Identification of glioma tumor-initiating cells

描述（由申请人提供）：恶性胶质瘤是最常见的原发性脑肿瘤，其特征为侵袭性生长和对当前治疗的耐受性。在神经胶质瘤细胞类型中，多能CD 133+细胞具有在免疫缺陷小鼠中引发疾病的能力（Singh等人，2004年）。脑肿瘤中肿瘤起始细胞类型的鉴定表明，与血液恶性肿瘤一样，神经胶质瘤的细胞异质性代表分化状态的分级排列（Clarke et al.，2006年）。根据该范例，肿瘤起始细胞的消除可以提供最大的治疗益处（Park等人，2009年）。在神经胶质瘤生物学中研究这一基本概念的主要障碍是缺乏表征神经胶质瘤肿瘤起始细胞表型异质性的细胞标记物。我们在原发性异种移植模型中的背景数据表明，CD133表达包括具有不同生物学特性的胶质瘤细胞的离散亚群。 为了研究CD133表达所包含的细胞异质性，我们建议通过用从恶性胶质瘤亚型分离的CD133+细胞免疫七鳃鳗来产生胶质瘤祖细胞的单克隆可变淋巴细胞受体（VLR）抗体。七鳃鳗抗体，这是结构上不同的蛋白质比我们的抗体，将分析其潜力，以确定肿瘤起始细胞和他们的谱系在直接原位异种移植模型。原理验证研究表明，重组单克隆VLR抗体可针对代表B淋巴细胞分化不同阶段的人肿瘤细胞制备。我们假设，在无颌脊椎动物的VLR抗体所特有的其它优点中，由于自身耐受性，哺乳动物抗体库不允许的细胞表位将可接近七鳃鳗抗体（Herrin et al.，2008年）。 公共卫生相关性：恶性神经胶质瘤对目前的治疗是无效的，患有这种疾病的患者目前预后不良。确定负责肿瘤生长和复发的细胞类型可能会导致更有效的治疗方法的发展。在这项提议中，一种新的方法，无颌脊椎动物的适应性免疫系统，将被用来确定胶质瘤肿瘤起始细胞和他们的谱系在直接原位异种移植模型。

DESCRIPTION (provided by applicant): Malignant gliomas are the most common primary brain tumors and are characterized by invasive growth and recalcitrance to current therapies. Among glioma cell types, multipotent CD133+ cells have the capacity to initiate disease in immunodeficient mice (Singh et al., 2004). The identification of a tumor-initiating cell type in brain tumors suggests that, like hematological malignancies, the cellular heterogeneity of gliomas represents a hierarchical arrangement of differentiation states (Clarke et al., 2006). According to this paradigm, elimination of tumor-initiating cells may provide the greatest therapeutic benefit (Park et al., 2009). A primary impediment to investigating this fundamental concept in glioma biology is the lack of cell markers for characterizing the phenotypic heterogeneity of glioma tumor-initiating cells. Our background data in a primary xenotransplantation model suggest that CD133 expression encompasses discrete subpopulations of glioma cells with different biological characteristics. To study the cellular heterogeneity encompassed by CD133 expression, we propose to generate monoclonal variable lymphocyte receptor (VLR) antibodies for glioma progenitor cells by immunizing lampreys with CD133+ cells isolated from malignant glioma subtypes. The lamprey antibodies, which are structurally different proteins than our antibodies, will be analyzed for their potential to identify tumor-initiating cells and their lineages in a direct orthotopic xenotransplantation model. Proof-of-principle studies demonstrate that recombinant monoclonal VLR antibodies can be made against human tumor cells representative of different stages in B lymphocyte differentiation. We postulate that among other advantages unique to the VLR antibodies of jawless vertebrates, cellular epitopes otherwise impermissible to a mammalian antibody repertoire, because of self-tolerance, will be accessible to lamprey antibodies (Herrin et al., 2008). PUBLIC HEALTH RELEVANCE: Malignant gliomas are recalcitrant to current therapies and patients with this disease currently have a poor prognosis. The identification of cell types responsible for tumor growth and recurrence may lead to the development of more effective therapies. In this proposal a novel method, the adaptive immune system of jawless vertebrates, will be used to identify glioma tumor-initiating cells and their lineages in a direct orthotopic xenotransplantation model.