Targeting Wnt signaling pathway

蛋白质-蛋白质相互作用（PPI）是生物有机化学和药物化学越来越重要的目标， 鉴于无数蛋白质复合物在重要的生物学过程中的关键作用，包括信号转导、细胞 由于增强的稳定性和功能多样性，螺旋肽模拟物具有 作为靶向PPI的有前途的策略出现，但其应用仍然有限，因为它们通常 由于它们在三维螺旋结构上的差异，不能很好地模拟α-螺旋。比如说， BCL 9/β-catenin和TCF/β-catenin PPI参与Wnt信号通路，在胚胎发育中发挥重要作用。 发育和组织稳态，并与几种类型的癌症有关。因此，分子破坏 BCL 9/β-catenin或TCF/β-catenin PPIs均可能通过抑制Wnt/β-catenin而成为新的抗癌药物 发信号。然而，基于非天然支架的螺旋抑制剂的成功设计阻断PPI是不可能的。 以前未知的。 我们最近开发了一系列前所未有的螺旋磺酰-γ-AA肽， 蛋白质的结构域。考虑到β-catenin/BCL 9和TCF/β-catenin PPI的重要性，我们认为mod- 评估这些生产者价格指数可以作为一个很好的机会，制定针对任何 其他涉及α-螺旋的PPI。与不表现出细胞活性的BCL 9和TCF肽相比，我们的 初步研究表明，磺基-γ-AA肽不仅可以模拟这些螺旋结构域， 具有高度的细胞渗透性，可以选择性地抑制Wnt/β-catenin信号过度活跃的癌细胞生长。 据我们所知，我们的研究结果代表了基于非天然多肽的螺旋肽模拟物的第一个例子。 破坏这些PPI的骨干。因此，我们的长期目标是开发新的螺旋磺酰基-γ-AA肽 其作为蛋白水解稳定的和细胞穿透的分子实体，能够调节多种 医学相关PPI。本文的目的是建立磺基-γ-AA肽的设计策略， 螺旋结构域模拟物以最佳效力破坏β-连环蛋白/BCL 9和TCF/β-连环蛋白PPI。我们将首先 鉴定在体外有效破坏β−连环蛋白/BCL 9和TCF/β-连环蛋白PPI的螺旋磺基-γ-AA肽。福尔- 在此基础上，我们将证实先导化合物的分子机制是通过调节Wnt信号传导， 使用共聚焦光谱、TOPFlash和FOPFlash测定、细胞接合测定和相关信号传导 在细胞水平上评估这些序列的选择性、特异性和效力的测定。最后我们将 使用小鼠肿瘤模型来验证抑制剂在体内抑制Wnt信号传导和肿瘤生长的能力。 这项工作是非常重要的，因为这些研究很有可能导致新一代的治疗方法。 靶向β-catenin/BCL 9 PPI和β-catenin/TCF PPI的药物，这将确保抑制Wnt的目标 信号这项工作是创新性的，因为我们的策略，蛋白质结构域模拟使用螺旋 磺基-γ-AA肽是全新的，未来可用于靶向多种疾病相关PPI。

Protein-protein interactions (PPIs) are increasingly important targets for bioorganic and medicinal chemistry, given the critical role of myriad protein complexes in vital biological processes including signal transduction, cell growth and proliferation, etc. Due to enhanced stability and functional diversity, helical peptidomimetics have emerged as a promising strategy for targeting PPIs, however their application is still limited as they generally do not mimic α-helices well owing to their difference in the three-dimensional helical structures. For instance, BCL9/β-catenin and TCF/β-catenin PPIs involved in Wnt signaling pathway play an important role in embryonic development and tissue homeostasis and are linked to several types of cancers. As such, molecules disrupting either BCL9/β-catenin or TCF/β-catenin PPIs could become novel anti-cancer agents by inhibiting Wnt/β-catenin signaling. However, the successful design of helical inhibitors based on unnatural scaffold to block the PPIs is previously unknown. We have recently developed a series of unprecedented helical sulfono-γ-AApeptides that can mimic α-helical domain of proteins. Given by the significance of β−catenin/BCL9 and TCF/β-catenin PPIs, we believe that mod- ulating these PPIs could serve as an excellent opportunity to formulate the general strategy for targeting any other PPIs involving α-helices. Compared to the BCL9 and TCF peptides not exhibiting cellular activity, our preliminary studies indicated that sulfono-γ-AApeptides not only can mimic these helical domains, but also are highly cell permeable and can selectively inhibit growth of cancer cells with hyperactive Wnt/β−catenin signaling. To the best of knowledge, our findings represents the first example of helical peptidomimetics based on unnatural backbone in disrupting these PPIs. As such, our long-term goal is to develop novel helical sulfono-γ-AApeptides that serve as proteolytically stable and cell-penetrating molecular entities capable of modulating a myriad of medicinally relevant PPIs. The objective here, is to establish the design strategy of sulfono-γ-AApeptides as helical domain mimetics to disrupt β−catenin/ BCL9 and TCF/β-catenin PPIs with optimal potency. We will first identify helical sulfono-γ-AApeptides that potently disrupt β−catenin/BCL9 and TCF/β-catenin PPIs in vitro. Fol- lowing that, we will confirm molecular mechanism of lead compounds is through modulation of Wnt signaling, by using confocal spectroscopy, TOPFlash and FOPFlash assay, cellular engagement assay, and related signaling assays to assess the selectivity, specificity and potency of these sequences on the cellular level. Finally, we will use a mouse tumor model to validate the ability of the inhibitors to inhibit Wnt signaling and tumor growth in vivo. The proposed work is significant, as these studies are highly likely to lead to a new generation of therapeutic agents targeting both β−catenin/BCL9 PPI and β-catenin/TCF PPIs, which will secure the goal of inhibiting Wnt signaling. The proposed work is innovative, because our strategy of protein-domain-mimicking using helical sulfono-γ-AApeptides is completely new and can be adopted to target myriad disease-related PPIs in the future.