Mnk Pathways and IFN-responses in Malignant Cells

描述（由申请方提供）：干扰素（IFN）在体外和体内均表现出重要的抗肿瘤特性，是抗癌免疫监视的关键要素。这些细胞因子在临床医学中具有广泛的应用，但它们在许多恶性肿瘤的治疗中的效用经常受到肿瘤细胞抗性的发展的限制。我们已经确定了一种新的干扰素信号级联，涉及激酶Mnk 1和Mnk 2。我们的数据已经确定，Mnk激酶在IFN依赖的mRNA翻译和生长抑制中发挥关键作用，提供了MAPK途径和IFN刺激基因（ISG）的mRNA翻译之间的直接联系。该途径的参与最终调节在IFN系统中具有关键功能作用的蛋白质产物的表达，例如介导ISG化的ISG 15和具有生长抑制特性的其他蛋白质。目前的建议是一个系统的方法来建立的Mnk途径的作用，在产生IFN-介导的反应，并定义缺陷的重要性，在恶性细胞的IFN-抗性的发展中激活这个级联反应。具体目标1将确定上游效应机制和参与Mnk途径调控的信号传导事件。将进行研究以确定IFNR相关的Jak激酶在Mnk 1/2激活中的作用，同时将确定Jak 2对核Mnk 2b和mRNA核输出功能的潜在调节作用。还将评估不同的MAPKKK和MAPKK在IFNR参与Mnk中的贡献。具体目标2将确定该途径的下游元件，并将剖析它们在产生IFN依赖性β效应中的作用。将检查eIF 4 E磷酸化的功能相关性以及hnRNPA 1和Sprouty蛋白（Spry 1和2）在IFN信号传导中的参与。还将进行研究，以确定是否Mnks调节SLFN基因的mRNA翻译，一个新的家庭的细胞周期调节因子，我们最近确定为介质的干扰素抗增殖反应。具体目标3将确定Mnk激酶在JAK 2 V617 F突变的Ph（-）骨髓增生性肿瘤中产生IFNa抑制作用的作用。将检查Mnk活性在诱导IFNa对来自患有P. Vera和ET的患者的原代克隆造血祖细胞的作用中的需求;并且将确定IFNa在具有Mnk 1和/或Mnk 2基因的靶向破坏的JAK 2 V617 F小鼠模型中诱导应答的能力。总之，这些研究将促进我们对IFN依赖性抗白血病反应产生机制的理解;提供导致恶性细胞耐药的事件的重要信息;并形成开发新的抗白血病药物和克服这种耐药方法的基础。

DESCRIPTION (provided by applicant): Interferons (IFNs) exhibit important antineoplastic properties in vitro and in vivo and are key elements in the immune surveillance against cancer. These cytokines have widespread applications in clinical medicine, but their utility in the treatment of many malignancies is frequently limited by the development of neoplastic cell resistance. We have identified a novel IFN-signaling cascade, involving the kinases Mnk1 and Mnk2. Our data have established that Mnk kinases play key roles in IFN-dependent mRNA translation and growth suppression, providing a direct link between MAPK pathways and mRNA translation of IFN-stimulated genes (ISGs). The engagement of this pathway ultimately regulates expression of protein products with key functional roles in the IFN-system, such as ISG15 which mediates ISGylation and other proteins with growth inhibitory properties. The current proposal is a systematic approach to establish the roles of Mnk pathways in the generation of IFN-mediated responses and to define the importance of defects in the activation of this cascade in the development of IFN-resistance in malignant cells. Specific aim 1 will identify upstream effector mechanisms and signaling events involved in the regulation of the Mnk pathway. Studies to define the roles of IFNR-associated Jak kinases in the activation of Mnk 1/2 will be performed, while the potential regulatory effects of Jak2 on the function of nuclear Mnk2b and mRNA nuclear export will be determined. The contribution of distinct MAPKKKs and MAPKKs in engagement of Mnks by the IFNR will be also assessed. Specific aim 2 will identify downstream elements of the pathway and will dissect their roles in the generation of IFN-dependent antineoplastic effects. The functional relevance of eIF4E phosphorylation and the involvement of hnRNPA1 and Sprouty proteins (Spry1 and 2) in IFN-signaling will be examined. Studies will be also performed to determine whether Mnks regulate mRNA translation of SLFN genes, a novel family of cell-cycle regulators that we have recently identified as mediators of IFN-antiproliferative responses. Specific aim 3 will determine the role of Mnk kinases in the generation of the suppressive effects of IFNa in Ph (-) myeloproliferative neoplasms with the JAK2V617F mutation. The requirement of Mnk activity in the induction of IFNa effects on primary clonal hematopoietic progenitors from patients with P. Vera and ET will be examined; and the ability of IFNa to induce responses in JAK2V617F mouse models with targeted disruption of the Mnk1 and/or Mnk2 genes will be determined. Altogether, these studies will advance our understanding of the mechanisms of generation of IFN-dependent antileukemic responses; provide important information on the events that lead to malignant cell resistance; and form the basis for the development of novel antineoplastic agents and approaches to overcome such resistance.