Signal Transduction of Type 1 Interferons in Malignant Cells

描述(申请人提供)：这是一个竞争性的更新申请，其总体目标是确定干扰素(干扰素)信号在恶性细胞中的机制。干扰素在体外和体内都表现出重要的抗肿瘤特性，是抗癌免疫监视的关键成分，但它们产生这种作用的机制尚不清楚。我们提供了第一个证据，证明mTOR信号级联是由干扰素受体(IFNRs)参与的，并通过控制真核细胞启动因子4E(EIF4E)和eIF4F复合体来调节帽依赖的mRNA翻译。值得注意的是，与致癌信号相比，我们的研究为IFN对mTORC2复合体的信号特异性和差异性使用提供了证据。我们的研究表明，mTORC2复合体在干扰素信号转导中起双重调节作用，控制下游调节ISGs转录和mRNA翻译的途径。目前的建议是一种系统的方法来剖析这些复合体在干扰素信号转导中的功能和作用，并确定它们在干扰素抗肿瘤效应产生中的相关性。具体目标1将确定IFNR上游产生的导致mTORC2激活的信号，并将确定I型IFNR参与mTORC2的特异性机制。它包括：研究IFNR相关的激酶在这一过程中的作用；研究确定不同的SIN1亚型的不同参与是否解释了干扰素系统的特异性；以及筛选新的Rictor和SIN1相互作用的干扰素信号元件。具体目标2将确定mTORC2复合体控制ISG表达的机制以及它们在肿瘤细胞中产生干扰素抑制反应中的作用。它包括确定mTORC2复合体在IFNR激活的调节ISGs转录激活和mRNA翻译的信号级联中的作用的实验；关于干扰素激活的mTORC2复合体对AGC激酶的影响的实验；以及剖析mTOR通路中不同的下游效应元件在产生干扰素抗增殖反应中的需求的研究。具体目标3将研究依赖mTOR的信号在干扰素在Ph(-)骨髓增生性肿瘤(MPN)中的抗肿瘤作用中的作用。将在AKT-/-、S6K-/-和Pdcd4-/-KO小鼠中建立JAK2V617F小鼠模型，并将评估干扰素在体内诱导抗白血病反应的能力，无论是否存在该途径的不同效应物。体外和体内MPNS患者的原始造血祖细胞中依赖干扰素的mTOR通路的激活将被评估并与干扰素敏感性相关。综上所述，这些研究将促进我们对控制干扰素抗肿瘤反应产生的信号机制的理解，并将为导致肿瘤细胞对干扰素产生耐药性的事件提供重要信息。最终，它们可能形成克服干扰素耐药性的新方法的基础。

DESCRIPTION (provided by applicant): This is a competing renewal application whose overall objective is to define the mechanisms of interferon (IFN)-signaling in malignant cells. IFNs exhibit important antineoplastic properties in vitro and in vivo and are key elements in the immune surveillance against cancer, but the mechanisms by which they generate such effects remain to be defined. We have provided the first evidence that the mTOR signaling cascade is engaged by IFN receptors (IFNRs) and regulates cap-dependent mRNA translation via control of the eukaryotic initiation factor 4E (eIF4E) and the eIF4F complex. Remarkably, our studies have provided evidence for signaling specificity and differential use of mTORC2 complexes by IFNs, as compared to oncogenic signals. Our studies suggest dual regulatory roles for mTORC2 complexes in IFN-signaling, controlling downstream pathways that regulate both transcription and mRNA translation of ISGs. The current proposal is a systematic approach to dissect the functions and roles of these complexes in IFN-signaling and to define their relevance in the generation of the antineoplastic effects of IFNs. Specific aim 1 will identify upstream IFNR-generated signals that lead to mTORC2 activation and will determine the mechanisms of specificity of mTORC2 engagement by the Type I IFNR. It includes studies to dissect the role of IFNR-associated kinases in the process; studies to define whether differential engagement of distinct Sin1 isoforms accounts for specificity in the IFN-system; and screening efforts to identif novel Rictor- and Sin1-interacting IFN-signaling elements. Specif ic aim 2 will define the mechanisms by which mTORC2 complexes control ISG expression and their roles in the generation of IFN-inhibitory responses in malignant cells. It includes experiments to define the roles of mTORC2 complexes in IFNR-activated signaling cascades that regulate transcriptional activation and mRNA translation of ISGs; experiments on the effects of IFN¿-activated mTORC2 complexes on AGC kinases; and studies to dissect the requirement of distinct downstream effector elements of mTOR pathways in the generation of IFN-antiproliferative responses. Specif ic aim 3 will examine the roles of mTOR-dependent signals in the antineoplastic effects of IFNs in Ph (-) myeloproliferative neoplasms (MPNs). JAK2V617F mouse models will be established in AKT -/-, S6K -/- and Pdcd4 -/- KO mice, and the ability of IFN¿ to induce antileukemic responses in vivo, in the presence or absence of distinct effectors of the pathway, will be assessed. The activation of IFN-dependent mTOR pathways in primary hematopoietic precursors from patients with MPNs in vitro and in vivo will be assessed and correlated with IFN-sensitivity. Altogether, these studies will advance our understanding of the signaling mechanisms controlling generation of IFN-antitumor responses and will provide important information on the events that lead to malignant cell resistance to IFNs. Ultimately, they may form the basis for new approaches to overcome IFN-resistance.