STEM CELLS IN TRANSGENIC MOUSE MAMMARY TUMORIGENESIS

转基因小鼠乳腺肿瘤发生中的干细胞

• 批准号: 6167145
• 负责人: ROBERT B. DICKSON
• 金额: $ 11.66万
• 依托单位: GEORGETOWN UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-03-08 至 2003-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6167145
• 关键词: breast neoplasms; bromodeoxyuridine; centrosome; flow cytometry; fluorescent in situ hybridization; genetically modified animals; hyperplasia; immunocytochemistry; laboratory mouse; mammary epithelium; mouse mammary tumor virus; neoplasm /cancer genetics; neoplasm /cancer immunology; proliferating cell nuclear antigen; protooncogene; stem cells; transforming growth factors; viral carcinogenesis

DESCRIPTION: (Applicant's Description) A priority research area identified by the NCI Breast Cancer Progress Review Group is to determine how epithelial stem cells may serve as targets of important etiologic agents in breast cancer. We propose that this process critically depends upon the progressive defects in the centrosomes of stem cell. Only the division competent stem cells of the gland, as distinct from terminally differentiated cells are thought to pass on genetic damage, leading to tumors. Our morphological description of mouse mammary stem cells, and our recent application of molecular cytogenetic techniques to the study of mouse chromosomes are now combined to allow an innovative approach to the study of stem cells in mammary tumorigenesis. Specifically, the current grant will explore the mechanistic bases for alterations in mammary epithelial stem cell pathways that give rise to hyperplasias and malignant tumors in the MMTV-c-myc transgenic mammary tumor model and in the highly malignant MT-TGF-alpha X MMTV-c-myc bitransgenic model. The c-myc transgene leads initially to small, apoptotic mammary tumors that do not appear to have defects in the diversity of their stem cell pathways. However, these tumors do display amplifications in their centrosomes and alterations, such as aneuploidy, of their chromosomes. As these tumors enlarge, clearly distinct, non-apoptotic foci of cells reproducibly arise. These foci are composed primarily of the two mammary epithelial stem cell morphotypes, small light cells (SLC) and undifferentiated light cells (ULLC). The foci appear to be deficient in myoepithelial and differentiated secretory cells, consistent with further centrosomal defects, blocking their abilities to undergo the normal, asymmetric and symmetric mitoses (respectively) in the later steps of the mammary differentiation program. In contrast, bitransgenic c-Myc/TGF-alpha mammary tumors are aneuploid, but non-apoptotic from the start, and remarkably, appear to bypass the requirement for this focal block in differentiation. Our study will begin with a morphometric analysis of all cell types in the non transgenic gland and in hyperplasias and tumors of our transgenic models. We then propose to use immunohistochemistry for PCNA (proliferating cellular nuclear antigen) and labeling with a thymidine analog (BrDu) to determine the sizes of the different division-competent cell populations in normal and mouse epithelium. Next we will characterize the degree of centrosome amplification and aneuploidy in proliferative cells using immunohistochemical and FISH approaches, respectively. We expect the results of this novel proposal to demonstrate how stem cells are involved in neoplastic transformation and progression, and to suggest how different types of aberrations in the centrosomes of stem cells may be involved in causing these defects.

描述：（申请人的描述） NCI乳腺癌进度审查确定的优先研究领域 组是为了确定上皮干细胞如何用作目标 乳腺癌的重要病因。 我们建议这个过程 严重取决于茎中心体的渐进缺陷 细胞。 只有腺体的胜任干细胞，不同于 终端分化的细胞被认为传递了遗传损害，导致 到肿瘤。 我们对小鼠乳细胞的形态学描述，我们 分子细胞遗传学技术最近应用于小鼠的研究 现在将染色体合并为允许研究的创新方法 乳腺肿瘤发生中的干细胞。 具体来说，当前的赠款将 探索乳腺上皮干细胞改变的机械基础 在MMTV-C-MYC中引起增生和恶性肿瘤的途径 转基因乳腺肿瘤模型和高度恶性的MT-TGF-Alpha x MMTV-C-MYC BITCHINIC模型。 C-Myc转基因最初导致小型， 凋亡的乳腺肿瘤似乎没有多样性缺陷 它们的干细胞通路。 但是，这些肿瘤确实显示出扩增 在它们的中心体和变化中，例如非整倍性 染色体。 随着这些肿瘤的增大，明显不同的非凋亡灶 细胞可重复出现。这些焦点主要由两个乳房组成 上皮干细胞形态，小光细胞（SLC）和未分化的 光细胞（ULLC）。 该灶似乎缺乏肌上皮和 分离的分泌细胞与进一步的中心缺陷一致， 阻止他们经历正常，不对称和对称的能力 在乳腺分化的后期步骤中（分别） 程序。 相比之下，Bittransgenic C-Myc/TGF-Alpha乳腺肿瘤是 非整倍体，但从一开始就非凋亡，而且显着，似乎绕过 在分化中对这种焦点的要求。 我们的研究将开始 通过对非转基因腺中所有细胞类型的形态分析， 在我们的转基因模型的增生和肿瘤中。 然后我们建议使用 PCNA的免疫组织化学（增殖的细胞核抗原）和 用胸苷类似物（BRDU）标记以确定 正常和小鼠上皮的不同分裂竞争性细胞群体。 接下来，我们将表征中心体扩增的程度和 使用免疫组织化学和鱼类的增生细胞中的非整倍性 分别方法。 我们期望这个小说提议的结果 证明干细胞如何参与肿瘤转化和 进展，并暗示如何在 干细胞的中心体可能参与引起这些缺陷。