Neuronal activity-regulated mechanisms of glioma growth

 描述（由申请人提供）：高级别胶质瘤是儿童和成人脑肿瘤相关死亡的主要原因。我们最近的研究表明，皮质神经元的活动促进高级别胶质瘤在体外和体内的生长。介导神经元活性对高级别胶质瘤的生长促进作用的一个主要机制是突触蛋白神经连接素-3（NLGN 3）胞外域的活性调节分泌，我们已经证明这在原位和体外都是充分和必要的。可溶性神经配素-3刺激 PI 3 K-mTOR信号通路在胶质瘤细胞中起重要作用，并且还诱导胶质瘤NLGN 3的前馈表达，但上游信号事件尚未阐明。在该提议的目的1中，我们现在试图确认NLGN 3对于体内胶质瘤生长的必要性，并使用组成型和诱导型NLGN 3遗传缺失策略连同体内光遗传学技术和患者来源的原位异种移植模型来确定分泌的NLGN 3的细胞来源。在目标2中，我们将使用药理学和遗传学策略确定负责NLGN 3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科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NLGN 3结合伴侣。拟议的实验将加深我们对神经元在胶质瘤微环境中促进癌症生长的机制的理解，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.