NG2-PG in tumor vascularization and progression

在小鼠乳腺肿瘤病毒启动子（MMTV-PyMT）控制下表达多瘤中T癌蛋白的雌性转基因小鼠100%会出现多灶性乳腺肿瘤。通过几个标准，包括肿瘤潜伏期、生长速率和转移，跨膜NG 2蛋白聚糖的基因消融极大地减缓了MMTV-FyMT模型中的乳腺肿瘤进展。尽管NG 2不被MMTV-PyMT小鼠中的乳腺肿瘤细胞表达，但它被肿瘤基质中的三种重要细胞类型表达：肿瘤微血管中的周细胞、乳腺脂肪垫中的脂肪细胞和从循环侵入肿瘤的巨噬细胞。因此，我们假设NG 2对血管形成、脂肪生成和巨噬细胞募集的影响可能通过改变肿瘤细胞与这三种关键基质成分的相互作用来影响乳腺肿瘤的进展。该提案的这个缩短的ARRA版本的具体目的是检查微血管NG 2和巨噬细胞NG 2对MMTV-PyMT模型中乳腺肿瘤血管形成和进展的各自影响。 在目的1中，我们将比较在野生型和NG 2非瘤细胞中观察到的MMTV-P7 MT肿瘤血管形成模式。Thi'MTF iñciuddéth TntiödfVàëUIàr fUhcf[oh（通畅性、基底层沉积、组织缺氧）、形态学（迂曲）和密度，沿着检查周细胞/内皮细胞关系，导致两种细胞类型成熟。我们还将使用Pdgfrb/Cre转基因小鼠，结合floxed NG 2等位基因，以产生周细胞特异性NG 2无效小鼠。在MMTV-PyMT背景下的该小鼠中的乳腺肿瘤进展将更充分地阐明NG 2对肿瘤发生的周细胞特异性作用。 在目标2中，我们将研究NG 2在巨噬细胞依赖性肿瘤进展中的作用。这将包括巨噬细胞向发展中的肿瘤的募集，以及巨噬细胞在肿瘤血管形成、肿瘤细胞内渗和肿瘤转移中的作用。我们还将使用溶菌酶M/Cre小鼠结合floxed NG 2等位基因，在MMTV-PyMT背景下产生巨噬细胞特异性NG 2敲除小鼠。该模型将揭示NG 2对乳腺肿瘤血管形成和进展的巨噬细胞特异性作用

100% of female transgenic mice expressing the polyoma middle T oncoprotein under control of the mouse mammary tumor virus promoter (MMTV-PyMT) develop multifocal mammary tumors. By several criteria, including tumor latency, growth rate, and metastasis, genetic ablation of the membrane-spanning NG2 proteoglycan greatly slows mammary tumor progression in the MMTV-FyMT model. Although NG2 is not expressed by mammary tumor cells in the MMTV-PyMT mouse, it is expressed by three important cell types in the tumor stroma: pericytes in the tumor microvasculature, adipocytes in the mammary fat pad, and macrophages that invade tumors from the circulation. We therefore hypothesize that effects of NG2 on vascularization, adipogenesis, and macrophage recruitment may affect mammary tumor progression by altering tumor cell interactions with these three key stromal elements. The specific aims of this shortened ARRA version of the proposal will be to examine the respective effects of microvascular NG2 and macrophage NG2 on mammary tumor vascularization and progression in the MMTV-PyMT model. In Aim 1, we will compare the tumor vascularization patterns seen in wild type and NG2 nulFrriice oñ the MMTV-P7MT baökgroUnd. Thi'MTF iñciuddéth Tntiöñ dfVàëUIàr fUhcf[oh (patency, basal lamina deposition, tissue hypoxia), morphology (tortuousity), and density, along with examination of pericyte/endothelial cell relationships leading to maturation of both cell types. We will also use Pdgfrb/Cre transgenic mice, in conjunction with a floxed NG2 allele, to generate a pericyte-specific NG2 null mouse. Mammary tumor progression in this mouse on the MMTV-PyMT background will more fully illuminate the pericyte-specific effects of NG2 on tumorigenesis. In Aim 2 we will study the role of NG2 in macrophage-dependent tumor progression. This will include the recruitment of macrophages to developing tumors, and the role of macrophages in tumor vascularization, tumor cell intravasation, and tumor metastasis. We will also produce a macrophage-specific NG2 knockout mouse on the MMTV-PyMT background, using the lysozyme M/Cre mouse in conjunction with a floxed NG2 allele. This model will reveal macrophage-specific effects of NG2 on mammary tumor vascularization and progression