Development of SHP-2 Phophatase Inhibitors

描述（由申请人提供）：近年来，信号蛋白的结构分析在理解细胞信号转导途径的调控方面取得了重要进展。然而，如何结合蛋白质的结构和功能信息来设计小分子配体来研究蛋白质的生物学作用仍然是一个挑战。本研究项目的总体目标是开发特异性抑制蛋白酪氨酸磷酸酶SHP-2的小环非磷酸化肽，以探索该酶在细胞信号传导中的作用。SHP-2是一种广泛表达的细胞质酪氨酸磷酸酶，参与生长因子、细胞因子、激素和免疫信号传导。在一些研究中，已经发现SHP-2是生长因子信号转导的积极介质，作用于有丝分裂原活化蛋白（MAP）激酶途径的上游，并影响细胞发育过程。最近发现，发育障碍努南综合征的遗传原因，其特征是面部畸形，身材矮小，心脏病和骨骼畸形，可以映射到SHP-2突变。假设这些突变导致SHP-2磷酸酶活性增加，从而影响生长因子受体信号传导。SHP-2活性与细胞生长激活之间的联系也表明SHP-2可能参与肿瘤发生，因此是抗癌药物的潜在靶点。SHP-2的环肽抑制剂将根据该酶的现有晶体结构设计，这表明该蛋白的n端src-homology 2 （SH2）结构域具有自抑制机制。将采用不同的合成环化策略，并结合质子核磁共振（1H-NMR）研究获得的结构信息，开发具有高抑制活性的约束肽。然后将具有最高效力和选择性的抑制剂递送到细胞中，并通过测定EGF刺激细胞时MAP激酶途径中不同蛋白质的磷酸化状态来测试其对表皮生长因子（EGF）受体信号通路的影响。这些研究将为SHP-2作用模式的分子细节提供新的见解，包括它的底物，以及它在细胞对生长因子的反应中的抑制作用。了解SHP-2的调控可以将该蛋白作为开发细胞疾病治疗药物的靶点。

DESCRIPTION (provided by applicant): In recent years, structural analysis of signaling proteins has led to important advances in understanding the regulation of cellular signal transduction pathways. However, it still remains a challenge to be able to combine protein structural and functional information to design small molecule ligands that can be used to study the biological roles of proteins. The overall goal of this research project is to develop small cyclic non-phosphorylated peptides that specifically inhibit protein tyrosine phosphatase, SHP-2, in order to probe the role of this enzyme in cellular signaling. SHP-2 is a widely expressed cytoplasmic tyrosine phosphatase involved in growth factor, cytokine, hormone, and immune signaling. In several studies, SHP-2 has been found to be a positive mediator of growth factor signal transduction, acting upstream of mitogen activated protein (MAP) kinase pathways, and effecting cellular developmental processes. It has recently been found that the genetic cause of the developmental disorder Noonan syndrome, characterized by dysmorphic facial features, short stature, heart disease, and skeletal malformations can be mapped to mutations in SHP-2. It is hypothesized that these mutations lead to increased SHP-2 phosphatase activity that would effect growth factor receptor signaling. The link between SHP-2 activity and the activation of cell growth also suggests that SHP-2 may be involved in tumorigenesis and therefore, a potential target for anti-cancer drugs. Cyclic peptide inhibitors of SHP-2 will be designed based on the existing crystal structure of the enzyme, which suggests an autoinhibitory mechanism by the N-terminal src-homology 2 (SH2) domain of the protein. Different synthetic cyclization strategies will be applied and combined with structural information obtained from proton nuclear magnetic resonance (1H-NMR) studies to develop constrained peptides with high inhibitory activity. Inhibitors with the highest potency and selectivity will then be delivered into cells and tested for their effect on the epidermal growth factor (EGF) receptor signaling pathway by determining the phosphorylation state of different proteins in the MAP kinase pathway upon stimulation of the cells with EGF. These studies will give new insights into the molecular details of SHP-2's mode of action, including its substrate(s), and the effects of its inhibition in cellular responses to growth factors. Understanding the regulation of SHP-2 can establish this protein as a target for the development of therapeutic drugs for cellular disorders.