Macrocyclic inhibitors of upstream protein activators of the Hedgehog pathway

描述（由申请人提供）：Hedgehog信号通路在胚胎发育和胚胎后调控成体干细胞更新和再生过程中发挥关键作用。Hedgehog通路的异常激活与几种人类恶性肿瘤的发生和进展有关，包括白血病、肺癌、胰腺癌、前列腺癌和结肠癌。Hedgehog通路的化学调节剂已被证明对于阐明其功能以及确定治疗Hedgehog通路相关癌症的有希望的临床候选药物至关重要。然而，目前大多数可用的Hedgehog途径拮抗剂靶向跨膜受体Smoothened (Smo)，并且在较小程度上靶向参与Gli转录因子激活和Gli调控基因转录的下游途径组分。相比之下，对于能够有效干扰Hedgehog途径激活上游事件（即Hedgehog信号蛋白与补丁受体之间的相互作用，后者负责Smo的去抑制以及随后诱导gli调节基因）的化学制剂，仍然存在根本性的空白。本项目的目标是开发一类新的大环有机肽抑制剂，抑制Hedgehog/Patched蛋白-蛋白相互作用。为了实现这一目标，我们将利用模块化和高效的策略来创建功能复杂的巨循环的庞大和高度多样化的库，并结合强大的高通量系统来对这些库进行功能筛选。以这种方式分离的刺猬靶向大环将在二次体外和基于细胞的实验中进行评估，以表征其抑制效力、选择性和阻断哺乳动物细胞中刺猬通路信号的能力。最终，本研究有望为研究干细胞生物学和癌症生物学中Hedgehog信号通路提供急需的化学探针，并为开发下一代抗癌药物提供易于进一步优化的新先导结构。该项目的另一个相关贡献将是实现一个通用的、集成的平台，用于进化蛋白质复合物的大环抑制剂，这可以很容易地应用于各种其他癌症相关的靶蛋白-蛋白质相互作用。

DESCRIPTION (provided by applicant): The Hedgehog signaling pathway plays a key role during embryonic development and, post-embryonically, in regulating adult stem cell renewal and regeneration. Aberrant activation of the Hedgehog pathway has been linked to the development and progression of several human malignancies, including leukemia, lung, pancreatic, prostate, and colon cancers. Chemical modulators of the Hedgehog pathway have proven essential for elucidating its function as well as identifying promising clinical candidates for the treatment of Hedgehog pathway-related cancers. The majority of currently available Hedgehog pathway antagonists, however, target the transmembrane receptor Smoothened (Smo) and, to a minor extent, downstream pathway components involved in the activation of Gli transcription factors and transcription of Gli-regulated genes. In contrast, a fundamental gap remains with respect to chemical agents that can potently interfere with upstream events of Hedgehog pathway activation, namely the interaction between the Hedgehog signaling proteins and the Patched receptor, which is responsible for de-repression of Smo and consequent induction of Gli-regulated genes. The goal of this project is to develop a new class of macrocyclic organo-peptide inhibitors of the Hedgehog/Patched protein-protein interaction. To achieve this goal, we will utilize a modular and efficient strategy for creating vast and highly diverse libraries of functionally complex macrocycles in combination with a powerful, high-throughput system for functional screening of these libraries. The Hedgehog-targeting macrocycles isolated in this manner will be evaluated in secondary in vitro and cell-based assays in order to characterize their inhibitory potency, selectivity, and ability to block Hedgeho pathway signaling in mammalian cells. Ultimately, this research is expected to provide highly needed chemical probes for investigating the Hedgehog signaling pathway in stem cell biology and cancer biology, as well as new lead structures, readily amenable to further optimization, for the development of next-generation anticancer agents. Another relevant contribution of this project will be the implementation of a general, integrated platform for evolving macrocyclic inhibitors of protein complexes, which could be readily applied to a variety of other cancer-related target protein-protein interactions.