Identification of Novel Drug Targets For Use in Preventing Deafness Caused by NF2

鉴定用于预防 NF2 引起的耳聋的新药物靶点

基本信息

批准号：
7878605
负责人：
CRISTINA Maria FERNANDEZ-VALLE
金额：
$ 29.66万
依托单位：
UNIVERSITY OF CENTRAL FLORIDA
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-07-01 至 2014-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7878605
关键词：
Acoustic Nerve Acoustic Neuroma Actins Adult Apoptosis Auditory Brain Stem Implants Autocrine Communication Axon Basal lamina Binding Brain Stem Cancer Biology Cell Death Cell Shape Cell membrane Cell physiology Cell-Cell Adhesion Cells Cellular Morphology Complete Hearing Loss Complex Cues Cyclic AMP-Dependent Protein Kinases Cytokinesis Cytoskeleton Defect Development Disease Drug Delivery Systems Effectiveness Equilibrium Excision Facial paralysis Genes Goals Growth Hearing Human In Vitro Individual Integrins Investigation LIM Domain Kinase 1 Laminin Life Ligands Link Malignant Neoplasms Measures Membrane Membrane Proteins Mitotic spindle Molecular Monitor Morphology Mus Mutate Mutation Nerve Neuregulins Neurilemmoma Neurofibromatoses Neurofibromatosis 2 Neurofibromin 2 Neurons Operative Surgical Procedures Orphan Outcome Pathogenesis Pathway interactions Patients Peptides Pharmaceutical Preparations Pharmacological Treatment Phenotype Phosphorylation Plasmids Play Positioning Attribute Process Proteins Rattus Reagent Regulation Reporting Research Personnel Risk Role Schwann Cells Serine Shapes Signal Pathway Signal Transduction Signaling Protein Site Spinal Ganglia Stream Subfamily lentivirinae Symptoms Teenagers Testing Therapeutic Tumor Suppressor Proteins Virus Work bilateral acoustic schwannoma bilateral vestibular Schwannoma cell motility cofilin cofilin 2 deafness density effective therapy experience extracellular genetic regulatory protein hearing impairment in vitro Model irradiation novel novel therapeutics p21 activated kinase paxillin polymerization prevent receptor repaired response success tumor tumor growth

项目摘要

DESCRIPTION (provided by applicant): Neurofibromatosis type 2 (NF2) is a tumor disorder characterized by development of bilateral vestibular schwannomas also called acoustic neuromas. 98% of all NF2 patients experience partial to complete loss of hearing. Treatment for NF2 is balanced between monitoring tumor growth and the slow but progressive loss of hearing with surgical removal of larger tumors impinging on brainstem function and complete and permanent deafness. Cochlear and auditory brainstem implants have been used to partially restore hearing in a subset of patients with varying success. Therapeutics that slow or reverse tumor growth whilst maintaining hearing are currently lacking. This proposal tests the hypothesis that correcting the cytoskeletal defects in supernumerary schwannoma cells lacking function of the nf2 gene product, schwannomin/merlin, will allow these cells to interact with axons and receive cues promoting their differentiation and/or apoptosis. Identifying proteins that directly bind actin and regulate Schwann cell morphology is of the utmost importance. These proteins can serve as targets for drugs that will repair actin dynamics in schwannoma cells and restore axonal contact. Alternatively, drugs that modify actin regulatory proteins could promote cell death as a result of failed cytokinesis and mitotic spindle organization. One function of schwanomin/merlin is to inhibit Cdc42/Rac activation of p21 activated kinase (PAK). We will investigate LIM kinase (LIMK) and cofilin, terminal targets in a PAK signaling pathway. LIMK is a substrate for PAK, thus its activity is predicted to be high in schwannomas. Cofilin is a ubiquitously expressed actin-binding factor that depolymerizes f-actin and creates nucleation sites for new actin polymerization. Cofilin's function is inhibited by phosphorylation on serine-3 by LIMK. Our preliminary studies demonstrate that LIMK and cofilin modulate actin dynamics and function in Schwann cells. Moreover, our results suggest that LIMK and cofilin act down-stream of Schwannomin/merlin. We propose studies to: 1) identify the role of these proteins in controlling actin polymerization and cellular function in normal rat Schwann cells, 2) establish an in vitro model for NF2 using nf2ex2deleted mouse SCs to determine if inactivation of schwannomin/merlin leads to de-regulation of LIMK and cofilin activity and loss of SC function, and 3) determine if modulators of LIMK and cofilin restore the morphology and function of nf2ex2deleted SCs. These studies are initial steps in validating LIMK and/or cofilin as drug targets for development of an effective treatment for NF2 aimed at preserving hearing. The work in this proposal is relevant to the loss of hearing caused by Neurofibromatosis type 2. This disorder is characterized by development of bilateral acoustic schwannomas and loss of hearing in 98% of patients. As an outcome of this proposal, we hope to create a well characterized in vitro model for NF2 and advance a novel therapeutic direction, the actin modifying proteins LIMK and cofilin.

