Epithelial-stromal cell interactions in breast cancer

描述（由申请人提供）：我们分别使用基因表达序列分析和SNP阵列分析了构成正常乳腺组织以及原位和浸润性乳腺癌的所有细胞类型的基因表达和遗传谱。基于这些数据，我们确定在乳腺肿瘤进展过程中，基因表达变化发生在所有细胞类型中，而克隆选择的遗传改变仅在癌上皮细胞中发现。为了研究表观遗传改变在乳腺肿瘤发生中的作用，我们开发了一种新的全基因组甲基化分析方法，甲基化特异性数字核型（MSDK）。对正常乳腺组织、原位乳腺癌和浸润性乳腺癌分离的上皮细胞、肌上皮细胞和间质成纤维细胞进行MSDK分析，确定了所有三种细胞类型的细胞类型和肿瘤特异性DNA甲基化模式。为了研究肌上皮细胞和间质成纤维细胞在乳腺肿瘤发生中的作用，我们分析了MCFDCIS.com人类异种移植物模型，并确定MCFDCIS.com细胞能够同时产生上皮细胞和肌上皮细胞。这些细胞的分化和异种移植物的组织学受到肌上皮细胞和成纤维细胞共同注射的影响：正常肌上皮细胞促进DCIS肿瘤表型，而成纤维细胞抑制DCIS肿瘤表型。本应用程序的目的是利用体内和体外模型系统以及人类乳腺肿瘤，表征肌上皮细胞和间质成纤维细胞在原位癌向浸润性癌进展和乳腺上皮祖细胞分化中的作用。具体目的：(1)利用人异种移植模型和体外3D共培养系统，确定上皮-肌上皮/成纤维细胞相互作用在乳腺肿瘤进展和乳腺上皮祖细胞分化中的作用。(2)利用Aim 1中描述的模型，评估肿瘤肌上皮细胞和基质细胞中表观遗传改变的基因在乳腺肿瘤发生中的作用。在初步研究中发现的异常甲基化基因将被表征并研究其在乳腺癌中的作用。(3)验证Aims 1和2在人乳腺肿瘤中的发现。本项目的完成不仅有助于我们了解上皮-基质细胞相互作用在乳腺癌中的作用，而且肿瘤微环境中表观遗传改变的基因和异常表达的旁分泌因子可能为乳腺癌治疗提供新的靶点。

DESCRIPTION (provided by applicant): We analyzed the gene expression and genetic profiles of all cell types composing normal breast tissue and in situ and invasive breast carcinomas using Serial Analysis of Gene Expression and SNP arrays, respectively. Based on these data we determined that gene expression changes occur in all cell types during breast tumor progression, while clonally selected genetic alterations were only found in cancer epithelial cells. To investigate the role of epigenetic alterations in breast tumorigenesis, we developed a novel genome-wide methylation profiling method, methylation specific digital karyotyping (MSDK). MSDK analysis of epithelial and myoepithelial cells and stromal fibroblasts isolated from normal breast tissue and in situ and invasive breast carcinomas identified cell type and tumor specific DNA methylation patterns in all three cell types. To investigate the role of myoepithelial cells and stromal fibroblasts in breast tumorigenesis we analyzed the MCFDCIS.com human xenograft model and determined that MCFDCIS.com cells are able to give raise to both epithelial and myoepithelial cells. The differentiation of these cells and the histology of the resulting xenografts are influenced by co-injected myoepithelial cells and fibroblasts: normal myoepithelial cells promote while fibroblasts inhibit the DCIS tumor phenotype. The goal of this application is to characterize the role of myoepithelial cells and stromal fibroblasts in the in situ to invasive carcinoma progression and in the differentiation of breast epithelial progenitors using in vivo and in vitro model systems, and human breast tumors. Specific aims: (1) To determine the role of epithelial-myoepithelial/fibroblast cell interactions in breast tumor progression and in the differentiation of mammary epithelial progenitor cells using human xenograft models in mice and in vitro 3D co-culture systems. (2) To evaluate the role of genes epigenetically altered in tumor myoepithelial and stromal cells in breast tumorigenesis using models described in Aim 1. Aberrantly methylated genes identified in preliminary studies will be characterized and their role in breast cancer investigated. (3) To validate the findings of Aims 1 and 2 in human breast tumors. The completion of this project will not only help us understand the role of epithelial-stromal cell interactions in breast cancer, but epigenetically altered genes and abnormally expressed paracrine factors in the tumor microenvironment may provide new targets for breast cancer treatment.