Microglia promote dispersal of glioma cells through Pyk2 intracellular signaling

描述(申请人提供)：多形性胶质母细胞瘤预后极差，确诊后中位生存期约一年，这在很大程度上是由于胶质瘤细胞的高度浸润性行为，否定了目前医学方法的有效性。小胶质细胞渗透到大多数胶质瘤中，并释放影响肿瘤侵袭的因子。我们的初步数据表明，小胶质细胞释放的可溶性因子激活了人和啮齿动物胶质瘤细胞系的迁移/侵袭，并上调了PYK2的磷酸化。靶向Pyk2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，我们推测，在肿瘤微环境中，小胶质细胞通过激活胶质瘤细胞内的PYK-2信号通路，释放促进胶质瘤细胞向其他脑区迁移和扩散的可溶性因子。在目前的研究中，我们将利用细胞生物学的方法，研究小胶质细胞释放的可溶性因子对Pyk2激活/磷酸化的影响。为了消除小胶质细胞对胶质瘤细胞扩散的影响，我们还将在小鼠模型中检验用Pyk2阻滞剂辅助传统的脑胶质瘤化疗的有效性。为了验证我们的假设，我们提出了以下特定目标：特定目标#1：验证小胶质细胞通过细胞内通路激活胶质瘤细胞迁移/侵袭的假设。具体目的#2：验证磷脂酶C？1(PLC？1)和表皮生长因子受体(EGFR)介导小胶质细胞激活的胶质瘤移动性的假设。具体目标#3：测试替莫唑胺(替莫唑胺)和PF-562271联合治疗与目前单独使用替莫唑胺治疗相比在减少胶质瘤生长和扩散方面的有效性。我们的假设的验证将为开发旨在防止胶质瘤细胞扩散到健康大脑区域的治疗策略提供一个平台。

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.