Investigating ASPM regulation of asymmetric division for therapeutic opportunities

项目总结/摘要 目前迫切需要新的治疗方法来改善胶质瘤患者的预后。 开发这样的方法将需要描绘出神经胶质瘤细胞特有的关键调控网络 并导致肿瘤转化和使肿瘤生长。过去在小鼠模型中的研究 确定少突胶质细胞祖细胞（OPC）为星形细胞瘤的假定细胞来源， 少突胶质细胞瘤我们实验室的数据显示，从不对称的，自我维持的， 对称的自我更新分裂是OPC肿瘤转化的关键步骤。疗法 预期特异性干扰异常对称细胞分裂可消除恶性OPC， 破坏肿瘤生长。我们的长期目标是通过定义神经胶质瘤的作用来开发这种疗法- 相关的遗传改变的不对称到对称的细胞分裂模式开关。的目标 本研究的目的是检验异常梭形小头畸形与Aspm mRNA相关的假设， 在胶质瘤细胞中，通过PI 3 K-1介导的组成型活性受体酪氨酸激酶信号传导上调表达。 Akt.我们进一步提出，Aspm蛋白积极调节对称分裂，从而促进 肿瘤转化和恶性生长。在功能上，Aspm正调控有丝分裂纺锤体 完整性和定位我们将通过追求两个独立的目标来实现我们的目标。目标1： 建议识别OPC中从不对称分裂到对称分裂的分子开关， 确定PDGFRα/EGFR-PI 3 K-AKT轴的激活是否直接升高Aspm转录水平， 从而正向调节细胞的对称分裂方式，提高增殖速率。我们预计 在完成这些实验后，我们将首次证明细胞的开关 分裂模式由外在信号通过调节Aspm水平来调节。在目标2中。我们将 验证Aspm作为原癌基因和Aspm作为治疗机会的功能。我们将 在具有组成型活性胶质瘤细胞中使用RNAi抑制Aspm表达 PDGFRα或EGFR信号传导。我们预计，抑制Aspm将导致胶质瘤细胞有利于 不对称分裂，这将降低其增殖率并降低其恶性潜力。我们 预期Aspm纺锤体调节功能在神经胶质瘤细胞中提供新的治疗弱点。 这些研究可以描绘一个范例，强制对称细胞分裂和肿瘤发生在所有 祖细胞驱动的肿瘤通过阐明Aspm上调是肿瘤发生的一个特定步骤， 通过祖细胞的转化，我们确定了癌症治疗的易感性点，并提供了一种治疗方法。 其他祖细胞衍生癌症的治疗范例。

PROJECT SUMMARY/ABSTRACT Novel therapeutic approaches are desperately needed to improve the prognosis for glioma patients. Developing such approaches will require the delineation of key regulatory networks specific to glioma cells and leading to neoplastic transformation and enabling tumor growth. Past studies in mouse models identified oligodendrocyte progenitor cells (OPC) as putative cellular origin of astrocytoma and oligodendroglioma. Data from our lab showed that the switch from asymmetric, self-sustaining to symmetric, self-renewing divisions is a critical step in the neoplastic transformation of OPC. Therapies specifically interfering with aberrant symmetric cell divisions are expected to eliminate malignant OPCs and disrupt tumor growth. It is our long-term goal to develop such therapies, by defining the effect of glioma- associated genetic alterations on the asymmetric-to-symmetric cell division mode switch. The objective of this proposal is to test the hypothesis that abnormal spindle microcephaly associated Aspm mRNA expression is upregulated in glioma cells by constitutive-active receptor tyrosine kinase signaling via PI3K- AKT. We further propose that Aspm protein positively regulates symmetric divisions and thereby promotes neoplastic transformation and malignant growth. Functionally, Aspm positively regulates mitotic spindle integrity and positioning. We will achieve our objective by pursuing two independent aims. In Aim 1, we propose to identify the molecular switch from asymmetric to symmetric division in OPC, by determining if activation of the PDGFRα/EGFR-PI3K-AKT axis directly elevates Aspm transcript levels and thereby positively regulates symmetric cell division mode and increases proliferation rate. We expect that upon completion of these experiments, we will for the first time have demonstrated that the switch of cell division mode is regulated by an extrinsic signal through modulation of Aspm levels. In Aim 2. we will validate Aspm as a proto-oncogene and Aspm functions as therapeutic opportunities. We will suppress Aspm expression using RNAi in a selected panel of glioma cells with constitutively active PDGFRα or EGFR signaling. We anticipate that Aspm suppression will cause glioma cells to favor asymmetric divisions, which will decrease their proliferation rate and reduce their malignant potential. We anticipate that Aspm spindle regulatory functions provide novel therapeutic vulnerabilities in glioma cells. These studies can delineate a paradigm for enforcing symmetric cell division and tumorigenesis in all progenitor-driven tumors. By unraveling Aspm upregulation as a specific step in the neoplastic transformation of progenitor cells we identify a point of susceptibility for cancer therapies and provide a treatment paradigm for other progenitor-derived cancers.