Regulation and function of IKKe in breast cancer initiation and maintenance

描述(申请人提供)：核因子-κB(核因子-κB)转录因子家族的成员在调节包括先天免疫和获得性免疫在内的许多生理过程中发挥核心作用。此外，越来越多的证据表明，在许多类型的人类癌症中都存在着NF-κB的不适当激活。事实上，基因组特征研究已经发现，在血液病和上皮性肿瘤中，涉及到NF-κB信号级联的许多成分的基因改变，并且越来越多的证据表明，NF-κB信号与靶向癌症治疗的耐药性有关。利用整合基因组学方法，我们鉴定了两个密切相关的、非典型的κB激酶抑制剂：IKKϵ(IKBKE，IKKI)和TbK1，它们分别是一个扩增的乳腺癌癌基因和KRAS驱动的人类癌症中的一个必需基因。在过去的资助期间，我们使用了生化、遗传学和分子生物学的方法来解决这两个IKK的结构，并确定了这两个IKK的底物对细胞转化至关重要。我们还确认K63连接的泛素化是调节这些IKK的一种机制，对于它们的致瘤功能是必不可少的。这些观察结果为这些IKK在先天和致癌背景下的功能提供了新的见解。基于这些观察，这项建议重点描述这些免疫调节因子促进恶性转化的机制(S)，并证明IKKϵ和Tbk1抑制剂。我们将进行机制研究，以了解干扰IKKϵ功能如何影响肿瘤维持，并将开发IKKϵ的小分子抑制剂。具体地说，将应用生化、遗传学、分子生物学和药理学的方法来研究IKKϵ在免疫和致癌环境中的调节，以确定介导IKKϵ诱导的细胞转化的效应通路，并在临床前验证IKKϵ抑制剂。研究IKKϵ在乳腺癌发生发展中的调控和功能，不仅可以加深我们对这种非典范的IKK调控因子的机制的理解，还将有助于阐明NF-κB信号在人类上皮性肿瘤发生发展中的作用。此外，这些研究将为针对这种癌基因的治疗策略提供基础。

DESCRIPTION (provided by applicant): Members of the nuclear-factor-κB (NF-κB) transcription factor family play a central role in regulating many physiological processes including innate and adaptive immunity. In addition, accumulating evidence suggests that inappropriate activation of NF-κB occurs in many types of human cancers. Indeed, genome characterization studies have uncovered genetic alterations involving many components of the NF-κB signaling cascade in both hematopoietic and epithelial cancers, and accumulating evidence indicates that NF-κB signaling contributes to resistance to targeted cancer therapy. Using integrated genomic approaches, we identified the two closely related, non-canonical inhibitors of κB kinase, IKKϵ (IKBKE, IKKi) and TBK1, as an amplified breast cancer oncogene and an essential gene in KRAS-driven human cancers, respectively. During the past funding period, we have used biochemical, genetic and molecular biological approaches to solve the structure of these two IKKs and identify substrates of these two IKKs critical for cell transformation. We have also identified K63-linked ubiquitination as one mechanism of regulation of these IKKs, essential for their tumorigenic function. These observations provide new insights into the function of these IKKs in both innate and oncogenic contexts. Based on these observations, this proposal focuses on delineate the mechanism(s) by which these immune regulators contribute to malignant transformation and to credential IKKϵ and TBK1 inhibitors. We will perform mechanistic studies critical to understanding how perturbing IKKϵ function affects tumor maintenance and will develop small molecule inhibitors of IKKϵ. Specifically, biochemical, genetic, molecular biological and pharmacologic approaches will be applied to interrogate the regulation of IKKϵ in both immune and oncogenic contexts, to identify effector pathways that mediate IKKϵ-induced cell transformation and to validate IKKϵ inhibitors preclinically. Investigating the regulation and function of IKKϵ in breast cancer development will not only enhance our mechanistic understanding of this non-canonical IKK regulator but will also clarify the role of NF-κB signaling in the development of human epithelial cancers. In addition, these studies will provide a foundation for strategies to target this kinase oncogene therapeutically.