Hematopoietic Stem Cell-Derived Carcinoma Associated Fibroblasts in Tumor

描述（申请人提供）：肿瘤间质微环境作为治疗靶点具有令人兴奋的潜力。实体瘤基质的主要成分是癌相关成纤维细胞（CAF），它产生结构基质，刺激肿瘤生长，支持新生血管形成，促进肿瘤转移。研究表明，CAFs的来源多种多样，包括组织成纤维细胞、上皮-间充质转分化（EMT）和骨髓（即间充质干细胞）。我们已经开发了一种新的移植模型，在该模型中，致命辐照受体小鼠的骨髓由单个EGFP+造血干细胞（HSC）衍生的克隆细胞群重建。我们使用该模型的研究表明，CAFs和循环成纤维细胞前体（CFPs）起源于HSC，并促进肿瘤生长。这种新的成纤维细胞前体和CAFs的HSC来源是拟议研究的基础。我们假设造血干细胞衍生的CFPs和CAFs在肿瘤的增殖、侵袭、迁移和转移中起关键作用；然而，这些hsc来源的CAFs和CFPs在肿瘤进展中的具体作用尚未被研究。也没有对hsc衍生的CAFs与非hsc衍生的“居民”人群进行直接比较。拟开展的研究将利用我们的克隆细胞移植模型结合Lewis肺癌（LLC）肿瘤模型来分析这一独特的细胞群，并确定它们对肿瘤进展的影响，具体目的如下：1)确定hsc衍生的CFPs和CAFs促进肿瘤进展的机制。本研究的第一个目标是通过流式细胞术、免疫组织化学和分子谱分析来比较hsc衍生的EGFP+ CAFs和EGFP-“常驻”CAFs。hsc衍生的CFPs对肿瘤增殖、迁移和侵袭的影响将在体外进行研究，并在功能获得和/或功能丧失研究中确定和验证肿瘤促进因子。2)确定hsc源性CFP在肿瘤微环境中的募集、归巢、分化和成熟的调控因素。研究将通过体外功能实验研究调节hsc来源的CFPs对肿瘤的贡献的因素。3)确定hsc来源的CFPs和CAFs在体内对肿瘤的贡献。这些研究将检验hsc衍生的CFPs增强LLC致瘤性、进展和转移的能力。在目标1和目标2中鉴定的蛋白质/基因的功能重要性也将使用遗传缺陷模型或siRNA方法进行评估。总之，这些研究不仅将使人们更好地了解基本的肿瘤生物学，而且有可能导致鉴定独特的癌症相关分子特征和hsc衍生的CFP/ caff特异性因子，这些因子可能被靶向抑制实体肿瘤的生长和进展。

DESCRIPTION (provided by applicant): The tumor stromal microenvironment holds exciting potential as a therapeutic target. The major component of solid tumor stroma is the carcinoma associated fibroblast (CAF), which generates structural matrix, stimulates growth, supports neovascularization and promotes metastasis of tumor. Studies suggest various sources for CAFs including tissue fibroblasts, epithelial-to-mesenchymal transdifferentiation (EMT) and bone marrow (i.e., mesenchymal stem cells). We have developed a novel transplantation model in which the bone marrow of lethally irradiated recipient mice is reconstituted by a clonal population of cells derived from a single EGFP+ hematopoietic stem cell (HSC). Our studies using this model demonstrate that CAFs and circulating fibroblast precursors (CFPs) are of HSC origin and promote tumor growth. This novel HSC source for both fibroblast precursors and CAFs is the basis for the proposed studies. It is our hypothesis that HSC-derived CFPs and CAFs play a critical role in tumor proliferation, invasion, migration and metastasis; however the specific role of these HSC-derived CAFs and CFPs in tumor progression has not yet been investigated. Nor has direct comparison of HSC-derived CAFs to non-HSC-derived "resident" populations been conducted. The proposed studies will profile this unique population of cells and determine their influence on tumor progression using our clonal cell transplantation model in conjunction with Lewis lung carcinoma (LLC) tumor models through the following Specific Aims: 1) To determine the mechanisms by which HSC-derived CFPs and CAFs promote tumor progression. The first goal of this Aim is to compare HSC-derived EGFP+ CAFs and EGFP- "resident" CAFs via flow cytometric, immunohistochemical and molecular profiling. The effects of HSC-derived CFPs on tumor proliferation, migration and invasion will then be examined in vitro and the tumor-promoting factors responsible identified and validated in gain of function and/or loss of function studies. 2) To identify factors which regulate HSC-derived CFP recruitment, homing, differentiation and maturation in the tumor microenvironment. Studies will examine factors regulating the contribution of HSC-derived CFPs to tumor via functional in vitro experiments. 3) To determine the contributions of HSC-derived CFPs and CAFs to tumor in vivo. These studies will examine the ability of HSC-derived CFPs to enhance LLC tumorigenicity, progression and metastasis. The functional importance of proteins/genes identified in Aims 1 and 2 will also be evaluated using models of genetic deficiency or siRNA methods. Together these studies will not only lead to a better understanding of basic tumor biology, but have the potential to lead to the identification of unique cancer associated molecular signatures and HSC-derived CFP/CAF-specific factors that may be targeted to inhibit solid tumor growth and progression.