Regulation and function of IKKe in breast cancer initiation and maintenance

描述（由申请人提供）：核因子-κB （NF-κB）转录因子家族成员在调节许多生理过程中发挥核心作用，包括先天免疫和适应性免疫。此外，越来越多的证据表明，NF-κB的不适当激活发生在许多类型的人类癌症中。事实上，基因组表征研究已经揭示了造血和上皮癌中涉及NF-κB信号级联的许多组分的遗传改变，并且越来越多的证据表明NF-κB信号有助于对靶向癌症治疗的抵抗。利用整合的基因组方法，我们确定了两个密切相关的非典型κB激酶抑制剂ikkλ (IKBKE, IKKi)和TBK1，分别作为扩增的乳腺癌致癌基因和kras驱动的人类癌症的必需基因。在过去的资助期内，我们已经使用生化，遗传和分子生物学方法来解决这两个ikk的结构，并确定这两个ikk的底物对细胞转化至关重要。我们还发现k63连接的泛素化是这些ikk的调控机制之一，对它们的致瘤功能至关重要。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。基于这些观察结果，本提案的重点是描述这些免疫调节因子促进恶性转化的机制以及ikk御柱和TBK1抑制剂。我们将进行机制研究，以了解扰乱ikk御柱功能如何影响肿瘤维持，并将开发ikk御柱的小分子抑制剂。具体而言，将应用生化、遗传、分子生物学和药理学方法来询问ikk御柱在免疫和致癌背景下的调控，确定介导IKKϵ-induced细胞转化的效应通路，并在临床前验证ikk御柱抑制剂。研究ikk御柱在乳腺癌发展中的调控和功能不仅将增强我们对这种非规范IKK调节因子的机制理解，还将阐明NF-κB信号传导在人类上皮癌发展中的作用。此外，这些研究将为靶向该激酶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.