Isolation and Characterization of ER+ Breast Cancer Cells with High Bone Metastat

描述（由申请方提供）：雌激素受体阳性（ER+）管腔型乳腺癌占所有乳腺癌病例的75%，是最有可能转移至骨的乳腺癌亚型，形成无法治愈的溶解性病变，在大多数情况下也是ER+。相比之下，研究乳腺癌骨转移（B-MET）的发病机制和治疗的流行临床前模型采用人乳腺癌细胞的ER-基底亚型。在缺乏ER+管腔B-MET的标准模型的情况下，无法质疑关于骨微环境中这些肿瘤细胞生物学的基本问题，包括肿瘤细胞雌激素信号传导在促进骨微环境中转移进展中的可能作用。本提案的目的是利用体内选择和通常研究的ER+管腔人乳腺癌细胞系来建立ER+裂解性B-MET的稳健临床前模型，然后使用功能基因组学对其进行查询，以检查这种情况下骨转移的发病机制，将这些发现与先前在ER-基底细胞模型中获得的发现进行比较和对比。在特定目标1中，将通过心内（IC）接种“低转移性”人ER+管腔乳腺癌细胞（MCF-7、ZR-75-1或T47 D）异质群体至裸鼠后，通过体内选择分离具有形成裂解性B-MET的高转移潜力的ER+细胞的不同亚群。这些研究将利用并建立在我们实验室已经使用这种方法分离的独特的骨向性ER+ MCF-7衍生细胞系的基础上。在特定目标2中，功能基因组研究，比较在转移进展的最后阶段专门选择的骨嗜性细胞中的基因表达（成骨细胞，如AIM 1中所述）与它们所来源的“低转移性”细胞，将进行鉴定其组成性或雌激素刺激表达与骨转移中的肿瘤进展和骨质溶解相关的基因。利基”。通过体内试验确定这些骨细胞的雌激素依赖性和增强肿瘤进展的位点特异性，将进一步有助于解释与溶骨性ER+相关基因的功能意义。 管腔B-MET表型。实现这些目标的成功可能是因为：1）我们概括了用于确定ER-基底细胞乳腺癌B-MET的发病机制的实验方法，和2）我们已经分离了亲骨性ER+ MCF-7细胞，并在初步实验中在IC接种ER+ T47 D细胞的裸鼠中鉴定了溶骨性B-MET。这些研究的意义在于其新奇，因为尚未开发裂解性B-MET的ER+管腔模型用于功能基因组研究中的询问，以及它们与乳腺癌的临床相关性，因为这些研究解决了无法治愈的常见临床情况。我们的最终目标是通过目前和未来使用本文提出的R 03研究中获得的新工具和信息，改善预防和治疗ER+管腔型乳腺癌B-MET的策略，提高诊断为乳腺癌的女性的生存率。

DESCRIPTION (provided by applicant): Estrogen receptor-positive (ER+) luminal breast cancers, which account for 75% of all breast cancer cases, are the subtype of breast cancer most likely to metastasize to bone, forming incurable lytic lesions that are, in a majority of case, also ER+. In contradistinction, prevailing pre-clinical models investigating the pathogenesis and treatment of breast cancer bone metastases (B-MET) employ ER- basal subtypes of human breast cancer cells. In the absence of standard models of ER+ luminal B-MET, basic questions regarding the biology of these tumor cells within the bone microenvironment cannot be queried, including a possible role for tumor cell estrogen signaling in promoting metastasis progression within the bone microenvironment. The objective of this proposal is to utilize in vivo selection and commonly studied ER+ luminal human breast cancer cell lines to establish robust pre-clinical models of ER+ lytic B-MET which will then be queried, using functional genomics, to examine the pathogenesis of bone metastasis in this setting, comparing and contrasting these findings with those previously obtained in ER- basal cell models. In Specific Aim 1, distinct subpopulations of ER+ cells with a high metastatic potential for formation of lytic B-MET will be isolated by in vivo selection following intracardiac (IC) inoculation of heterogeneous populations of "low-metastatic" human ER+ luminal breast cancer cells (MCF-7, ZR-75-1, or T47D) into nude mice. These studies will take advantage of, and build upon, unique osteotropic ER+ MCF-7-derived cell lines already isolated by our laboratory using this approach. In Specific Aim 2, functional genomic studies, comparing gene expression in cells specifically selected for their bone tropism during the final stage of metastatic progression (osteotropic cells, as described in aim 1) vs. "low- metastatic" cells from which they are derived, will be undertaken to identify genes whose constitutive or estrogen-stimulated expression is associated with tumor progression and osteolysis in the bone metastatic "niche". In vivo testing to determine estrogen-dependency and site-specificity of enhanced tumor progression for these osteotropic cells will further aid in interpreting the functional significance of genes associated with the osteolytic ER+ luminal B-MET phenotype. Success in achieving these aims is likely given that: 1) we are recapitulating the experimental approach used to determine the pathogenesis of ER- basal cell breast cancer B-MET, and 2 ) we have already isolated osteotropic ER+ MCF-7 cells and identified osteolytic B-MET in nude mice inoculated IC with ER+ T47D cells in preliminary experiments. The significance of these studies lies in their novelty, as ER+ luminal models of lytic B-MET have not been developed for interrogation in functional genomic studies, and their clinical relevance to breast cancer, as these studies address a common clinical situation for which there is no cure. Our ultimate goal is to increase survivorship in women diagnosed with breast cancer by improving strategies to prevent and treat ER+ luminal breast cancer B-MET through the current and future use of the novel tools and information acquired in the R03 studies proposed here.