Tumor-Inhibitory Effects of P1D1 in Gliomas

描述（由申请人提供）：该项目的重点是PID 1（磷酸酪氨酸相互作用结构域包含1）在胶质瘤中的作用。PID 1是一种含磷酸酪氨酸结合（PTB）结构域的蛋白质，于2006年发现，从未在癌症背景下进行过研究。PID 1的异位表达对不同细胞类型的增殖具有相反的作用。利用微阵列和定量RT-PCR，我们发现PID 1的高表达与两种类型的脑肿瘤（神经胶质瘤和髓母细胞瘤）的良好预后相关。我们在体外的初步数据进一步表明，异位表达PID 1具有生长抑制作用的脑肿瘤细胞系从三种不同类型的脑肿瘤：胶质母细胞瘤，髓母细胞瘤，和非典型畸胎样横纹肌样瘤（ATRT）。我们选择将这个以PID 1为中心的R21建议集中在神经胶质瘤上，因为它们构成了人类最常见的原发性脑肿瘤，并且在恶性时具有严峻的预后。 本研究的目的是揭示PID 1介导胶质瘤抑制作用的分子机制。具体来说，我们将测试的假设，PID 1发挥其抑制作用，在恶性胶质瘤的一部分，通过其PTB域。我们提出以下两个具体目标： 1)确定在GBM细胞系中介导其抑制功能的PID 1的关键结构域。在这个目标中，我们将制造已知和预测的PID 1结构域的突变体，并测试它们降低增殖和诱导凋亡的能力。 2)研究PID 1表达对NOD-SCID小鼠颅内人细胞系来源的GBM肿瘤生长的影响。在这个目标中，我们将使用PID 1的调节表达，并检查PID 1表达对肿瘤生长，存活，增殖和凋亡的影响。 这项工作是新颖的，具有很高的影响力，因为它将进一步加深我们对PID 1在胶质瘤中的分子机制和功能的了解，形成关于PID 1在任何脑肿瘤和任何癌症中的知识的第一个基础。我们在初步数据中发现的临床相关性突出了这一主题的相关性和重要性。此外，我们在三种不同类型的脑肿瘤中发现了PID 1的抑制功能，这表明PID 1可能在其他癌症中也很重要，可能在其他疾病中也很重要，这可能会扩大我们工作的影响。 公共卫生相关性：脑肿瘤，其中包括神经胶质瘤，是一个重大的健康问题，有理由进行研究，以了解其生物学和设计改进的治疗方法。PID 1（磷酸酪氨酸相互作用结构域1）是最近发现的基因，从未与癌症有关，我们的数据表明它在神经胶质瘤和其他两种类型的脑肿瘤中具有生长抑制作用。我们的工作将研究PID 1在胶质瘤中抑制作用的分子机制，其结果对于理解胶质瘤的生物学，也可能对于理解其他脑肿瘤具有重要意义。

DESCRIPTION (provided by applicant): This project focuses on the role of PID1 (Phosphotyrosine Interaction Domain containing 1) in gliomas. PID1 is a phosphotyrosine binding (PTB) domain-containing protein that was discovered in 2006 and which has never been studied in the context of cancer. Ectopic expression of PID1 has opposite effects on proliferation in different cell types. Using microarrays and quantitative RT-PCR, we found that high expression of PID1 correlates with better outcome in two types of brain tumors, gliomas and medulloblastomas. Our in vitro preliminary data further show that ectopic expression of PID1 has growth-inhibitory effects in brain tumor cell lines from three different types of brain tumors: glioblastomas, medulloblastomas, and atypical teratoid rhabdoid tumors (ATRT). We chose to focus this PID1-centered R21 proposal on gliomas since they constitute the most common primary brain tumor in humans and have grim prognosis when malignant. The goal of this proposal is to uncover the molecular mechanisms by which PID1 mediates its inhibitory effect in gliomas. Specifically, we will test the hypothesis that PID1 exerts its inhibitory effect in malignant gliomas in part through its PTB domain. We propose the following two Specific Aims: 1) To determine the critical domain(s) of PID1 that mediate(s) its inhibitory function in GBM cell lines. In this Aim, we will make mutants of known and predicted domains of PID1 and test their ability to decrease proliferation and induce apoptosis. 2) To examine the effect of PID1 expression on growth of intracranial human cell line-derived GBM tumors in NOD-SCID mice. In this Aim, we will use regulated expression of PID1 and examine the effects of PID1 expression on tumor growth, survival, proliferation, and apoptosis. This work is novel and of high impact, as it will further our knowledge on the molecular mechanisms and functions of PID1 in gliomas, forming the first basis of knowledge about PID1 in any brain tumor and any cancer. The clinical correlation we uncovered in our Preliminary Data highlights the relevance and significance of this topic. In addition, our finding of an inhibitory function for PID1 in three different types of brain tumors suggest that PID1 may also be important in other cancers, and possibly in other diseases, potentially expanding the impact of our work. PUBLIC HEALTH RELEVANCE: Brain tumors, and among them gliomas, are a significant health problem, justifying research to understand their biology and to design improved therapies. PID1 (Phosphotyrosine Interaction Domain 1) is a recently discovered gene which has never been linked to cancer, and that our data suggest has growth-inhibitory effects in gliomas and in two other types of brain tumors. Our work will examine the molecular mechanism of the inhibitory effects of PID1 in gliomas and its results will be important for understanding the biology of gliomas, and possibly also for understanding other brain tumors.