Neuronal activity-regulated mechanisms of glioma growth

 描述(申请人提供)：高级别胶质瘤是导致儿童和成人脑肿瘤相关死亡的主要原因。我们最近发现，在体外和体内，皮质神经元的活性促进了高级别胶质瘤的生长。神经元活性在高级别胶质瘤中促进生长的一个主要机制是活性调节的突触蛋白神经连接蛋白3(NLGN3)胞外结构域的分泌，我们在体内和体外都证明了这是充分和必要的。可溶性神经连接蛋白-3刺激血管内皮细胞 PI3K-mTOR信号转导通路也可诱导神经胶质瘤NLGN3的前馈表达，但其上游信号转导机制尚不清楚。在这项建议的目标1中，我们现在试图证实NLGN3在体内胶质瘤生长中的必要性，并利用结构性和可诱导的NLGN3基因缺失策略，结合体内光遗传学技术和患者来源的异种移植模型，确定分泌的NLGN3的细胞来源(S)。在目标2中，我们将使用药理学和遗传策略来鉴定负责NLGN3分泌的活性调节酶。在目标3中，我们将使用我们开发的成人和儿童患者来源的高级别胶质瘤模型、免疫共沉淀和质谱分析来鉴定胶质瘤细胞中的NLGN3结合伙伴。拟议的实验将加深我们对神经元在胶质瘤微环境中促进肿瘤生长的机制的理解，并将确定这些致命癌症的潜在治疗靶点。

 DESCRIPTION (provided by applicant): High-grade gliomas are the leading cause of brain tumor-related death in both children and adults. We have recently shown that cortical neuronal activity promotes the growth of high-grade glioma in vitro and in vivo. A major mechanism mediating the growth-promoting effect of neuronal activity on high grade glioma is activity-regulated secretion of the synaptic protein neuroligin-3 (NLGN3) ectodomain, which we have shown to be both sufficient and necessary in situ and in vitro. Soluble neuroligin-3 stimulates the PI3K-mTOR pathway in glioma cells and also induces feed-forward expression of glioma NLGN3, but the upstream signaling events are not yet elucidated. In Aim 1 of this proposal, we now seek to confirm the necessity of NLGN3 for in vivo glioma growth and to determine the cellular origin(s) of secreted NLGN3 using constitutive and inducible NLGN3 genetic deletion strategies together with in vivo optogenetic techniques and patient-derived orthotopic xenograft models. In Aim 2 we will identify the activity-regulated enzyme responsible for NLGN3 secretion using pharmacological and genetic strategies. In Aim 3 we will identify the NLGN3 binding partner in glioma cells using the range of adult and pediatric patient-derived high grade glioma models we have developed, co-immunoprecipitation and mass spectrometric analysis. The proposed experiments will deepen our understanding of the mechanisms by which neurons promote cancer growth in the glioma microenvironment and will identify potential targets of therapy for these deadly cancers.