Investigating ASPM regulation of asymmetric division for therapeutic opportunities

项目摘要/摘要 为了改善脑胶质瘤患者的预后，迫切需要新的治疗方法。 开发这样的方法将需要描绘特定于胶质瘤细胞的关键调控网络 并导致肿瘤转化和肿瘤生长。过去对小鼠模型的研究 少突胶质细胞前体细胞(OPC)被认为是星形细胞瘤的细胞起源 少突胶质瘤。我们实验室的数据显示，从不对称、自我维持到 对称的、自我更新的分割是OPC肿瘤性转化的关键步骤。治疗方法 具体地说，干扰异常的对称细胞分裂有望消除恶性OPC和 干扰肿瘤生长。我们的长期目标是开发这样的治疗方法，通过定义胶质瘤的影响- 不对称到对称细胞分裂模式开关上的相关遗传改变。的目标是 这一建议是为了验证纺锤体小头畸形与Aspm mRNAs相关的假设。 构成活性受体酪氨酸激酶通过PI3K信号通路上调胶质瘤细胞的表达 AKT。我们进一步认为，Aspm蛋白正向调节对称分裂，从而促进 肿瘤性转化和恶性生长。在功能上，Aspm正向调节有丝分裂纺锤体 诚信和定位。我们将通过追求两个独立的目标来实现我们的目标。在目标1中，我们 建议通过以下方法识别OPC中从不对称分裂到对称分裂的分子开关 确定PDGFRα/EGFR-PI3K-AKT轴的激活是否直接上调ASPM转录水平和 从而正向调节对称的细胞分裂方式，提高细胞增殖率。我们期待着 在完成这些实验后，我们将首次证明细胞的开关 通过调制ASPM电平，由外部信号调节分频模式。在目标2中，我们将 验证Aspm作为原癌基因和Aspm作为治疗机会的作用。我们会 利用RNAi抑制Aspm在一组具有结构性活性的胶质瘤细胞中的表达 PDGFRα或EGFR信令。我们预计抑制Aspm将导致胶质瘤细胞有利于 不对称分裂，这将降低它们的增殖率，降低它们的恶性潜能。我们 预期天冬氨酸氨基转移酶纺锤体调节功能在胶质瘤细胞中提供了新的治疗脆弱性。 这些研究可以描绘出一种在ALL中强制执行对称细胞分裂和肿瘤形成的范例 祖细胞驱动的肿瘤。通过解开Aspm上调作为肿瘤中的一个特定步骤 祖细胞的转化我们确定了癌症治疗的敏感点，并提供了 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.