Prolyl isomerase function during Jak Stat signaling in breast cancer

描述（由申请方提供）：受体相关酪氨酸激酶，如Jak 2和Src，作为配体结合的近端介质。大量的数据表明，这两种激酶显着有助于乳腺癌的发病机制，但导致其激活的机制仍然不确定。我们的研究集中在乳腺癌相关的催乳素受体（PRLr）上，发现肽脯氨酰异构酶（PPI），亲环素A（CypA）是激活这些激酶所必需的。这些研究结果表明，PPI的CypA活性参与了构象重组的受体激酶复合物，有助于其激活。另外的研究已经揭示了PRLr、Jak 2、Src和CypA之间的多聚体复合物的形成是配体诱导的PRLr相关信号复合物的活化所必需的。在翻译水平上，这些结果已进一步证实了我们的评估CypA基因敲除模型和成功使用的PPI抑制剂环孢素A（CsA）和NIM 811在体外和体内的乳腺癌模型。综上所述，我们的研究结果使我们假设，这些蛋白质之间的分子间相互作用和PPI活性的CypA的结果在触发Jak 2和Src后配体接合，并且这些事件是高度相关的乳腺癌的发病机制。该假设将在三个具体目标中进行测试，如下：首先，将使用乳腺癌细胞内的诱变、过表达和敲低方法来评估PRLr/Jak 2/Src/CypA内蛋白质-蛋白质相互作用的功能作用。第二，体外激酶和可溶性和固态NMR光谱将用于评估由CypA的PPI活性调节的PRLr/Jak 2/Src复合物的构象状态。第三，获得和丧失功能的方法将用于遗传和异种移植物为基础的小鼠模型，以评估蛋白质相互作用和PPI功能的作用，在乳腺癌的发病过程中的PRLr复合物。这些研究建议是非常重要的，因为这将为我们理解PPI活性CypA调节的受体Jak 2/Src激活过程中的结构/功能关系提供分子基础，并将这些发现通过细胞转化为乳腺癌小鼠模型。

DESCRIPTION (provided by applicant): Receptor-associated tyrosine kinases, such as Jak2 and Src, serve as proximal mediators of ligand binding. Abundant data indicate that both of these kinases significantly contribute to the pathogenesis of breast cancer, and yet the mechanisms leading to their activation has remained uncertain. Our research, which has focused on the breast cancer-relevant receptor for prolactin (PRLr), has revealed that the peptidly prolyl isomerase (PPI), cyclophilin A (CypA) is required for the activation of these kinases. These findings would indicate that PPI activity of CypA is involved in a conformational restructuring of this receptor-kinase complex that contributes to its activation. Additional studie have revealed that the formation of a multimeric complex between the PRLr, Jak2, Src, and CypA is necessary of ligand-induced activation of the PRLr-associated signaling complex. At a translational level, these results have been further corroborated by our evaluation of a CypA knockout model and the successful use in breast cancer models of the PPI inhibitors cyclosporine A (CsA) and NIM811 both in vitro and in vivo. Taken together, our findings lead us to hypothesize that the intermolecular interactions between these proteins and the PPI activity of CypA result in the triggering of Jak2 and Src following ligand engagement, and that such events are highly relevant to the pathogenesis of breast cancer. This hypothesis will be tested in three specific aims, as follows: First, the functional role of protein- protein interactions withinthe PRLr/Jak2/Src/CypA will be evaluated using mutagenic, overexpression, and knockdown approaches within breast cancer cells. Second, in vitro kinase and soluble and solid state NMR spectroscopy will be used to assess conformer status with the PRLr/Jak2/Src complex as regulated by the PPI activity of CypA. Third, both gain- and loss-of-function approaches will be used in genetic and xenograft-based murine models to assess the role of protein interactions and PPI function within the PRLr complex during the pathogenesis of mammary cancer. The studies proposes are highly significant in that the will provide a molecular foundation for our understanding of the structure/function relationships during receptor-Jak2/Src activation as modulated by the PPI activity CypA and translate these discoveries through cellular to mouse models of breast cancer.