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日益重要的研究对象。 鉴于无数蛋白质复合体在重要的生物过程中的关键作用，包括信号转导，细胞 生长和增殖等。由于增强的稳定性和功能多样性，螺旋肽仿制药具有 作为一种有前景的针对PPI的策略，但它们的应用仍然像通常那样受到限制 由于α-螺旋在三维螺旋结构上的不同，不能很好地模拟它们。例如, 参与Wnt信号通路的bcl9/β-catenin和Tcf/β-catenin PPI在胚胎发育中发挥重要作用 发育和组织动态平衡，并与几种类型的癌症有关。因此，分子分裂 Bcl9/β-连环蛋白或Tcf/β-连环蛋白PPI可通过抑制Wnt/β-连环蛋白而成为新型抗癌药物 发信号。然而，基于非天然支架来封闭PPI的螺旋抑制剂的成功设计是 此前不为人知。 我们最近开发了一系列史无前例的螺旋磺化γ-A肽，可以模拟α-螺旋 蛋白质的结构域。鉴于β−连环蛋白/bcl9和Tcf/β-连环蛋白PPI的重要性，我们认为MOD- 编制这些PPI可以作为一个极好的机会来制定针对 其他涉及α-螺旋的PPI。与不显示细胞活性的BCL9和TCF肽相比，我们的 初步研究表明，磺化-γ-A肽不仅可以模拟这些螺旋结构域，而且还可以 具有高度的细胞渗透性，并可通过高活性的WNT/β−连环蛋白信号选择性地抑制癌细胞的生长。 据我们所知，我们的发现代表了第一个基于非自然的螺旋肽仿生学的例子。 破坏这些PPI的中坚力量。因此，我们的长期目标是开发新型的螺旋磺化-γ-A肽 作为蛋白质分解稳定和穿透细胞的分子实体，能够调节无数的 医学上相关的PPI指数。本研究的目的是建立磺化-γ-A多肽AS的设计策略 螺旋结构域模拟，以最佳效力破坏β−连环蛋白/bcl9和Tcf/β-连环蛋白PPI。我们将首先 在体外鉴定能够有效干扰γ/β−和β/Tcf-catenin PPI的螺旋磺化-BCL-A多肽。FOL- 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，通过 使用共聚焦光谱、TOPFlash和FOPFlash分析、细胞参与分析和相关信号 在细胞水平上评估这些序列的选择性、特异性和效价。最后，我们会 使用小鼠肿瘤模型来验证这些抑制剂在体内抑制Wnt信号和肿瘤生长的能力。 这项拟议的工作意义重大，因为这些研究极有可能导致新一代治疗 靶向β−连环蛋白/BCL9PPI和β-连环蛋白/TCFPPI的药物，将确保抑制WNT的目标 发信号。这项拟议的工作是创新的，因为我们使用螺旋模拟蛋白质结构域的策略 磺化-γ-A多肽是一种全新的多肽，未来可用于靶向无数与疾病相关的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.