、MDM2/MDMX结合和膜通透性方面评价它们的功能和结构性质。(2)验证MDM2和MDMX的高亲和力、抗蛋白酶和穿透细胞的D-肽拮抗剂通过细胞周期停滞和/或诱导细胞凋亡重新激活P53通路和杀伤肿瘤细胞的假说。我们将使用带有或不带有野生型P53的多种肿瘤细胞株来评估侧链交联型DPMI-d的肿瘤杀伤活性。我们的长期目标是开发基于D-肽的P53激活剂，作为一类新型的抗癌治疗药物用于临床。

DESCRIPTION (provided by applicant): The proposed multi-disciplinary research combines contemporary synthetic peptide/protein chemistry, structural biology, cancer biology, and various biochemical and biophysical techniques, showcasing a powerful, innovative, and integrated approach to filling an important gap in peptide-based anticancer drug discovery. If funded, this project will lead to the addition of new weapons to the existing anticancer arsenal, and broadly impact the development of peptide therapeutics for targeted molecular therapy of many other human diseases as well. Background: p53 is activated as a transcription factor to induce powerful growth inhibitory and apoptotic responses to cellular stress, but is otherwise tightly controlled in normal cells by its negative regulators MDM2 and MDMX. Impairment of the p53 pathway is a hallmark of almost all human tumors where either the TP53 gene is mutated or the p53 protein is functionally inactivated by MDM2 and MDMX. Over-expression or amplification of MDM2 and MDMX in many tumors correlates with a normal (wild type) status of p53, contributing to robust p53 inhibition and degradation. Recent studies have validated inhibition of the p53-MDM2/MDMX interaction as a new therapeutic paradigm for cancer treatment. Our laboratory has developed a series of high-affinity D- peptide antagonists of MDM2 and MDMX (DPMI-¿, ¿, ?, d) that, when delivered via a liposomal carrier vehicle, are capable of killing tumor cells in vitro and in vivo by activating the p53 pathway. Objective: Using DPMI-d as a parent molecule (KD = 220 pM for MDM2 and 200 nM for MDMX), we seek to develop high-affinity, protease-resistant, and cell-penetrating D-peptide antagonists of MDM2 and MDMX for potential anticancer therapy. Specific Aims: (1) Design side-chain cross- linked forms of DPMI-d capable of traversing the cell membrane to stabilize intracellular p53. We will use the hydrocarbon stapling technique to design a series of side-chain cross-linked analogs of DPMI- d, and evaluate their functional and structural properties with respect to ?-helicity, MDM2/MDMX binding, and membrane permeabilization. (2) Test the hypothesis that high-affinity, protease- resistant, and cell-penetrating D-peptide antagonists of MDM2 and MDMX reactivate the p53 pathway and kill tumor cells through cell cycle arrest and/or apoptosis induction. We will evaluate tumor-killing activity of side-chain cross-linked forms of DPMI-d using a variety of tumor cell lines with or without wild type p53. Our long-term objective is to develop D-peptide-based p53 activators as a novel class of anticancer therapeutics for clinical use.