The Role of IKK and NF-kappaB in Controlling mTOR Signaling and TSC Progression

描述(申请人提供)：结节性硬化症(TSC)是一种人类综合征，其特征是良性肿瘤在皮肤、脑、肺、心脏和肾脏等多种器官广泛发展。TSC是由TSC1或TSC2基因突变引起的。最近的研究表明，TSC1和TSC2抑制哺乳动物雷帕霉素(MTOR)信号通路的靶点，以控制细胞生长，因此，TSC1或TSC2基因突变导致的mTOR信号异常激活可能是TSC发病的基础。虽然与mTOR调控和mTOR下游效应相关的机制已经部分描述，但关于这些机制仍有许多未知之处。重要的是，TSC的治疗是姑息性的，目前还没有有效的治疗方法。我们最近发现，IKK复合体(转录因子NF-kB的关键上游调节因子)与mTOR复合体相互作用，显著增加mTORC1和mTORC2的活性。此外，我们的结果显示，mTOR对IKK/NF-NF-kB的激活具有双向调控作用。这些结果表明IKK/NF-kappaB通路可能是TSC/mTOR信号通路的一种新的调节因子。我的数据还表明，TSC2和雷帕霉素都以Akt依赖的方式通过mTORC1调节IKK/NF-kB的活性。根据我已发表的研究和初步数据，我推测IKK和NF-kB在控制TSC进展的过程中可能是mTOR和Akt的重要调节者和效应者，雷帕霉素联合IKK抑制剂可以有效地阻断mTOR、Akt和IKK/NF-kB的活性，最终阻止TSC的进展。我将描述IKK1在几个癌细胞和TSC2-/-MEF细胞中控制TORC1和mTORC2活性的机制。我将深入研究TSC2和雷帕霉素如何与IKK抑制剂相结合，影响细胞和TSC动物模型中的NF-kB活性和TSC进展。本研究的目的是从机制上理解IKK/NF-kB和mTOR信号通路在促进细胞存活、生长和TSC进展中的相互作用。拟议的遗传和生化分析和动物模型研究将为TSC/mTOR和IKK/NF-kB通路的调控和功能以及TSC的进展提供新的见解。进一步的研究可能导致新的治疗靶点的确定，并最终帮助开发针对TSC和TSC相关肿瘤的合理的、基于机制的治疗策略。 公共卫生相关性：结节性硬化症(TSC)是一种人类综合征，其特征是良性肿瘤在多个组织中广泛发展，原因是TSC1或TSC2抑癌基因突变，随后mTOR异常激活。尽管mTOR抑制剂，如雷帕霉素，在临床试验中显示出一些好处，但到目前为止，还没有有效的治疗TSC的方法。我已发表的和初步的研究表明，IKK和转录因子NF-kB在控制TSC2/mTOR信号通路中起着关键作用。我们推测，基因抑制IKK1或通过IKK抑制剂和雷帕霉素联合抑制mTOR和IKK/NF-kB将有效地阻断TSC的进展。基于细胞和动物模型的研究被用来检验我们的假设。该项目的完成可能导致新的治疗靶点的确定，并最终帮助开发合理的基于机制的治疗策略，在TSC临床试验中针对TSC。此外，这些研究将为mTOR复合体(mTORC1和mTORC2)的控制提供新的见解，并随后对Akt等关键下游调控因子产生影响。

DESCRIPTION (provided by applicant): Tuberous sclerosis complex (TSC) is a human syndrome characterized by widespread development of benign tumors in a variety of organs including skin, brain, lung, heart and kidney. TSC is caused by mutation in either the TSC1 or TSC2 gene. Recent studies have indicated that TSC1 and TSC2 suppress the mammalian target of rapamycin (mTOR) signaling pathway to control cell growth; thus, abnormal activation of mTOR signaling as a result of mutation in TSC1 or TSC2 gene may underlie the pathogenesis of TSC. While mechanisms associated with mTOR regulation and with mTOR downstream effects have been partly characterized, much is still unknown regarding these mechanisms. Importantly, treatment of TSC is palliative and no effective cure is known. We have recently found that the IKK complex (key upstream regulator of the transcription factor NF-kB) interacts with the mTOR complex and significantly increases both mTORC1 and mTORC2 activity. Additionally, our results revealed that mTOR controls IKK/NF-NF-kB activation reciprocally. These results implicate IKK/NF- kappaB pathway as a novel regulator of TSC/mTOR signaling pathway. My data also demonstrate that both TSC2 and rapamycin regulate IKK/NF-kB activity through mTORC1 in an Akt-dependent manner. Based on my published studies and preliminary data, I hypothesize that IKK and NF-kB are critical regulators and effectors for mTOR and Akt in controlling the progression of TSC, and that rapamycin in combination with an IKK inhibitor could effectively block the activity of mTOR, Akt and IKK/NF-kB and ultimately block progression of TSC in TSC animal models. I will characterize the mechanism whereby IKK1 controls TORC1 and mTORC2 activity in several cancer cells and in TSC2 -/- MEF cells. I will extensively examine how TSC2 and rapamycin, in combination with an IKK inhibitor, affect NF-kB activity and TSC progression in cells and TSC animal models. The goal of this proposal is to achieve a mechanistic understanding of the interaction between IKK/NF-kB and mTOR pathways in promoting cell survival and growth, and progression of TSC. The proposed genetic and biochemical analyses and animal model studies will provide novel insight into the regulation and function of TSC/mTOR and IKK/NF-kB pathways, and the progression of TSC. Further studies could lead to the identification of new therapeutic targets and ultimately help develop rational, mechanism- based treatment strategies that target TSC and TSC-related tumors. PUBLIC HEALTH RELEVANCE: Tuberous Sclerosis Complex (TSC) is a human syndrome characterized by widespread development of benign tumors in multiple tissues, caused by the mutations in either TSC1 or TSC2 tumor suppressor genes and the subsequent abnormal activation of mTOR. So far, there is no effective cure for TSC although mTOR inhibitors, such as rapamycin, have shown some benefit in clinical trials. My published and preliminary studies indicated that IKK and the transcription factor NF-kB play critical roles in controlling the TSC2/mTOR signaling pathway. We hypothesize that genetic inhibition of IKK1 or combination inhibition of mTOR and IKK/NF- kB by IKK inhibitors and rapamycin will effectively block progression of TSC. Cell-based and animal model studies are proposed to test our hypothesis. The completion of the project could lead to the identification of new therapeutic targets and ultimately help develop rational mechanism-based treatment strategies that target TSC in a TSC clinical trial. Additionally, the studies will provide new insight into the control of both mTOR complexes (mTORC1 and mTORC2), with subsequent effects on key downstream regulators such as Akt.