Microglia promote dispersal of glioma cells through Pyk2 intracellular signaling

描述（由申请人提供）：多形性胶质母细胞瘤预后极差，诊断后中位生存期约为1年，这在很大程度上是由于胶质瘤细胞的高度浸润行为否定了当前医学方法的有效性。小胶质细胞浸润大多数胶质瘤并释放影响肿瘤侵袭的因子。我们的初步数据表明，由小胶质细胞释放的可溶性因子激活迁移/侵袭，并上调人类和啮齿动物胶质瘤细胞系中Pyk 2的磷酸化。靶向Pyk 2的siRNA消除了小胶质细胞对胶质瘤细胞迁移的影响。基于这些数据，我们假设在肿瘤微环境中，小胶质细胞释放可溶性因子，其通过激活胶质瘤细胞中的Pyk-2细胞内信号传导途径促进胶质瘤细胞迁移和分散到其他脑区域。在本研究中，使用细胞生物学的方法，我们将研究参与Pyk 2激活/磷酸化反应的小胶质细胞释放的可溶性因子的细胞内机制。我们还将在小鼠模型中研究用Pyk 2阻断剂补充传统化疗胶质瘤治疗的有效性，以消除小胶质细胞对胶质瘤细胞扩散的影响。为了验证我们的假设，我们提出了以下具体目标：具体目标#1：为了验证小胶质细胞通过Pyk 2细胞内途径激活胶质瘤细胞迁移/侵袭的假设。具体目标#2：要测试的假设，磷脂酶C？1（PLC？1)和表皮生长因子受体（EGFR）介导小胶质细胞活化的胶质瘤移动性。具体目标3：检测替莫唑胺（TMZ）和PF-562271联合治疗与当前TMZ单独治疗相比在减少胶质瘤生长和扩散方面的有效性。验证我们的假设将提供一个平台，旨在防止神经胶质瘤细胞扩散到健康的大脑区域的治疗策略。

DESCRIPTION (provided by applicant): Glioblastoma multiforme, carries an exceptionally poor prognosis with median survival of approximately one year following diagnosis, in large part, due to the highly infiltrative behavior of glioma cells negating the effectiveness of current medical approaches. Microglia infiltrate most gliomas and release factors which influence tumor invasion. Our preliminary data indicate that soluble factors, released by microglia activate migration/invasion and up regulate phosphorylation of Pyk2 in human and rodent glioma cell lines. siRNA targeting Pyk2 eliminates the microglial effect on glioma cell migration. Based on these data we hypothesize that in the tumor microenvironment microglia release soluble factors which promote migration and dispersal of glioma cells to other brain regions through activation of the Pyk-2 intracellular signaling pathway in glioma cells. In the present study using cell biology approaches, we will examine the intracellular mechanisms involved in Pyk2 activation/phosphorylation in response to soluble factors released by microglia. We will also examine, in a murine model, the effectiveness of supplementing traditional chemotherapeutic glioma treatment with a Pyk2 blocker in order to eliminate the effect of microglia on glioma cell dispersal. To test our hypothesis we propose the following specific aims: Specific Aim #1: To test the hypothesis that microglia activate migration/invasion of glioma cells through a Pyk2 intracellular pathway. Specific Aim #2: To test the hypothesis that phospholipase C?1 (PLC?1) and epidermal growth factor receptor (EGFR) mediate microglial activated glioma mobility. Specific aim #3: To test the effectiveness of combined treatment of temozolomide (TMZ) and PF-562271 in decreasing glioma growth and dispersal as compared to the current treatment of TMZ alone. Validation of our hypothesis will provide a platform for developing therapeutic strategies aimed at prevention of glioma cell dispersal into healthy brain regions.