描述（由申请人提供）：2 型神经纤维瘤病（NF2）是一种肿瘤疾病，其特征是出现双侧前庭神经鞘瘤，也称为听神经瘤。 98% 的 NF2 患者会出现部分或完全丧失听力的情况。 NF2 的治疗在监测肿瘤生长和缓慢但进行性听力丧失之间取得平衡，手术切除影响脑干功能的较大肿瘤，导致完全和永久性耳聋。人工耳蜗和听觉脑干植入物已被用于部分恢复部分患者的听力，并取得了不同程度的成功。目前缺乏减缓或逆转肿瘤生长同时保持听力的治疗方法。该提案测试了以下假设：纠正缺乏 nf2 基因产物 schwannomin/merlin 功能的多余神经鞘瘤细胞中的细胞骨架缺陷，将使这些细胞与轴突相互作用并接收促进其分化和/或凋亡的线索。鉴定直接结合肌动蛋白并调节雪旺细胞形态的蛋白质至关重要。这些蛋白质可以作为药物的靶标，修复神经鞘瘤细胞中的肌动蛋白动力学并恢复轴突接触。或者，修饰肌动蛋白调节蛋白的药物可能会因胞质分裂和有丝分裂纺锤体组织失败而促进细胞死亡。 schwanomin/merlin 的一项功能是抑制 p21 激活激酶 (PAK) 的 Cdc42/Rac 激活。我们将研究 PAK 信号通路中的终端靶标 LIM 激酶 (LIMK) 和丝切蛋白 (cofilin)。 LIMK 是 PAK 的底物，因此预计其在神经鞘瘤中的活性很高。 Cofilin 是一种普遍表达的肌动蛋白结合因子，可解聚 f-肌动蛋白并为新肌动蛋白聚合创建成核位点。 Cofilin 的功能受到 LIMK 对丝氨酸 3 的磷酸化的抑制。我们的初步研究表明 LIMK 和丝切蛋白调节雪旺细胞中的肌动蛋白动力学和功能。此外，我们的结果表明 LIMK 和 cofilin 作用于 Schwannomin/merlin 的下游。我们建议进行以下研究：1) 确定这些蛋白质在控制正常大鼠雪旺细胞中肌动蛋白聚合和细胞功能中的作用，2) 使用 nf2ex2 缺失的小鼠 SC 建立 NF2 体外模型，以确定雪旺诺蛋白/merlin 失活是否会导致-LIMK和丝切蛋白活性的调节和SC功能的丧失，以及3)确定LIMK和丝切蛋白的调节剂是否恢复细胞的形态和功能nf2ex2删除了 SC。这些研究是验证 LIMK 和/或 cofilin 作为药物靶点的初步步骤，以开发旨在保留听力的 NF2 有效治疗方法。本提案中的工作与 2 型神经纤维瘤病引起的听力损失有关。这种疾病的特点是出现双侧听神经鞘瘤，并且 98% 的患者出现听力损失。作为该提案的成果，我们希望创建一个特征良好的 NF2 体外模型，并推进一个新的治疗方向，即肌动蛋白修饰蛋白 LIMK 和丝切蛋白。