Mechanistic and pharmacologic studies of selective mithramycin analogues targeting EWS-FLI1 in Ewing sarcoma

尤文肉瘤家族肿瘤（ESFT）是一个家族的弹性破坏性癌症的骨和软组织 主要影响儿童和年轻人。目前五种药物的高细胞毒性联合治疗提供了 只有30%的存活率仅存在于肿瘤细胞中的异常转录因子EWS-FLI 1是致癌因子。 EWS的司机。然而，转录因子被认为是“不可用的”，直到最近的NCI筛选， 发现光神霉素（MTM）作为一种有效的EWS-FLI 1拮抗剂。MTM已被证明毒性太大， 治疗窗和不良的药代动力学（PK）特性。在这里，我们提出了机制和药理学 具有显著降低的毒性、增加的靶向特异性和 大大改善了PK性能。与其他地方报道的其他类似物相比， 在PK性质方面，MTM-SA类似物显示出上级动力学和降低的毒性。该项目的目标是 通过结构、生物化学和药理学研究获得MTM作用模式的分子见解 以产生高度有效和选择性的抗ESFT治疗。帮助目标1的合成工作，并确定 具有临床潜力的类似物，我们将在目标2中进行分子结构-功能水平研究，以确定 转录因子EWS-FLI 1如何与DNA微卫星重复序列和转录因子Runx 2相互作用（每个 肿瘤发生的必要相互作用），以及MTM-SA如何破坏这些致癌功能。在Aim中 3将评估体外细胞毒性和靶标选择性，以鉴定将在 药理学研究，将评估人源化肝小鼠中的毒性、PK和代谢以及疗效 在尤文肉瘤的异种移植物和PDx模型中。该项目将由一个具有既定 在基于片段的药物设计和天然药物的半合成路线方面拥有丰富经验的合作伙伴 产品、X射线晶体学、生物物理学和分子生物学研究以及药理学评价。 我们希望这些结构-功能研究将确定一个可能进入临床试验的候选药物， ESFT的治疗

Ewing sarcoma family of tumors (ESFT) is a family of resilient devastating cancers of bone and soft tissue affecting primarily children and young adults. Current highly cytotoxic combination therapy of five drugs provides only 30% overall survival. The aberrant transcription factor EWS-FLI1 present only in tumor cells is the oncogenic driver of EWS. However, transcription factors were believed to be “undruggable”, until a recent NCI screening found mithramycin (MTM) to act as a potent EWS-FLI1 antagonist. MTM has proven to be too toxic with a narrow therapeutic window and poor pharmacokinetic (PK) properties. Here we propose mechanistic and pharmacology studies of novel MTM analogues (MTM-SA) with significantly reduced toxicity, increased target specificity and greatly improved PK properties. In contrast to other analogues reported elsewhere, which still suffer from poor PK properties, the MTM-SA analogs display superior kinetics and reduced toxicity. The goal of this project is to gain molecular insights into the mode of action of MTM via structural, biochemical and pharmacological studies to generate a highly efficacious and selective anti-ESFT treatment. To aid synthetic efforts in Aim1 and identify analogues with clinical potential, we will perform molecular structure-function level studies in Aim 2 to determine how transcription factor EWS-FLI1 interacts with DNA microsatellite repeats and transcription factor Runx2 (each a necessary interaction for oncogenesis), and how these oncogenic functions are disrupted by MTM-SA. In Aim 3 will assess the in vitro cytotoxicity and target selectivity to identify analogues that will be evaluated in pharmacologic studies that will assess toxicity in humanized liver mice, PK and metabolism, as well as efficacy in xenograft and PDx models of Ewing Sarcoma. The project will be carried out by a team with an established collaboration who have extensive experience in fragment-based drug design and semi-synthetic routes of natural products, X-ray crystallographic, biophysical and molecular biology studies, and pharmacological evaluations. We expect that these structure-function studies will identify a lead-candidate that could enter a clinical trial for the treatment of ESFT.